Global finite-time attitude consensus tracking control for a group of rigid spacecraft

NASA Astrophysics Data System (ADS)

Li, Penghua

2017-10-01

The problem of finite-time attitude consensus for multiple rigid spacecraft with a leader-follower architecture is investigated in this paper. To achieve the finite-time attitude consensus, at the first step, a distributed finite-time convergent observer is proposed for each follower to estimate the leader's attitude in a finite time. Then based on the terminal sliding mode control method, a new finite-time attitude tracking controller is designed such that the leader's attitude can be tracked in a finite time. Finally, a finite-time observer-based distributed control strategy is proposed. It is shown that the attitude consensus can be achieved in a finite time under the proposed controller. Simulation results are given to show the effectiveness of the proposed method.

Pupil Control Ideology as a Source of Stress: The Student Teacher's Dilemma.

ERIC Educational Resources Information Center

Jones, Dan R.

One type of adaptation made by each student teacher is the development of attitudes toward controlling pupils. The student teachers' attitudes toward pupil control may be at odds with those of other educators and this difference in attitude, particularly in the case of the cooperating teacher, can cause stress. Attitudes toward pupil control can…

The Association Between Implicit and Explicit Attitudes Toward Smoking and Support for Tobacco Control Measures

PubMed Central

Chassin, Laurie; Presson, Clark C.

2013-01-01

Introduction: This study examined the association between implicit and explicit attitudes toward smoking and support for tobacco control policies. Methods: Participants were from an ongoing longitudinal study of the natural history of smoking who also completed a web-based assessment of implicit attitudes toward smoking (N = 1,337). Multiple regression was used to test the association between covariates (sex, age, educational attainment, parent status, and smoking status), implicit attitude toward smoking, and explicit attitude toward smoking and support for tobacco control policies. The moderating effect of the covariates on the relation between attitudes and support for policies was also tested. Results: Females, those with higher educational attainment, parents, and nonsmokers expressed more support for tobacco control policy measures. For nonsmokers, only explicit attitude was significantly associated with support for policies. For smokers, both explicit and implicit attitudes were significantly associated with support. The effect of explicit attitude was stronger for those with lower educational attainment. Conclusions: Both explicit and implicit smoking attitudes are important for building support for tobacco control policies, particularly among smokers. More research is needed on how to influence explicit and implicit attitudes to inform policy advocacy campaigns. PMID:22581941

The association between implicit and explicit attitudes toward smoking and support for tobacco control measures.

PubMed

Macy, Jonathan T; Chassin, Laurie; Presson, Clark C

2013-01-01

This study examined the association between implicit and explicit attitudes toward smoking and support for tobacco control policies. Participants were from an ongoing longitudinal study of the natural history of smoking who also completed a web-based assessment of implicit attitudes toward smoking (N = 1,337). Multiple regression was used to test the association between covariates (sex, age, educational attainment, parent status, and smoking status), implicit attitude toward smoking, and explicit attitude toward smoking and support for tobacco control policies. The moderating effect of the covariates on the relation between attitudes and support for policies was also tested. Females, those with higher educational attainment, parents, and nonsmokers expressed more support for tobacco control policy measures. For nonsmokers, only explicit attitude was significantly associated with support for policies. For smokers, both explicit and implicit attitudes were significantly associated with support. The effect of explicit attitude was stronger for those with lower educational attainment. Both explicit and implicit smoking attitudes are important for building support for tobacco control policies, particularly among smokers. More research is needed on how to influence explicit and implicit attitudes to inform policy advocacy campaigns.

Integrated orbit and attitude hardware-in-the-loop simulations for autonomous satellite formation flying

NASA Astrophysics Data System (ADS)

Park, Han-Earl; Park, Sang-Young; Kim, Sung-Woo; Park, Chandeok

2013-12-01

Development and experiment of an integrated orbit and attitude hardware-in-the-loop (HIL) simulator for autonomous satellite formation flying are presented. The integrated simulator system consists of an orbit HIL simulator for orbit determination and control, and an attitude HIL simulator for attitude determination and control. The integrated simulator involves four processes (orbit determination, orbit control, attitude determination, and attitude control), which interact with each other in the same way as actual flight processes do. Orbit determination is conducted by a relative navigation algorithm using double-difference GPS measurements based on the extended Kalman filter (EKF). Orbit control is performed by a state-dependent Riccati equation (SDRE) technique that is utilized as a nonlinear controller for the formation control problem. Attitude is determined from an attitude heading reference system (AHRS) sensor, and a proportional-derivative (PD) feedback controller is used to control the attitude HIL simulator using three momentum wheel assemblies. Integrated orbit and attitude simulations are performed for a formation reconfiguration scenario. By performing the four processes adequately, the desired formation reconfiguration from a baseline of 500-1000 m was achieved with meter-level position error and millimeter-level relative position navigation. This HIL simulation demonstrates the performance of the integrated HIL simulator and the feasibility of the applied algorithms in a real-time environment. Furthermore, the integrated HIL simulator system developed in the current study can be used as a ground-based testing environment to reproduce possible actual satellite formation operations.

Attitude Control Subsystem for the Advanced Communications Technology Satellite

NASA Technical Reports Server (NTRS)

Hewston, Alan W.; Mitchell, Kent A.; Sawicki, Jerzy T.

1996-01-01

This paper provides an overview of the on-orbit operation of the Attitude Control Subsystem (ACS) for the Advanced Communications Technology Satellite (ACTS). The three ACTS control axes are defined, including the means for sensing attitude and determining the pointing errors. The desired pointing requirements for various modes of control as well as the disturbance torques that oppose the control are identified. Finally, the hardware actuators and control loops utilized to reduce the attitude error are described.

Implicit and explicit attitudes predict smoking cessation: moderating effects of experienced failure to control smoking and plans to quit.

PubMed

Chassin, Laurie; Presson, Clark C; Sherman, Steven J; Seo, Dong-Chul; Macy, Jonathan T

2010-12-01

The current study tested implicit and explicit attitudes as prospective predictors of smoking cessation in a Midwestern community sample of smokers. Results showed that the effects of attitudes significantly varied with levels of experienced failure to control smoking and plans to quit. Explicit attitudes significantly predicted later cessation among those with low (but not high or average) levels of experienced failure to control smoking. Conversely, however, implicit attitudes significantly predicted later cessation among those with high levels of experienced failure to control smoking, but only if they had a plan to quit. Because smoking cessation involves both controlled and automatic processes, interventions may need to consider attitude change interventions that focus on both implicit and explicit attitudes. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

Attitude control system conceptual design for the GOES-N spacecraft series

NASA Technical Reports Server (NTRS)

Markley, F. L.; Bauer, F. H.; Deily, J. J.; Femiano, M. D.

1991-01-01

The attitude determination sensing and processing of the system are considered, and inertial reference units, star trackers, and beacons and landmarks are discussed as well as an extended Kalman filter and expected attitude-determination performance. The baseline controller is overviewed, and a spacecraft motion compensation (SMC) algorithm, disturbance environment, and SMC performance expectations are covered. Detailed simulation results are presented, and emphasis is placed on dynamic models, attitude estimation and control, and SMC disturbance accommmodation. It is shown that the attitude control system employing gyro/star tracker sensing and active three-axis control with reaction wheels is capable of maintaining attitude errors of 1.7 microrad or less on all axes in the absence of attitude disturbances, and that the sensor line-of-sight pointing errors can be reduced to 0.1 microrad by SMC.

Design and Integration of an All-Magnetic Attitude Control System for FASTSAT-HSV01's Multiple Pointing Objectives

NASA Technical Reports Server (NTRS)

DeKock, Brandon; Sanders, Devon; Vanzwieten, Tannen; Capo-Lugo, Pedro

2011-01-01

The FASTSAT-HSV01 spacecraft is a microsatellite with magnetic torque rods as it sole attitude control actuator. FASTSAT s multiple payloads and mission functions require the Attitude Control System (ACS) to maintain Local Vertical Local Horizontal (LVLH)-referenced attitudes without spin-stabilization, while the pointing errors for some attitudes be significantly smaller than the previous best-demonstrated for this type of control system. The mission requires the ACS to hold multiple stable, unstable, and non-equilibrium attitudes, as well as eject a 3U CubeSat from an onboard P-POD and recover from the ensuing tumble. This paper describes the Attitude Control System, the reasons for design choices, how the ACS integrates with the rest of the spacecraft, and gives recommendations for potential future applications of the work.

Attitude control with realization of linear error dynamics

NASA Technical Reports Server (NTRS)

Paielli, Russell A.; Bach, Ralph E.

1993-01-01

An attitude control law is derived to realize linear unforced error dynamics with the attitude error defined in terms of rotation group algebra (rather than vector algebra). Euler parameters are used in the rotational dynamics model because they are globally nonsingular, but only the minimal three Euler parameters are used in the error dynamics model because they have no nonlinear mathematical constraints to prevent the realization of linear error dynamics. The control law is singular only when the attitude error angle is exactly pi rad about any eigenaxis, and a simple intuitive modification at the singularity allows the control law to be used globally. The forced error dynamics are nonlinear but stable. Numerical simulation tests show that the control law performs robustly for both initial attitude acquisition and attitude control.

Coupled attitude-orbit dynamics and control for an electric sail in a heliocentric transfer mission.

PubMed

Huo, Mingying; Zhao, Jun; Xie, Shaobiao; Qi, Naiming

2015-01-01

The paper discusses the coupled attitude-orbit dynamics and control of an electric-sail-based spacecraft in a heliocentric transfer mission. The mathematical model characterizing the propulsive thrust is first described as a function of the orbital radius and the sail angle. Since the solar wind dynamic pressure acceleration is induced by the sail attitude, the orbital and attitude dynamics of electric sails are coupled, and are discussed together. Based on the coupled equations, the flight control is investigated, wherein the orbital control is studied in an optimal framework via a hybrid optimization method and the attitude controller is designed based on feedback linearization control. To verify the effectiveness of the proposed control strategy, a transfer problem from Earth to Mars is considered. The numerical results show that the proposed strategy can control the coupled system very well, and a small control torque can control both the attitude and orbit. The study in this paper will contribute to the theory study and application of electric sail.

Coupled Attitude-Orbit Dynamics and Control for an Electric Sail in a Heliocentric Transfer Mission

PubMed Central

Huo, Mingying; Zhao, Jun; Xie, Shaobiao; Qi, Naiming

2015-01-01

The paper discusses the coupled attitude-orbit dynamics and control of an electric-sail-based spacecraft in a heliocentric transfer mission. The mathematical model characterizing the propulsive thrust is first described as a function of the orbital radius and the sail angle. Since the solar wind dynamic pressure acceleration is induced by the sail attitude, the orbital and attitude dynamics of electric sails are coupled, and are discussed together. Based on the coupled equations, the flight control is investigated, wherein the orbital control is studied in an optimal framework via a hybrid optimization method and the attitude controller is designed based on feedback linearization control. To verify the effectiveness of the proposed control strategy, a transfer problem from Earth to Mars is considered. The numerical results show that the proposed strategy can control the coupled system very well, and a small control torque can control both the attitude and orbit. The study in this paper will contribute to the theory study and application of electric sail. PMID:25950179

High Accuracy Attitude Control of a Spacecraft Using Feedback Linearization

DTIC Science & Technology

1992-05-01

High Accuracy Attitude Control of a Spacecraft Using Feedback Linearization A Thesis Presented by Louis Joseph PoehIman, Captain, USAF B.S., U.S. Air...High Accuracy Attitude Control of a Spacecraft Using Feedback Linearization by Louis Joseph Poehlman, Captain, USAF Submitted to the Department of...31 2-4 Attitude Determination and Control System Architecture ................. 33 3-1 Exact Linearization Using Nonlinear Feedback

Maternal and Paternal Psychological Control as Moderators of the Link between Peer Attitudes and Adolescents' Risky Sexual Behavior

ERIC Educational Resources Information Center

Oudekerk, Barbara A.; Allen, Joseph P.; Hafen, Christopher A.; Hessel, Elenda T.; Szwedo, David E.; Spilker, Ann

2014-01-01

Maternal and paternal psychological control, peer attitudes, and the interaction of psychological control and peer attitudes at age 13 were examined as predictors of risky sexual behavior before age 16 in a community sample of 181 youth followed from age 13 to 16. Maternal psychological control moderated the link between peer attitudes and sexual…

Maternal and Paternal Psychological Control as Moderators of the Link between Peer Attitudes and Adolescents' Risky Sexual Behavior.

PubMed

Oudekerk, Barbara A; Allen, Joseph P; Hafen, Christopher A; Hessel, Elenda T; Szwedo, David E; Spilker, Ann

2014-05-01

Maternal and paternal psychological control, peer attitudes, and the interaction of psychological control and peer attitudes at age 13 were examined as predictors of risky sexual behavior before age 16 in a community sample of 181 youth followed from age 13 to 16. Maternal psychological control moderated the link between peer attitudes and sexual behavior. Peer acceptance of early sex predicted greater risky sexual behaviors, but only for teens whose mothers engaged in high levels of psychological control. Paternal psychological control demonstrated the same moderating effect for girls; for boys, however, high levels of paternal control predicted risky sex regardless of peer attitudes. Results are consistent with the theory that peer influences do not replace parental influences with regard to adolescent sexual behavior; rather, parental practices continue to serve an important role either directly forecasting sexual behavior or moderating the link between peer attitudes and sexual behavior.

Maternal and Paternal Psychological Control as Moderators of the Link between Peer Attitudes and Adolescents’ Risky Sexual Behavior

PubMed Central

Oudekerk, Barbara A.; Allen, Joseph P.; Hafen, Christopher A.; Hessel, Elenda T.; Szwedo, David E.; Spilker, Ann

2013-01-01

Maternal and paternal psychological control, peer attitudes, and the interaction of psychological control and peer attitudes at age 13 were examined as predictors of risky sexual behavior before age 16 in a community sample of 181 youth followed from age 13 to 16. Maternal psychological control moderated the link between peer attitudes and sexual behavior. Peer acceptance of early sex predicted greater risky sexual behaviors, but only for teens whose mothers engaged in high levels of psychological control. Paternal psychological control demonstrated the same moderating effect for girls; for boys, however, high levels of paternal control predicted risky sex regardless of peer attitudes. Results are consistent with the theory that peer influences do not replace parental influences with regard to adolescent sexual behavior; rather, parental practices continue to serve an important role either directly forecasting sexual behavior or moderating the link between peer attitudes and sexual behavior. PMID:25328265

Event-triggered attitude control of spacecraft

NASA Astrophysics Data System (ADS)

Wu, Baolin; Shen, Qiang; Cao, Xibin

2018-02-01

The problem of spacecraft attitude stabilization control system with limited communication and external disturbances is investigated based on an event-triggered control scheme. In the proposed scheme, information of attitude and control torque only need to be transmitted at some discrete triggered times when a defined measurement error exceeds a state-dependent threshold. The proposed control scheme not only guarantees that spacecraft attitude control errors converge toward a small invariant set containing the origin, but also ensures that there is no accumulation of triggering instants. The performance of the proposed control scheme is demonstrated through numerical simulation.

Adaptive mass expulsion attitude control system

NASA Technical Reports Server (NTRS)

Rodden, John J. (Inventor); Stevens, Homer D. (Inventor); Carrou, Stephane (Inventor)

2001-01-01

An attitude control system and method operative with a thruster controls the attitude of a vehicle carrying the thruster, wherein the thruster has a valve enabling the formation of pulses of expelled gas from a source of compressed gas. Data of the attitude of the vehicle is gathered, wherein the vehicle is located within a force field tending to orient the vehicle in a first attitude different from a desired attitude. The attitude data is evaluated to determine a pattern of values of attitude of the vehicle in response to the gas pulses of the thruster and in response to the force field. The system and the method maintain the attitude within a predetermined band of values of attitude which includes the desired attitude. Computation circuitry establishes an optimal duration of each of the gas pulses based on the pattern of values of attitude, the optimal duration providing for a minimal number of opening and closure operations of the valve. The thruster is operated to provide gas pulses having the optimal duration.

Distributed attitude synchronization of formation flying via consensus-based virtual structure

NASA Astrophysics Data System (ADS)

Cong, Bing-Long; Liu, Xiang-Dong; Chen, Zhen

2011-06-01

This paper presents a general framework for synchronized multiple spacecraft rotations via consensus-based virtual structure. In this framework, attitude control systems for formation spacecrafts and virtual structure are designed separately. Both parametric uncertainty and external disturbance are taken into account. A time-varying sliding mode control (TVSMC) algorithm is designed to improve the robustness of the actual attitude control system. As for the virtual attitude control system, a behavioral consensus algorithm is presented to accomplish the attitude maneuver of the entire formation and guarantee a consistent attitude among the local virtual structure counterparts during the attitude maneuver. A multiple virtual sub-structures (MVSSs) system is introduced to enhance current virtual structure scheme when large amounts of spacecrafts are involved in the formation. The attitude of spacecraft is represented by modified Rodrigues parameter (MRP) for its non-redundancy. Finally, a numerical simulation with three synchronization situations is employed to illustrate the effectiveness of the proposed strategy.

Energy management and attitude control for spacecraft

NASA Astrophysics Data System (ADS)

Costic, Bret Thomas

2001-07-01

This PhD dissertation describes the design and implementation of various control strategies centered around spacecraft applications: (i) an attitude control system for spacecraft, (ii) flywheels used for combined attitude and energy tracking, and (iii) an adaptive autobalancing control algorithm. The theory found in each of these sections is demonstrated through simulation or experimental results. An introduction to each of these three primary chapters can be found in chapter one. The main problem addressed in the second chapter is the quaternion-based, attitude tracking control of rigid spacecraft without angular velocity measurements and in the presence of an unknown inertia matrix. As a stepping-stone, an adaptive, full-state feedback controller that compensates for parametric uncertainty while ensuring asymptotic attitude tracking errors is designed. The adaptive, full-state feedback controller is then redesigned such that the need for angular velocity measurements is eliminated. The proposed adaptive, output feedback controller ensures asymptotic attitude tracking. This work uses a four-parameter representation of the spacecraft attitude that does not exhibit singular orientations as in the case of the previous three-parameter representation-based results. To the best of my knowledge, this represents the first solution to the adaptive, output feedback, attitude tracking control problem for the quaternion representation. Simulation results are included to illustrate the performance of the proposed output feedback control strategy. The third chapter is devoted to the use of multiple flywheels that integrate the energy storage and attitude control functions in space vehicles. This concept, which is referred to as an Integrated Energy Management and Attitude Control (IEMAC) system, reduces the space vehicle bus mass, volume, cost, and maintenance requirements while maintaining or improving the space vehicle performance. To this end, two nonlinear IEMAC strategies (model-based and adaptive) that simultaneously track a desired attitude trajectory and desired energy/power profile are presented. Both strategies ensure asymptotic tracking while the adaptive controller compensates for uncertain spacecraft inertia. In the final chapter, a control strategy is designed for a rotating, unbalanced disk. The control strategy, which is composed of a control torque and two control forces, regulates the disk displacement and ensures angular velocity tracking. The controller uses a desired compensation adaptation law and a gain adjusted forgetting factor to achieve exponential stability despite the lack of knowledge of the imbalance-related parameters, provided a mild persistency of excitation condition is satisfied.

Attributions and Attitudes of Mothers and Fathers in the United States.

PubMed

Lansford, Jennifer E; Bornstein, Marc H; Dodge, Kenneth A; Skinner, Ann T; Putnick, Diane L; Deater-Deckard, Kirby

2011-01-01

OBJECTIVE.: The present study examined mean level similarities and differences as well as correlations between U.S. mothers' and fathers' attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. DESIGN.: Interviews were conducted with both mothers and fathers in 139 European American, Latin American, and African American families. RESULTS.: Interactions between parent gender and ethnicity emerged for adult-controlled failure and perceived control over failure. Fathers reported higher adult-controlled failure and child-controlled failure attributions than did mothers, whereas mothers reported attitudes that were more progressive and modern than did fathers; these differences remained significant after controlling for parents' age, education, and possible social desirability bias. Ethnic differences emerged for five of the seven attributions and attitudes examined; four remained significant after controlling for parents' age, education, and possible social desirability bias. Medium effect sizes were found for concordance between parents in the same family for attributions regarding uncontrollable success, child-controlled failure, progressive attitudes, authoritarian attitudes, and modernity of attitudes after controlling for parents' age, education, and possible social desirability bias. CONCLUSIONS.: This work elucidates ways that parent gender and ethnicity relate to attributions regarding U.S. parents' successes and failures in caregiving situations and to their progressive versus authoritarian parenting attitudes.

Attributions and Attitudes of Mothers and Fathers in the United States

PubMed Central

Lansford, Jennifer E.; Bornstein, Marc H.; Dodge, Kenneth A.; Skinner, Ann T.; Putnick, Diane L.; Deater-Deckard, Kirby

2011-01-01

SYNOPSIS Objective. The present study examined mean level similarities and differences as well as correlations between U.S. mothers’ and fathers’ attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. Design. Interviews were conducted with both mothers and fathers in 139 European American, Latin American, and African American families. Results. Interactions between parent gender and ethnicity emerged for adult-controlled failure and perceived control over failure. Fathers reported higher adult-controlled failure and child-controlled failure attributions than did mothers, whereas mothers reported attitudes that were more progressive and modern than did fathers; these differences remained significant after controlling for parents’ age, education, and possible social desirability bias. Ethnic differences emerged for five of the seven attributions and attitudes examined; four remained significant after controlling for parents’ age, education, and possible social desirability bias. Medium effect sizes were found for concordance between parents in the same family for attributions regarding uncontrollable success, child-controlled failure, progressive attitudes, authoritarian attitudes, and modernity of attitudes after controlling for parents’ age, education, and possible social desirability bias. Conclusions. This work elucidates ways that parent gender and ethnicity relate to attributions regarding U.S. parents’ successes and failures in caregiving situations and to their progressive versus authoritarian parenting attitudes. PMID:21822402

SSS-A attitude control prelaunch analysis and operations plan

NASA Technical Reports Server (NTRS)

Werking, R. D.; Beck, J.; Gardner, D.; Moyer, P.; Plett, M.

1971-01-01

A description of the attitude control support being supplied by the Mission and Data Operations Directorate is presented. Descriptions of the computer programs being used to support the mission for attitude determination, prediction, control, and definitive attitude processing are included. In addition, descriptions of the operating procedures which will be used to accomplish mission objectives are provided.

Some optimal considerations in attitude control systems. [evaluation of value of relative weighting between time and fuel for relay control law

NASA Technical Reports Server (NTRS)

Boland, J. S., III

1973-01-01

The conventional six-engine reaction control jet relay attitude control law with deadband is shown to be a good linear approximation to a weighted time-fuel optimal control law. Techniques for evaluating the value of the relative weighting between time and fuel for a particular relay control law is studied along with techniques to interrelate other parameters for the two control laws. Vehicle attitude control laws employing control moment gyros are then investigated. Steering laws obtained from the expression for the reaction torque of the gyro configuration are compared to a total optimal attitude control law that is derived from optimal linear regulator theory. This total optimal attitude control law has computational disadvantages in the solving of the matrix Riccati equation. Several computational algorithms for solving the matrix Riccati equation are investigated with respect to accuracy, computational storage requirements, and computational speed.

Modular design attitude control system

NASA Technical Reports Server (NTRS)

Chichester, F. D.

1982-01-01

A hybrid multilevel linear quadratic regulator (ML-LQR) approach was developed and applied to the attitude control of models of the rotational dynamics of a prototype flexible spacecraft and of a typical space platform. Three axis rigid body flexible suspension models were developed for both the spacecraft and the space platform utilizing augmented body methods. Models of the spacecraft with hybrid ML-LQR attitude control and with LQR attitude control were simulated and their response with the two different types of control were compared.

Robustness and Actuator Bandwidth of MRP-Based Sliding Mode Control for Spacecraft Attitude Control Problems

NASA Astrophysics Data System (ADS)

Keum, Jung-Hoon; Ra, Sung-Woong

2009-12-01

Nonlinear sliding surface design in variable structure systems for spacecraft attitude control problems is studied. A robustness analysis is performed for regular form of system, and calculation of actuator bandwidth is presented by reviewing sliding surface dynamics. To achieve non-singular attitude description and minimal parameterization, spacecraft attitude control problems are considered based on modified Rodrigues parameters (MRP). It is shown that the derived controller ensures the sliding motion in pre-determined region irrespective of unmodeled effects and disturbances.

A simple attitude control of quadrotor helicopter based on Ziegler-Nichols rules for tuning PD parameters.

PubMed

He, ZeFang; Zhao, Long

2014-01-01

An attitude control strategy based on Ziegler-Nichols rules for tuning PD (proportional-derivative) parameters of quadrotor helicopters is presented to solve the problem that quadrotor tends to be instable. This problem is caused by the narrow definition domain of attitude angles of quadrotor helicopters. The proposed controller is nonlinear and consists of a linear part and a nonlinear part. The linear part is a PD controller with PD parameters tuned by Ziegler-Nichols rules and acts on the quadrotor decoupled linear system after feedback linearization; the nonlinear part is a feedback linearization item which converts a nonlinear system into a linear system. It can be seen from the simulation results that the attitude controller proposed in this paper is highly robust, and its control effect is better than the other two nonlinear controllers. The nonlinear parts of the other two nonlinear controllers are the same as the attitude controller proposed in this paper. The linear part involves a PID (proportional-integral-derivative) controller with the PID controller parameters tuned by Ziegler-Nichols rules and a PD controller with the PD controller parameters tuned by GA (genetic algorithms). Moreover, this attitude controller is simple and easy to implement.

[Development of knowledge, attitude and practice questionnaire on prevention and control of occupational diseases].

PubMed

Gao, Yuan; Feng, Yuchao; Wang, Min; Su, Yiwei; Li, Yanhua; Wang, Zhi; Tang, Shihao

2015-04-01

To develop the knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for occupational groups, and to provide a convenient and effective tool for the survey of knowledge, attitude, and behavior on the prevention and control of occupational diseases in occupational groups and the evaluation of intervention effect. The initial questionnaire which was evaluated by the experts was used to carry out a pre-survey in Guangzhou, China. The survey results were statistically analyzed by t test, identification index method, correlation analysis, and Cronbach's a coefficient method. And then the questionnaire was further modified, and the content of the questionnaire was determined finally. After modification, there were 18 items on knowledge, 16 items on attitude, and 12 items on behavior in the "Knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for enterprise managers"; there were 19 items on knowledge, 10 items on attitude, and 11 items on behavior in the "Knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for workers". The knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for occupational groups is developed successfully, and it is a convenient and effective tool for the survey of knowledge, attitude, and behavior on the prevention and control of occupational diseases in occupational groups and the evaluation of intervention effect.

Integrated Orbit and Attitude Control for a Nanosatellite with Power Constraints

NASA Technical Reports Server (NTRS)

Naasz, Bo; Hall, Christopher; Berry, Matthew; Hy-Young, Kim

2003-01-01

Small satellites tend to be power-limited, so that actuators used to control the orbit and attitude must compete with each other as well as with other subsystems for limited electrical power. The Virginia Tech nanosatellite project, HokieSat, must use its limited power resources to operate pulsed-plasma thrusters for orbit control and magnetic torque coils for attitude control, while also providing power to a GPS receiver, a crosslink transceiver, and other subsystems. The orbit and attitude control strategies were developed independently. The attitude control system is based on an application of Linear Quadratic Regulator (LQR) to an averaged system of equations, whereas the orbit control is based on orbit element feedback. In this paper we describe the strategy for integrating these two control systems and present simulation results to verify the strategy.

Trying to trust: Brain activity during interpersonal social attitude change.

PubMed

Filkowski, Megan M; Anderson, Ian W; Haas, Brian W

2016-04-01

Interpersonal trust and distrust are important components of human social interaction. Although several studies have shown that brain function is associated with either trusting or distrusting others, very little is known regarding brain function during the control of social attitudes, including trust and distrust. This study was designed to investigate the neural mechanisms involved when people attempt to control their attitudes of trust or distrust toward another person. We used a novel control-of-attitudes fMRI task, which involved explicit instructions to control attitudes of interpersonal trust and distrust. Control of trust or distrust was operationally defined as changes in trustworthiness evaluations of neutral faces before and after the control-of-attitudes fMRI task. Overall, participants (n = 60) evaluated faces paired with the distrust instruction as being less trustworthy than faces paired with the trust instruction following the control-of-distrust task. Within the brain, both the control-of-trust and control-of-distrust conditions were associated with increased temporoparietal junction, precuneus (PrC), inferior frontal gyrus (IFG), and medial prefrontal cortex activity. Individual differences in the control of trust were associated with PrC activity, and individual differences in the control of distrust were associated with IFG activity. Together, these findings identify a brain network involved in the explicit control of distrust and trust and indicate that the PrC and IFG may serve to consolidate interpersonal social attitudes.

Attitude control challenges for earth orbiters of the 1980's

NASA Technical Reports Server (NTRS)

Hibbard, W.

1980-01-01

Experience gained in designing attitude control systems for orbiting spacecraft of the late 1980's is related. Implications for satellite attitude control design of the guidance capabilities, rendezvous and recovery requirements, use of multiple-use spacecraft and the development of large spacecraft associated with the advent of the Space Shuttle are considered. Attention is then given to satellite attitude control requirements posed by the Tracking and Data Relay Satellite System, the Global Positioning System, the NASA End-to-End Data System, and Shuttle-associated subsatellites. The anticipated completion and launch of the Space Telescope, which will provide one of the first experiences with the new generation of attitude control, is also pointed out.

Self-Regulation and Implicit Attitudes Toward Physical Activity Influence Exercise Behavior.

PubMed

Padin, Avelina C; Emery, Charles F; Vasey, Michael; Kiecolt-Glaser, Janice K

2017-08-01

Dual-process models of health behavior posit that implicit and explicit attitudes independently drive healthy behaviors. Prior evidence indicates that implicit attitudes may be related to weekly physical activity (PA) levels, but the extent to which self-regulation attenuates this link remains unknown. This study examined the associations between implicit attitudes and self-reported PA during leisure time among 150 highly active young adults and evaluated the extent to which effortful control (one aspect of self-regulation) moderated this relationship. Results indicated that implicit attitudes toward exercise were unrelated to average workout length among individuals with higher effortful control. However, those with lower effortful control and more negative implicit attitudes reported shorter average exercise sessions compared with those with more positive attitudes. Implicit and explicit attitudes were unrelated to total weekly PA. A combination of poorer self-regulation and negative implicit attitudes may leave individuals vulnerable to mental and physical health consequences of low PA.

Autonomous control system reconfiguration for spacecraft with non-redundant actuators

NASA Astrophysics Data System (ADS)

Grossman, Walter

1995-05-01

The Small Satellite Technology Initiative (SSTI) 'CLARK' spacecraft is required to be single-failure tolerant, i.e., no failure of any single component or subsystem shall result in complete mission loss. Fault tolerance is usually achieved by implementing redundant subsystems. Fault tolerant systems are therefore heavier and cost more to build and launch than non-redundent, non fault-tolerant spacecraft. The SSTI CLARK satellite Attitude Determination and Control System (ADACS) achieves single-fault tolerance without redundancy. The attitude determination system system uses a Kalman Filter which is inherently robust to loss of any single attitude sensor. The attitude control system uses three orthogonal reaction wheels for attitude control and three magnetic dipoles for momentum control. The nominal six-actuator control system functions by projecting the attitude correction torque onto the reaction wheels while a slower momentum management outer loop removes the excess momentum in the direction normal to the local B field. The actuators are not redundant so the nominal control law cannot be implemented in the event of a loss of a single actuator (dipole or reaction wheel). The spacecraft dynamical state (attitude, angular rate, and momentum) is controllable from any five-element subset of the six actuators. With loss of an actuator the instantaneous control authority may not span R(3) but the controllability gramian integral(limits between t,0) Phi(t, tau)B(tau )B(prime)(tau) Phi(prime)(t, tau)d tau retains full rank. Upon detection of an actuator failure the control torque is decomposed onto the remaining active axes. The attitude control torque is effected and the over-orbit momentum is controlled. The resulting control system performance approaches that of the nominal system.

A case study in nonlinear dynamics and control of articulated spacecraft: The Space Station Freedom with a mobile remote manipulator system

NASA Technical Reports Server (NTRS)

Bennett, William H.; Kwatny, Harry G.; Lavigna, Chris; Blankenship, Gilmer

1994-01-01

The following topics are discussed: (1) modeling of articulated spacecraft as multi-flex-body systems; (2) nonlinear attitude control by adaptive partial feedback linearizing (PFL) control; (3) attitude dynamics and control for SSF/MRMS; and (4) performance analysis results for attitude control of SSF/MRMS.

Single Axis Attitude Control and DC Bus Regulation with Two Flywheels

NASA Technical Reports Server (NTRS)

Kascak, Peter E.; Jansen, Ralph H.; Kenny, Barbara; Dever, Timothy P.

2002-01-01

A computer simulation of a flywheel energy storage single axis attitude control system is described. The simulation models hardware which will be experimentally tested in the future. This hardware consists of two counter rotating flywheels mounted to an air table. The air table allows one axis of rotational motion. An inertia DC bus coordinator is set forth that allows the two control problems, bus regulation and attitude control, to be separated. Simulation results are presented with a previously derived flywheel bus regulator and a simple PID attitude controller.

Attitude ground support system for the solar maximum mission spacecraft

NASA Technical Reports Server (NTRS)

Nair, G.

1980-01-01

The SMM attitude ground support system (AGSS) supports the acquisition of spacecraft roll attitude reference, performs the in-flight calibration of the attitude sensor complement, supports onboard control autonomy via onboard computer data base updates, and monitors onboard computer (OBC) performance. Initial roll attitude acquisition is accomplished by obtaining a coarse 3 axis attitude estimate from magnetometer and Sun sensor data and subsequently refining it by processing data from the fixed head star trackers. In-flight calibration of the attitude sensor complement is achieved by processing data from a series of slew maneuvers designed to maximize the observability and accuracy of the appropriate alignments and biases. To ensure autonomy of spacecraft operation, the AGSS selects guide stars and computes sensor occultation information for uplink to the OBC. The onboard attitude control performance is monitored on the ground through periodic attitude determination and processing of OBC data in downlink telemetry. In general, the control performance has met mission requirements. However, software and hardware problems have resulted in sporadic attitude reference losses.

A Simple Attitude Control of Quadrotor Helicopter Based on Ziegler-Nichols Rules for Tuning PD Parameters

PubMed Central

He, ZeFang

2014-01-01

An attitude control strategy based on Ziegler-Nichols rules for tuning PD (proportional-derivative) parameters of quadrotor helicopters is presented to solve the problem that quadrotor tends to be instable. This problem is caused by the narrow definition domain of attitude angles of quadrotor helicopters. The proposed controller is nonlinear and consists of a linear part and a nonlinear part. The linear part is a PD controller with PD parameters tuned by Ziegler-Nichols rules and acts on the quadrotor decoupled linear system after feedback linearization; the nonlinear part is a feedback linearization item which converts a nonlinear system into a linear system. It can be seen from the simulation results that the attitude controller proposed in this paper is highly robust, and its control effect is better than the other two nonlinear controllers. The nonlinear parts of the other two nonlinear controllers are the same as the attitude controller proposed in this paper. The linear part involves a PID (proportional-integral-derivative) controller with the PID controller parameters tuned by Ziegler-Nichols rules and a PD controller with the PD controller parameters tuned by GA (genetic algorithms). Moreover, this attitude controller is simple and easy to implement. PMID:25614879

X-33 Attitude Control System Design for Ascent, Transition, and Entry Flight Regimes

NASA Technical Reports Server (NTRS)

Hall, Charles E.; Gallaher, Michael W.; Hendrix, Neal D.

1998-01-01

The Vehicle Control Systems Team at Marshall Space Flight Center, Systems Dynamics Laboratory, Guidance and Control Systems Division is designing under a cooperative agreement with Lockheed Martin Skunkworks, the Ascent, Transition, and Entry flight attitude control system for the X-33 experimental vehicle. Ascent flight control begins at liftoff and ends at linear aerospike main engine cutoff (NECO) while Transition and Entry flight control begins at MECO and concludes at the terminal area energy management (TAEM) interface. TAEM occurs at approximately Mach 3.0. This task includes not only the design of the vehicle attitude control systems but also the development of requirements for attitude control system components and subsystems. The X-33 attitude control system design is challenged by a short design cycle, the design environment (Mach 0 to about Mach 15), and the X-33 incremental test philosophy. The X-33 design-to-launch cycle of less than 3 years requires a concurrent design approach while the test philosophy requires design adaptation to vehicle variations that are a function of Mach number and mission profile. The flight attitude control system must deal with the mixing of aerosurfaces, reaction control thrusters, and linear aerospike engine control effectors and handle parasitic effects such as vehicle flexibility and propellant sloshing from the uniquely shaped propellant tanks. The attitude control system design is, as usual, closely linked to many other subsystems and must deal with constraints and requirements from these subsystems.

ATS-6 engineering performance report. Volume 2: Orbit and attitude controls

NASA Technical Reports Server (NTRS)

Wales, R. O. (Editor)

1981-01-01

Attitude control is reviewed, encompassing the attitude control subsystem, spacecraft attitude precision pointing and slewing adaptive control experiment, and RF interferometer experiment. The spacecraft propulsion system (SPS) is discussed, including subsystem, SPS design description and validation, orbital operations and performance, in-orbit anomalies and contingency operations, and the cesium bombardment ion engine experiment. Thruster failure due to plugging of the propellant feed passages, a major cause for mission termination, are considered among the critical generic failures on the satellite.

Attitude Control Propulsion Components, Volume 1

NASA Technical Reports Server (NTRS)

1974-01-01

Effort was made to include as much engineering information on each component as possible, consistent with usefulness and catalog size limitations. The contents of this catalog contain components which were qualified for use with spacecraft monopropellant hydrazine and inert gas attitude control systems. Thrust ranges up to 44.5 N (10.0 lbf) for hydrazine and inert gas sytems were considered. Additionally, some components qualified for uses other than spacecraft attitude control are included because they are suitable for use in attitude controls systems.

Adaptive Jacobian Fuzzy Attitude Control for Flexible Spacecraft Combined Attitude and Sun Tracking System

NASA Astrophysics Data System (ADS)

Chak, Yew-Chung; Varatharajoo, Renuganth

2016-07-01

Many spacecraft attitude control systems today use reaction wheels to deliver precise torques to achieve three-axis attitude stabilization. However, irrecoverable mechanical failure of reaction wheels could potentially lead to mission interruption or total loss. The electrically-powered Solar Array Drive Assemblies (SADA) are usually installed in the pitch axis which rotate the solar arrays to track the Sun, can produce torques to compensate for the pitch-axis wheel failure. In addition, the attitude control of a flexible spacecraft poses a difficult problem. These difficulties include the strong nonlinear coupled dynamics between the rigid hub and flexible solar arrays, and the imprecisely known system parameters, such as inertia matrix, damping ratios, and flexible mode frequencies. In order to overcome these drawbacks, the adaptive Jacobian tracking fuzzy control is proposed for the combined attitude and sun-tracking control problem of a flexible spacecraft during attitude maneuvers in this work. For the adaptation of kinematic and dynamic uncertainties, the proposed scheme uses an adaptive sliding vector based on estimated attitude velocity via approximate Jacobian matrix. The unknown nonlinearities are approximated by deriving the fuzzy models with a set of linguistic If-Then rules using the idea of sector nonlinearity and local approximation in fuzzy partition spaces. The uncertain parameters of the estimated nonlinearities and the Jacobian matrix are being adjusted online by an adaptive law to realize feedback control. The attitude of the spacecraft can be directly controlled with the Jacobian feedback control when the attitude pointing trajectory is designed with respect to the spacecraft coordinate frame itself. A significant feature of this work is that the proposed adaptive Jacobian tracking scheme will result in not only the convergence of angular position and angular velocity tracking errors, but also the convergence of estimated angular velocity to the actual angular velocity. Numerical results are presented to demonstrate the effectiveness of the proposed scheme in tracking the desired attitude, as well as suppressing the elastic deflection effects of solar arrays during maneuver.

A new momentum management controller for the space station

NASA Technical Reports Server (NTRS)

Wie, B.; Byun, K. W.; Warren, V. W.

1988-01-01

A new approach to CMG (control moment gyro) momentum management and attitude control of the Space Station is developed. The control algorithm utilizes both the gravity-gradient and gyroscopic torques to seek torque equilibrium attitude in the presence of secular and cyclic disturbances. Depending upon mission requirements, either pitch attitude or pitch-axis CMG momentum can be held constant: yaw attitude and roll-axis CMG momentum can be held constant, while roll attitude and yaw-axis CMG momentum cannot be held constant. As a result, the overall attitude and CMG momentum oscillations caused by cyclic aero-dynamic disturbances are minimized. A state feedback controller with minimal computer storage requirement for gain scheduling is also developed. The overall closed-loop system is stable for + or - 30 percent inertia matrix variations and has more than + or - 10 dB and 45 deg stability margins in each loop.

Research on Design of MUH Attitude Stability Augmentation Control System

NASA Astrophysics Data System (ADS)

Fan, Shigang

2017-09-01

Attitude stability augmentation control system with a lower cost need to be designed so that MUH (Mini Unmanned Helicopter) can adapt to different types of geographic environment and fly steadily although the weather may be bad. Attitude feedback was calculated mainly by filtering estimation within attitude acquisition module in this system. Stability augmentation can be improved mainly by PI. This paper will depict running principle and designing process of MUH attitude stability augmentation control system and algorithm that is considered as an important part in this system.

Satellite recovery - Attitude dynamics of the targets

NASA Technical Reports Server (NTRS)

Cochran, J. E., Jr.; Lahr, B. S.

1986-01-01

The problems of categorizing and modeling the attitude dynamics of uncontrolled artificial earth satellites which may be targets in recovery attempts are addressed. Methods of classification presented are based on satellite rotational kinetic energy, rotational angular momentum and orbit and on the type of control present prior to the benign failure of the control system. The use of approximate analytical solutions and 'exact' numerical solutions to the equations governing satellite attitude motions to predict uncontrolled attitude motion is considered. Analytical and numerical results are presented for the evolution of satellite attitude motions after active control termination.

Steady-state simulation program for attitude control propulsion systems

NASA Technical Reports Server (NTRS)

Heinmiller, P. J.

1973-01-01

The formulation and the engineering equations employed in the steady state attitude control propulsion system simulation program are presented. The objective of this program is to aid in the preliminary design and development of propulsion systems used for spacecraft attitude control. The program simulates the integrated operation of the many interdependent components typically comprising an attitude control propulsion system. Flexibility, generality, ease of operation, and speed consistent with adequate accuracy were overriding considerations during the development of this program. Simulation modules were developed representing the various types of fluid components typically encountered in an attitude control propulsion system. These modules are basically self-contained and may be arranged by the program user into desired configuration through the program input data.

[Knowledge, attitude and practice on schistosomiasis control of chronic schistosomiasis patients in Poyang Lake area, Nanchang City].

PubMed

Guo-Hua, Peng; Zhu-Hua, Hu; Wei, Hua; Ke, Qian; Xiao-Gang, Li; Zhi-Shu, Zhang; Zhi-Gang, Chen; Xiao-Wu, Feng

2017-06-26

To understand the present situation of the chronic schistosomiasis patients' knowledge, attitude and practice on schistosomiasis control in Nanchang City. The knowledge, attitude and values on schistosomiasis control of 523 chronic schistosomiasis patients in Nanchang County, Jinxian County and Xinjian District in the Poyang Lake District were investigated with questionnaires. And the accuracy rates of the knowledge, attitude and practice among the patient groups of different counties, genders, age groups, occupations and educational levels were analyzed. The accuracy rates of the knowledge, attitude and practice of patients on schistosomiasis control were 95.76%, 82.80%, and 81.73% in Nanchang County; 91.37%, 93.32%, and 76.48% in Jinxian County; 88.25%, 67.56%, and 49.40% in Xinjian District. In the accuracy rates of knowledge, attitude and practice, the differences among the three counties (districts) were statistically significant ( χ 2 = 57.511-301.378, all P < 0.05) . The accuracy rates of chronic schistosomiasis patients' attitude and practice on schistosomiasis control in Nanchang City remain low. Therefore, the intensity of attitude and practice intervention should be strengthened in the Poyang Lake District in order to enhance the self-protection awareness of the patients.

Attitude stabilization of a rigid spacecraft using two momentum wheel actuators

NASA Technical Reports Server (NTRS)

Krishnan, Hariharan; Mcclamroch, N. Harris; Reyhanoglu, Mahmut

1993-01-01

It is well known that three momentum wheel actuators can be used to control the attitude of a rigid spacecraft and that arbitrary reorientation maneuvers of the spacecraft can be accomplished using smooth feedback. If failure of one of the momentum wheel actuators occurs, it is demonstrated that two momentum wheel actuators can be used to control the attitude of a rigid spacecraft and that arbitrary reorientation maneuvers of the spacecraft can be accomplished. Although the complete spacecraft equations are not controllable, the spacecraft equations are small time locally controllable in a reduced nonlinear sense. The reduced spacecraft dynamics cannot be asymptotically stabilized to any equilibrium attitude using a time-variant continuous feedback control law, but discontinuous feedback control strategies are constructed which stabilize any equilibrium attitude of the spacecraft in finite time. Consequently, reorientation of the spacecraft can be accomplished using discontinuous feedback control.

Categorization and Prediction of Crimes of Passion Based on Attitudes Toward Violence.

PubMed

Guan, Muzhen; Li, Xiaojing; Xiao, Wei; Miao, Danmin; Liu, Xufeng

2017-11-01

The present study explored implicit and explicit attitudes toward violence in crimes of passion. Criminals ( n = 96) who had perpetrated crimes of passion and students ( n = 100) participated in this study. Explicit attitudes toward violence were evaluated using the Abnormal Personality Risk Inventory (APRI), and implicit attitude toward violence was evaluated using the Implicit Association Test (IAT). Results indicated that APRI scores of the perpetrators were significantly higher than that of the control group ( p < .05), suggesting that explicit attitudes toward violence could discriminate between the criminals and the control group. There was a significant IAT effect demonstrating a negative implicit attitude toward violence in both the control group and in the criminals ( n = 68); whereas there was a significant IAT effect manifesting a positive implicit attitude toward violence in the criminals ( n = 16) only. These results suggest that combining explicit and implicit attitudes could provide an empirical classification of crimes of passion.

Finite-Time Attitude Tracking Control for Spacecraft Using Terminal Sliding Mode and Chebyshev Neural Network.

PubMed

An-Min Zou; Kumar, K D; Zeng-Guang Hou; Xi Liu

2011-08-01

A finite-time attitude tracking control scheme is proposed for spacecraft using terminal sliding mode and Chebyshev neural network (NN) (CNN). The four-parameter representations (quaternion) are used to describe the spacecraft attitude for global representation without singularities. The attitude state (i.e., attitude and velocity) error dynamics is transformed to a double integrator dynamics with a constraint on the spacecraft attitude. With consideration of this constraint, a novel terminal sliding manifold is proposed for the spacecraft. In order to guarantee that the output of the NN used in the controller is bounded by the corresponding bound of the approximated unknown function, a switch function is applied to generate a switching between the adaptive NN control and the robust controller. Meanwhile, a CNN, whose basis functions are implemented using only desired signals, is introduced to approximate the desired nonlinear function and bounded external disturbances online, and the robust term based on the hyperbolic tangent function is applied to counteract NN approximation errors in the adaptive neural control scheme. Most importantly, the finite-time stability in both the reaching phase and the sliding phase can be guaranteed by a Lyapunov-based approach. Finally, numerical simulations on the attitude tracking control of spacecraft in the presence of an unknown mass moment of inertia matrix, bounded external disturbances, and control input constraints are presented to demonstrate the performance of the proposed controller.

Eating on impulse: Implicit attitudes, self-regulatory resources, and trait self-control as determinants of food consumption.

PubMed

Wang, Yan; Wang, Lei; Cui, Xianghua; Fang, Yuan; Chen, Qianqiu; Wang, Ya; Qiang, Yao

2015-12-01

Self-regulatory resources and trait self-control have been found to moderate the impulse-behavior relationship. The current study investigated whether the interaction of self-regulatory resources and trait self-control moderates the association between implicit attitudes and food consumption. One hundred twenty female participants were randomly assigned to either a depletion condition in which their self-regulatory resources were reduced or a no-depletion condition. Participants' implicit attitudes for chocolate were measured with the Single Category Implicit Association Test and self-report measures of trait self-control were collected. The dependent variable was chocolate consumption in an ostensible taste and rate task. Implicit attitudes predicted chocolate consumption in depleted participants but not in non-depleted participants. However, this predictive power of implicit attitudes on eating in depleted condition disappeared in participants with high trait self-control. Thus, trait self-control and self-regulatory resources interact to moderate the prediction of implicit attitude on eating behavior. Results suggest that high trait self-control buffers the effect of self-regulatory depletion on impulsive eating. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experiments study on attitude coupling control method for flexible spacecraft

NASA Astrophysics Data System (ADS)

Wang, Jie; Li, Dongxu

2018-06-01

High pointing accuracy and stabilization are significant for spacecrafts to carry out Earth observing, laser communication and space exploration missions. However, when a spacecraft undergoes large angle maneuver, the excited elastic oscillation of flexible appendages, for instance, solar wing and onboard antenna, would downgrade the performance of the spacecraft platform. This paper proposes a coupling control method, which synthesizes the adaptive sliding mode controller and the positive position feedback (PPF) controller, to control the attitude and suppress the elastic vibration simultaneously. Because of its prominent performance for attitude tracking and stabilization, the proposed method is capable of slewing the flexible spacecraft with a large angle. Also, the method is robust to parametric uncertainties of the spacecraft model. Numerical simulations are carried out with a hub-plate system which undergoes a single-axis attitude maneuver. An attitude control testbed for the flexible spacecraft is established and experiments are conducted to validate the coupling control method. Both numerical and experimental results demonstrate that the method discussed above can effectively decrease the stabilization time and improve the attitude accuracy of the flexible spacecraft.

The accuracy of dynamic attitude propagation

NASA Technical Reports Server (NTRS)

Harvie, E.; Chu, D.; Woodard, M.

1990-01-01

Propagating attitude by integrating Euler's equation for rigid body motion has long been suggested for the Earth Radiation Budget Satellite (ERBS) but until now has not been implemented. Because of limited Sun visibility, propagation is necessary for yaw determination. With the deterioration of the gyros, dynamic propagation has become more attractive. Angular rates are derived from integrating Euler's equation with a stepsize of 1 second, using torques computed from telemetered control system data. The environmental torque model was quite basic. It included gravity gradient and unshadowed aerodynamic torques. Knowledge of control torques is critical to the accuracy of dynamic modeling. Due to their coarseness and sparsity, control actuator telemetry were smoothed before integration. The dynamic model was incorporated into existing ERBS attitude determination software. Modeled rates were then used for attitude propagation in the standard ERBS fine-attitude algorithm. In spite of the simplicity of the approach, the dynamically propagated attitude matched the attitude propagated with good gyros well for roll and yaw but diverged up to 3 degrees for pitch because of the very low resolution in pitch momentum wheel telemetry. When control anomalies significantly perturb the nominal attitude, the effect of telemetry granularity is reduced and the dynamically propagated attitudes are accurate on all three axes.

Mood state dependency of dysfunctional attitudes in bipolar affective disorder.

PubMed

Babakhani, Anet; Startup, Mike

2012-01-01

Studies of cognitive styles among euthymic people with bipolar affective disorder (BAD) without use of mood induction techniques to access those cognitive styles give misleading impressions of normality of those cognitions. The aim of this study was to assess dysfunctional attitudes of participants with BAD, and control participants with no previous psychiatric histories, after mood inductions. Sad and happy moods were induced within 49 BAD and 37 controls. Dysfunctional attitudes were measured following mood inductions using the Dysfunctional Attitude Scale-short form (DAS-24), which has three subscales of achievement, interpersonal, and goal attainment. It was hypothesised that within BAD the sad mood induction would help in accessing dysfunctional attitudes in all three domains relative to the happy mood induction. This was supported. It was also hypothesised that the mood inductions would not affect dysfunctional attitudes within controls. This was supported. When diagnosis was entered as a between group variable, achievement dysfunctional attitudes were significantly higher in BAD compared to controls after a happy induction. Both sad and happy moods provoked higher levels of dysfunctional attitudes within BAD. Euphoria may be related to elevated achievement dysfunctional attitudes, raising risk for mania.

Attitude Control System Design for the Solar Dynamics Observatory

NASA Technical Reports Server (NTRS)

Starin, Scott R.; Bourkland, Kristin L.; Kuo-Chia, Liu; Mason, Paul A. C.; Vess, Melissa F.; Andrews, Stephen F.; Morgenstern, Wendy M.

2005-01-01

The Solar Dynamics Observatory mission, part of the Living With a Star program, will place a geosynchronous satellite in orbit to observe the Sun and relay data to a dedicated ground station at all times. SDO remains Sun- pointing throughout most of its mission for the instruments to take measurements of the Sun. The SDO attitude control system is a single-fault tolerant design. Its fully redundant attitude sensor complement includes 16 coarse Sun sensors, a digital Sun sensor, 3 two-axis inertial reference units, 2 star trackers, and 4 guide telescopes. Attitude actuation is performed using 4 reaction wheels and 8 thrusters, and a single main engine nominally provides velocity-change thrust. The attitude control software has five nominal control modes-3 wheel-based modes and 2 thruster-based modes. A wheel-based Safehold running in the attitude control electronics box improves the robustness of the system as a whole. All six modes are designed on the same basic proportional-integral-derivative attitude error structure, with more robust modes setting their integral gains to zero. The paper details the mode designs and their uses.

Attributions and Attitudes of Mothers and Fathers in Italy

PubMed Central

Bombi, Anna Silvia; Pastorelli, Concetta; Bacchini, Dario; Di Giunta, Laura; Miranda, Maria C.; Zelli, Arnaldo

2011-01-01

SYNOPSIS Objective The present study examined mean level similarities and differences as well as correlations between mothers’ and fathers’ attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. Design Interviews were conducted with both mothers and fathers in 177 Italian families from Rome and Naples. Results Fathers’ attributions reflected higher perceived control over failure than did mothers’ attributions, whereas mothers reported attitudes that were more progressive than did fathers. Only the difference in progressive attitudes remained significant after controlling for parents’ age, education, and possible social desirability bias. Site differences emerged for four of the seven attributions and attitudes examined; three remained significant after controlling for parents’ age, education, and possible social desirability bias. Medium effect sizes were found for concordance between parents in the same family for authoritarian attitudes and modernity of attitudes after controlling for parents’ age, education, and possible social desirability bias. Conclusions This work elucidates ways that parent gender and cultural context relate to attributions regarding parents’ success and failure in caregiving situations and to progressive versus authoritarian parenting attitudes. PMID:21927586

Attributions and Attitudes of Mothers and Fathers in Italy.

PubMed

Bombi, Anna Silvia; Pastorelli, Concetta; Bacchini, Dario; Di Giunta, Laura; Miranda, Maria C; Zelli, Arnaldo

2011-07-01

OBJECTIVE: The present study examined mean level similarities and differences as well as correlations between mothers' and fathers' attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. DESIGN: Interviews were conducted with both mothers and fathers in 177 Italian families from Rome and Naples. RESULTS: Fathers' attributions reflected higher perceived control over failure than did mothers' attributions, whereas mothers reported attitudes that were more progressive than did fathers. Only the difference in progressive attitudes remained significant after controlling for parents' age, education, and possible social desirability bias. Site differences emerged for four of the seven attributions and attitudes examined; three remained significant after controlling for parents' age, education, and possible social desirability bias. Medium effect sizes were found for concordance between parents in the same family for authoritarian attitudes and modernity of attitudes after controlling for parents' age, education, and possible social desirability bias. CONCLUSIONS: This work elucidates ways that parent gender and cultural context relate to attributions regarding parents' success and failure in caregiving situations and to progressive versus authoritarian parenting attitudes.

Docking Offset Between the Space Shuttle and the International Space Station and Resulting Impacts to the Transfer of Attitude Reference and Control

NASA Technical Reports Server (NTRS)

Helms, W. Jason; Pohlkamp, Kara M.

2011-01-01

The Space Shuttle does not dock at an exact 90 degrees to the International Space Station (ISS) x-body axis. This offset from 90 degrees, along with error sources within their respective attitude knowledge, causes the two vehicles to never completely agree on their attitude, even though they operate as a single, mated stack while docked. The docking offset can be measured in flight when both vehicles have good attitude reference and is a critical component in calculations to transfer attitude reference from one vehicle to another. This paper will describe how the docking offset and attitude reference errors between both vehicles are measured and how this information would be used to recover Shuttle attitude reference from ISS in the event of multiple failures. During STS-117, ISS on-board Guidance, Navigation and Control (GNC) computers began having problems and after several continuous restarts, the systems failed. The failure took the ability for ISS to maintain attitude knowledge. This paper will also demonstrate how with knowledge of the docking offset, the contingency procedure to recover Shuttle attitude reference from ISS was reversed in order to provide ISS an attitude reference from Shuttle. Finally, this paper will show how knowledge of the docking offset can be used to speed up attitude control handovers from Shuttle to ISS momentum management. By taking into account the docking offset, Shuttle can be commanded to hold a more precise attitude which better agrees with the ISS commanded attitude such that start up transients with the ISS momentum management controllers are reduced. By reducing start-up transients, attitude control can be transferred from Shuttle to ISS without the use of ISS thrusters saving precious on-board propellant, crew time and minimizing loads placed upon the mated stack.

Attitude control fault protection - The Voyager experience

NASA Technical Reports Server (NTRS)

Litty, E. C.

1980-01-01

The length of the Voyager mission and the communication delay caused by the distances involved made fault protection a necessary part of the Voyager Attitude and Articulation Control Subsystem (AACS) design. An overview of the Voyager attitude control fault protection is given and flight experiences relating to fault protection are provided.

Spacecraft methods and structures with enhanced attitude control that facilitates gyroscope substitutions

NASA Technical Reports Server (NTRS)

Li, Rongsheng (Inventor); Kurland, Jeffrey A. (Inventor); Dawson, Alec M. (Inventor); Wu, Yeong-Wei A. (Inventor); Uetrecht, David S. (Inventor)

2004-01-01

Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Kalman filter is temporarily replaced with a substantially greater interim process-noise covariance Q. This replacement increases the weight given to the most recent attitude measurements and hastens the reduction of attitude errors and gyroscope bias errors. The error effect of the substituted gyroscopes is reduced and the absolute-attitude sensors are not driven out of their capture range. In another method embodiment, this replacement is preceded by the temporary replacement of an operational measurement-noise variance R with a substantially larger interim measurement-noise variance R to reduce transients during the gyroscope substitutions.

Relative Attitude Determination of Earth Orbiting Formations Using GPS Receivers

NASA Technical Reports Server (NTRS)

Lightsey, E. Glenn

2004-01-01

Satellite formation missions require the precise determination of both the position and attitude of multiple vehicles to achieve the desired objectives. In order to support the mission requirements for these applications, it is necessary to develop techniques for representing and controlling the attitude of formations of vehicles. A generalized method for representing the attitude of a formation of vehicles has been developed. The representation may be applied to both absolute and relative formation attitude control problems. The technique is able to accommodate formations of arbitrarily large number of vehicles. To demonstrate the formation attitude problem, the method is applied to the attitude determination of a simple leader-follower along-track orbit formation. A multiplicative extended Kalman filter is employed to estimate vehicle attitude. In a simulation study using GPS receivers as the attitude sensors, the relative attitude between vehicles in the formation is determined 3 times more accurately than the absolute attitude.

On the generalization of attitude accessibility after repeated attitude expression

PubMed Central

Spruyt, Adriaan; Fazio, Russell H.; Hermans, Dirk

2016-01-01

Abstract The more accessible an attitude is, the stronger is its influence on information processing and behavior. Accessibility can be increased through attitude rehearsal, but it remains unknown whether attitude rehearsal also affects the accessibility of related attitudes. To investigate this hypothesis, participants in an experimental condition repeatedly expressed their attitudes towards exemplars of several semantic categories during an evaluative categorization task. Participants in a control condition performed a non‐evaluative task with the same exemplars and evaluated unrelated attitude objects. After a 30‐minute interval, participants in the experimental condition were faster than controls to evaluate not only the original exemplars but also novel exemplars of the same categories. This finding suggests that the effect of attitude rehearsal on accessibility generalizes to attitudes towards untrained but semantically related attitude objects. © 2016 The Authors. European Journal of Social Psychology published by John Wiley & Sons, Ltd. PMID:28701803

Overview of the Miniature Sensor Technology Integration (MSTI) spacecraft attitude control system

NASA Technical Reports Server (NTRS)

Mcewen, Rob

1994-01-01

Msti2 is a small, 164 kg (362 lb), 3-axis stabilized, low-Earth-orbiting satellite whose mission is missile booster tracking. The spacecraft is actuated by 3 reaction wheels and 12 hot gas thrusters. It carries enough fuel for a projected life of 6 months. The sensor complement consists of a Horizon Sensor, a Sun Sensor, low-rate gyros, and a high rate gyro for despin. The total pointing control error allocation is 6 mRad (.34 Deg), and this is while tracking a target on the Earth's surface. This paper describes the Attitude Control System (ACS) algorithms which include the following: attitude acquisition (despin, Sun and Earth acquisition), attitude determination, attitude control, and linear stability analysis.

Attitude analysis of the Earth Radiation Budget Satellite (ERBS) yaw turn anomaly

NASA Technical Reports Server (NTRS)

Kronenwetter, J.; Phenneger, M.; Weaver, William L.

1988-01-01

The July 2 Earth Radiation Budget Satellite (ERBS) hydrazine thruster-controlled yaw inversion maneuver resulted in a 2.1 deg/sec attitude spin. This mode continued for 150 minutes until the spacecraft was inertially despun using the hydrazine thrusters. The spacecraft remained in a low-rate Y-axis spin of .06 deg/sec for 3 hours until the B-DOT control mode was activated. After 5 hours in this mode, the spacecraft Y-axis was aligned to the orbit normal, and the spacecraft was commanded to the mission mode of attitude control. This work presents the experience of real-time attitude determination support following analysis using the playback telemetry tape recorded for 7 hours from the start of the attitude control anomaly.

Positive thinking elevates tolerance: Experimental effects of happiness on adolescents' attitudes toward asylum seekers.

PubMed

Tenenbaum, Harriet R; Capelos, Tereza; Lorimer, Jessica; Stocks, Thomas

2018-04-01

Inducing emotional reactions toward social groups can influence individuals' political tolerance. This study examines the influence of incidental fear and happiness on adolescents' tolerant attitudes and feelings toward young Muslim asylum seekers. In our experiment, 219 16- to 21-year-olds completed measures of prejudicial attitudes. After being induced to feel happiness, fear, or no emotion (control), participants reported their tolerant attitudes and feelings toward asylum-seeking young people. Participants assigned to the happiness condition demonstrated more tolerant attitudes toward asylum-seeking young people than did those assigned to the fear or control conditions. Participants in the control condition did not differ from participants in the fear condition. The participants in the happiness condition also had more positive feelings toward asylum-seeking young people than did participants in the control condition. The findings suggest that one way to increase positive attitudes toward asylum-seeking young people is to improve general emotional state.

Attributions and Attitudes of Mothers and Fathers in Sweden.

PubMed

Sorbring, Emma; Gurdal, Sevtap

2011-07-01

OBJECTIVE: The present study examined mean level similarities and differences as well as correlations between mothers' and fathers' attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. DESIGN: Interviews were conducted with both mothers and fathers in 77 Swedish families. RESULTS: Fathers reported higher adult-controlled failure and child-controlled failure attributions than did mothers; these differences remained significant after controlling for parents' age, education, and possible social desirability bias. Significant positive correlations were found for mothers' and fathers' progressive attitudes, authoritarian attitudes, and modernity of attitudes after controlling for parents' age, education, and possible social desirability bias. CONCLUSIONS: We conclude that in Sweden fathers are more likely to attribute failures in caregiving situations both to themselves and to children than are mothers and that there is moderate concordance between fathers and mothers within the same family in progressive and authoritarian parenting attitudes.

IMP-J attitude control prelaunch analysis and operations plan

NASA Technical Reports Server (NTRS)

Hooper, H. L.; Mckendrew, J. B.; Repass, G. D.

1973-01-01

A description of the attitude control support being supplied for the Explorer 50 mission is given. Included in the document are descriptions of the computer programs being used to support attitude determination, prediction, and control for the mission and descriptions of the operating procedures that will be used to accomplish mission objectives.

The Relationship of Pupil Control Ideology to Students' Rights Attitudes.

ERIC Educational Resources Information Center

Jones, Lynn

As a result of increased court intervention in favor of students' rights, a review of a sample of teachers concerning their attitudes about student control was examined. Taking into consideration the teachers' attitudes concerning student rights, the Pupil Control Ideology test and the Students' Rights Acceptance Scale were used as measurement…

Spacecraft Hybrid (Mixed-Actuator) Attitude Control Experiences on NASA Science Missions

NASA Technical Reports Server (NTRS)

Dennehy, Cornelius J.

2014-01-01

There is a heightened interest within NASA for the design, development, and flight implementation of mixed-actuator hybrid attitude control systems for science spacecraft that have less than three functional reaction wheel actuators. This interest is driven by a number of recent reaction wheel failures on aging, but what could be still scientifically productive, NASA spacecraft if a successful hybrid attitude control mode can be implemented. Over the years, hybrid (mixed-actuator) control has been employed for contingency attitude control purposes on several NASA science mission spacecraft. This paper provides a historical perspective of NASA's previous engineering work on spacecraft mixed-actuator hybrid control approaches. An update of the current situation will also be provided emphasizing why NASA is now so interested in hybrid control. The results of the NASA Spacecraft Hybrid Attitude Control Workshop, held in April of 2013, will be highlighted. In particular, the lessons learned captured from that workshop will be shared in this paper. An update on the most recent experiences with hybrid control on the Kepler spacecraft will also be provided. This paper will close with some future considerations for hybrid spacecraft control.

An investigation of quasi-inertial attitude control for a solar power satellite

NASA Technical Reports Server (NTRS)

Juang, J.-N.; Wang, S. J.

1982-01-01

An efficient means, a quasi-inertial attitude mode, is developed for maintaining the normal solar orientation of a space satellite for power collection in a synchronous orbit. Formulae are presented which establish the basic parametric properties for ideal quasi-inertial attitude and phasing. An active control system is necessary to compensate for the energy loss since energy dissipation in widely oscillating flexible bodies produces an instability of the quasi-inertial attitude in the sense that the spacecraft will tumble at the orbit rate. A fixed terminal time and state optimal control problem is formulated and an algorithm for determining the optimal control as a means for the periodical attitude and phase compensation is developed. The vehicle orientation affected by internal disturbance (structural flexibility) and external disturbances (e.g., drag forces) is maintained by a specialized controller design.

Perception of Locus of Control as a Predictor of Attitude Toward Students' Evaluation of University Faculty. AIR Forum Paper 1978.

ERIC Educational Resources Information Center

Kohler, Emmett T.; Christal, Melodie E.

Student and faculty attitudes about faculty evaluation and the relationship of the attitudes to the concept of locus of control were investigated. Student respondents consisted of 172 males and 256 females, and 108 faculty responses were received. The measure of locus of control closely resembles the Rotter Internal-External Control Scale. Student…

Comparison of Different Attitude Correction Models for ZY-3 Satellite Imagery

NASA Astrophysics Data System (ADS)

Song, Wenping; Liu, Shijie; Tong, Xiaohua; Niu, Changling; Ye, Zhen; Zhang, Han; Jin, Yanmin

2018-04-01

ZY-3 satellite, launched in 2012, is the first civilian high resolution stereo mapping satellite of China. This paper analyzed the positioning errors of ZY-3 satellite imagery and conducted compensation for geo-position accuracy improvement using different correction models, including attitude quaternion correction, attitude angle offset correction, and attitude angle linear correction. The experimental results revealed that there exist systematic errors with ZY-3 attitude observations and the positioning accuracy can be improved after attitude correction with aid of ground controls. There is no significant difference between the results of attitude quaternion correction method and the attitude angle correction method. However, the attitude angle offset correction model produced steady improvement than the linear correction model when limited ground control points are available for single scene.

A longitudınal study on the effect of tailored training and counseling on the professional attitude of nursing students.

PubMed

Karadağ, Ayise; Hisar, Filiz; Göçmen Baykara, Zehra; Çalışkan, Nurcan; Karabulut, Hatice; Öztürk, Deniz

2015-01-01

The development of professional attitudes in nursing students is influenced by their learning experiences (knowledge, skills, and attitudes) and instructors' professional behaviors. Instructors can enhance students' professional attitude by organizing the training environment, being a role model, and providing counseling. This study was conducted as a tailoring intervention study over 4 years (2010-2013) examining 73 nursing students (34 intervention, 39 control) to determine the effect of training and counseling on nursing students' professional attitudes. Data were collected utilizing the Introductory Characteristics Form and the Instrument of Professional Attitude for Student Nurses. Intervention group students were provided training and counseling complementing their current education to develop their professional attitudes. Controls proceeded with their current education. Instrument for Professional Attitude for Student Nurses posttest scores of the intervention group were significantly higher than those of control group students. Furthermore, intervention group scores on all subscales other than "competence and continuous education" significantly increased after training. Controls showed no growth in professional attitudes, other than in "contribution to scientific knowledge." The training and counseling program had a positive influence on the professional attitudes of nursing students. Thus, providing tailored training and counseling associated to professionalism throughout the educational process at schools providing nursing training is recommended. Copyright © 2015 Elsevier Inc. All rights reserved.

Attitude determination with three-axis accelerometer for emergency atmospheric entry

NASA Technical Reports Server (NTRS)

Garcia-Llama, Eduardo (Inventor)

2012-01-01

Two algorithms are disclosed that, with the use of a 3-axis accelerometer, will be able to determine the angles of attack, sideslip and roll of a capsule-type spacecraft prior to entry (at very high altitudes, where the atmospheric density is still very low) and during entry. The invention relates to emergency situations in which no reliable attitude and attitude rate are available. Provided that the spacecraft would not attempt a guided entry without reliable attitude information, the objective of the entry system in such case would be to attempt a safe ballistic entry. A ballistic entry requires three controlled phases to be executed in sequence: First, cancel initial rates in case the spacecraft is tumbling; second, maneuver the capsule to a heat-shield-forward attitude, preferably to the trim attitude, to counteract the heat rate and heat load build up; and third, impart a ballistic bank or roll rate to null the average lift vector in order to prevent prolonged lift down situations. Being able to know the attitude, hence the attitude rate, will allow the control system (nominal or backup, automatic or manual) to cancel any initial angular rates. Also, since a heat-shield forward attitude and the trim attitude can be specified in terms of the angles of attack and sideslip, being able to determine the current attitude in terms of these angles will allow the control system to maneuver the vehicle to the desired attitude. Finally, being able to determine the roll angle will allow for the control of the roll ballistic rate during entry.

Touchless attitude correction for satellite with constant magnetic moment

NASA Astrophysics Data System (ADS)

Ao, Hou-jun; Yang, Le-ping; Zhu, Yan-wei; Zhang, Yuan-wen; Huang, Huan

2017-09-01

Rescue of satellite with attitude fault is of great value. Satellite with improper injection attitude may lose contact with ground as the antenna points to the wrong direction, or encounter energy problems as solar arrays are not facing the sun. Improper uploaded command may set the attitude out of control, exemplified by Japanese Hitomi spacecraft. In engineering practice, traditional physical contact approaches have been applied, yet with a potential risk of collision and a lack of versatility since the mechanical systems are mission-specific. This paper puts forward a touchless attitude correction approach, in which three satellites are considered, one having constant dipole and two having magnetic coils to control attitude of the first. Particular correction configurations are designed and analyzed to maintain the target's orbit during the attitude correction process. A reference coordinate system is introduced to simplify the control process and avoid the singular value problem of Euler angles. Based on the spherical triangle basic relations, the accurate varying geomagnetic field is considered in the attitude dynamic mode. Sliding mode control method is utilized to design the correction law. Finally, numerical simulation is conducted to verify the theoretical derivation. It can be safely concluded that the no-contact attitude correction approach for the satellite with uniaxial constant magnetic moment is feasible and potentially applicable to on-orbit operations.

Satellite Dynamic Damping via Active Force Control Augmentation

NASA Astrophysics Data System (ADS)

Varatharajoo, Renuganth

2012-07-01

An approach that incorporates the Active Force Control (AFC) technique into a conventional Proportional-Derivative (PD) controller is proposed for a satellite active dynamic damping towards a full attitude control. The AFC method has been established to facilitate a robust motion control of dynamical systems in the presence of disturbances, parametric uncertainties and changes that are commonly prevalent in the real-world environment. The usefulness of the method can be extended by introducing intelligent mechanisms to approximate the mass or inertia matrix of the dynamic system to trigger the compensation effect of the controller. AFC is a technique that relies on the appropriate estimation of the inertial or mass parameters of the dynamic system and the measurements of the acceleration and force signals induced by the system if practical implementation is ever considered. In AFC, it is shown that the system subjected to a number of disturbances remains stable and robust via the compensating action of the control strategy. We demonstrate that it is possible to design a spacecraft attitude feedback controller that will ensure the system dynamics set point remains unchanged even in the presence of the disturbances provided that the actual disturbances can be modeled effectively. In order to further facilitate this analysis, a combined energy and attitude control system (CEACS) is proposed as a model satellite attitude control actuator. All the governing equations are established and the proposed satellite attitude control architecture is made amenable to numerical treatments. The results show that the PD-AFC attitude damping performances are superiorly better than that of the solely PD type. It is also shown that the tunings of the AFC system gains are crucial to ensure a better attitude damping performance and this process is mandatory for AFC systems. Finally, the results demonstrate an important satellite dynamic damping enhancement capability using the AFC technique. Keywords: Satellite, Dynamic Damping, Attitude Control, AFC Technique,

Sensor fault detection and recovery in satellite attitude control

NASA Astrophysics Data System (ADS)

Nasrolahi, Seiied Saeed; Abdollahi, Farzaneh

2018-04-01

This paper proposes an integrated sensor fault detection and recovery for the satellite attitude control system. By introducing a nonlinear observer, the healthy sensor measurements are provided. Considering attitude dynamics and kinematic, a novel observer is developed to detect the fault in angular rate as well as attitude sensors individually or simultaneously. There is no limit on type and configuration of attitude sensors. By designing a state feedback based control signal and Lyapunov stability criterion, the uniformly ultimately boundedness of tracking errors in the presence of sensor faults is guaranteed. Finally, simulation results are presented to illustrate the performance of the integrated scheme.

Autonomous spacecraft attitude control using magnetic torquing only

NASA Technical Reports Server (NTRS)

Musser, Keith L.; Ebert, Ward L.

1989-01-01

Magnetic torquing of spacecraft has been an important mechanism for attitude control since the earliest satellites were launched. Typically a magnetic control system has been used for precession/nutation damping for gravity-gradient stabilized satellites, momentum dumping for systems equipped with reaction wheels, or momentum-axis pointing for spinning and momentum-biased spacecraft. Although within the small satellite community there has always been interest in expensive, light-weight, and low-power attitude control systems, completely magnetic control systems have not been used for autonomous three-axis stabilized spacecraft due to the large computational requirements involved. As increasingly more powerful microprocessors have become available, this has become less of an impediment. These facts have motivated consideration of the all-magnetic attitude control system presented here. The problem of controlling spacecraft attitude using only magnetic torquing is cast into the form of the Linear Quadratic Regulator (LQR), resulting in a linear feedback control law. Since the geomagnetic field along a satellite trajectory is not constant, the system equations are time varying. As a result, the optimal feedback gains are time-varying. Orbit geometry is exploited to treat feedback gains as a function of position rather than time, making feasible the onboard solution of the optimal control problem. In simulations performed to date, the control laws have shown themselves to be fairly robust and a good candidate for an onboard attitude control system.

Negative eating attitudes and behaviors among adolescents: The role of parental control and perceived peer support.

PubMed

Pace, Ugo; D'Urso, Giulio; Zappulla, Carla

2018-02-01

In the present study, we examined from a longitudinal perspective the relationship between parental (both maternal and paternal) psychological control, perceived peer support, and negative eating attitudes and behaviors, focusing on the moderating role that perceived peer support may play in the relationship between parental psychological control in early adolescence and negative eating attitudes and behaviors in late adolescence. In Wave 1, participants were 507 adolescents (249 boys and 258 girls) aged from 14 to 15 years (M = 14.76; SD = 0.63). Three years later (Wave 2), the same adolescents participated again in the study (M = 17.88 years; SD = 0.57). Regression analyses displayed that paternal, but not maternal, achievement-oriented psychological control during early adolescence positively predicted negative eating attitudes and behaviors in late adolescence, whereas perceived peer support negatively predicted negative eating attitudes and behaviors. Results also showed a moderator effect of perceived peer support in the relationship between father's psychological control and negative eating attitudes and behaviors, such that at higher levels of paternal achievement-oriented psychological control, negative eating attitudes and behaviors tended to be higher when perceived peer support was low and to be lower when perceived peer support was high. Copyright © 2017. Published by Elsevier Ltd.

Application Number 3: Using Tethers for Attitude Control

NASA Technical Reports Server (NTRS)

Muller, R. M.

1985-01-01

Past application of the gravity gradient concept to satellite attitude control produced attitude stabilities of from 1 to 10 degrees. The satellite members were rigigly interconnected and any motion in one part of the satellite would cause motion in all members. This experience has restricted gravity gradient stabilization to applications that need attitude stability no better than 1 degree. A gravity gradient technique that combines the flexible tether with an active control that will allow control stability much better than 1 degree is proposed. This could give gravity gradient stabilization much broader application. In fact, for a large structure like a space station, it may become the preferred method. Two possible ways of demonstrating the techniques using the Tethered Satellite System (TSS) tether to control the attitude of the shuttle are proposed. Then a possible space station tether configuration is shown that could be used to control the initial station. It is then shown how the technique can be extended to the control of space stations of virtually any size.

Integrated Attitude Control Strategy for the Asteroid Redirect Mission

NASA Technical Reports Server (NTRS)

Lopez, Pedro, Jr.; Price, Hoppy; San Martin, Miguel

2014-01-01

A deep-space mission has been proposed to redirect an asteroid to a distant retrograde orbit around the moon using a robotic vehicle, the Asteroid Redirect Vehicle (ARV). In this orbit, astronauts will rendezvous with the ARV using the Orion spacecraft. The integrated attitude control concept that Orion will use for approach and docking and for mated operations will be described. Details of the ARV's attitude control system and its associated constraints for redirecting the asteroid to the distant retrograde orbit around the moon will be provided. Once Orion is docked to the ARV, an overall description of the mated stack attitude during all phases of the mission will be presented using a coordinate system that was developed for this mission. Next, the thermal and power constraints of both the ARV and Orion will be discussed as well as how they are used to define the optimal integrated stack attitude. Lastly, the lighting and communications constraints necessary for the crew's extravehicular activity planned to retrieve samples from the asteroid will be examined. Similarly, the joint attitude control strategy that employs both the Orion and the ARV attitude control assets prior, during, and after each extravehicular activity will also be thoroughly discussed.

Design and Stability of an On-Orbit Attitude Control System Using Reaction Control Thrusters

NASA Technical Reports Server (NTRS)

Hall, Robert A.; Hough, Steven; Orphee, Carolina; Clements, Keith

2016-01-01

NASA is providing preliminary design and requirements for the Space Launch System Exploration Upper Stage (EUS). The EUS will provide upper stage capability for vehicle ascent as well as on-orbit control capability. Requirements include performance of on-orbit burn to provide Orion vehicle with escape velocity. On-orbit attitude control is accommodated by a on-off Reaction Control System (RCS). Paper provides overview of approaches for design and stability of an attitude control system using a RCS.

Using constructivist teaching strategies in high school science classrooms to cultivate positive attitudes toward science

NASA Astrophysics Data System (ADS)

Heron, Lory Elen

This study investigated the premise that the use of constructivist teaching strategies (independent variable) in high school science classrooms can cultivate positive attitudes toward science (dependent variable) in high school students. Data regarding the relationship between the use of constructivist strategies and change in student attitude toward science were collected using the Science Attitude Assessment Tool (SAAT) (Heron & Beauchamp, 1996). The format of this study used the pre-test, post-test, control group-experimental group design. The subjects in the study were high school students enrolled in biology, chemistry, or environmental science courses in two high schools in the western United States. Ten teachers and twenty-eight classes, involving a total of 249 students participated in the study. Six experimental group teachers and four control group teachers were each observed an average of six times using the Science Observation Guide (Chapman, 1995) to measure the frequency of observed constructivist behaviors. The mean for the control group teachers was 12.89 and the mean for experimental group teachers was 20.67; F(1, 8) = 16.2, p =.004, revealing teaching behaviors differed significantly between the two groups. After a four month experimental period, the pre-test and post-test SAAT scores were analyzed. Students received a score for their difference in positive attitude toward science. The null hypothesis stating there would be no change in attitude toward science as a subject, between students exposed to constructivist strategies, and students not exposed to constructivist strategies was rejected F(1, 247) = 8.04, p =.005. The control group had a generally higher reported grade in their last science class than the experimental group, yet the control group attitude toward science became more negative (-1.18) while attitude toward science in the experimental group became more positive (+1.34) after the four-month period. An analysis of positive attitude toward science vs. gender was undertaken. An initial significant difference in positive attitude toward science between females and males in the experimental group was established (p =.05). There was no significant difference in positive attitude toward science between those same females and males after the experimental period. Consistent with other results, attitudes toward science for both males and females in the control group became less positive after the study, while males and females in the experimental group had a more positive attitude toward science after four months of using constructivist strategies. Looking at females only, the control group started out with a significantly more positive attitude toward science (mean = 43.40) compared to the experimental group (mean = 39.26, p =.0261). Although a significant difference in positive attitude between females in both groups was not found after the treatment period, the mean attitude score for females in the experimental group increased 2.044, while the mean attitude score for females in the control group decreased by 1.750. Constructivist strategies and their relationship with fostering positive attitudes toward science, might prove a viable solution for addressing the major concern of gender equity and enrollment in higher level science and mathematics courses.

Using Science Activities To Internalize Locus of Control and Influence Attitudes towards Science.

ERIC Educational Resources Information Center

Rowland, Paul McD.

This study investigated the relationships between science activities that emphasize cause-and-effect and a learner's locus of control. Pretests included the Nowicki-Strickland Abbreviated Scale 7-12 to measure locus of control, and a modification of the Test of Science Related Attitudes to measure attitudes toward science. The findings suggest…

AE-C attitude determination and control prelaunch analysis and operations plan

NASA Technical Reports Server (NTRS)

Werking, R. D.; Headrick, R. D.; Manders, C. F.; Woolley, R. D.

1973-01-01

A description of attitude control support being supplied by the Mission and Data Operations Directorate is presented. Included are descriptions of the computer programs being used to support the missions for attitude determination, prediction, and control. In addition, descriptions of the operating procedures which will be used to accomplish mission objectives are provided.

Quaternion-based adaptive output feedback attitude control of spacecraft using Chebyshev neural networks.

PubMed

Zou, An-Min; Dev Kumar, Krishna; Hou, Zeng-Guang

2010-09-01

This paper investigates the problem of output feedback attitude control of an uncertain spacecraft. Two robust adaptive output feedback controllers based on Chebyshev neural networks (CNN) termed adaptive neural networks (NN) controller-I and adaptive NN controller-II are proposed for the attitude tracking control of spacecraft. The four-parameter representations (quaternion) are employed to describe the spacecraft attitude for global representation without singularities. The nonlinear reduced-order observer is used to estimate the derivative of the spacecraft output, and the CNN is introduced to further improve the control performance through approximating the spacecraft attitude motion. The implementation of the basis functions of the CNN used in the proposed controllers depends only on the desired signals, and the smooth robust compensator using the hyperbolic tangent function is employed to counteract the CNN approximation errors and external disturbances. The adaptive NN controller-II can efficiently avoid the over-estimation problem (i.e., the bound of the CNNs output is much larger than that of the approximated unknown function, and hence, the control input may be very large) existing in the adaptive NN controller-I. Both adaptive output feedback controllers using CNN can guarantee that all signals in the resulting closed-loop system are uniformly ultimately bounded. For performance comparisons, the standard adaptive controller using the linear parameterization of spacecraft attitude motion is also developed. Simulation studies are presented to show the advantages of the proposed CNN-based output feedback approach over the standard adaptive output feedback approach.

Attitudes and beliefs as verbal behavior

PubMed Central

Guerin, Bernard

1994-01-01

Attitudes and beliefs are analyzed as verbal behavior. It is argued that shaping by a verbal community is an essential part of the formation and maintenance of both attitudes and beliefs, and it is suggested that verbal communities mediate the important shift in control from events in the environment (attitudes and beliefs as tacts) to control by other words (attitudes and beliefs as intraverbals). It appears that both attitudes and beliefs are constantly being socially negotiated through autoclitic functions. That is, verbal communities reinforce (a) reporting general rather than specific attitudes and beliefs, (b) presentation of intraverbals as if they were tacts, and (c) presentation of beliefs as if they were attitudes. Consistency among and between attitudes, beliefs, and behavior is also contingent upon the reinforcing practices of verbal communities. Thus, attitudes and beliefs can be studied as social behavior rather than as private, cognitive processes. PMID:22478181

Attitude coordination of multi-HUG formation based on multibody system theory

NASA Astrophysics Data System (ADS)

Xue, Dong-yang; Wu, Zhi-liang; Qi, Er-mai; Wang, Yan-hui; Wang, Shu-xin

2017-04-01

Application of multiple hybrid underwater gliders (HUGs) is a promising method for large scale, long-term ocean survey. Attitude coordination has become a requisite for task execution of multi-HUG formation. In this paper, a multibody model is presented for attitude coordination among agents in the HUG formation. The HUG formation is regarded as a multi-rigid body system. The interaction between agents in the formation is described by artificial potential field (APF) approach. Attitude control torque is composed of a conservative torque generated by orientation potential field and a dissipative term related with angular velocity. Dynamic modeling of the multibody system is presented to analyze the dynamic process of the HUG formation. Numerical calculation is carried out to simulate attitude synchronization with two kinds of formation topologies. Results show that attitude synchronization can be fulfilled based on the multibody method described in this paper. It is also indicated that different topologies affect attitude control quality with respect to energy consumption and adjusting time. Low level topology should be adopted during formation control scheme design to achieve a better control effect.

Adaptive attitude control and momentum management for large-angle spacecraft maneuvers

NASA Technical Reports Server (NTRS)

Parlos, Alexander G.; Sunkel, John W.

1992-01-01

The fully coupled equations of motion are systematically linearized around an equilibrium point of a gravity gradient stabilized spacecraft, controlled by momentum exchange devices. These equations are then used for attitude control system design of an early Space Station Freedom flight configuration, demonstrating the errors caused by the improper approximation of the spacecraft dynamics. A full state feedback controller, incorporating gain-scheduled adaptation of the attitude gains, is developed for use during spacecraft on-orbit assembly or operations characterized by significant mass properties variations. The feasibility of the gain adaptation is demonstrated via a Space Station Freedom assembly sequence case study. The attitude controller stability robustness and transient performance during gain adaptation appear satisfactory.

On-orbit experience with the HEAO attitude control subsystem

NASA Technical Reports Server (NTRS)

Hoffman, D. P.; Berkery, E. A.

1978-01-01

The first satellite (HEAO-1) in the High Energy Astronomy Observatory Program series was launched successfully on Aug. 12, 1977. To date it has completed over nine months of orbital operation in a science data gathering mode. During this period all attitude control modes have been exercised and all primary mission objectives have been achieved. This paper highlights the characteristics of the attitude control subsystem design and compares the predicted performance with the actual flight operations experience. Environmental disturbance modeling, component hardware/software characteristics, and overall attitude control performance are reviewed and are found to compare very well with the prelaunch analytical predictions. Brief comments are also included regarding the operations aspects of the attitude control subsystem. The experience in this regard demonstrates the effectiveness of the design flexibility afforded by the presence of a general purpose digital processor in the subsystem flight hardware implementation.

RECOGNIZING FARMERS' ATTITUDES AND IMPLEMENTING NONPOINT SOURCE POLLUTION CONTROL POLICIES

EPA Science Inventory

This report examines the role of farmer attitudes and corresponding communication activities in the implementation of nonpoint source water pollution control programs. The report begins with an examination of the basis for and function of attitudes in influencing behavior. The ro...

Attitude output feedback control for rigid spacecraft with finite-time convergence.

PubMed

Hu, Qinglei; Niu, Guanglin

2017-09-01

The main problem addressed is the quaternion-based attitude stabilization control of rigid spacecraft without angular velocity measurements in the presence of external disturbances and reaction wheel friction as well. As a stepping stone, an angular velocity observer is proposed for the attitude control of a rigid body in the absence of angular velocity measurements. The observer design ensures finite-time convergence of angular velocity state estimation errors irrespective of the control torque or the initial attitude state of the spacecraft. Then, a novel finite-time control law is employed as the controller in which the estimate of the angular velocity is used directly. It is then shown that the observer and the controlled system form a cascaded structure, which allows the application of the finite-time stability theory of cascaded systems to prove the finite-time stability of the closed-loop system. A rigorous analysis of the proposed formulation is provided and numerical simulation studies are presented to help illustrate the effectiveness of the angular-velocity observer for rigid spacecraft attitude control. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Precision Attitude Control for the BETTII Balloon-Borne Interferometer

NASA Technical Reports Server (NTRS)

Benford, Dominic J.; Fixsen, Dale J.; Rinehart. Stephen

2012-01-01

The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-meter baseline far-infrared interferometer to fly on a high altitude balloon. Operating at wavelengths of 30-90 microns, BETTII will obtain spatial and spectral information on science targets at angular resolutions down to less than half an arcsecond, a capability unmatched by other far-infrared facilities. This requires attitude control at a level ofless than a tenth of an arcsecond, a great challenge for a lightweight balloon-borne system. We have designed a precision attitude determination system to provide gondola attitude knowledge at a level of 2 milliarcseconds at rates up to 100Hz, with accurate absolute attitude determination at the half arcsecond level at rates of up to 10Hz. A mUlti-stage control system involving rigid body motion and tip-tilt-piston correction provides precision pointing stability to the level required for the far-infrared instrument to perform its spatial/spectral interferometry in an open-loop control. We present key aspects of the design of the attitude determination and control and its development status.

Magsat attitude dynamics and control: Some observations and explanations

NASA Technical Reports Server (NTRS)

Stengle, T. H.

1980-01-01

Before its reentry 7 months after launch, Magsat transmitted an abundance of valuable data for mapping the Earth's magnetic field. As an added benefit, a wealth of attitude data for study by spacecraft dynamicists was also collected. Because of its unique configuration, Magsat presented new control problems. With its aerodynamic trim boom, attitude control was given an added dimension. Minimization of attitude drift, which could be mapped in relative detail, became the goal. Momentum control, which was accomplished by pitching the spacecraft in order to balance aerodynamic and gravity gradient torques, was seldom difficult to achieve. Several interesting phenomena observed as part of this activity included occasional momentum wheel instability and a rough correlation between solar flux and the pitch angle required to maintain acceptable momentum. An overview is presented of the attitude behavior of Magsat and some of the control problems encountered. Plausible explanations for some of this behavior are offered. Some of the control philosophy used during the mission is examined and aerodynamic trimming operations are summarized.

MSFC Skylab attitude and pointing control system mission evaluation

NASA Technical Reports Server (NTRS)

Chubb, W. B.

1974-01-01

The results of detailed performance analyses of the attitude and pointing control system in-orbit hardware and software on Skylab are reported. Performance is compared with requirements, test results, and prelaunch predictions. A brief history of the altitude and pointing control system evolution leading to the launch configuration is presented. The report states that the attitude and pointing system satisfied all requirements.

The MK VI - A second generation attitude control system

NASA Astrophysics Data System (ADS)

Meredith, P. J.

1986-10-01

The MK VI, a new multipurpose attitude control system for the exoatmospheric attitude control of sounding rocket payloads, is described. The system employs reprogrammable microcomputer memory for storage of basic control logic and for specific mission event control data. The paper includes descriptions of MK VI specifications and configuration; sensor characteristics; the electronic, analog, and digital sections; the pneumatic system; ground equipment; the system operation; and software. A review of the MK VI performance for the Comet Halley flight is presented. Block diagrams are included.

Dynamics and Control of Attitude, Power, and Momentum for a Spacecraft Using Flywheels and Control Moment Gyroscopes

NASA Technical Reports Server (NTRS)

Roithmayr, Carlos M.; Karlgaard, Christopher D.; Kumar, Renjith R.; Seywald, Hans; Bose, David M.

2003-01-01

Several laws are designed for simultaneous control of the orientation of an Earth-pointing spacecraft, the energy stored by counter-rotating flywheels, and the angular momentum of the flywheels and control moment gyroscopes used together as an integrated set of actuators for attitude control. General, nonlinear equations of motion are presented in vector-dyadic form, and used to obtain approximate expressions which are then linearized in preparation for design of control laws that include feedback of flywheel kinetic energy error as a means of compensating for damping exerted by rotor bearings. Two flywheel steering laws are developed such that torque commanded by an attitude control law is achieved while energy is stored or discharged at the required rate. Using the International Space Station as an example, numerical simulations are performed to demonstrate control about a torque equilibrium attitude, and illustrate the benefits of kinetic energy error feedback. Control laws for attitude hold are also developed, and used to show the amount of propellant that can be saved when flywheels assist the CMGs. Nonlinear control laws for large-angle slew maneuvers perform well, but excessive momentum is required to reorient a vehicle like the International Space Station.

Attitudes toward euthanasia and physician-assisted suicide: a study of the multivariate effects of healthcare training, patient characteristics, religion and locus of control.

PubMed

Hains, Carrie-Anne Marie; Hulbert-Williams, Nicholas J

2013-11-01

Public and healthcare professionals differ in their attitudes towards euthanasia and physician-assisted suicide (PAS), the legal status of which is currently in the spotlight in the UK. In addition to medical training and experience, religiosity, locus of control and patient characteristics (eg, patient age, pain levels, number of euthanasia requests) are known influencing factors. Previous research tends toward basic designs reporting on attitudes in the context of just one or two potentially influencing factors; we aimed to test the comparative importance of a larger range of variables in a sample of nursing trainees and non-nursing controls. One hundred and fifty-one undergraduate students (early-stage nursing training, late-stage nursing training and non-nursing controls) were approached on a UK university campus and asked to complete a self-report questionnaire. Participants were of mixed gender and were on average 25.5 years old. No significant differences in attitude were found between nursing and non-nursing students. There was a significant positive correlation between higher religiosity and positive attitude toward euthanasia (r=0.19, p<0.05) and a significant negative relationship between internal locus of control and positive attitude toward PAS (r=-0.263, p<0.01). Multivariate analyses revealed differing predictor models for attitudes towards euthanasia and PAS, and confirm the importance of individual differences in determining these attitudes. The unexpected direction of association between religiosity and attitudes may reflect a broader cultural shift in attitudes since earlier research in this area. Furthermore, these findings suggest it possible that experience, more than training itself, may be a bigger influence on attitudinal differences in healthcare professionals.

Alternative Attitude Commanding and Control for Precise Spacecraft Landing

NASA Technical Reports Server (NTRS)

Singh, Gurkirpal

2004-01-01

A report proposes an alternative method of control for precision landing on a remote planet. In the traditional method, the attitude of a spacecraft is required to track a commanded translational acceleration vector, which is generated at each time step by solving a two-point boundary value problem. No requirement of continuity is imposed on the acceleration. The translational acceleration does not necessarily vary smoothly. Tracking of a non-smooth acceleration causes the vehicle attitude to exhibit undesirable transients and poor pointing stability behavior. In the alternative method, the two-point boundary value problem is not solved at each time step. A smooth reference position profile is computed. The profile is recomputed only when the control errors get sufficiently large. The nominal attitude is still required to track the smooth reference acceleration command. A steering logic is proposed that controls the position and velocity errors about the reference profile by perturbing the attitude slightly about the nominal attitude. The overall pointing behavior is therefore smooth, greatly reducing the degree of pointing instability.

Experimental study on line-of-sight (LOS) attitude control using control moment gyros under micro-gravity environment

NASA Astrophysics Data System (ADS)

Kojima, Hirohisa; Hiraiwa, Kana; Yoshimura, Yasuhiro

2018-02-01

This paper presents the results of line-of-sight (LOS) attitude control using control moment gyros under a micro-gravity environment generated by parabolic flight. The W-Z parameters are used to describe the spacecraft attitude. In order to stabilize the current LOS to the target LOS, backstepping-based feedback control is considered using the W-Z parameters. Numerical simulations and experiments under a micro-gravity environment are carried out, and their results are compared in order to validate the proposed control methods.

A pilot's assessment of helicopter handling-quality factors common to both agility and instrument flying tasks

NASA Technical Reports Server (NTRS)

Gerdes, R. M.

1980-01-01

A series of simulation and flight investigations were undertaken to evaluate helicopter flying qualities and the effects of control system augmentation for nap-of-the-Earth (NOE) agility and instrument flying tasks. Handling quality factors common to both tasks were identified. Precise attitude control was determined to be a key requirement for successful accomplishment of both tasks. Factors that degraded attitude controllability were improper levels of control sensitivity and damping, and rotor system cross coupling due to helicopter angular rate and collective pitch input. Application of rate command, attitude command, and control input decouple augmentation schemes enhanced attitude control and significantly improved handling qualities for both tasks. The NOE agility and instrument flying handling quality considerations, pilot rating philosophy, and supplemental flight evaluations are also discussed.

Velocity-free attitude coordinated tracking control for spacecraft formation flying.

PubMed

Hu, Qinglei; Zhang, Jian; Zhang, Youmin

2018-02-01

This article investigates the velocity-free attitude coordinated tracking control scheme for a group of spacecraft with the assumption that the angular velocities of the formation members are not available in control feedback. Initially, an angular velocity observer is constructed based on each individual's attitude quarternion. Then, the distributed attitude coordinated control law is designed by using the observed states, in which adaptive control method is adopted to handle the external disturbances. Stability of the overall closed-loop system is analyzed theoretically, which shows the system trajectory converges to a small set around origin with fast convergence rate. Numerical simulations are performed to demonstrate fast convergence and improved tracking performance of the proposed control strategy. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

A system for spacecraft attitude control and energy storage

NASA Technical Reports Server (NTRS)

Shaughnessy, J. D.

1974-01-01

A conceptual design for a double-gimbal reaction-wheel energy-wheel device which has three-axis attitude control and electrical energy storage capability is given. A mathematical model for the three-axis gyroscope (TAG) was developed, and a system of multiple units is proposed for attitude control and energy storage for a class of spacecraft. Control laws were derived to provide the required attitude-control torques and energy transfer while minimizing functions of TAG gimbal angles, gimbal rates, reaction-wheel speeds, and energy-wheel speed differences. A control law is also presented for a magnetic torquer desaturation system. A computer simulation of a three-TAG system for an orbiting telescope was used to evaluate the concept. The results of the study indicate that all control and power requirements can be satisfied by using the TAG concept.

Controlled comparison of attitudes of psychiatrists, general practitioners, homosexual doctors and homosexual men to male homosexuality.

PubMed Central

Bhugra, D; King, M

1989-01-01

A controlled analysis of the attitudes of doctors and homosexual men to male homosexuality is reported. Not surprisingly the homosexual men held the most liberal attitudes which served as a yard-stick against which the doctors' attitudes could be assessed. The implications of these data, collected before the AIDS era, are discussed in terms of the current needs of homosexual patients. PMID:2810298

Feedback attitude sliding mode regulation control of spacecraft using arm motion

NASA Astrophysics Data System (ADS)

Shi, Ye; Liang, Bin; Xu, Dong; Wang, Xueqian; Xu, Wenfu

2013-09-01

The problem of spacecraft attitude regulation based on the reaction of arm motion has attracted extensive attentions from both engineering and academic fields. Most of the solutions of the manipulator’s motion tracking problem just achieve asymptotical stabilization performance, so that these controllers cannot realize precise attitude regulation because of the existence of non-holonomic constraints. Thus, sliding mode control algorithms are adopted to stabilize the tracking error with zero transient process. Due to the switching effects of the variable structure controller, once the tracking error reaches the designed hyper-plane, it will be restricted to this plane permanently even with the existence of external disturbances. Thus, precise attitude regulation can be achieved. Furthermore, taking the non-zero initial tracking errors and chattering phenomenon into consideration, saturation functions are used to replace sign functions to smooth the control torques. The relations between the upper bounds of tracking errors and the controller parameters are derived to reveal physical characteristic of the controller. Mathematical models of free-floating space manipulator are established and simulations are conducted in the end. The results show that the spacecraft’s attitude can be regulated to the position as desired by using the proposed algorithm, the steady state error is 0.000 2 rad. In addition, the joint tracking trajectory is smooth, the joint tracking errors converges to zero quickly with a satisfactory continuous joint control input. The proposed research provides a feasible solution for spacecraft attitude regulation by using arm motion, and improves the precision of the spacecraft attitude regulation.

Integrated Power and Attitude Control for a Spacecraft with Flywheels and Control Moment Gyroscopes

NASA Technical Reports Server (NTRS)

Roithmayr, Carlos M.; Karlgaard, Christopher D.; Kumar, Renjith R.; Bose, David M.

2003-01-01

A law is designed for simultaneous control of the orientation of an Earth-pointing spacecraft, the energy stored by counter-rotating flywheels, and the angular momentum of the flywheels and control moment gyroscopes used together as all integrated set of actuators for attitude control. General. nonlinear equations of motion are presented in vector-dyadic form, and used to obtain approximate expressions which are then linearized in preparation for design of control laws that include feedback of flywheel kinetic energy error as it means of compensating for damping exerted by rotor bearings. Two flywheel 'steering laws' are developed such that torque commanded by all attitude control law is achieved while energy is stored or discharged at the required rate. Using the International Space Station as an example, numerical simulations are performed to demonstrate control about a torque equilibrium attitude and illustrate the benefits of kinetic energy error feedback.

Modelling and simulation of Space Station Freedom berthing dynamics and control

NASA Technical Reports Server (NTRS)

Cooper, Paul A.; Garrison, James L., Jr.; Montgomery, Raymond C.; Wu, Shih-Chin; Stockwell, Alan E.; Demeo, Martha E.

1994-01-01

A large-angle, flexible, multibody, dynamic modeling capability has been developed to help validate numerical simulations of the dynamic motion and control forces which occur during berthing of Space Station Freedom to the Shuttle Orbiter in the early assembly flights. This paper outlines the dynamics and control of the station, the attached Shuttle Remote Manipulator System, and the orbiter. The simulation tool developed for the analysis is described and the results of two simulations are presented. The first is a simulated maneuver from a gravity-gradient attitude to a torque equilibrium attitude using the station reaction control jets. The second simulation is the berthing of the station to the orbiter with the station control moment gyros actively maintaining an estimated torque equilibrium attitude. The influence of the elastic dynamic behavior of the station and of the Remote Manipulator System on the attitude control of the station/orbiter system during each maneuver was investigated. The flexibility of the station and the arm were found to have only a minor influence on the attitude control of the system during the maneuvers.

Affectionless control by the same-sex parents increases dysfunctional attitudes about achievement.

PubMed

Otani, Koichi; Suzuki, Akihito; Matsumoto, Yoshihiko; Sadahiro, Ryoichi; Enokido, Masanori

2014-08-01

The affectionless control parenting has been associated with depression in recipients. The aim of this study was to examine the effect of this parenting style on dysfunctional attitudes predisposing to depression. The subjects were 666 Japanese volunteers. Perceived parental rearing was evaluated by the Parental Bonding Instrument, which has the care and protection subscales. Parental rearing was classified into four types, i.e., optimal parenting (high care/low protection), affectionate constraint (high care/high protection), neglectful parenting (low care/low protection), and affectionless control (low care/high protection). Dysfunctional attitudes were evaluated by the 24-item Dysfunctional Attitude Scale, which has the achievement, dependency and self-control subscales. Males with paternal affectionless control had higher achievement scores than those with paternal optimal parenting (P=.016). Similarly, females with maternal affectionless control had higher achievement scores than those with maternal optimal parenting (P=.016). The present study suggests that affectionless control by the same-sex parents increases dysfunctional attitudes about achievement. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Attitude tracking control of flexible spacecraft with large amplitude slosh

NASA Astrophysics Data System (ADS)

Deng, Mingle; Yue, Baozeng

2017-12-01

This paper is focused on attitude tracking control of a spacecraft that is equipped with flexible appendage and partially filled liquid propellant tank. The large amplitude liquid slosh is included by using a moving pulsating ball model that is further improved to estimate the settling location of liquid in microgravity or a zero-g environment. The flexible appendage is modelled as a three-dimensional Bernoulli-Euler beam, and the assumed modal method is employed. A hybrid controller that combines sliding mode control with an adaptive algorithm is designed for spacecraft to perform attitude tracking. The proposed controller has proved to be asymptotically stable. A nonlinear model for the overall coupled system including spacecraft attitude dynamics, liquid slosh, structural vibration and control action is established. Numerical simulation results are presented to show the dynamic behaviors of the coupled system and to verify the effectiveness of the control approach when the spacecraft undergoes the disturbance produced by large amplitude slosh and appendage vibration. Lastly, the designed adaptive algorithm is found to be effective to improve the precision of attitude tracking.

Magnetic attitude control torque generation of a gravity gradient stabilized satellite

NASA Astrophysics Data System (ADS)

Suhadis, N. M.; Salleh, M. B.; Rajendran, P.

2018-05-01

Magnetic torquer is used to generate a magnetic dipole moment onboard satellites whereby a control torque for attitude control purposes is generated when it couples with the geomagnetic field. This technique has been considered very attractive for satellites operated in Low Earth Orbit (LEO) as the strength of the geomagnetic field is relatively high below the altitude of 1000 km. This paper presents the algorithm used to generate required magnetic dipole moment by 3 magnetic torquers mounted onboard a gravity gradient stabilized satellite operated at an altitude of 540 km with nadir pointing mission. As the geomagnetic field cannot be altered and its magnitude and direction vary with respect to the orbit altitude and inclination, a comparison study of attitude control torque generation performance with various orbit inclination is performed where the structured control algorithm is simulated for 13°, 33° and 53° orbit inclinations to see how the variation of the satellite orbit affects the satellite's attitude control torque generation. Results from simulation show that the higher orbit inclination generates optimum magnetic attitude control torque for accurate nadir pointing mission.

Orbit-attitude coupled motion around small bodies: Sun-synchronous orbits with Sun-tracking attitude motion

NASA Astrophysics Data System (ADS)

Kikuchi, Shota; Howell, Kathleen C.; Tsuda, Yuichi; Kawaguchi, Jun'ichiro

2017-11-01

The motion of a spacecraft in proximity to a small body is significantly perturbed due to its irregular gravity field and solar radiation pressure. In such a strongly perturbed environment, the coupling effect of the orbital and attitude motions exerts a large influence that cannot be neglected. However, natural orbit-attitude coupled dynamics around small bodies that are stationary in both orbital and attitude motions have yet to be observed. The present study therefore investigates natural coupled motion that involves both a Sun-synchronous orbit and Sun-tracking attitude motion. This orbit-attitude coupled motion enables a spacecraft to maintain its orbital geometry and attitude state with respect to the Sun without requiring active control. Therefore, the proposed method can reduce the use of an orbit and attitude control system. This paper first presents analytical conditions to achieve Sun-synchronous orbits and Sun-tracking attitude motion. These analytical solutions are then numerically propagated based on non-linear coupled orbit-attitude equations of motion. Consequently, the possibility of implementing Sun-synchronous orbits with Sun-tracking attitude motion is demonstrated.

Attitude towards littering as a mediator of the relationship between personality attributes and responsible environmental behavior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ojedokun, Oluyinka, E-mail: yinkaoje2004@yahoo.com

Highlights: > Independently, altruism and locus of control contributed significantly toward attitude towards littering. > Altruism and locus of control jointly contributed significantly to attitude towards littering. > The results further show a significant joint influence of altruism and locus of control on REB. > The independent contributions reveal that altruism and locus of control contribute significantly to REB. > Attitude towards littering mediates the relationship between locus of control and REB. - Abstract: The study tested whether attitude towards littering mediates the relationship between personality attributes (altruism and locus of control) and responsible environmental behavior (REB) among some residentsmore » of Ibadan metropolis, Nigeria. Using multistage sampling technique, measures of each construct were administered to 1360 participants. Results reveal significant independent and joint influence of personality attributes on attitude towards littering and responsible environmental behavior, respectively. Attitude towards littering also mediates the relationship between personality characteristics and REB. These findings imply that individuals who possess certain desirable personality characteristics and who have unfavorable attitude towards littering have more tendencies to engage in pro-environmental behavior. Therefore, stakeholders who have waste management as their priority should incorporate this information when guidelines for public education and litter prevention programs are being developed. It is suggested that psychologists should be involved in designing of litter prevention strategies. This will ensure the inclusion of behavioral issues in such strategies. An integrated approach to litter prevention that combines empowerment, cognitive, social, and technical solutions is recommended as the most effective tool of tackling the litter problem among residents of Ibadan metropolis.« less

Multiple Model Adaptive Attitude Control of LEO Satellite with Angular Velocity Constraints

NASA Astrophysics Data System (ADS)

Shahrooei, Abolfazl; Kazemi, Mohammad Hosein

2018-04-01

In this paper, the multiple model adaptive control is utilized to improve the transient response of attitude control system for a rigid spacecraft. An adaptive output feedback control law is proposed for attitude control under angular velocity constraints and its almost global asymptotic stability is proved. The multiple model adaptive control approach is employed to counteract large uncertainty in parameter space of the inertia matrix. The nonlinear dynamics of a low earth orbit satellite is simulated and the proposed control algorithm is implemented. The reported results show the effectiveness of the suggested scheme.

Space station systems technology study (add-on task). Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1985-01-01

System concepts were characterized in order to define cost versus benefits for autonomous functional control and for controls and displays for OMV, OTV, and spacecraft servicing and operation. The attitude control topic focused on characterizing the Space Station attitude control problem through simulation of control system responses to structural disturbances. The first two topics, mentioned above, focused on specific technology items that require advancement in order to support an early 1990s initial launch of a Space Station, while the attitude control study was an exploration of the capability of conventional controller techniques.

A Flight Control Approach for Small Reentry Vehicles

NASA Technical Reports Server (NTRS)

Bevacqoa, Tim; Adams, Tony; Zhu. J. Jim; Rao, P. Prabhakara

2004-01-01

Flight control of small crew return vehicles during atmospheric reentry will be an important technology in any human space flight mission undertaken in the future. The control system presented in this paper is applicable to small crew return vehicles in which reaction control system (RCS) thrusters are the only actuators available for attitude control. The control system consists of two modules: (i) the attitude controller using the trajectory linearization control (TLC) technique, and (ii) the reaction control system (RCS) control allocation module using a dynamic table-lookup technique. This paper describes the design and implementation of the TLC attitude control and the dynamic table-lookup RCS control allocation for nonimal flight along with design verification test results.

Mariner Mars 1971 attitude control subsystem flight performance

NASA Technical Reports Server (NTRS)

Schumacher, L.

1973-01-01

The flight performance of the Mariner 71 attitude control subsystem is discussed. Each phase of the mission is delineated and the attitude control subsystem is evaluated within the observed operational environment. Performance anomalies are introduced and discussed within the context of general performance. Problems such as the sun sensor interface incompatibility, gas valve leaks, and scan platform dynamic coupling effects are given analytical considerations.

Casual hook up sex during the first year of college: Prospective associations with attitudes about sex and love relationships.

PubMed

Katz, Jennifer; Schneider, Monica E

2013-11-01

This study examined bidirectional relationships among emerging adults' involvement in casual hook up sex and attitudes about sex and love relationships. At the start and end of their first year in college, undergraduates (N = 163) responded to measures of sexual behavior, sexual attitudes, and attitudes about love relationships. In cross-sectional analyses, attitudes about sex and love both were associated with involvement in casual hook up sex. In prospective analyses, initial attitudes about sexual instrumentality uniquely predicted involvement in later hook up sex, even after controlling for past hook up sex. Furthermore, involvement in hook up sex during the first year of college predicted greater sexual permissiveness and comfort with casual genital contact, even after controlling for initial sexual attitudes and hook up behaviors. None of the associations between attitudes and behavior were qualified by gender. Experiences of causal hook up sex appear to have implications primarily for emerging adults' attitudes about sexual interactions rather than their attitudes about love relationships.

Using the implicit relational assessment procedure to compare implicit pro-thin/anti-fat attitudes of patients with anorexia nervosa and non-clinical controls.

PubMed

Parling, Thomas; Cernvall, Martin; Stewart, Ian; Barnes-Holmes, Dermot; Ghaderi, Ata

2012-01-01

Implicit pro-thin/anti-fat attitudes were investigated among a mixed group of patients with full and sub-threshold Anorexia Nervosa (n = 17), and a matched-age control group (n = 17). The Implicit Relational Assessment Procedure (IRAP) was employed to measure implicit pro-thin and anti-fat attitudes towards Self and Others in addition to "striving for thinness" and "avoidance of fatness." The clinical group showed an implicit pro-fat attitude towards Others and stronger anti-fat attitudes towards Self and avoidance of fatness compared with controls. The findings are discussed in relation to the over-evaluation of weight and shape in the clinical group.

Nudging Resisters Toward Change: Self-Persuasion Interventions for Reducing Attitude Certainty.

PubMed

Greenberg, Spencer; Brand, Danielle; Pluta, Aislinn; Moore, Douglas; DeConti, Kirsten

2018-05-01

To identify effective self-persuasion protocols that could easily be adapted to face-to-face clinical sessions or health-related computer applications as a first step in breaking patient resistance. Two self-persuasion interventions were tested against 2 controls in a between-subject randomized control experiment. GuidedTrack-a web-based platform for social science experiments. Six hundred seventeen adult participants recruited via Mechanical Turk. The experimental interventions prompted participants for self-referenced pro- and counterattitudinal arguments to elicit attitude-related thought (ART) and subsequent doubt about the attitude. The hypothesis was that the self-persuasion interventions would elicit larger and more frequent attitude certainty decreases than the controls. In the experimental groups, we also predicted a correlation between the amount of ART and attitude certainty decreases. Changes in attitude certainty were measured by participants' pre- and post-ratio scale ratings; ART was measured by the number of words participants used to respond to the interventions. Analysis of variance (ANOVA), χ 2 , and correlation. A goodness-of-fit χ 2 showed that the number of participants who decreased their attitude certainty was not equally distributed between the combined experimental groups (n = 104) and the combined control groups (n = 39), χ 2 (1, n = 143) = 28.64, P < .001. Within each intervention, goodness-of-fit χ 2 with a Bonferroni correction ( P = .01 or .05/4) indicated there were significantly more "decreasers" than "increasers" in intervention 1, χ 2 (1, n = 86) = 6.16, P = .01, but not intervention 2, χ 2 (1, n = 84) = 2.02, P = .16, the nonsense control, χ 2 (1, n = 42) = .22, P = .64), or the distraction control, χ 2 (1, n = 34) = .02, P = .89. A 1-way ANOVA revealed a significant main effect for intervention on mean certainty change ( F 3,613 = 4.62, P = .003). Five post hoc comparisons using Tukey's honest significant difference (HSD) test indicated that the mean decrease in attitude certainty resulting from intervention 1 (M = -3.29) was significantly larger than the mean decrease in attitude certainty resulting from the nonsense control (M = -0.62, t = -2.72, P = .03), the distraction control (M = 0.11, t = 3.48, P = .003), but not intervention 2 (M = -0.87, t = -2.54, P = .06). Attitude-related thought was significantly correlated with attitude certainty change in intervention 1, r(158) = -.17, t = -4.28, P = .02, but not intervention 2, r(161) = -.002, t = -.03, P = .98. The implication for clinical practitioners and designers of health applications is that it may be worthwhile to let patients elaborate on their personal reasons for initially forming an unhealthy attitude to increase doubt about the strongly held attitude.

Gun Attitudes and Fear of Crime.

ERIC Educational Resources Information Center

Heath, Linda; Weeks, Kyle; Murphy, Marie Mackay

1997-01-01

Using three studies, examined the relationship between attitudes toward guns and fear of crime. Findings indicate a connection between fear of crime and attitudes toward guns: people higher in fear of crime favored gun control. Results also established a relationship between stereotypical beliefs about gun victims and support for gun control. (RJM)

Students' Attitudes towards Control Methods in Computer-Assisted Instruction.

ERIC Educational Resources Information Center

Hintze, Hanne; And Others

1988-01-01

Describes study designed to investigate dental students' attitudes toward computer-assisted teaching as applied in programs for oral radiology in Denmark. Programs using personal computers and slide projectors with varying degrees of learner and teacher control are described, and differences in attitudes between male and female students are…

Design, dynamics and control of an Adaptive Singularity-Free Control Moment Gyroscope actuator for microspacecraft Attitude Determination and Control System

NASA Astrophysics Data System (ADS)

Viswanathan, Sasi Prabhakaran

Design, dynamics, control and implementation of a novel spacecraft attitude control actuator called the "Adaptive Singularity-free Control Moment Gyroscope" (ASCMG) is presented in this dissertation. In order to construct a comprehensive attitude dynamics model of a spacecraft with internal actuators, the dynamics of a spacecraft with an ASCMG, is obtained in the framework of geometric mechanics using the principles of variational mechanics. The resulting dynamics is general and complete model, as it relaxes the simplifying assumptions made in prior literature on Control Moment Gyroscopes (CMGs) and it also addresses the adaptive parameters in the dynamics formulation. The simplifying assumptions include perfect axisymmetry of the rotor and gimbal structures, perfect alignment of the centers of mass of the gimbal and the rotor etc. These set of simplifying assumptions imposed on the design and dynamics of CMGs leads to adverse effects on their performance and results in high manufacturing cost. The dynamics so obtained shows the complex nonlinear coupling between the internal degrees of freedom associated with an ASCMG and the spacecraft bus's attitude motion. By default, the general ASCMG cluster can function as a Variable Speed Control Moment Gyroscope, and reduced to function in CMG mode by spinning the rotor at constant speed, and it is shown that even when operated in CMG mode, the cluster can be free from kinematic singularities. This dynamics model is then extended to include the effects of multiple ASCMGs placed in the spacecraft bus, and sufficient conditions for non-singular ASCMG cluster configurations are obtained to operate the cluster both in VSCMG and CMG modes. The general dynamics model of the ASCMG is then reduced to that of conventional VSCMGs and CMGs by imposing the standard set of simplifying assumptions used in prior literature. The adverse effects of the simplifying assumptions that lead to the complexities in conventional CMG design, and how they lead to CMG singularities, are described. General ideas on control of the angular momentum of the spacecraft using changes in the momentum variables of a finite number of ASCMGs, are provided. Control schemes for agile and precise attitude maneuvers using ASCMG cluster in the absence of external torques and when the total angular momentum of the spacecraft is zero, is presented for both constant speed and variable speed modes. A Geometric Variational Integrator (GVI) that preserves the geometry of the state space and the conserved norm of the total angular momentum is constructed for numerical simulation and microcontroller implementation of the control scheme. The GVI is obtained by discretizing the Lagrangian of the rnultibody systems, in which the rigid body attitude is globally represented on the Lie group of rigid body rotations. Hardware and software architecture of a novel spacecraft Attitude Determination and Control System (ADCS) based on commercial smartphones and a bare minimum hardware prototype of an ASCMG using low cost COTS components is also described. A lightweight, dynamics model-free Variational Attitude Estimator (VAE) suitable for smartphone implementation is employed for attitude determination and the attitude control is performed by ASCMG actuators. The VAE scheme presented here is implemented and validated onboard an Unmanned Aerial Vehicle (UAV) platform and the real time performance is analyzed. On-board sensing, data acquisition, data uplink/downlink, state estimation and real-time feedback control objectives can be performed using this novel spacecraft ADCS. The mechatronics realization of the attitude determination through variational attitude estimation scheme and control implementation using ASCMG actuators are presented here. Experimental results of the attitude estimation (filtering) scheme using smartphone sensors as an Inertial Measurement Unit (IMU) on the Hardware In the Loop (HIL) simulator testbed are given. These results, obtained in the Spacecraft Guidance, Navigation and Control Laboratory at New Mexico State University, demonstrate the performance of this estimation scheme with the noisy raw data from the smartphone sensors. Keywords: Spacecraft, momentum exchange devices, control moment gyroscope, variational mechanics, geometric mechanics, variational integrators, attitude determination, attitude control, ADCS, estimation, ASCMG, VSCMG, cubesat, mechatronics, smartphone, Android, MEMS sensor, embedded programming, microcontroller, brushless DC drives, HIL simulation.

Review of Research On Guidance for Recovery from Pitch Axis Upsets

NASA Technical Reports Server (NTRS)

Harrison, Stephanie J.

2016-01-01

A literature review was conducted to identify past efforts in providing control guidance for aircraft upset recovery including stall recovery. Because guidance is integrally linked to the intended function of aircraft attitude awareness and upset recognition, it is difficult, if not impossible, to consider these issues separately. This literature review covered the aspects of instrumentation and display symbologies for attitude awareness, aircraft upset recognition, upset and stall alerting, and control guidance. Many different forms of symbology have been investigated including, but not limited to, pitch scale depictions, attitude indicator icons, horizon symbology, attitude recovery arrows, and pitch trim indicators. Past research on different visual and alerting strategies that provide advisories, cautions, and warnings to pilots before entering an unusual attitude (UA) are also discussed. Finally, potential control guidance for recovery from upset or unusual attitudes, including approach-to-stall and stall conditions, are reviewed. Recommendations for future research are made.

ATTITUDES TOWARD SUICIDE: THE EFFECT OF SUICIDE DEATH IN THE FAMILY*

PubMed Central

Zhang, Jie; Jia, Cun-Xian

2011-01-01

There have been few reports on the effect of suicide death on family members’ attitudes toward suicide. In order to estimate the extent to which suicide death affects attitudes toward suicide among family members of suicides, data of 264 informants from a case-control psychological autopsy study were analyzed. The results showed that there were no significant differences in attitudes toward suicide, measured by the General Social Survey’s (GSS) four questions, between informants of suicides and informants of living controls, between family members of suicides and family members of living controls, or between family members of suicides and non-family members of suicides. Our findings did not support the hypothesis that suicide death affects the attitudes toward suicide in suicides’ family members. However, some factors were found to be related to the pro-suicide attitudes measured by the four questions included in the GSS. PMID:20397616

Attitudes toward menstruation in females with schizophrenia or schizoaffective disorders in Taiwan.

PubMed

Liang, H-Y; Lee, L-W; Kelsen, B A; Hsu, S-C; Liu, C-Y; Chen, C-Y

2013-12-01

The aims of this cross-sectional, case-controlled, observational study were to examine attitudes toward menstruation in female patients with schizophrenia or schizoaffective disorder and in a control group, and to explore the associations between attitudes toward menstruation and psychopathology, menstrual regularity during antipsychotic treatment, and menstrual distress symptoms. Fifty-eight patients treated with anti-psychotic medications for at least the previous 6 months were placed in irregular (irregular menstrual cycle) (n = 31) and regular (regular menstrual cycle) (n = 27) groups. Sixty-two, age-matched, healthy female participants with regular menstrual cycles were enrolled as a control group. Psychopathology was assessed by psychiatrists using the Positive and Negative Syndrome Scale (PANSS). The Menstrual Attitude Questionnaire (MAQ) was used to assess attitudes toward menstruation, and symptom checklists based on the Moos Menstruation Distress Questionnaire (MMDQ) were used to assess menstrual distress symptoms. Patients with psychotic disorders (both irregular and regular groups) had more negative attitudes toward menstruation than the control group. In the Schizophrenia group, there was no association between the severity of psychotic symptoms and their influence on attitudes toward menstruation. Moreover, regular menstrual cycles during antipsychotic treatment and fewer menstrual distress symptoms were the two main predictors for more positive attitudes toward menstruation in the patient group. This is one of the first studies to explore the relationship between psychotic symptoms and attitudes toward menstruation. The findings provide more support for the assumption that attitudes toward menstruation are derived from a woman's perception of her bodily experience rather than a psychiatric disorder.

Model predictive and reallocation problem for CubeSat fault recovery and attitude control

NASA Astrophysics Data System (ADS)

Franchi, Loris; Feruglio, Lorenzo; Mozzillo, Raffaele; Corpino, Sabrina

2018-01-01

In recent years, thanks to the increase of the know-how on machine-learning techniques and the advance of the computational capabilities of on-board processing, expensive computing algorithms, such as Model Predictive Control, have begun to spread in space applications even on small on-board processor. The paper presents an algorithm for an optimal fault recovery of a 3U CubeSat, developed in MathWorks Matlab & Simulink environment. This algorithm involves optimization techniques aiming at obtaining the optimal recovery solution, and involves a Model Predictive Control approach for the attitude control. The simulated system is a CubeSat in Low Earth Orbit: the attitude control is performed with three magnetic torquers and a single reaction wheel. The simulation neglects the errors in the attitude determination of the satellite, and focuses on the recovery approach and control method. The optimal recovery approach takes advantage of the properties of magnetic actuation, which gives the possibility of the redistribution of the control action when a fault occurs on a single magnetic torquer, even in absence of redundant actuators. In addition, the paper presents the results of the implementation of Model Predictive approach to control the attitude of the satellite.

A pilot's assessment of helicopter handling-quality factors common to both agility and instrument flying tasks

NASA Technical Reports Server (NTRS)

Gerdes, R. M.

1980-01-01

Results from a series of simulation and flight investigations undertaken to evaluate helicopter flying qualities and the effects of control system augmentation for nap-of-the-earth (NOE) agility and instrument flying tasks were analyzed to assess handling-quality factors common to both tasks. Precise attitude control was determined to be a key requirement for successful accomplishment of both tasks. Factors that degraded attitude controllability were improper levels of control sensitivity and damping and rotor-system cross-coupling due to helicopter angular rate and collective pitch input. Application of rate-command, attitude-command, and control-input decouple augmentation schemes enhanced attitude control and significantly improved handling qualities for both tasks. NOE agility and instrument flying handling-quality considerations, pilot rating philosophy, and supplemental flight evaluations are also discussed.

Low drag attitude control for Skylab orbital lifetime extension

NASA Technical Reports Server (NTRS)

Glaese, J. R.; Kennel, H. F.

1981-01-01

In the fall of 1977 it was determined that Skylab had started to tumble and that the original orbit lifetime predictions were much too optimistic. A decision had to be made whether to accept an early uncontrolled reentry with its inherent risks or try to attempt to control Skylab to a lower drag attitude in the hope that there was enough time to develop a Teleoperator Retrieval System, bring it up on the Space Shuttle and then decide whether to boost Skylab to a higher longer life orbit or to reenter it in a controlled fashion. The end-on-velocity (EOVV) control method is documented, which was successfully applied for about half a year to keep Skylab in a low drag attitude with the aid of the control moment gyros and a minimal expenditure of attitude control gas.

Interior and exterior ballistics coupled optimization with constraints of attitude control and mechanical-thermal conditions

NASA Astrophysics Data System (ADS)

Liang, Xin-xin; Zhang, Nai-min; Zhang, Yan

2016-07-01

For solid launch vehicle performance promotion, a modeling method of interior and exterior ballistics associated optimization with constraints of attitude control and mechanical-thermal condition is proposed. Firstly, the interior and external ballistic models of the solid launch vehicle are established, and the attitude control model of the high wind area and the stage of the separation is presented, and the load calculation model of the drag reduction device is presented, and thermal condition calculation model of flight is presented. Secondly, the optimization model is established to optimize the range, which has internal and external ballistic design parameters as variables selected by sensitivity analysis, and has attitude control and mechanical-thermal conditions as constraints. Finally, the method is applied to the optimal design of a three stage solid launch vehicle simulation with differential evolution algorithm. Simulation results are shown that range capability is improved by 10.8%, and both attitude control and mechanical-thermal conditions are satisfied.

Research on Robot Pose Control Technology Based on Kinematics Analysis Model

NASA Astrophysics Data System (ADS)

Liu, Dalong; Xu, Lijuan

2018-01-01

In order to improve the attitude stability of the robot, proposes an attitude control method of robot based on kinematics analysis model, solve the robot walking posture transformation, grasping and controlling the motion planning problem of robot kinematics. In Cartesian space analytical model, using three axis accelerometer, magnetometer and the three axis gyroscope for the combination of attitude measurement, the gyroscope data from Calman filter, using the four element method for robot attitude angle, according to the centroid of the moving parts of the robot corresponding to obtain stability inertia parameters, using random sampling RRT motion planning method, accurate operation to any position control of space robot, to ensure the end effector along a prescribed trajectory the implementation of attitude control. The accurate positioning of the experiment is taken using MT-R robot as the research object, the test robot. The simulation results show that the proposed method has better robustness, and higher positioning accuracy, and it improves the reliability and safety of robot operation.

Solar Sail Attitude Control Performance Comparison

NASA Technical Reports Server (NTRS)

Bladt, Jeff J.; Lawrence, Dale A.

2005-01-01

Performance of two solar sail attitude control implementations is evaluated. One implementation employs four articulated reflective vanes located at the periphery of the sail assembly to generate control torque about all three axes. A second attitude control configuration uses mass on a gimbaled boom to alter the center-of-mass location relative to the center-of-pressure producing roll and pitch torque along with a pair of articulated control vanes for yaw control. Command generation algorithms employ linearized dynamics with a feedback inversion loop to map desired vehicle attitude control torque into vane and/or gimbal articulation angle commands. We investigate the impact on actuator deflection angle behavior due to variations in how the Jacobian matrix is incorporated into the feedback inversion loop. Additionally, we compare how well each implementation tracks a commanded thrust profile, which has been generated to follow an orbit trajectory from the sun-earth L1 point to a sub-L1 station.

Psychological mechanisms underlying doping attitudes in sport: motivation and moral disengagement.

PubMed

Hodge, Ken; Hargreaves, Elaine A; Gerrard, David; Lonsdale, Chris

2013-08-01

We examined whether constructs outlined in self-determination theory (Deci & Ryan, 2002), namely, autonomy-supportive and controlling motivational climates and autonomous and controlled motivation, were related to attitudes toward performance-enhancing drugs (PEDs) in sport and drug-taking susceptibility. We also investigated moral disengagement as a potential mediator. We surveyed a sample of 224 competitive athletes (59% female; M age = 20.3 years; M = 10.2 years of experience participating in their sport), including 81 elite athletes. Using structural equation modeling analyses, our hypothesis proposing positive relationships with controlling climates, controlled motivation, and PEDs attitudes and susceptibility was largely supported, whereas our hypothesis proposing negative relationships among autonomous climate, autonomous motivation, and PEDs attitudes and susceptibility was not supported. Moral disengagement was a strong predictor of positive attitudes toward PEDs, which, in turn, was a strong predictor of PEDs susceptibility. These findings are discussed from both motivational and moral disengagement viewpoints.

Adaptive control applied to Space Station attitude control system

NASA Technical Reports Server (NTRS)

Lam, Quang M.; Chipman, Richard; Hu, Tsay-Hsin G.; Holmes, Eric B.; Sunkel, John

1992-01-01

This paper presents an adaptive control approach to enhance the performance of current attitude control system used by the Space Station Freedom. The proposed control law was developed based on the direct adaptive control or model reference adaptive control scheme. Performance comparisons, subject to inertia variation, of the adaptive controller and the fixed-gain linear quadratic regulator currently implemented for the Space Station are conducted. Both the fixed-gain and the adaptive gain controllers are able to maintain the Station stability for inertia variations of up to 35 percent. However, when a 50 percent inertia variation is applied to the Station, only the adaptive controller is able to maintain the Station attitude.

LQG/LTR Optimal Attitude Control of Small Flexible Spacecraft Using Free-Free Boundary Conditions

DTIC Science & Technology

2006-08-03

particular on attitude control of flex- ible space structures. Croopnick et al .[50] present a literature survey in the areas of attitude control...modeling and control of space structures is compiled by Nurre et al .[161]. One important thing to note from the surveys listed above is the 21 focus on the...papers surveyed by Croopnick et al . in 1979, by Meirovitch in 1979, Balas in 1982, and Nurre et al . in 1984. The focus of the papers included in all

A preliminary 6 DOF attitude and translation control system design for Starprobe

NASA Technical Reports Server (NTRS)

Mak, P.; Mettler, E.; Vijayarahgavan, A.

1981-01-01

The extreme thermal environment near perihelion and the high-accuracy gravitational science experiments impose unique design requirements on various subsystems of Starprobe. This paper examines some of these requirements and their impact on the preliminary design of a six-degree-of-freedom attitude and translational control system. Attention is given to design considerations, the baseline attitude/translational control system, system modeling, and simulation studies.

Attitude Control of Nanosatellites by Paddle Motion Using Elastic Hinges Actuated by Shape Memory Alloy

NASA Astrophysics Data System (ADS)

Iai, Masafumi; Durali, Mohammad; Hatsuzawa, Takeshi

Recent research has been extending the applications of small satellites called microsatellites, nanosatellites, or picosatellites. To further improve capability of those satellites, a lightweight, active attitude-control mechanism is needed. This paper proposes a concept of inertial orientation control, an attitude control method using movable solar arrays. This method is made suitable for nanosatellites by the use of shape memory alloy (SMA)-actuated elastic hinges and a simple maneuver generation algorithm. The combination of SMA and an elastic hinge allows the hinge to remain lightweight and free of frictional or rolling contacts. Changes in the shrinking and stretching speeds of the SMA were measured in a vacuum chamber. The proposed algorithm constructs a maneuver to achieve arbitrary attitude change by repeating simple maneuvers called unit maneuvers. Provided with three types of unit maneuvers, each degree of freedom of the satellite can be controlled independently. Such construction requires only simple calculations, making it a practical algorithm for a nanosatellite with limited computational capability. In addition, power generation variation caused by maneuvers was analyzed to confirm that a maneuver from any initial attitude to an attitude facing the sun was justifiable in terms of the power budget.

Stabilization of a programmed rotation mode for a satellite with electrodynamic attitude control system

NASA Astrophysics Data System (ADS)

Aleksandrov, A. Yu.; Aleksandrova, E. B.; Tikhonov, A. A.

2018-07-01

The paper deals with a dynamically symmetric satellite in a circular near-Earth orbit. The satellite is equipped with an electrodynamic attitude control system based on Lorentz and magnetic torque properties. The programmed satellite attitude motion is such that the satellite slowly rotates around the axis of its dynamical symmetry. Unlike previous publications, we consider more complex and practically more important case where the axis is fixed in the orbital frame in an inclined position with respect to the local vertical axis. The satellite stabilization in the programmed attitude motion is studied. The gravitational disturbing torque acting on the satellite attitude dynamics is taken into account since it is the largest disturbing torque. The novelty of the proposed approach is based on the usage of electrodynamic attitude control system. With the aid of original construction of a Lyapunov function, new conditions under which electrodynamic control solves the problem are obtained. Sufficient conditions for asymptotic stability of the programmed motion are found in terms of inequalities for the values of control parameters. The results of a numerical simulation are presented to demonstrate the effectiveness of the proposed approach.

Hubble Space Telescope Magnetometer and Two-Gyro Control Law Design, Implementation, and On-Orbit Performance. Part 1

NASA Technical Reports Server (NTRS)

Wirzburger, John H.

2005-01-01

For f i h years, the science mission of the Hubble Space Telescope (HST) required using at least three of six rate gyros for attitude control. In the past, HST has mitigated gyro hardware failures by replacement of the failed units through Space Shuttle Servicing Missions. Following the tragic loss of Space Shuttle Columbia on STS-107, the desire to have a safe haven for astronauts during missions has resulted in the cancellation of all planned maxu14 missions to HST. While a robotic servicing mission is being currently being planned, controlling with alternate sensors to replace failed gyros can extend the HST Science mission until the robotic mission can be performed and extend science at HST s end of life. A two-gym control law has been designed and implemented using magnetometers (Magnetic Sensing System - MSS), fixed head star trackers (FHSTs), and Fine Guidance Sensors (FGSs) to control vehicle rate about the missing gyro axis. The three aforementioned sensors are used in succession to reduce HST boresight jitter to less than 7 milli-arcseconds rms and attitude error to less than 10 milli-arcseconds prior to science imaging. The MSS and 2-Gyro (M2G) control law is used for large angle maneuvers and attitude control during earth occultation of FHSTs and FGSs. The Tracker and 2-Gyro (T2G) control law dampens M2G rates and corrects the majority of attitude error in preparation for guide star acquisition with the FGSs. The Fine Guidance Sensor and 2-Gyro (F2G) control law d a m p T2G rates and controls HST attitude during science imaging. This paper describes the M2G control law. Details of M2G algorithms are presented, including computation of the HST 3-axis attitude error estimate, design of the M2G control law, SISO hear stability analyses, and restrictions on operations to maintain the h d t h and safety requirement of a 10degree maximum attitude error. Results of simulations performed in HSTSIM, a high-fidelity non-linear time domain simulation, are presented to predict HST on-orbit performance in attitude hold and maneuver modes. Simulation results are compared to on-orbit data from M2G flight tests performed in November and December 2004 and February 2005. Flight telemetry, using a currently available third gyro, shows that HST attitude error with the new M2G control law is maintained below the 10-degree requirement, and attitude errors are under 2 degrees for 95% of the time.

The role of tobacco-specific media exposure, knowledge, and smoking status on selected attitudes toward tobacco control.

PubMed

Blake, Kelly D; Viswanath, K; Blendon, Robert J; Vallone, Donna

2010-02-01

In August 2007, the President's Cancer Panel urged the leadership of the nation to "summon the political will to address the public health crisis caused by tobacco use" (President's Cancer Panel, N, 2007, Promoting healthy lifestyles: Policy, program, and personal recommendations for reducing cancer risk. http://deainfo.nci.nih.gov/advisory/pcp/pcp07rpt/pcp07rpt.pdf). While some research has examined predictors of public support for tobacco control measures, little research has examined modifiable factors that may influence public attitudes toward tobacco control. We used the American Legacy Foundation's 2003 American Smoking and Health Survey 2 to examine the contribution of smoking status, knowledge of the negative effects of tobacco, and tobacco-specific media exposure (antitobacco messages, news coverage of tobacco issues, and protobacco advertising) on U.S. adults' attitudes toward tobacco control. In addition, we assessed whether smoking status moderates the relationship between tobacco-specific media exposure and policy attitudes. Weighted multivariable logistic regression models were employed. Results suggest that knowledge of the negative effects of tobacco and smoking status are associated with attitudes toward tobacco control and that exposure to tobacco-specific information in the media plays a role only in some instances. We found no evidence of effect modification by smoking status on the impact of exposure to tobacco-specific media on attitudes toward tobacco control. Understanding the impact of readily modifiable factors that shape policy attitudes is essential if we are to target outreach and education in a way that is likely to sway public support for tobacco control.

Decentralized finite-time attitude synchronization for multiple rigid spacecraft via a novel disturbance observer.

PubMed

Zong, Qun; Shao, Shikai

2016-11-01

This paper investigates decentralized finite-time attitude synchronization for a group of rigid spacecraft by using quaternion with the consideration of environmental disturbances, inertia uncertainties and actuator saturation. Nonsingular terminal sliding mode (TSM) is used for controller design. Firstly, a theorem is proven that there always exists a kind of TSM that converges faster than fast terminal sliding mode (FTSM) for quaternion-descripted attitude control system. Controller with this kind of TSM has faster convergence and reduced computation than FTSM controller. Then, combining with an adaptive parameter estimation strategy, a novel terminal sliding mode disturbance observer is proposed. The proposed disturbance observer needs no upper bound information of the lumped uncertainties or their derivatives. On the basis of undirected topology and the disturbance observer, decentralized attitude synchronization control laws are designed and all attitude errors are ensured to converge to small regions in finite time. As for actuator saturation problem, an auxiliary variable is introduced and accommodated by the disturbance observer. Finally, simulation results are given and the effectiveness of the proposed control scheme is testified. Copyright © 2016. Published by Elsevier Ltd.

MEMS Reaction Control and Maneuvering for Picosat Beyond LEO

NASA Technical Reports Server (NTRS)

Alexeenko, Alina

2016-01-01

The MEMS Reaction Control and Maneuvering for Picosat Beyond LEO project will further develop a multi-functional small satellite technology for low-power attitude control, or orientation, of picosatellites beyond low Earth orbit (LEO). The Film-Evaporation MEMS Tunable Array (FEMTA) concept initially developed in 2013, is a thermal valving system which utilizes capillary forces in a microchannel to offset internal pressures in a bulk fluid. The local vapor pressure is increased by resistive film heating until it exceeds meniscus strength in a nozzle which induces vacuum boiling and provides a stagnation pressure equal to vapor pressure at that point which is used for propulsion. Interplanetary CubeSats can utilize FEMTA for high slew rate attitude corrections in addition to desaturating reaction wheels. The FEMTA in cooling mode can be used for thermal control during high-power communication events, which are likely to accompany the attitude correction. Current small satellite propulsion options are limited to orbit correction whereas picosatellites are lacking attitude control thrusters. The available attitude control systems are either quickly saturated reaction wheels or movable high drag surfaces with long response times.

Improving Primary Teachers' Attitudes toward Science by Attitude-Focused Professional Development

ERIC Educational Resources Information Center

van Aalderen-Smeets, Sandra I.; van der Molen, Juliette H. Walma

2015-01-01

This article provides a description of a novel, attitude-focused, professional development intervention, and presents the results of an experimental pretest-posttest control group study investigating the effects of this intervention on primary teachers' personal attitudes toward science, attitudes toward teaching science, and their science…

Two Axis Pointing System (TAPS) attitude acquisition, determination, and control

NASA Technical Reports Server (NTRS)

Azzolini, John D.; Mcglew, David E.

1990-01-01

The Two Axis Pointing System (TAPS) is a 2 axis gimbal system designed to provide fine pointing of Space Transportation System (STS) borne instruments. It features center-of-mass instrument mounting and will accommodate instruments of up to 1134 kg (2500 pounds) which fit within a 1.0 by 1.0 by 4.2 meter (40 by 40 by 166 inch) envelope. The TAPS system is controlled by a microcomputer based Control Electronics Assembly (CEA), a Power Distribution Unit (PDU), and a Servo Control Unit (SCU). A DRIRU-II inertial reference unit is used to provide incremental angles for attitude propagation. A Ball Brothers STRAP star tracker is used for attitude acquisition and update. The theory of the TAPS attitude determination and error computation for the Broad Band X-ray Telescope (BBXRT) are described. The attitude acquisition is based upon a 2 star geometric solution. The acquisition theory and quaternion algebra are presented. The attitude control combines classical position, integral and derivative (PID) control with techniques to compensate for coulomb friction (bias torque) and the cable harness crossing the gimbals (spring torque). Also presented is a technique for an adaptive bias torque compensation which adjusts to an ever changing frictional torque environment. The control stability margins are detailed, with the predicted pointing performance, based upon simulation studies. The TAPS user interface, which provides high level operations commands to facilitate science observations, is outlined.

Model predictive control of attitude maneuver of a geostationary flexible satellite based on genetic algorithm

NASA Astrophysics Data System (ADS)

TayyebTaher, M.; Esmaeilzadeh, S. Majid

2017-07-01

This article presents an application of Model Predictive Controller (MPC) to the attitude control of a geostationary flexible satellite. SIMO model has been used for the geostationary satellite, using the Lagrange equations. Flexibility is also included in the modelling equations. The state space equations are expressed in order to simplify the controller. Naturally there is no specific tuning rule to find the best parameters of an MPC controller which fits the desired controller. Being an intelligence method for optimizing problem, Genetic Algorithm has been used for optimizing the performance of MPC controller by tuning the controller parameter due to minimum rise time, settling time, overshoot of the target point of the flexible structure and its mode shape amplitudes to make large attitude maneuvers possible. The model included geosynchronous orbit environment and geostationary satellite parameters. The simulation results of the flexible satellite with attitude maneuver shows the efficiency of proposed optimization method in comparison with LQR optimal controller.

1999 Flight Mechanics Symposium

NASA Technical Reports Server (NTRS)

Lynch, John P. (Editor)

1999-01-01

This conference publication includes papers and abstracts presented at the Flight Mechanics Symposium held on May 18-20, 1999. Sponsored by the Guidance, Navigation and Control Center of Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination, and control; attitude sensor calibration; attitude determination error analysis; attitude dynamics; and orbit decay and maneuver strategy. Government, industry, and the academic community participated in the preparation and presentation of these papers.

Does Exonerating an Accused Researcher Restore the Researcher's Credibility?

PubMed

Greitemeyer, Tobias; Sagioglou, Christina

2015-01-01

Scientific misconduct appears to be on the rise. However, an accused researcher may later be exonerated. The present research examines to what extent participants adhere to their attitude toward a researcher who allegedly committed academic misconduct after learning that the researcher is innocent. In two studies, participants in an exoneration and an uncorrected accusation condition learned that the ethics committee of a researcher's university demanded the retraction of one of the researcher's articles, whereas participants in a control condition did not receive this information. As intended, this manipulation led to a more favorable attitude toward the researcher in the control compared to the exoneration and the uncorrected accusation conditions (pre-exoneration attitude). Then, participants in the exoneration condition learned that the researcher was exonerated and that the article was not retracted. Participants in the uncorrected accusation and the control condition were not informed about the exoneration. Results revealed that the exoneration effectively worked, in that participants in the exoneration condition had a more favorable attitude (post-exoneration attitude) toward the researcher than did participants in the uncorrected accusation condition. Moreover, the post-exoneration attitude toward the researcher was similar in the exoneration and the control conditions. Finally, in the exoneration condition only, participants' post-exoneration attitude was more favorable than their pre-exoneration attitude. These findings suggest that an exoneration of an accused researcher restores the researcher's credibility.

Parental attitudes and aggression in the Emo subculture.

PubMed

Chęć, Magdalena; Potemkowski, Andrzej; Wąsik, Marta; Samochowiec, Agnieszka

2016-01-01

A better functioning of adolescents involves proper relationships with parents, whereas negative relationships lead to aggressive behaviour. Young members of Emo subculture, characterised by deep emotional sensitivity, are particularly vulnerable to parental influence. The aim was to specify a relationship between parental attitudes and aggression among adolescents from the Emo subculture in comparison with a control group. 3,800 lower secondary school students took part in the introductory research. A target group constituted 41 people from the Emo subculture as well as a control group involving 48 people. A screening survey, the Parental Attitudes Scale, the Aggression Questionnaire and the author's questionnaire including questions concerning the functioning in the Emo subculture were used in the study. The results obtained in the research study suggest that there is a relationship between the indicated improper parental attitudes and aggressive behaviour among adolescents from the Emo subculture in comparison with the control group. In the Emo subculture, teenagers'aggressive behaviour is related to improper parental attitudes. It has been stated that mother's attitudes, irrespective of subculture, are much more strongly associated with the aggression among adolescents than father's attitudes. Moreover, aggressive behaviour in the Emo subculture occurs when father displays an excessively demanding attitude. A reduction of the level of almost all kinds of aggression manifested among teenagers from the Emo subculture is associated with mothers' attitude of acceptance. Mothers' autonomous attitude leads to an increase in the aggression in this group, whereas an inconsistent attitude of mothers fosters an increase in aggression among all teenagers.

X-33 Attitude Control Using the XRS-2200 Linear Aerospike Engine

NASA Technical Reports Server (NTRS)

Hall, Charles E.; Panossian, Hagop V.

1999-01-01

The Vehicle Control Systems Team at Marshall Space Flight Center, Structures and Dynamics Laboratory, Guidance and Control Systems Division is designing, under a cooperative agreement with Lockheed Martin Skunkworks, the Ascent, Transition, and Entry flight attitude control systems for the X-33 experimental vehicle. Test flights, while suborbital, will achieve sufficient altitudes and Mach numbers to test Single Stage To Orbit, Reusable Launch Vehicle technologies. Ascent flight control phase, the focus of this paper, begins at liftoff and ends at linear aerospike main engine cutoff (MECO). The X-33 attitude control system design is confronted by a myriad of design challenges: a short design cycle, the X-33 incremental test philosophy, the concurrent design philosophy chosen for the X-33 program, and the fact that the attitude control system design is, as usual, closely linked to many other subsystems and must deal with constraints and requirements from these subsystems. Additionally, however, and of special interest, the use of the linear aerospike engine is a departure from the gimbaled engines traditionally used for thrust vector control (TVC) in launch vehicles and poses certain design challenges. This paper discusses the unique problem of designing the X-33 attitude control system with the linear aerospike engine, requirements development, modeling and analyses that verify the design.

Novel approach to improve the attitude update rate of a star tracker.

PubMed

Zhang, Shuo; Xing, Fei; Sun, Ting; You, Zheng; Wei, Minsong

2018-03-05

The star tracker is widely used in attitude control systems of spacecraft for attitude measurement. The attitude update rate of a star tracker is important to guarantee the attitude control performance. In this paper, we propose a novel approach to improve the attitude update rate of a star tracker. The electronic Rolling Shutter (RS) imaging mode of the complementary metal-oxide semiconductor (CMOS) image sensor in the star tracker is applied to acquire star images in which the star spots are exposed with row-to-row time offsets, thereby reflecting the rotation of star tracker at different times. The attitude estimation method with a single star spot is developed to realize the multiple attitude updates by a star image, so as to reach a high update rate. The simulation and experiment are performed to verify the proposed approaches. The test results demonstrate that the proposed approach is effective and the attitude update rate of a star tracker is increased significantly.

Application of GPS attitude determination to gravity gradient stabilized spacecraft

NASA Technical Reports Server (NTRS)

Lightsey, E. G.; Cohen, Clark E.; Parkinson, Bradford W.

1993-01-01

Recent advances in the Global Positioning System (GPS) technology have initiated a new era in aerospace navigation and control. GPS receivers have become increasingly compact and affordable, and new developments have made attitude determination using subcentimeter positioning among two or more antennas feasible for real-time applications. GPS-based attitude control systems will become highly portable packages which provide time, navigation, and attitude information of sufficient accuracy for many aerospace needs. A typical spacecraft application of GPS attitude determination is a gravity gradient stabilized satellite in low Earth orbit that employs a GPS receiver and four body mounted patch antennas. The coupled, linearized equations of motion enable complete position and attitude information to be extracted from only two antennas. A discussion of the various error sources for spaceborne GPS attitude measurement systems is included. Attitude determination of better than 0.3 degrees is possible for 1 meter antenna separation. Suggestions are provided to improve the accuracy of the attitude solution.

[Knowledge, attitude and practice related to schistosomiasis control among rural residents in Wanjiang River region after a flood].

PubMed

Huan, Liu; Ai-Xia, Wang; Yuan-Zhen, Li; Ming-Ming, Zhou

2017-02-22

To investigate the status of knowledge, attitude and behavior of schistosomiasis control of rural residents in Wanjiang River region after a flood, so as to provide the reference for targeted health education. The multistage sampling was applied to select the respondents in rural residents in Wanjiang River region, and the self-designed questionnaire was used to investigate the current situation of knowledge, attitude and behavior of schistosomiasis prevention and control of the rural residents. The total awareness rate of knowledge about the prevention and control of schistosomiasis was 47.92%. The age, education, family income, relatives and friends with medical background, and health education significantly influenced the awareness rate ( χ 2 = 12.76, 89.19, 18.19, 50.83 and 92.60 respectively, all P < 0.05). The accuracy rates of attitude and behavior in schistosomiasis control were 62.89% and 52.37% respectively. The awareness rate of knowledge about the prevention and control of schistosomiasis, and the accuracy rates of attitude and behavior in schistosomiasis control of the rural residents in Wanjiang River region are all inefficient, and therefore, the targeted health education should be strengthened to decrease the risk of schistosomiasis transmission.

Large scale static tests of a tilt-nacelle V/STOL propulsion/attitude control system

NASA Technical Reports Server (NTRS)

1978-01-01

The concept of a combined V/STOL propulsion and aircraft attitude control system was subjected to large scale engine tests. The tilt nacelle/attitude control vane package consisted of the T55 powered Hamilton Standard Q-Fan demonstrator. Vane forces, moments, thermal and acoustic characteristics as well as the effects on propulsion system performance were measured under conditions simulating hover in and out of ground effect.

Active control and synchronization chaotic satellite via the geomagnetic Lorentz force

NASA Astrophysics Data System (ADS)

Abdel-Aziz, Yehia

2016-07-01

The use of geomagnetic Lorentz force is considered in this paper for the purpose of satellite attitude control. A satellite with an electrostatic charge will interact with the Earth's magnetic field and experience the Lorentz force. An analytical attitude control and synchronization two identical chaotic satellite systems with different initial condition Master/ Slave are proposed to allows a charged satellite remains near the desired attitude. Asymptotic stability for the closed-loop system are investigated by means of Lyapunov stability theorem. The control feasibility depend on the charge requirement. Given a significantly and sufficiently accurate insertion, a charged satellite could maintains the desired attitude orientation without propellant. Simulations is performed to prove the efficacy of the proposed method.

Impact and change of attitudes toward Internet interventions within a randomized controlled trial on individuals with depression symptoms.

PubMed

Schröder, Johanna; Berger, Thomas; Meyer, Björn; Lutz, Wolfgang; Späth, Christina; Michel, Pia; Rose, Matthias; Hautzinger, Martin; Hohagen, Fritz; Klein, Jan Philipp; Moritz, Steffen

2018-05-01

Most individuals with depression do not receive adequate treatment. Internet interventions may help to bridge this gap. Research on attitudes toward Internet interventions might facilitate the dissemination of such interventions by identifying factors that help or hinder uptake and implementation, and by clarifying who is likely to benefit. This study examined whether attitudes toward Internet interventions moderate the effects of a depression-focused Internet intervention, and how attitudes change over the course of treatment among those who do or do not benefit. We recruited 1,004 adults with mild-to-moderate depression symptoms and investigated how attitudes toward Internet interventions are associated with the efficacy of the program deprexis, and how attitudes in the intervention group change from pre to post over a 3 months intervention period, compared to a control group (care as usual). This study consists of a subgroup analysis of the randomized controlled EVIDENT trial. Positive initial attitudes toward Internet interventions were associated with greater efficacy (η 2 p  = .014) independent of usage time, whereas a negative attitude (perceived lack of personal contact) was associated with reduced efficacy (η 2 p  = .012). Users' attitudes changed during the trial, and both the magnitude and direction of attitude change were associated with the efficacy of the program over time (η 2 p  = .030). Internet interventions may be the most beneficial for individuals with positive attitudes toward them. Informing potential users about evidence-based Internet interventions might instill positive attitudes and thereby optimize the benefits such interventions can provide. Assessing attitudes prior to treatment might help identify suitable users. © 2018 Wiley Periodicals, Inc.

Crew exploration vehicle (CEV) attitude control using a neural-immunology/memory network

NASA Astrophysics Data System (ADS)

Weng, Liguo; Xia, Min; Wang, Wei; Liu, Qingshan

2015-01-01

This paper addresses the problem of the crew exploration vehicle (CEV) attitude control. CEVs are NASA's next-generation human spaceflight vehicles, and they use reaction control system (RCS) jet engines for attitude adjustment, which calls for control algorithms for firing the small propulsion engines mounted on vehicles. In this work, the resultant CEV dynamics combines both actuation and attitude dynamics. Therefore, it is highly nonlinear and even coupled with significant uncertainties. To cope with this situation, a neural-immunology/memory network is proposed. It is inspired by the human memory and immune systems. The control network does not rely on precise system dynamics information. Furthermore, the overall control scheme has a simple structure and demands much less computation as compared with most existing methods, making it attractive for real-time implementation. The effectiveness of this approach is also verified via simulation.

Attitude and vibration control of a large flexible space-based antenna

NASA Technical Reports Server (NTRS)

Joshi, S. M.

1982-01-01

Control systems synthesis is considered for controlling the rigid body attitude and elastic motion of a large deployable space-based antenna. Two methods for control systems synthesis are considered. The first method utilizes the stability and robustness properties of the controller consisting of torque actuators and collocated attitude and rate sensors. The second method is based on the linear-quadratic-Gaussian control theory. A combination of the two methods, which results in a two level hierarchical control system, is also briefly discussed. The performance of the controllers is analyzed by computing the variances of pointing errors, feed misalignment errors and surface contour errors in the presence of sensor and actuator noise.

International Space Station Attitude Motion Associated With Flywheel Energy Storage

NASA Technical Reports Server (NTRS)

Roithmayr, Carlos M.

1999-01-01

Flywheels can exert torque that alters the Station's attitude motion, either intentionally or unintentionally. A design is presented for a once planned experiment to contribute torque for Station attitude control, while storing or discharging energy. Two contingencies are studied: the abrupt stop of one rotor while another rotor continues to spin at high speed, and energy storage performed with one rotor instead of a counter rotating pair. Finally, the possible advantages to attitude control offered by a system of ninety-six flywheels are discussed.

2001 Flight Mechanics Symposium

NASA Technical Reports Server (NTRS)

Lynch, John P. (Editor)

2001-01-01

This conference publication includes papers and abstracts presented at the Flight Mechanics Symposium held on June 19-21, 2001. Sponsored by the Guidance, Navigation and Control Center of Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to attitude/orbit determination, prediction and control; attitude simulation; attitude sensor calibration; theoretical foundation of attitude computation; dynamics model improvements; autonomous navigation; constellation design and formation flying; estimation theory and computational techniques; Earth environment mission analysis and design; and, spacecraft re-entry mission design and operations.

Attitude estimation of earth orbiting satellites by decomposed linear recursive filters

NASA Technical Reports Server (NTRS)

Kou, S. R.

1975-01-01

Attitude estimation of earth orbiting satellites (including Large Space Telescope) subjected to environmental disturbances and noises was investigated. Modern control and estimation theory is used as a tool to design an efficient estimator for attitude estimation. Decomposed linear recursive filters for both continuous-time systems and discrete-time systems are derived. By using this accurate estimation of the attitude of spacecrafts, state variable feedback controller may be designed to achieve (or satisfy) high requirements of system performance.

Attributions and Attitudes of Mothers and Fathers in Kenya.

PubMed

Oburu, Paul Odhiambo

2011-07-01

OBJECTIVE: The present study examined differences and similarities between Kenyan mothers and fathers in attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. DESIGN: Interviews were conducted with both mothers and fathers in 100 two-parent families in Kenya. RESULTS: Mothers were more likely to make attributions regarding adult-controlled failure in caregiving situations than were fathers, but mothers and fathers did not differ on attributions regarding uncontrollable success, child-controlled failure, or authoritarian or progressive attitudes. Moderate to large correlations were found between mothers and fathers in terms of attributions regarding uncontrollable success, authoritarian attitudes, and modernity of attitudes. CONCLUSIONS: Kenyan mothers and fathers hold very similar attributions for success and failures in caregiving situations as well as parenting attitudes.

Discipline in Public and Religious Elementary and Secondary Schools: A Comparative Analysis.

ERIC Educational Resources Information Center

Denig, Stephen J.

Previous studies using the Pupil-Control Ideology Scale (PCI) have found that in general, secondary school teachers have a more custodial attitude toward pupil control than do primary school teachers, and that public school teachers have a more custodial attitude than do religious school teachers. Teachers with custodial attitudes tend to distrust…

The Connection between Environmental Attitude-Behavior Gap and Other Individual Inconsistencies: A Call for Strengthening Self-Control

ERIC Educational Resources Information Center

Redondo, Ignacio; Puelles, María

2017-01-01

What is going on with environmental education, which is currently unable to promote pro-environmental behaviors as effectively as it promotes pro-environmental attitudes? A tentative answer is that the environmental attitude-behavior gap observed in some individuals is just one manifestation of their lack of self-control for maintaining…

Knowledge, attitudes and practices among parents and teachers about soil-transmitted helminthiasis control programs for school children in Guimaras, Philippines.

PubMed

Parikh, Divya Sinha; Totañes, Francis I G; Tuliao, Alex H; Ciro, Raezelle N T; Macatangay, Bernard J C; Belizario, Vicente Y

2013-09-01

We determined the attitudes toward and practices regarding soil-transmitted helminthes (STH) control among parents and school teachers to identify reasons behind attitudes and practices that do not promote STH control. Written knowledge, attitudes and practices surveys were distributed to parents (N = 531) and teachers (N = 105) of students at 11 elementary schools in Guimaras Province, the Philippines. The survey addressed attitudes about mass drug administration (MDA), knowledge about STH control, hygienic practices, and acceptability of distributing deworming tablets among teachers. More than 90% of parents and teachers held favorable attitudes towards MDA. Sixty-nine percent of parents and 75.5% of teachers believed stool exams were necessary before MDA. Thirty-seven percent of parents stated they would not allow teachers to administer deworming tablets and 91.5% of parents feared teachers would not detect side effects of the medication. Forty-eight percent of teachers felt they could safely give deworming tablets and 81.4% of teachers were afraid of managing the side effects of deworming tablets. Forty-seven point eight percent of parents and 42.2% of teachers stated defecation in the open occured in their community. Although attitudes toward STH control were largely favorable, misconceptions about the MDA strategy, lack of support for teachers giving deworming tablets, and the practice of open defecation still exist as barriers to STH control efforts. The next step to achieve effective STH control will be to clarify misconceptions in education campaigns, to train teachers about medication administration, campaign to improve sanitation and hygiene and begin targeted mass treatment in Guimaras, the Philippines.

Magnetic bearing momentum wheels with magnetic gimballing capability for 3-axis active attitude control and energy storage

NASA Technical Reports Server (NTRS)

Sindlinger, R. S.

1977-01-01

A 3-axis active attitude control system with only one rotating part was developed using a momentum wheel with magnetic gimballing capability as a torque actuator for all three body axes. A brief description of magnetic bearing technology is given. It is concluded that based on this technology an integrated energy storage/attitude control system with one air of counterrotating rings could reduce the complexity and weight of conventional systems.

Primary teachers conducting inquiry projects: effects on attitudes towards teaching science and conducting inquiry

NASA Astrophysics Data System (ADS)

van Aalderen-Smeets, Sandra I.; Walma van der Molen, Juliette H.; van Hest, Erna G. W. C. M.; Poortman, Cindy

2017-01-01

This study used an experimental, pretest-posttest control group design to investigate whether participation in a large-scale inquiry project would improve primary teachers' attitudes towards teaching science and towards conducting inquiry. The inquiry project positively affected several elements of teachers' attitudes. Teachers felt less anxious about teaching science and felt less dependent on contextual factors compared to the control group. With regard to attitude towards conducting inquiry, teachers felt less anxious and more able to conduct an inquiry project. There were no effects on other attitude components, such as self-efficacy beliefs or relevance beliefs, or on self-reported science teaching behaviour. These results indicate that practitioner research may have a partially positive effect on teachers' attitudes, but that it may not be sufficient to fully change primary teachers' attitudes and their actual science teaching behaviour. In comparison, a previous study showed that attitude-focused professional development in science education has a more profound impact on primary teachers' attitudes and science teaching behaviour. In our view, future interventions aiming to stimulate science teaching should combine both approaches, an explicit focus on attitude change together with familiarisation with inquiry, in order to improve primary teachers' attitudes and classroom practices.

Study of the effects of informational and persuasive messages on the attitudes of high school students toward the use of nuclear energy for electrical production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Showers, D.E.

1986-01-01

This investigation assessed the relationship between knowledge about and attitudes toward nuclear energy. The study's purpose was accomplished by attempting to manipulate knowledge about and attitude toward nuclear energy independently. Over two thousand high school students participated in the study. A Non-Equivalent Control Group quasi-experimental design was used involving random assignment by intact groups to treatments. A knowledge treatment was designed to increase student knowledge without affecting attitudes. An attitude treatment was designed to change attitudes without changing knowledge, and a control treatment was employed for comparison to the experimental treatments. Each treatment consisted of a videotape with a viewingmore » guide and a homework assignment. The Nuclear Energy Assessment Battery was used as a pretest, post-test, and retention test. Males scored significantly higher in knowledge and positive attitudes, but no interaction between gender and treatment was found. The study concluded that (1) there is a correlation between nuclear knowledge and attitudes, (2) knowledge about nuclear energy can be changed without affecting attitude and attitude can be changed without affecting knowledge, and (3) students show differences and attitude based on gender.« less

Verification of Spin Magnetic Attitude Control System using air-bearing-based attitude control simulator

NASA Astrophysics Data System (ADS)

Ousaloo, H. S.; Nodeh, M. T.; Mehrabian, R.

2016-09-01

This paper accomplishes one goal and it was to verify and to validate a Spin Magnetic Attitude Control System (SMACS) program and to perform Hardware-In-the-Loop (HIL) air-bearing experiments. A study of a closed-loop magnetic spin controller is presented using only magnetic rods as actuators. The magnetic spin rate control approach is able to perform spin rate control and it is verified with an Attitude Control System (ACS) air-bearing MATLAB® SIMULINK® model and a hardware-embedded LABVIEW® algorithm that controls the spin rate of the test platform on a spherical air bearing table. The SIMULINK® model includes dynamic model of air-bearing, its disturbances, actuator emulation and the time delays caused by on-board calculations. The air-bearing simulator is employed to develop, improve, and carry out objective tests of magnetic torque rods and spin rate control algorithm in the experimental framework and to provide a more realistic demonstration of expected performance of attitude control as compared with software-based architectures. Six sets of two torque rods are used as actuators for the SMACS. It is implemented and simulated to fulfill mission requirement including spin the satellite up to 12 degs-1 around the z-axis. These techniques are documented for the full nonlinear equations of motion of the system and the performances of these techniques are compared in several simulations.

Integrated identification and control for nanosatellites reclaiming failed satellite

NASA Astrophysics Data System (ADS)

Han, Nan; Luo, Jianjun; Ma, Weihua; Yuan, Jianping

2018-05-01

Using nanosatellites to reclaim a failed satellite needs nanosatellites to attach to its surface to take over its attitude control function. This is challenging, since parameters including the inertia matrix of the combined spacecraft and the relative attitude information of attached nanosatellites with respect to the given body-fixed frame of the failed satellite are all unknown after the attachment. Besides, if the total control capacity needs to be increased during the reclaiming process by new nanosatellites, real-time parameters updating will be necessary. For these reasons, an integrated identification and control method is proposed in this paper, which enables the real-time parameters identification and attitude takeover control to be conducted concurrently. Identification of the inertia matrix of the combined spacecraft and the relative attitude information of attached nanosatellites are both considered. To guarantee sufficient excitation for the identification of the inertia matrix, a modified identification equation is established by filtering out sample points leading to ill-conditioned identification, and the identification performance of the inertia matrix is improved. Based on the real-time estimated inertia matrix, an attitude takeover controller is designed, the stability of the controller is analysed using Lyapunov method. The commanded control torques are allocated to each nanosatellite while the control saturation constraint being satisfied using the Quadratic Programming (QP) method. Numerical simulations are carried out to demonstrate the feasibility and effectiveness of the proposed integrated identification and control method.

Application of experiential learning model using simple physical kit to increase attitude toward physics student senior high school in fluid

NASA Astrophysics Data System (ADS)

Johari, A. H.; Muslim

2018-05-01

Experiential learning model using simple physics kit has been implemented to get a picture of improving attitude toward physics senior high school students on Fluid. This study aims to obtain a description of the increase attitudes toward physics senior high school students. The research method used was quasi experiment with non-equivalent pretest -posttest control group design. Two class of tenth grade were involved in this research 28, 26 students respectively experiment class and control class. Increased Attitude toward physics of senior high school students is calculated using an attitude scale consisting of 18 questions. Based on the experimental class test average of 86.5% with the criteria of almost all students there is an increase and in the control class of 53.75% with the criteria of half students. This result shows that the influence of experiential learning model using simple physics kit can improve attitude toward physics compared to experiential learning without using simple physics kit.

Evaluating the effectiveness of an intervention program to influence attitudes of students towards peers with disabilities.

PubMed

de Boer, Anke; Pijl, Sip Jan; Minnaert, Alexander; Post, Wendy

2014-03-01

In this study we examine the effectiveness of an intervention program to influence attitudes of elementary school students towards peers with intellectual, physical and severe physical and intellectual disabilities. A quasi-experimental longitudinal study was designed with an experimental group and a control group, both comprising two rural schools. An intervention program was developed for kindergarten (n(experimental) = 22, n(control) = 31) and elementary school students without disabilities (n(experimental) = 91, n(control) = 127) (age range 4-12 years old). This intervention consisted of a 3 weeks education project comprising six lessons about disabilities. The Acceptance Scale for Kindergarten-revised and the Attitude Survey to Inclusive Education were used to measure attitudes at three moments: prior to the start of the intervention, after the intervention and 1 year later. The outcomes of the multilevel analysis showed positive, immediate effects on attitudes of kindergarten students, but limited effects on elementary school students' attitudes.

The relationships among nurses' job characteristics and attitudes toward web-based continuing learning.

PubMed

Chiu, Yen-Lin; Tsai, Chin-Chung; Fan Chiang, Chih-Yun

2013-04-01

The purpose of this study was to explore the relationships between job characteristics (job demands, job control and social support) and nurses' attitudes toward web-based continuing learning. A total of 221 in-service nurses from hospitals in Taiwan were surveyed. The Attitudes toward Web-based Continuing Learning Survey (AWCL) was employed as the outcome variables, and the Chinese version Job Characteristic Questionnaire (C-JCQ) was administered to assess the predictors for explaining the nurses' attitudes toward web-based continuing learning. To examine the relationships among these variables, hierarchical regression was conducted. The results of the regression analysis revealed that job control and social support positively associated with nurses' attitudes toward web-based continuing learning. However, the relationship of job demands to such learning was not significant. Moreover, a significant demands×job control interaction was found, but the job demands×social support interaction had no significant relationships with attitudes toward web-based continuing learning. Copyright © 2013 Elsevier Ltd. All rights reserved.

Predictors of Attitudes toward Childlessness.

ERIC Educational Resources Information Center

Spreadbury, Connie

The study assessed young adults' attitudes toward childlessness and identified certain factors which predict positive or negative attitudes toward childlessness. The author anticipated finding changes in attitudes because of recent social developments such as awareness of world overpopulation, availability of birth control methods, pressure for…

Case-based e-learning to improve the attitude of medical students towards occupational health, a randomised controlled trial.

PubMed

Smits, P B A; de Graaf, L; Radon, K; de Boer, A G; Bos, N R; van Dijk, F J H; Verbeek, J H A M

2012-04-01

Undergraduate medical teaching in occupational health (OH) is a challenge in universities around the world. Case-based e-learning with an attractive clinical context could improve the attitude of medical students towards OH. The study question is whether case-based e-learning for medical students is more effective in improving knowledge, satisfaction and a positive attitude towards OH than non-case-based textbook learning. Participants, 141 second year medical students, were randomised to either case-based e-learning or text-based learning. Outcome measures were knowledge, satisfaction and attitude towards OH, measured at baseline, directly after the intervention, after 1 week and at 3-month follow-up. Of the 141 participants, 130 (92%) completed the questionnaires at short-term follow-up and 41 (29%) at 3-month follow-up. At short-term follow-up, intervention and control groups did not show a significant difference in knowledge nor satisfaction but attitude towards OH was significantly more negative in the intervention group (F=4.041, p=0.047). At 3-month follow-up, there were no significant differences between intervention and control groups for knowledge, satisfaction and attitude. We found a significant decrease in favourable attitude during the internship in the experimental group compared with the control group. There were no significant differences in knowledge or satisfaction between case-based e-learning and text-based learning. The attitude towards OH should be further investigated as an outcome of educational programmes.

Pitch attitude, flight path, and airspeed control during approach and landing of a powered lift STOL aircraft

NASA Technical Reports Server (NTRS)

Franklin, J. A.; Innis, R. C.

1972-01-01

Analytical investigations and piloted moving base simulator evaluations were conducted for manual control of pitch attitude, flight path, and airspeed for the approach and landing of a powered lift jet STOL aircraft. Flight path and speed response characteristics were described analytically and were evaluated for the simulation experiments which were carried out on a large motion simulator. The response characteristics were selected and evaluated for a specified path and speed control technique. These charcteristics were: (1) the initial pitch response and steady pitch rate sensitivity for control of attitude with a pitch rate command/ attitude hold system, (2) the initial flight path response, flight path overshoot, and flight path-airspeed coupling in response to a change in thrust, and (3) the sensitivity of airspeed to pitch attitude changes. Results are presented in the form of pilot opinion ratings and commentary, substantiated where appropriate by response time histories and aircraft states at the point of touchdown.

Report of the Attitude Control and Attitude Determination Panel. [spacecraft instrumentation technology

NASA Technical Reports Server (NTRS)

1979-01-01

Failures and deficiencies in flight programs are reviewed and suggestions are made for avoiding them. The technology development problem areas considered are control configured vehicle design, gyros, solid state star sensors, control instrumentation, tolerant/accomodating control systems, large momentum exchange devices, and autonomous rendezvous and docking.

Design study for LANDSAT D attitude control system

NASA Technical Reports Server (NTRS)

Iwens, R. P.; Bernier, G. E.; Hofstadter, R. F.

1976-01-01

A design and performance evaluation is presented for the LANDSAT D attitude control system (ACS). Control and configuration of the gimballed Ku-band antenna system for communication with the tracking and data relay satellite (TDRS). Control of the solar array drive considered part of the ACS is also addressed.

Skylab

NASA Image and Video Library

1970-01-01

This photograph shows technicians installing the meteoroid shield on the Thruster Attitude Control Subsystem (TACS). At one end of the Orbital Workshop (OWS), the TACS provided short-term control of the attitude of the Skylab.

Spacecraft attitude control for a solar electric geosynchronous transfer mission

NASA Technical Reports Server (NTRS)

Leroy, B. E.; Regetz, J. D., Jr.

1975-01-01

A study of the Attitude Control System (ACS) is made for a solar electric propulsion geosynchronous transfer mission. The basic mission considered is spacecraft injection into a low altitude, inclined orbit followed by low thrust orbit changing to achieve geosynchronous orbit. Because of the extended thrusting time, the mission performance is a strong function of the attitude control system. Two attitude control system design options for an example mission evolve from consideration of the spacecraft configuration, the environmental disturbances, and the probable ACS modes of operation. The impact of these design options on other spacecraft subsystems is discussed. The factors which must be considered in determining the ACS actuation and sensing subsystems are discussed. The effects of the actuation and sensing subsystems on the mission performance are also considered.

Precision tethered satellite attitude control. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Kline-Schoder, Robert J.

1990-01-01

Tethered spacecraft possess unique dynamic characteristics which make them advantageous for certain classes of experiments. One use for which tethers are particularly well suited is to provide an isolated platform for spaceborne observatories. The advantages of tethering a pointing platform 1 or 2 km from a space shuttle or space station are that, compared to placing the observatory on the parent spacecraft, vibrational disturbances are attenuated and contamination is eliminated. In practice, all satellites have some requirement on the attitude control of the spacecraft, and tethered satellites are no exception. It has previously been shown that conventional means of performing attitude control for tethered satellites are insufficient for any mission with pointing requirements more stringent than about 1 deg. This is due mainly to the relatively large force applied by the tether to the spacecraft. A particularly effective method of implementing attitude control for tethered satellites is to use this tether tension force to generate control torques by moving the tether attach point relative to the subsatellite center of mass. A demonstration of this attitude control technique on an astrophysical pointing platform has been proposed for a space shuttle flight test project and is referred to as the Kinetic Isolation Tether Experiment (KITE).

Attributions and Attitudes of Mothers and Fathers in Colombia.

PubMed

Di Giunta, Laura; Tirado, Liliana M Uribe; Márquez, Luz A Araque

2011-07-01

OBJECTIVE: The present study examined mean level similarities and differences as well as correlations between mothers' and fathers' attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. DESIGN: Interviews were conducted with both mothers and fathers in 108 Colombian families. RESULTS: Fathers reported higher uncontrollable success attributions and higher authoritarian attitudes than did mothers, whereas mothers reported higher modernity of attitudes than did fathers; only the gender differences related to parental attitudes remained significant after controlling for parents' age, education, and possible social desirability bias. Medium effect sizes were found for concordance between parents in the same family for attributions regarding uncontrollable success and progressive attitudes after controlling for parents' age, education, and possible social desirability bias. CONCLUSIONS: This work elucidates ways that parent gender relates to attributions regarding parents' success and failure in caregiving and to progressive versus authoritarian parenting attitudes in Colombia.

Attributions and Attitudes of Mothers and Fathers in Colombia

PubMed Central

Di Giunta, Laura; Tirado, Liliana M. Uribe; Márquez, Luz A. Araque

2011-01-01

SYNOPSIS Objective The present study examined mean level similarities and differences as well as correlations between mothers’ and fathers’ attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. Design Interviews were conducted with both mothers and fathers in 108 Colombian families. Results Fathers reported higher uncontrollable success attributions and higher authoritarian attitudes than did mothers, whereas mothers reported higher modernity of attitudes than did fathers; only the gender differences related to parental attitudes remained significant after controlling for parents’ age, education, and possible social desirability bias. Medium effect sizes were found for concordance between parents in the same family for attributions regarding uncontrollable success and progressive attitudes after controlling for parents’ age, education, and possible social desirability bias. Conclusions This work elucidates ways that parent gender relates to attributions regarding parents’ success and failure in caregiving and to progressive versus authoritarian parenting attitudes in Colombia. PMID:21927585

Hardware Simulations of Spacecraft Attitude Synchronization Using Lyapunov-Based Controllers

NASA Astrophysics Data System (ADS)

Jung, Juno; Park, Sang-Young; Eun, Youngho; Kim, Sung-Woo; Park, Chandeok

2018-04-01

In the near future, space missions with multiple spacecraft are expected to replace traditional missions with a single large spacecraft. These spacecraft formation flying missions generally require precise knowledge of relative position and attitude between neighboring agents. In this study, among the several challenging issues, we focus on the technique to control spacecraft attitude synchronization in formation. We develop a number of nonlinear control schemes based on the Lyapunov stability theorem and considering special situations: full-state feedback control, full-state feedback control with unknown inertia parameters, and output feedback control without angular velocity measurements. All the proposed controllers offer absolute and relative control using reaction wheel assembly for both regulator and tracking problems. In addition to the numerical simulations, an air-bearing-based hardware-in-the-loop (HIL) system is used to verify the proposed control laws in real-time hardware environments. The pointing errors converge to 0.5{°} with numerical simulations and to 2{°} using the HIL system. Consequently, both numerical and hardware simulations confirm the performance of the spacecraft attitude synchronization algorithms developed in this study.

Generalized Beliefs and Attitudes: Locus of Control and Science Attitudes in High School and College Students.

ERIC Educational Resources Information Center

Stuessy, Carol L.; Rowland, Paul McD.

Locus of control, a generalized belief about causality in one's personal life, was identified as a potential variable impinging upon the acquisition of science-related attitudes in classes of high school students from 10th grade biology, and 11th and 12th grade chemistry, and of college elementary education majors. Correlations of the…

An Experimental Study of an Ultra-Mobile Vehicle for Off-Road Transportation.

DTIC Science & Technology

1983-02-01

Control with Active Compliance ....... 97 ( 5.5 Force Tracking .... ................. .... 97 5.6 Attitude Sensor Evaluation .. ........... . .101 6...93 5.7 OSU Hexapod Traversing Obstacle ............ ... 95 - 5.8 Vehicle Attitude Across Obstacle Using No Terrain- Adaptive ...Underspecified Gait Using Attitude Control and Active Compliance 100 5.12 Foot Force Tracking Using Active Compliance in an Underspecified Gait

Application of the concept of dynamic trim control and nonlinear system inverses to automatic control of a vertical attitude takeoff and landing aircraft

NASA Technical Reports Server (NTRS)

Smith, G. A.; Meyer, G.

1981-01-01

A full envelope automatic flight control system based on nonlinear inverse systems concepts has been applied to a vertical attitude takeoff and landing (VATOL) fighter aircraft. A new method for using an airborne digital aircraft model to perform the inversion of a nonlinear aircraft model is presented together with the results of a simulation study of the nonlinear inverse system concept for the vertical-attitude hover mode. The system response to maneuver commands in the vertical attitude was found to be excellent; and recovery from large initial offsets and large disturbances was found to be very satisfactory.

Linking Narcissism, Motivation, and Doping Attitudes in Sport: A Multilevel Investigation Involving Coaches and Athletes.

PubMed

Matosic, Doris; Ntoumanis, Nikos; Boardley, Ian David; Stenling, Andreas; Sedikides, Constantine

2016-12-01

Research on coaching (Bartholomew, Ntoumanis, & Thøgersen-Ntoumani, 2009) has shown that coaches can display controlling behaviors that have detrimental effects on athletes' basic psychological needs and quality of sport experiences. The current study extends this literature by considering coach narcissism as a potential antecedent of coaches' controlling behaviors. Further, the study tests a model linking coaches' (n = 59) own reports of narcissistic tendencies with athletes' (n = 493) perceptions of coach controlling behaviors, experiences of need frustration, and attitudes toward doping. Multilevel path analysis revealed that coach narcissism was directly and positively associated with athletes' perceptions of controlling behaviors and was indirectly and positively associated with athletes' reports of needs frustration. In addition, athletes' perceptions of coach behaviors were positively associated-directly and indirectly-with attitudes toward doping. The findings advance understanding of controlling coach behaviors, their potential antecedents, and their associations with athletes' attitudes toward doping.

Spherical gyroscopic moment stabilizer for attitude control of microsatellites

NASA Astrophysics Data System (ADS)

Keshtkar, Sajjad; Moreno, Jaime A.; Kojima, Hirohisa; Uchiyama, Kenji; Nohmi, Masahiro; Takaya, Keisuke

2018-02-01

This paper presents a new and improved concept of recently proposed two-degrees of freedom spherical stabilizer for triaxial orientation of microsatellites. The analytical analysis of the advantages of the proposed mechanism over the existing inertial attitude control devices are introduced. The extended equations of motion of the stabilizing satellite including the spherical gyroscope, for control law design and numerical simulations, are studied in detail. A new control algorithm based on continuous high-order sliding mode algorithms, for managing the torque produced by the stabilizer and therefore the attitude control of the satellite in the presence of perturbations/uncertainties, is presented. Some numerical simulations are carried out to prove the performance of the proposed mechanism and control laws.

Demonstration of Single Axis Combined Attitude Control and Energy Storage Using Two Flywheels

NASA Technical Reports Server (NTRS)

Kenny, Barbara H.; Jansen, Ralph; Kascak, Peter; Dever, Timothy; Santiago, Walter

2004-01-01

The energy storage and attitude control subsystems of the typical satellite are presently distinct and separate. Energy storage is conventionally provided by batteries, either NiCd or NiH, and active attitude control is accomplished with control moment gyros (CMGs) or reaction wheels. An overall system mass savings can be realized if these two subsystems are combined using multiple flywheels for simultaneous kinetic energy storage and momentum transfer. Several authors have studied the control of the flywheels to accomplish this and have published simulation results showing the feasibility and performance. This paper presents the first experimental results showing combined energy storage and momentum control about a single axis using two flywheels.

Autonomous Control Modes and Optimized Path Guidance for Shipboard Landing in High Sea States

DTIC Science & Technology

2017-01-09

due to the inherent nose up attitude of the helicopter. Once the tail gear makes contact (almost always with low relative velocity), the control...n V Z ( ft /s ) Front Gear 2 -10 -8 -6 -4 -2 0 2 4 6 8 10 0 2 4 6 8 10 Touchdown V Y (ft/s) Tail Gear This problem is a consequence of attitude ...mismatch at touchdown; where the aircraft attitude does not comply with the deck orientation. Attitude mismatch is a common for helicopter; even a land

A study of the effects of gender and different instructional media (computer-assisted instruction tutorials vs. textbook) on student attitudes and achievement in a team-taught integrated science class

NASA Astrophysics Data System (ADS)

Eardley, Julie Anne

The purpose of this study was to determine the effect of different instructional media (computer assisted instruction (CAI) tutorial vs. traditional textbook) on student attitudes toward science and computers and achievement scores in a team-taught integrated science course, ENS 1001, "The Whole Earth Course," which was offered at Florida Institute of Technology during the Fall 2000 term. The effect of gender on student attitudes toward science and computers and achievement scores was also investigated. This study employed a randomized pretest-posttest control group experimental research design with a sample of 30 students (12 males and 18 females). Students had registered for weekly lab sessions that accompanied the course and had been randomly assigned to the treatment or control group. The treatment group used a CAI tutorial for completing homework assignments and the control group used the required textbook for completing homework assignments. The Attitude toward Science and Computers Questionnaire and Achievement Test were the two instruments administered during this study to measure students' attitudes and achievement score changes. A multivariate analysis of covariance (MANCOVA), using hierarchical multiple regression/correlation (MRC), was employed to determine: (1) treatment versus control group attitude and achievement differences; and (2) male versus female attitude and achievement differences. The differences between the treatment group's and control group's homework averages were determined by t test analyses. The overall MANCOVA model was found to be significant at p < .05. Examining research factor set independent variables separately resulted in gender being the only variable that significantly contributed in explaining the variability in a dependent variable, attitudes toward science and computers. T test analyses of the homework averages showed no significant differences. Contradictory to the findings of this study, anecdotal information from personal communication, course evaluations, and homework assignments indicated favorable attitudes and higher achievement scores for a majority of the students in the treatment group.

Cognitive processes and attitudes in bipolar disorder: a study into personality, dysfunctional attitudes and attention bias in patients with bipolar disorder and their relatives.

PubMed

Jabben, Nienke; Arts, Baer; Jongen, Ellen M M; Smulders, Fren T Y; van Os, Jim; Krabbendam, Lydia

2012-12-20

Research in cognitive processes and attitudes in bipolar disorder is scarce and has provided mixed findings, possibly due to differences in current mood state. It is unclear whether alterations in cognitive processes and attitudes are only related to the depressive mood states of bipolar patients or also represent a vulnerability marker for the development of future (depressive) episodes. This was investigated in the current study. Both implicit (attentional bias for emotional words) and explicit (dysfunctional attitudes and personality characteristics) measures of cognitive processes and attitudes were assessed in 77 bipolar patients with varying levels of depressive symptoms (depressed=17, euthymic n=60), their healthy first-degree relatives (n=39) and a healthy control group (n=61). Analyses of variance were used to investigate differences between groups. Mildly depressed patients with bipolar disorder demonstrated an attentional bias away from positive emotional words and showed increased dysfunctional attitudes and higher levels of neuroticism. Euthymic patients were largely comparable to healthy controls and only differed from controls in higher levels of neuroticism. Relatives were similar to controls on all measures, although they significantly differed from bipolar patients in displaying less neuroticism and more extraversion. No firm conclusions regarding causality can be drawn from the associations that were found between cognitive processes and attitudes and the evolution of mood symptoms in bipolar disorder. Alterations in cognitive processes and attitudes in bipolar patients appear to be mostly related to the expression of mood symptomatology rather than to the vulnerability for bipolar disorder. Copyright © 2012 Elsevier B.V. All rights reserved.

75 FR 21040 - Submission for OMB Review: Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-22

...: National Survey of Public Attitudes Towards People With Disabilities. OMB Control Number: Pending. Agency... assess public attitudes towards people with disabilities with a focus on workplace relations. The survey... attitudes of individuals and develops ways of changing those attitudes to improve the employment rate and...

Solar and Heliospheric Observatory (SOHO) Flight Dynamics Simulations Using MATLAB (R)

NASA Technical Reports Server (NTRS)

Headrick, R. D.; Rowe, J. N.

1996-01-01

This paper describes a study to verify onboard attitude control laws in the coarse Sun-pointing (CSP) mode by simulation and to develop procedures for operational support for the Solar and Heliospheric Observatory (SOHO) mission. SOHO was launched on December 2, 1995, and the predictions of the simulation were verified with the flight data. This study used a commercial off the shelf product MATLAB(tm) to do the following: Develop procedures for computing the parasitic torques for orbital maneuvers; Simulate onboard attitude control of roll, pitch, and yaw during orbital maneuvers; Develop procedures for predicting firing time for both on- and off-modulated thrusters during orbital maneuvers; Investigate the use of feed forward or pre-bias torques to reduce the attitude handoff during orbit maneuvers - in particular, determine how to use the flight data to improve the feed forward torque estimates for use on future maneuvers. The study verified the stability of the attitude control during orbital maneuvers and the proposed use of feed forward torques to compensate for the attitude handoff. Comparison of the simulations with flight data showed: Parasitic torques provided a good estimate of the on- and off-modulation for attitude control; The feed forward torque compensation scheme worked well to reduce attitude handoff during the orbital maneuvers. The work has been extended to prototype calibration of thrusters from observed firing time and observed reaction wheel speed changes.

Food choice motives, attitude towards and intention to adopt personalised nutrition.

PubMed

Rankin, Audrey; Bunting, Brendan P; Poínhos, Rui; van der Lans, Ivo A; Fischer, Arnout Rh; Kuznesof, Sharron; Almeida, Mdv; Markovina, Jerko; Frewer, Lynn J; Stewart-Knox, Barbara J

2018-05-17

The present study explored associations between food choice motives, attitudes towards and intention to adopt personalised nutrition, to inform communication strategies based on consumer priorities and concerns.Design/SettingA survey was administered online which included the Food Choice Questionnaire (FCQ) and items assessing attitudes towards and intention to adopt personalised nutrition. Nationally representative samples were recruited in nine EU countries (n 9381). Structural equation modelling indicated that the food choice motives 'weight control', 'mood', 'health' and 'ethical concern' had a positive association and 'price' had a negative association with attitude towards, and intention to adopt, personalised nutrition. 'Health' was positively associated and 'familiarity' negatively associated with attitude towards personalised nutrition. The effects of 'weight control', 'ethical concern', 'mood' and 'price' on intention to adopt personalised nutrition were partially mediated by attitude. The effects of 'health' and 'familiarity' were fully mediated by attitude. 'Sensory appeal' was negatively and directly associated with intention to adopt personalised nutrition. Personalised nutrition providers may benefit from taking into consideration the importance of underlying determinants of food choice in potential users, particularly weight control, mood and price, when promoting services and in tailoring communications that are motivationally relevant.

Attitude Model of a Reaction Wheel/Fixed Thruster Based Satellite Using Telemetry Data

DTIC Science & Technology

2005-03-01

xii ATTITUDE MODEL OF A REACTION WHEEL/ FIXED THRUSTER BASED SATELLITE USING TELEMETRY DATA I. Introduction As technology advances and spacecraft ...Earth’s horizon to determine spacecraft attitude . Sun sensors use the Sun to determine spacecraft attitude and are currently the attitude determination...wheels and the rate of rotation of the gimbal. Gravity gradient stabilization is a passive attitude control technique that is designed to use the

Modeling Attitude Dynamics in Simulink: A Study of the Rotational and Translational Motion of a Spacecraft Given Torques and Impulses Generated by RMS Hand Controllers

NASA Technical Reports Server (NTRS)

Mauldin, Rebecca H.

2010-01-01

In order to study and control the attitude of a spacecraft, it is necessary to understand the natural motion of a body in orbit. Assuming a spacecraft to be a rigid body, dynamics describes the complete motion of the vehicle by the translational and rotational motion of the body. The Simulink Attitude Analysis Model applies the equations of rigid body motion to the study of a spacecraft?s attitude in orbit. Using a TCP/IP connection, Matlab reads the values of the Remote Manipulator System (RMS) hand controllers and passes them to Simulink as specified torque and impulse profiles. Simulink then uses the governing kinematic and dynamic equations of a rigid body in low earth orbit (LE0) to plot the attitude response of a spacecraft for five seconds given known applied torques and impulses, and constant principal moments of inertia.

Flight test results for a separate surface stability augmented Beech model 99

NASA Technical Reports Server (NTRS)

Jenks, G. E.; Henry, H. F.; Roskam, J.

1977-01-01

A flight evaluation of a Beech model 99 equipped with an attitude command control system incorporating separate surface stability augmentation (SSSA) was conducted to determine whether an attitude command control system could be implemented using separate surface controls, and to determine whether the handling and ride qualities of the aircraft were improved by the SSSA attitude command system. The results of the program revealed that SSSA is a viable approach to implementing attitude command and also that SSSA has the capability of performing less demanding augmentation tasks such as yaw damping, wing leveling, and pitch damping. The program also revealed that attitude command did improve the pilot rating and ride qualities of the airplane while flying an IFR mission in turbulence. Some disadvantages of the system included the necessity of holding aileron force in a banked turn and excessive stiffness in the pitch axis.

Intention to Seek Mental Health Treatment for Adolescent Girls: Comparison of Predictors in Mothers and Daughters

PubMed Central

Logsdon, M. Cynthia; Pinto, Melissa D.; LaJoie, A. Scott; Hertweck, Paige; Lynch, Tania; Flamini, Laura

2013-01-01

PROBLEM To examine predictors of intention to seek mental health treatment for adolescent girls in mothers and daughters. METHODS In this cross-sectional study, mothers and adolescent daughters (n = 71) completed measures of behavioral attitudes, subjective norms, perceived behavioral control, and intention to seek mental health treatment for the adolescent daughter. FINDINGS Behavioral attitude and perceived behavioral control predicted intention to seek mental health treatment among mothers. Behavioral attitude predicted intention among daughters. There were no associations between mothers and daughters on study variables. CONCLUSIONS To promote shared decision making and engagement in mental health treatment, clinicians may target interventions to the mother’s perceived behavioral control and behavioral attitudes of daughters and mothers. Based upon study results, clinicians should promote shared decision making and concordance between mothers and daughters on attitudes toward mental health treatment. PMID:24180603

14 CFR 23.147 - Directional and lateral control.

Code of Federal Regulations, 2010 CFR

2010-01-01

... attitude or encountering dangerous characteristics, in the event of a sudden and complete failure of the... continued safe flight and the ability to maintain attitudes suitable for a controlled landing without...

NASA Workshop on Hybrid (Mixed-Actuator) Spacecraft Attitude Control

NASA Technical Reports Server (NTRS)

Dennehy, Cornelius J.; Kunz, Nans

2014-01-01

At the request of the Science Mission Directorate Chief Engineer, the NASA Technical Fellow for Guidance, Navigation & Control assembled and facilitated a workshop on Spacecraft Hybrid Attitude Control. This multi-Center, academic, and industry workshop, sponsored by the NASA Engineering and Safety Center (NESC), was held in April 2013 to unite nationwide experts to present and discuss the various innovative solutions, techniques, and lessons learned regarding the development and implementation of the various hybrid attitude control system solutions investigated or implemented. This report attempts to document these key lessons learned with the 16 findings and 9 NESC recommendations.

Inflight redesign of the IUE attitude control system

NASA Technical Reports Server (NTRS)

Femiano, M. D.

1986-01-01

The one- and two-gyro system designs of the International Ultraviolet Explorer (IUE) attitude control system (ACS) are examined. The inertial reference assembly that provides the primary attitude reference for IUE consists of six rate sensors which are single-axis rate integrating gyros. The gyros operate in a pulse rebalanced mode that produces an output pulse for 0.01 arcsec of motion about the input axis. The functions of the fine error sensor, fine sun sensor (FSS), the IUE reaction wheels, the onboard computer, and the hold/slew algorithm are described. The use of the hold/slew algorithm to compute the control voltage for the ACS based on the Kalman filter is studied. A two-gyro system was incorporated into IUE following gyro failure. The procedures for establishing attitude control with the two-gyro design based on the FSS is analyzed. The performance of the two-gyro system is evaluated; it is observed that the pitch and yaw gyro control is 0.24 arcsec and the control is sufficient to permit extended periods of observation.

Simultaneous calibrations of Voyager celestial and inertial attitude control systems in flight

NASA Technical Reports Server (NTRS)

Jahanshahi, M. H.

1982-01-01

A mathematical description of the data reduction technique used to simultaneously calibrate the Voyager celestial and inertial attitude control subsystems is given. It is shown that knowledge of the spacecraft limit cycle motion, as measured by the celestial and the inertial sensors, is adequate to result in the estimates of a selected number of errors which adversely affect the spacecraft attitude knowledge.

Controlled versus automatic processes: which is dominant to safety? The moderating effect of inhibitory control.

PubMed

Xu, Yaoshan; Li, Yongjuan; Ding, Weidong; Lu, Fan

2014-01-01

This study explores the precursors of employees' safety behaviors based on a dual-process model, which suggests that human behaviors are determined by both controlled and automatic cognitive processes. Employees' responses to a self-reported survey on safety attitudes capture their controlled cognitive process, while the automatic association concerning safety measured by an Implicit Association Test (IAT) reflects employees' automatic cognitive processes about safety. In addition, this study investigates the moderating effects of inhibition on the relationship between self-reported safety attitude and safety behavior, and that between automatic associations towards safety and safety behavior. The results suggest significant main effects of self-reported safety attitude and automatic association on safety behaviors. Further, the interaction between self-reported safety attitude and inhibition and that between automatic association and inhibition each predict unique variances in safety behavior. Specifically, the safety behaviors of employees with lower level of inhibitory control are influenced more by automatic association, whereas those of employees with higher level of inhibitory control are guided more by self-reported safety attitudes. These results suggest that safety behavior is the joint outcome of both controlled and automatic cognitive processes, and the relative importance of these cognitive processes depends on employees' individual differences in inhibitory control. The implications of these findings for theoretical and practical issues are discussed at the end.

Controlled versus Automatic Processes: Which Is Dominant to Safety? The Moderating Effect of Inhibitory Control

PubMed Central

Xu, Yaoshan; Li, Yongjuan; Ding, Weidong; Lu, Fan

2014-01-01

This study explores the precursors of employees' safety behaviors based on a dual-process model, which suggests that human behaviors are determined by both controlled and automatic cognitive processes. Employees' responses to a self-reported survey on safety attitudes capture their controlled cognitive process, while the automatic association concerning safety measured by an Implicit Association Test (IAT) reflects employees' automatic cognitive processes about safety. In addition, this study investigates the moderating effects of inhibition on the relationship between self-reported safety attitude and safety behavior, and that between automatic associations towards safety and safety behavior. The results suggest significant main effects of self-reported safety attitude and automatic association on safety behaviors. Further, the interaction between self-reported safety attitude and inhibition and that between automatic association and inhibition each predict unique variances in safety behavior. Specifically, the safety behaviors of employees with lower level of inhibitory control are influenced more by automatic association, whereas those of employees with higher level of inhibitory control are guided more by self-reported safety attitudes. These results suggest that safety behavior is the joint outcome of both controlled and automatic cognitive processes, and the relative importance of these cognitive processes depends on employees' individual differences in inhibitory control. The implications of these findings for theoretical and practical issues are discussed at the end. PMID:24520338

Knowledge, Attitude, Practice, and Status of Infection Control among Iranian Dentists and Dental Students: A Systematic Review

PubMed Central

Moradi Khanghahi, Behnam; Jamali, Zahra; Pournaghi Azar, Fatemeh; Naghavi Behzad, Mohammad; Azami-Aghdash, Saber

2013-01-01

Background and aims Infection control is an important issue in dentistry, and the dentists are primarily responsible for observing the relevant procedures. Therefore, the present study evaluated knowledge, attitude, practice, and status of infection control among Iranian dentists through systematic review of published results. Materials and methods In this systematic review, the required data was collected searching for keywords including infection, infection control, behavior, performance, practice, attitude, knowledge, dent*, prevention, Iran* and their Persian equivalents in PubMed, Science Direct, Iranmedex, SID, Medlib, and Magiran databases with a time limit of 1985 to 2012. Out of 698 articles, 15 completely related articles were finally considered and the rest were excluded due to lake of relev-ance to the study goals. The required data were extracted and summarized in an Extraction Table and were analyzed ma-nually. Results Evaluating the results of studies indicated inappropriate knowledge, attitude, and practice regarding infection control among Iranian dentists and dental students. Using personal protection devices and observing measures required for infection control were not in accordance with global standards. Conclusion The knowledge, attitudes, and practice of infection control in Iranian dental settings were found to be inadequate. Therefore, dentists should be educated more on the subject and special programs should be in place to monitor the dental settings for observing infection control standards. PMID:23875081

Sexual Experience and Responses to a Birth Control Film.

ERIC Educational Resources Information Center

Herold, Edward S.; Thomas, Roger E.

1980-01-01

The relationship between sexual experience and contraceptive attitudinal responses to a birth control film is examined. Significant group differences were found regarding reinforcement of sexual attitudes but not for contraceptive attitudes. (JMF)

Cultural, contextual, and intrapersonal predictors of risky sexual attitudes among urban African American girls in early adolescence.

PubMed

Belgrave, F Z; Van Oss Marin, B; Chambers, D B

2000-08-01

The role of cultural factors in explaining sexual attitudes among African American urban girls, aged 10-13 years, was investigated in this study. The authors predicted that girls with higher school interest, family cohesion, religiosity, and behavioral self-esteem would endorse less risky sexual attitudes. Also, older girls were expected to have more risky sexual attitudes than younger girls, and girls from 1- rather than 2-parent households were expected to have more risky sexual attitudes. The authors hypothesized that ethnic identity and gender role orientations would contribute to explaining variability in sexual attitudes after controlling for contextual and intrapersonal variables. A questionnaire containing measures of the study constructs was administered to 214 girls who were participants in a substance abuse prevention program. Pretest data were used in analyses. A final regression model accounted for 23% of the variance in sexual attitudes. Age and behavioral self-esteem were significant predictors, with younger teens and teens with higher behavioral self-esteem having less risky sexual attitudes. Cultural variables contributed to explaining variation in sexual attitudes after other variables were controlled for. Higher levels of ethnic identity were associated with less risky sexual attitudes. A masculine gender role orientation was associated with more risky sexual attitudes.

Integrated Power/Attitude Control System (IPACS) study. Volume 1: Feasibility studies. [application of flywheels for power storage and generation

NASA Technical Reports Server (NTRS)

Notti, J. E.; Cormack, A., III; Schmill, W. C.

1974-01-01

An Integrated Power/Attitude Control System (IPACS) concept consisting of an array of spinning flywheels, with or without gimbals, capable of performing the dual function of power storage and generation, as well as attitude control has been investigated. This system provides attitude control through momentum storage, and replaces the storage batteries onboard the spacecraft. The results of the investigation are presented in two volumes. The trade-off studies performed to establish the feasibility, cost effectiveness, required level of development, and boundaries of application of IPACS to a wide variety of spacecraft are discussed. The conceptual designs for a free-flying research application module (RAM), and for a tracking and data relay satellite (TDRS) are presented. Results from dynamic analyses and simulations of the IPACS conceptual designs are included.

Attitude: A Component of Competent Performance.

ERIC Educational Resources Information Center

Meussling, Vonne

The findings of a survey of attitude studies to determine the effect of students' attitudes on communication competence as they enter the work force and develop their careers are reported in this paper. The paper explains how attitude improvement is an effective management tool in controlling costly absenteeism, output, job productivity, work…

Using the theory of planned behavior to explore attitudes and beliefs about dietary supplements among HIV-positive Black women.

PubMed

Lino, Stephanie; Marshak, Helen Hopp; Herring, R Patti; Belliard, Juan Carlos; Hilliard, Charles; Campbell, Danielle; Montgomery, Susanne

2014-04-01

This cross-sectional study investigated whether the theory of planned behavior (TPB) constructs: attitudes, subjective norms, and perceived behavioral control were related to intention of dietary supplements use among African-American women living with Human Immunodeficiency Virus and/or Acquired Immune Deficiency Syndrome (HIV/AIDS). A closed-ended questionnaire based on the TPB was utilized to explore the use of dietary supplements among a cohort of 153 HIV-positive African-American women. Overall, 45% of the respondents used dietary supplements to manage/control their HIV. Combined, attitudes, subjective norms and perceived behavioral control were significant predictors of intention toward dietary supplement use (69% of the variance explained, p<0.0001). Attitudes (β=0.23, p<0.001) and perceived behavioral control (β=0.45, p<0.0001) were found to be significant independent predictors of intention. Behavioral intention and proximal TPB constructs (attitudes, subjective norms, and perceived behavioral control), as well as their underlying beliefs about dietary supplements use, were all found to be significantly more positive in users of dietary supplements compared to non-users (p<0.001). Results showed that attitudes, subjective norms and perceived behavioral control are important predictors in the intention to use dietary supplements for control of HIV among African-American women. Implications from this study suggest that the TPB can be used to better identify and understand salient beliefs that surround intentions to use alternative therapies for management of disease. These beliefs can be used to develop interventions surrounding HIV treatment and care. Copyright © 2014 Elsevier Ltd. All rights reserved.

Spacecraft attitude control using neuro-fuzzy approximation of the optimal controllers

NASA Astrophysics Data System (ADS)

Kim, Sung-Woo; Park, Sang-Young; Park, Chandeok

2016-01-01

In this study, a neuro-fuzzy controller (NFC) was developed for spacecraft attitude control to mitigate large computational load of the state-dependent Riccati equation (SDRE) controller. The NFC was developed by training a neuro-fuzzy network to approximate the SDRE controller. The stability of the NFC was numerically verified using a Lyapunov-based method, and the performance of the controller was analyzed in terms of approximation ability, steady-state error, cost, and execution time. The simulations and test results indicate that the developed NFC efficiently approximates the SDRE controller, with asymptotic stability in a bounded region of angular velocity encompassing the operational range of rapid-attitude maneuvers. In addition, it was shown that an approximated optimal feedback controller can be designed successfully through neuro-fuzzy approximation of the optimal open-loop controller.

Facing death alone or together? Investigating the interdependence of death anxiety, dysfunctional attitudes and quality of life in patient-caregiver dyads confronting lung cancer.

PubMed

Lau, Bobo Hi-Po; Wong, Daniel F K; Fung, Y L; Zhou, Jillian; Chan, Cecilia L W; Chow, Amy Y M

2018-05-21

Based on the cognitive theory, anxiety arising from the awareness of death and dying may activate dysfunctional attitudes, which may then reduce quality of life. This study examined the interdependence and the mediating role of dysfunctional attitudes on the relationship between death anxiety and quality of life among patients with lung cancer and their caregivers. From March 2016 to April 2017, 173 pairs of patients and their caregivers enrolled in a randomized controlled trial of psychosocial support. Using the baseline data, actor-partner interdependence modelling was used to analyze the relationships among death anxiety, dysfunctional attitudes and quality of life. In patients, death anxiety was related to dependency (β=.51) and self-control (β=-.37); achievement (β=-.21) and self-control (β=.34) were related to quality of life. Among caregivers, death anxiety was related to all three dysfunctional attitudes of their own (βs=.23 to.32); dependency (β=-.22) was associated with quality of life. Caregiver quality of life were also associated with patient self-control (β=.22) and achievement (β=-.18). Patient self-control mediated the links between patient death anxiety with both patient and caregiver quality of life. The relationship between death anxiety and quality of life was mediated by dependency in caregivers. Death anxiety influences dysfunctional attitudes and quality of life of both patients and caregivers. Our results support the relevance of dysfunctional attitudes in understanding the impact of death anxiety and underscore the need for parallel psychosocial interventions. This article is protected by copyright. All rights reserved.

Attitudes and beliefs, not just knowledge, influence the effectiveness of environmental cleaning by environmental service workers.

PubMed

Matlow, Anne G; Wray, Rick; Richardson, Susan E

2012-04-01

Hospital environmental service workers (ESWs) play an important role in interrupting the chain of infection because the environment is a reservoir for nosocomial pathogens. Improving ESWs' knowledge through education has been shown to improve ESW cleaning, but the behavioral determinants of their work have not been studied. Understanding and targeting ESWs' attitudes and beliefs may inform strategies to improve environmental cleaning. With the theory of planned behavior as framework, we used questionnaires and focus groups to examine intensive care unit ESWs' attitudes, beliefs [behavioral, normative, and control], and control) and intent about their job. Baseline quantitative microbial cultures of high-touch services were performed before and after cleaning. After an educational intervention addressing their attitudes, beliefs, and general infection control knowledge, attitudes, beliefs, and microbial contamination were reassessed. Beliefs were uniformly strong (4.5/5-5/5), and normative beliefs correlated best with intent to clean (R(2) = 0.3). Themes elicited from the focus groups included "me versus them," lack of appreciation, pride in work, and "if it were me." The rate of environmental contamination was significantly improved after the intervention (P = .0074 vs P = .0023, respectively); the measured relationship among attitudes, beliefs, and intent was not significantly changed. ESWs' attitudes and beliefs about their job may impact their intent to clean and in turn the effectiveness of their efforts. Understanding and addressing these attitudes and beliefs can be used to inform strategies for sustained improvement of environmental cleaning. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Instructional strategies to improve women's attitudes toward science

NASA Astrophysics Data System (ADS)

Newbill, Phyllis Leary

Although negative attitudes toward science are common among women and men in undergraduate introductory science classes, women's attitudes toward science tend to be more negative than men's. The reasons for women's negative attitudes toward science include lack of self-confidence, fear of association with social outcasts, lack of women role models in science, and the fundamental differences between traditional scientific and feminist values. Attitudes are psychological constructs theorized to be composed of emotional, cognitive, and behavioral components. Attitudes serve functions, including social expressive, value expressive, utilitarian, and defensive functions, for the people who hold them. To change attitudes, the new attitudes must serve the same function as the old one, and all three components must be treated. Instructional designers can create instructional environments to effect attitude change. In designing instruction to improve women's attitudes toward science, instructional designers should (a) address the emotions that are associated with existing attitudes, (b) involve credible, attractive women role models, and (c) address the functions of the existing attitudes. Two experimental instructional modules were developed based on these recommendations, and two control modules were developed that were not based on these recommendations. The asynchronous, web-based modules were administered to 281 undergraduate geology and chemistry students at two universities. Attitude assessment revealed that attitudes toward scientists improved significantly more in the experimental group, although there was no significant difference in overall attitudes toward science. Women's attitudes improved significantly more than men's in both the experimental and control groups. Students whose attitudes changed wrote significantly more in journaling activities associated with the modules. Qualitative analysis of journals revealed that the guidelines worked exactly as predicted for some students.

Birth Control and Low-Income Mexican-American Women: The Impact of Three Values.

ERIC Educational Resources Information Center

Ortiz, Silvia; Casas, Jesus Manuel

1990-01-01

Assesses relationship between Mexican-American women's birth-control attitudes, knowledge, and usage, and values of motherhood, male dominance, and sexual expression. Multiple regression analysis links contraception attitudes with traditional values, regardless of acculturation. Establishes positive link between birth-control use and traditional…

The effects of educating mothers and girls on the girls' attitudes toward puberty health: a randomized controlled trial.

PubMed

Afsari, Atousa; Mirghafourvand, Mojgan; Valizadeh, Sousan; Abbasnezhadeh, Massomeh; Galshi, Mina; Fatahi, Samira

2017-04-01

The attitude of a girl toward her menstruation and puberty has a considerable impact on her role during motherhood, social adjustment, and future marital life. This study was conducted in 2014 with the aim of comparing the effects of educating mothers and girls on the attitudes of adolescent girls of Tabriz City, Iran, towards puberty health. This randomized control clinical trial was conducted on 364 adolescent girls who experienced menstruation. Twelve schools were selected randomly among 107 secondary schools for girls. One-third of the students of each school were selected randomly using a table of random numbers and socio-demographic and each participant was asked to answer the attitude questionnaires. The schools were randomly allocated to the groups of mother's education, girl's education, and no-intervention. The attitude questionnaire was filled out by the participants again 2 months after intervention. The general linear model, in which the baseline values were controlled, was employed to compare the scores of the three groups after the intervention. No significant differences were observed among the three groups in terms of the attitude score before intervention (p>0.05). Attitude score improvement after intervention in the girl's education group was significantly higher than the one of both mother's education (adjusted mean difference [AMD]: 1.8; [95% confidence interval (CI): 0.4-1.3]) and no-intervention groups (AMD: 1.3; [95% CI: 0.0-2.6]) by controlling the attitude score before intervention. Based on the findings, it is more effective to educate girls directly about puberty health to improve adolescent girls' attitudes than educating mothers and asking them to transfer information to the girls. Nevertheless, studies with longer training period and follow-up are proposed to determine the effects of educating girls (through their mothers) on their attitudes about puberty health.

Finite-time fault tolerant attitude stabilization control for rigid spacecraft.

PubMed

Huo, Xing; Hu, Qinglei; Xiao, Bing

2014-03-01

A sliding mode based finite-time control scheme is presented to address the problem of attitude stabilization for rigid spacecraft in the presence of actuator fault and external disturbances. More specifically, a nonlinear observer is first proposed to reconstruct the amplitude of actuator faults and external disturbances. It is proved that precise reconstruction with zero observer error is achieved in finite time. Then, together with the system states, the reconstructed information is used to synthesize a nonsingular terminal sliding mode attitude controller. The attitude and the angular velocity are asymptotically governed to zero with finite-time convergence. A numerical example is presented to demonstrate the effectiveness of the proposed scheme. © 2013 Published by ISA on behalf of ISA.

Visual attitude propagation for small satellites

NASA Astrophysics Data System (ADS)

Rawashdeh, Samir A.

As electronics become smaller and more capable, it has become possible to conduct meaningful and sophisticated satellite missions in a small form factor. However, the capability of small satellites and the range of possible applications are limited by the capabilities of several technologies, including attitude determination and control systems. This dissertation evaluates the use of image-based visual attitude propagation as a compliment or alternative to other attitude determination technologies that are suitable for miniature satellites. The concept lies in using miniature cameras to track image features across frames and extracting the underlying rotation. The problem of visual attitude propagation as a small satellite attitude determination system is addressed from several aspects: related work, algorithm design, hardware and performance evaluation, possible applications, and on-orbit experimentation. These areas of consideration reflect the organization of this dissertation. A "stellar gyroscope" is developed, which is a visual star-based attitude propagator that uses relative motion of stars in an imager's field of view to infer the attitude changes. The device generates spacecraft relative attitude estimates in three degrees of freedom. Algorithms to perform the star detection, correspondence, and attitude propagation are presented. The Random Sample Consensus (RANSAC) approach is applied to the correspondence problem to successfully pair stars across frames while mitigating falsepositive and false-negative star detections. This approach provides tolerance to the noise levels expected in using miniature optics and no baffling, and the noise caused by radiation dose on orbit. The hardware design and algorithms are validated using test images of the night sky. The application of the stellar gyroscope as part of a CubeSat attitude determination and control system is described. The stellar gyroscope is used to augment a MEMS gyroscope attitude propagation algorithm to minimize drift in the absence of an absolute attitude sensor. The stellar gyroscope is a technology demonstration experiment on KySat-2, a 1-Unit CubeSat being developed in Kentucky that is in line to launch with the NASA ELaNa CubeSat Launch Initiative. It has also been adopted by industry as a sensor for CubeSat Attitude Determination and Control Systems (ADCS). KEYWORDS: Small Satellites, Attitude Determination, Egomotion Estimation, RANSAC, Image Processing.

Learning to Dislike Chocolate: Conditioning Negative Attitudes toward Chocolate and Its Effect on Chocolate Consumption.

PubMed

Wang, Yan; Wang, Guosen; Zhang, Dingyuan; Wang, Lei; Cui, Xianghua; Zhu, Jinglei; Fang, Yuan

2017-01-01

Evaluative conditioning (EC) procedures can be used to form and change attitudes toward a wide variety of objects. The current study examined the effects of a negative EC procedure on attitudes toward chocolate, and whether it influenced chocolate evaluation and consumption. Participants were randomly assigned to the experimental condition in which chocolate images were paired with negative stimuli, or the control condition in which chocolate images were randomly paired with positive stimuli (50%) and negative stimuli (50%). Explicit and implicit attitudes toward chocolate images were collected. During an ostensible taste test, chocolate evaluation and consumption were assessed. Results revealed that compared to participants in the control condition, participants in the experimental condition showed more negative explicit and implicit attitudes toward chocolate images and evaluated chocolate more negatively during the taste test. However, chocolate consumption did not differ between experimental and control conditions. These findings suggest that pairing chocolate with negative stimuli can influence attitudes toward chocolate, though behavioral effects are absent. Intervention applications of EC provide avenues for future research and practices.

Learning to Dislike Chocolate: Conditioning Negative Attitudes toward Chocolate and Its Effect on Chocolate Consumption

PubMed Central

Wang, Yan; Wang, Guosen; Zhang, Dingyuan; Wang, Lei; Cui, Xianghua; Zhu, Jinglei; Fang, Yuan

2017-01-01

Evaluative conditioning (EC) procedures can be used to form and change attitudes toward a wide variety of objects. The current study examined the effects of a negative EC procedure on attitudes toward chocolate, and whether it influenced chocolate evaluation and consumption. Participants were randomly assigned to the experimental condition in which chocolate images were paired with negative stimuli, or the control condition in which chocolate images were randomly paired with positive stimuli (50%) and negative stimuli (50%). Explicit and implicit attitudes toward chocolate images were collected. During an ostensible taste test, chocolate evaluation and consumption were assessed. Results revealed that compared to participants in the control condition, participants in the experimental condition showed more negative explicit and implicit attitudes toward chocolate images and evaluated chocolate more negatively during the taste test. However, chocolate consumption did not differ between experimental and control conditions. These findings suggest that pairing chocolate with negative stimuli can influence attitudes toward chocolate, though behavioral effects are absent. Intervention applications of EC provide avenues for future research and practices. PMID:28900409

Attitude Control Propulsion Components, Volume 2

NASA Technical Reports Server (NTRS)

1974-01-01

Attitude control propulsion components are described, including hydrazine thrusters, hydrazine thruster and cold gas jet valves, and pressure and temperature transducers. Component-ordered data are presented in tabular form; the manufacturer and specific space program are included.

Speed-constrained three-axes attitude control using kinematic steering

NASA Astrophysics Data System (ADS)

Schaub, Hanspeter; Piggott, Scott

2018-06-01

Spacecraft attitude control solutions typically are torque-level algorithms that simultaneously control both the attitude and angular velocity tracking errors. In contrast, robotic control solutions are kinematic steering commands where rates are treated as the control variable, and a servo-tracking control subsystem is present to achieve the desired control rates. In this paper kinematic attitude steering controls are developed where an outer control loop establishes a desired angular response history to a tracking error, and an inner control loop tracks the commanded body angular rates. The overall stability relies on the separation principle of the inner and outer control loops which must have sufficiently different response time scales. The benefit is that the outer steering law response can be readily shaped to a desired behavior, such as limiting the approach angular velocity when a large tracking error is corrected. A Modified Rodrigues Parameters implementation is presented that smoothly saturates the speed response. A robust nonlinear body rate servo loop is developed which includes integral feedback. This approach provides a convenient modular framework that makes it simple to interchange outer and inner control loops to readily setup new control implementations. Numerical simulations illustrate the expected performance for an aggressive reorientation maneuver subject to an unknown external torque.

Evaluation and modeling of autonomous attitude thrust control for the Geostation Operational Environmental Satellite (GOES)-8 orbit determination

NASA Technical Reports Server (NTRS)

Forcey, W.; Minnie, C. R.; Defazio, R. L.

1995-01-01

The Geostationary Operational Environmental Satellite (GOES)-8 experienced a series of orbital perturbations from autonomous attitude control thrusting before perigee raising maneuvers. These perturbations influenced differential correction orbital state solutions determined by the Goddard Space Flight Center (GSFC) Goddard Trajectory Determination System (GTDS). The maneuvers induced significant variations in the converged state vector for solutions using increasingly longer tracking data spans. These solutions were used for planning perigee maneuvers as well as initial estimates for orbit solutions used to evaluate the effectiveness of the perigee raising maneuvers. This paper discusses models for the incorporation of attitude thrust effects into the orbit determination process. Results from definitive attitude solutions are modeled as impulsive thrusts in orbit determination solutions created for GOES-8 mission support. Due to the attitude orientation of GOES-8, analysis results are presented that attempt to absorb the effects of attitude thrusting by including a solution for the coefficient of reflectivity, C(R). Models to represent the attitude maneuvers are tested against orbit determination solutions generated during real-time support of the GOES-8 mission. The modeling techniques discussed in this investigation offer benefits to the remaining missions in the GOES NEXT series. Similar missions with large autonomous attitude control thrusting, such as the Solar and Heliospheric Observatory (SOHO) spacecraft and the INTELSAT series, may also benefit from these results.

Robust attitude control design for spacecraft under assigned velocity and control constraints.

PubMed

Hu, Qinglei; Li, Bo; Zhang, Youmin

2013-07-01

A novel robust nonlinear control design under the constraints of assigned velocity and actuator torque is investigated for attitude stabilization of a rigid spacecraft. More specifically, a nonlinear feedback control is firstly developed by explicitly taking into account the constraints on individual angular velocity components as well as external disturbances. Considering further the actuator misalignments and magnitude deviation, a modified robust least-squares based control allocator is employed to deal with the problem of distributing the previously designed three-axis moments over the available actuators, in which the focus of this control allocation is to find the optimal control vector of actuators by minimizing the worst-case residual error using programming algorithms. The attitude control performance using the controller structure is evaluated through a numerical example. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

High speed reaction wheels for satellite attitude control and energy storage

NASA Technical Reports Server (NTRS)

Studer, P.; Rodriguez, E.

1985-01-01

The combination of spacecraft attitude control and energy storage (ACES) functions in common hardware, to synergistically maintain three-axis attitude control while supplying electrical power during earth orbital eclipses, allows the generation of control torques by high rotating speed wheels that react against the spacecraft structure via a high efficiency bidirectional energy conversion motor/generator. An ACES system encompasses a minimum of four wheels, controlling power and the three torque vectors. Attention is given to the realization of such a system with composite flywheel rotors that yield high energy density, magnetic suspension technology yielding low losses at high rotational speeds, and an ironless armature permanent magnet motor/generator yielding high energy conversion efficiency.

Grasp Assist Device with Automatic Mode Control Logic

NASA Technical Reports Server (NTRS)

Laske, Evan (Inventor); Davis, Donald R. (Inventor); Ihrke, Chris A. (Inventor)

2018-01-01

A system includes a glove, sensors, actuator assemblies, and controller. The sensors include load sensors which measure an actual grasping force and attitude sensors which determine a glove attitude. The actuator assembly provides a grasp assist force to the glove. Respective locations of work cells in the work environment and permitted work tasks for each work cell are programmed into the controller. The controller detects the glove location and attitude. A work task is selected by the controller for the location. The controller calculates a required grasp assist force using measured actual grasping forces from the load sensors. The required grasp assist force is applied via the glove using the actuator assembly to thereby assist the operator in performing the identified work task.

Latent interaction effects in the theory of planned behaviour applied to quitting smoking.

PubMed

Hukkelberg, Silje Sommer; Hagtvet, Knut A; Kovac, Velibor Bobo

2014-02-01

This study applies three latent interaction models in the theory of planned behaviour (TPB; Ajzen, 1988, Attitudes, personality, and behavior. Homewood, IL: Dorsey Press; Ajzen, 1991, Organ. Behav. Hum. Decis. Process., 50, 179) to quitting smoking: (1) attitude × perceived behavioural control on intention; (2) subjective norms (SN) × attitude on intention; and (3) perceived behavioural control × intention on quitting behaviour. The data derive from a longitudinal Internet survey of 939 smokers aged 15-74 over a period of 4 months. Latent interaction effects were estimated using the double-mean-centred unconstrained approach (Lin et al., 2010, Struct. Equ. Modeling, 17, 374) in LISREL. Attitude × SN and attitude × perceived behavioural control both showed a significant interaction effect on intention. No significant interaction effect was found for perceived behavioural control × intention on quitting. The latent interaction approach is a useful method for investigating specific conditions between TPB components in the context of quitting behaviour. Theoretical and practical implications of the results are discussed. © 2013 The British Psychological Society.

Instrument Attitude Precision Control

NASA Technical Reports Server (NTRS)

Juang, Jer-Nan

2004-01-01

A novel approach is presented in this paper to analyze attitude precision and control for an instrument gimbaled to a spacecraft subject to an internal disturbance caused by a moving component inside the instrument. Nonlinear differential equations of motion for some sample cases are derived and solved analytically to gain insight into the influence of the disturbance on the attitude pointing error. A simple control law is developed to eliminate the instrument pointing error caused by the internal disturbance. Several cases are presented to demonstrate and verify the concept presented in this paper.

AAS/GSFC 13th International Symposium on Space Flight Dynamics. Volume 1

NASA Technical Reports Server (NTRS)

Stengle, Tom (Editor)

1998-01-01

This conference proceedings preprint includes papers and abstracts presented at the 13th International Symposium on Space Flight Dynamics. Cosponsored by American Astronautical Society and the Guidance, Navigation and Control Center of the Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination, and control; attitude sensor calibration; attitude dynamics; and mission design.

Attitude dynamics and control of spacecraft with a partially filled liquid tank and flexible panels

NASA Astrophysics Data System (ADS)

Liu, Feng; Yue, Baozeng; Zhao, Liangyu

2018-02-01

A liquid-filled flexible spacecraft is essentially a time-variant fully-coupled system, whose dynamics characteristics are closely associated with its motion features. This paper focuses on the mathematical modelling and attitude control of the spacecraft coupled with fuel sloshing dynamics and flexible solar panels vibration. The slosh motion is represented by a spherical pendulum, whose motion description method is improved by using split variable operation. Benefiting from this improvement, the nonlinear lateral sloshing and the rotary sloshing as well as the rigid motion of a liquid respect to the spacecraft can be approximately described. The assumed modes discretization method has been adopted to approximate the elastic displacements of the attached panels, and the coupled dynamics is derived by using the Lagrangian formulation. A variable substitution method is proposed to obtain the apparently-uncoupled mathematical model of the rigid-flexible-liquid spacecraft. After linearization, this model can be directly used for designing Lyapunov output-feedback attitude controller (OFAC). With only torque actuators, and attitude and rate sensors installed, this kind of attitude controller, as simulation results show, is capable of not only bringing the spacecraft to the desired orientation, but also suppressing the effect of flex and slosh on the attitude motion of the spacecraft.

Development of a hardware-in-loop attitude control simulator for a CubeSat satellite

NASA Astrophysics Data System (ADS)

Tapsawat, Wittawat; Sangpet, Teerawat; Kuntanapreeda, Suwat

2018-01-01

Attitude control is an important part in satellite on-orbit operation. It greatly affects the performance of satellites. Testing of an attitude determination and control subsystem (ADCS) is very challenging since it might require attitude dynamics and space environment in the orbit. This paper develops a low-cost hardware-in-loop (HIL) simulator for testing an ADCS of a CubeSat satellite. The simulator consists of a numerical simulation part, a hardware part, and a HIL interface hardware unit. The numerical simulation part includes orbital dynamics, attitude dynamics and Earth’s magnetic field. The hardware part is the real ADCS board of the satellite. The simulation part outputs satellite’s angular velocity and geomagnetic field information to the HIL interface hardware. Then, based on this information, the HIL interface hardware generates I2C signals mimicking the signals of the on-board rate-gyros and magnetometers and consequently outputs the signals to the ADCS board. The ADCS board reads the rate-gyro and magnetometer signals, calculates control signals, and drives the attitude actuators which are three magnetic torquers (MTQs). The responses of the MTQs sensed by a separated magnetometer are feedback to the numerical simulation part completing the HIL simulation loop. Experimental studies are conducted to demonstrate the feasibility and effectiveness of the simulator.

A randomised controlled trial of an online theory-based intervention to improve adult Australians' sun-protective behaviours.

PubMed

White, Katherine M; Starfelt, Louise C; Young, Ross McD; Hawkes, Anna L; Cleary, Catherine; Leske, Stuart; Wihardjo, Kylie

2015-03-01

To evaluate the effectiveness of a single-session online theory of planned behaviour (TPB)-based intervention to improve sun-protective attitudes and behaviour among Australian adults. Australian adults (N=534; 38.7% males; Mage=39.3 years) from major cities (80.9%), regional (17.6%) and remote areas (1.5%) were recruited and randomly allocated to an intervention (N=265) and information only group (N=267). The online intervention focused on fostering positive attitudes, perceptions of normative support, and control perceptions for sun protection. Participants completed questionnaires assessing standard TPB measures (attitude, subjective norm, perceived behavioural control, intention, behaviour) and extended TPB constructs of group norm (friends, family), personal norm, and image norm, pre-intervention (Time 1) and one week (Time 2) and one month post-intervention (Time 3). Repeated Measures Multivariate Analysis of Variance tested intervention effects across time. Intervention participants reported more positive attitudes towards sun protection and used sun-protective measures more often in the subsequent month than participants receiving information only. The intervention effects on control perceptions and norms were non-significant. A theory-based online intervention fostering more favourable attitudes towards sun safety can increase sun protection attitudes and self-reported behaviour among Australian adults in the short term. Copyright © 2015 Elsevier Inc. All rights reserved.

Internal-External Locus of Control and Attitude Toward Disability.

ERIC Educational Resources Information Center

MacDonald, A. P.

The relationship between internal-external locus of control and attitude and reaction toward disability is discussed. Apart from examining the relevant research literature, findings are presented which support the hypothesis that those non-disabled who have external control orientations are more threatened by physical disabilities (vis., internal…

Weight Control Beliefs, Body Shape Attitudes, and Physical Activity among Adolescents

ERIC Educational Resources Information Center

Martin, Scott B.; Rhea, Deborah J.; Greenleaf, Christy A.; Judd, Doryce E.; Chambliss, Heather O.

2011-01-01

Background: Relatively little is known about how perceived weight controllability influences important psychological health factors among adolescents. Thus, the purpose of this study is to explore adolescents' weight controllability beliefs and how those beliefs influence weight-related attitudes and behaviors. Methods: Adolescents (N = 369, mean…

Laboratory Control System's Effects on Student Achievement and Attitudes

ERIC Educational Resources Information Center

Cicek, Fatma Gozalan; Taspinar, Mehmet

2016-01-01

Problem Statement: The current study investigates whether the learning environment designed based on the laboratory control system affects the academic achievement, the attitude toward the learning-teaching process and the retention of the students in computer education. Purpose of Study: The study aims to identify the laboratory control system…

Improvement of helicopter attitude stability by active control of the conventional swash plate

NASA Technical Reports Server (NTRS)

Ham, Norman D.

1993-01-01

The Final Report on improvement of helicopter attitude stability by active control of the conventional swash plate covering the period from Nov. 1986 to Dec. 1993 is presented. A paper on the history, principles, and applications of helicopter individual-blade-control is included.

Trajectory tracking control for underactuated stratospheric airship

NASA Astrophysics Data System (ADS)

Zheng, Zewei; Huo, Wei; Wu, Zhe

2012-10-01

Stratospheric airship is a new kind of aerospace system which has attracted worldwide developing interests for its broad application prospects. Based on the trajectory linearization control (TLC) theory, a novel trajectory tracking control method for an underactuated stratospheric airship is presented in this paper. Firstly, the TLC theory is described sketchily, and the dynamic model of the stratospheric airship is introduced with kinematics and dynamics equations. Then, the trajectory tracking control strategy is deduced in detail. The designed control system possesses a cascaded structure which consists of desired attitude calculation, position control loop and attitude control loop. Two sub-loops are designed for the position and attitude control loops, respectively, including the kinematics control loop and dynamics control loop. Stability analysis shows that the controlled closed-loop system is exponentially stable. Finally, simulation results for the stratospheric airship to track typical trajectories are illustrated to verify effectiveness of the proposed approach.

Effects of Biggest Loser exercise depictions on exercise-related attitudes.

PubMed

Berry, Tanya R; McLeod, Nicole C; Pankratow, Melanie; Walker, Jessica

2013-01-01

To examine whether participants who watched an exercise-related segment of The Biggest Loser television program would have different explicit and implicit affective exercise-related attitudes than those of control participants. University students (N=138) watched a clip of The Biggest Loser or American Idol, then completed a Go/No-go Association Task, a thought-listing task, and questionnaires measuring explicit attitudes, activity level, and mood. Participants who watched The Biggest Loser had significantly lower explicit, but not implicit, attitudes towards exercise than did control participants. There is a need to examine the influence of popular media depictions of exercise.

Effecting attitudinal change towards rational drug use.

PubMed

Singh, T; Natu, M V

1995-01-01

Attitudes of 40 interns towards rational drug use (RDU) were assessed, using a standardized Likert type scale. The assessment was repeated after 4 months to evaluate the effect of usual working conditions of the hospital. After this period, the attitudes had slided towards negative side (p < 0.01). At this point, an intervention in the form of a workshop was provided for half the group while other half served as control. A repeat assessment after another period of 4 months revealed that the attitudes of test group returned towards positive side (p < 0.01) while control group maintained its negative attitudes.

Children and the New 3 Rs (Reduce, Reuse, Recycle): Attitudes toward the Environment.

ERIC Educational Resources Information Center

Malkus, Amy J.; Musser, Lynn M.

This study examined the relationship between children's environmental attitudes and their perceived competence and locus of control. The study sample consisted of 171 children in grades 3, 4, and 5. Children completed the Children's Attitudes Toward the Environment Scale (CATES) and the Janus Environmental Attitudes Scale (JEAS), which assessed…

A Decade of Change in Employer Attitudes Toward Epilepsy.

ERIC Educational Resources Information Center

Hartlage, Lawrence C.

The attitudes of parents and peers toward handicaps, particularly epilepsy, play an important part in determining how debilitating the handicap may actually be. This project compared attitudes of employers toward epilepsy in the early 1960's with their attitudes in the current decade. As a control for possible generalized shifts in employer…

Youth leadership program for changing self-image and attitude toward people with disabilities.

PubMed

Cohen, Ronen; Roth, Dana; York, Alan; Neikrug, Shimshon

2012-01-01

Society has a negative attitude toward people with intellectual disabilities or psychiatric disabilities. It is well documented that they are subjected to prejudice, stigma, and negative attitudes (Di Giulio, 2003; Finger, 1994). Professional literature indicates that information about disabilities and encounters with persons with disabilities can change negative attitudes (Carter, Hughes, Copeland, & Breen, 2001; Krajewski & Flaherty, 2000). This study accompanied 164 9th-grade students from various junior high schools throughout Israel. Half of the students participated in an integration program for changing attitudes toward persons with disabilities, and the other half served as the control group. The research examined the existence and the degree of relationship between participation in the program, changes in attitudes toward people with disabilities, and self-image. The research findings pointed to a positive change in attitudes of the participants of the program in comparison with the control group, resulting mainly from personal contact with people with disabilities. No relationship was found between levels of self-image of the research group and attitudes toward people with disabilities.

A tool to assess knowledge, attitude and behavior of Indonesian health care workers regarding infection control.

PubMed

Duerink, D O; Hadi, U; Lestari, E S; Roeshadi, Djoko; Wahyono, Hendro; Nagelkerke, N J D; Van der Meulen, R G; Van den Broek, P J

2013-07-01

to investigate knowledge, attitude and behaviour toward infection control in two teaching hospitals on the island of Java by means of a questionnaire and to evaluate the use of the questionnaire as a tool. we investigated knowledge, attitude and behaviour toward infection control in two teaching hospitals on the island of Java by means of a questionnaire to identify problem areas, barriers and facilitators. The target was to include at least 50% of all health care workers (physicians, nurses, assistant nurses and infection control nurses) in each hospital, department and profession. Differences between demographic variables and scores for individual questions and groups of questions were compared using the chi-square statistic and analysis of variance and Spearman's rho was used to test for correlations between knowledge, attitude, self-reported behaviour and perceived obstacles. more than half of the health care workers of the participating departments completed the questionnaire. Of the 1036 respondents (44% nurses, 37% physicians and 19% assistant nurses), 34% were vaccinated against hepatitis B, 77% had experienced needle stick accidents and 93% had been instructed about infection control. The mean of the correct answers to the knowledge questions was 44%; of the answers to the attitude questions 67% were in agreement with the correct attitude; obstacles to compliance with infection control guidelines were perceived in 30% of the questions and the mean self-reported compliance was 63%. Safe handling of sharps, hand hygiene and the use of personal protective equipment were identified as the most important aspects for interventions. Significant positive correlations were found between knowledge, attitude, self-reported behaviour and perceived obstacles. the questionnaire in conjunction with site visits and interviews was a valuable strategy to identify trouble spots in the hospitals and to determine barriers to facilitators of change that should be taken into account when planning interventions. Successful interventions should cover hospital management, the infection control team, as well as the health care workers on the wards.

Internalized model minority myth, Asian values, and help-seeking attitudes among Asian American students.

PubMed

Kim, Paul Youngbin; Lee, Donghun

2014-01-01

The present study examined cultural factors underlying help-seeking attitudes of Asian American college students (N = 106). Specifically, we explored internalized model minority myth as a predictor of help-seeking attitudes and tested an intrapersonal-interpersonal framework of Asian values as a mechanism by which the two are related. Results indicated that internalized model minority myth significantly predicted unfavorable help-seeking attitudes, and emotional self-control mediated this relationship. Interpersonal values and humility were nonsignificant mediators, contrary to our hypotheses. The findings suggest that the investigation of internalized model minority myth in help-seeking research is a worthwhile endeavor, and they also highlight emotional self-control as an important explanatory variable in help-seeking attitudes of Asian American college students.

Understanding the relationship between student attitudes and student learning

NASA Astrophysics Data System (ADS)

Cahill, Michael J.; McDaniel, Mark A.; Frey, Regina F.; Hynes, K. Mairin; Repice, Michelle; Zhao, Jiuqing; Trousil, Rebecca

2018-02-01

Student attitudes, defined as the extent to which one holds expertlike beliefs about and approaches to physics, are a major research topic in physics education research. An implicit but rarely tested assumption underlying much of this research is that student attitudes play a significant part in student learning and performance. The current study directly tested this attitude-learning link by measuring the association between incoming attitudes (Colorado Learning Attitudes about Science Survey) and student learning during the semester after statistically controlling for the effects of prior knowledge [early-semester Force Concept Inventory (FCI) or Brief Electricity and Magnetism Assessment (BEMA)]. This study spanned four different courses and included two complementary measures of student knowledge: late-semester concept inventory scores (FCI or BEMA) and exam averages. In three of the four courses, after controlling for prior knowledge, attitudes significantly predicted both late-semester concept inventory scores and exam averages, but in all cases these attitudes explained only a small amount of variance in concept-inventory and exam scores. Results indicate that after accounting for students' incoming knowledge, attitudes may uniquely but modestly relate to how much students learn and how well they perform in the course.

Predictive momentum management for the Space Station

NASA Technical Reports Server (NTRS)

Hatis, P. D.

1986-01-01

Space station control moment gyro momentum management is addressed by posing a deterministic optimization problem with a performance index that includes station external torque loading, gyro control torque demand, and excursions from desired reference attitudes. It is shown that a simple analytic desired attitude solution exists for all axes with pitch prescription decoupled, but roll and yaw coupled. Continuous gyro desaturation is shown to fit neatly into the scheme. Example results for pitch axis control of the NASA power tower Space Station are shown based on predictive attitude prescription. Control effector loading is shown to be reduced by this method when compared to more conventional momentum management techniques.

A Nonlinear Spacecraft Attitude Controller and Observer with an Unknown Constant Gyro Bias and Gyro Noise

NASA Technical Reports Server (NTRS)

Deutschmann, Julie; Sanner, Robert M.

2001-01-01

A nonlinear control scheme for attitude control of a spacecraft is combined with a nonlinear gyro bias observer for the case of constant gyro bias, in the presence of gyro noise. The observer bias estimates converge exponentially to a mean square bound determined by the standard deviation of the gyro noise. The resulting coupled, closed loop dynamics are proven to be globally stable, with asymptotic tracking which is also mean square bounded. A simulation of the proposed observer-controller design is given for a rigid spacecraft tracking a specified, time-varying attitude sequence to illustrate the theoretical claims.

Is Racial Attitude Change a Function of Locus of Control?

ERIC Educational Resources Information Center

Sharma, Vijay

1977-01-01

This study explores the relationship between counselors' locus of control and the degree of change on racial attitudes followed by a structured awareness program and counseling experience on racial and multi-ethnic cultures. (Author)

International Space Station Attitude Control and Energy Storage Experiment: Effects of Flywheel Torque

NASA Technical Reports Server (NTRS)

Roithmayr, Carlos M.

1999-01-01

The Attitude Control and Energy Storage Experiment is currently under development for the International Space Station; two counter-rotating flywheels will be levitated with magnetic bearings and placed in vacuum housings. The primary objective of the experiment is to store and discharge energy, in combination with existing batteries, into the electrical power system. The secondary objective is to use the flywheels to exert torque on the Station; a simple torque profile has been designed so that the Station's Control Moment Gyroscopes will be assisted in maintaining torque equilibrium attitude. Two energy storage contingencies could result in the inadvertent application of torque by the flywheels to the Station: an emergency shutdown of one flywheel rotor while the other remains spinning, and energy storage with only one rotor instead of the counterrotating pair. Analysis of these two contingencies shows that attitude control and the microgravity environment will not be adversely affected.

Science observations with the IUE using the one-gyro mode

NASA Technical Reports Server (NTRS)

Imhoff, C.; Pitts, R.; Arquilla, R.; Shrader, Chris R.; Perez, M. R.; Webb, J.

1990-01-01

The International Ultraviolet Explorer (IUE) attitude control system originally included an inertial reference package containing six gyroscopes for three axis stabilization. The science instrument includes a prime and redundant Field Error Sensor (FES) camera for target acquisition and offset guiding. Since launch, four of the six gyroscopes have failed. The current attitude control system utilizes the remaining two gyros and a Fine Sun Sensor (FSS) for three axis stabilization. When the next gyro fails, a new attitude control system will be uplinked which will rely on the remaining gyro and the FSS for general three axis stabilization. In addition to the FSS, the FES cameras will be required to assist in maintaining fine attitude control during target acquisition. This has required thoroughly determining the characteristics of the FES cameras and the spectrograph aperture plate as well as devising new target acquisition procedures. The results of this work are presented.

Science observations with the IUE using the one-gyro mode

NASA Technical Reports Server (NTRS)

Imhoff, C.; Pitts, R.; Arquilla, R.; Shrader, C.; Perez, M.; Webb, J.

1990-01-01

The International Ultraviolet Explorer (IUE) attitude control system originally included an inertial reference package containing six gyroscopes for three axis stabilization. The science instrument includes a prime and redundant Field Error Sensor (FES) camera for target acquisition and offset guiding. Since launch, four of the six gyroscopes have failed. The current attitude control system utilizes the remaining two gyros and a Fine Sun Sensor (FSS) for three axis stabilization. When the next gyro fails, a new attitude control system will be uplinked, which will relay on the remaining gyro and the FSS for general three axis stabilization. In addition to the FSS, the FES cameras will be required to assist in maintaining fine attitude control during target acquisition. This has required thoroughly determining the characteristics of the FES cameras and the spectrograph aperture plate as well as devising new target acquisition procedures. The results of this work are presented.

Zero-Propellant Maneuver[TM] Flight Results for 180 deg ISS Rotation

NASA Technical Reports Server (NTRS)

Bedrossian, Nazareth; Bhatt, Sagar; Lammers, Mike; Nguyen, Louis

2007-01-01

This paper presents results for the Zero Propellant Maneuver (ZPM) TradeMark attitude control concept flight demonstration. On March 3, 2007, a ZPM was used to reorient the International Space Station 180 degrees without using any propellant. The identical reorientation performed with thrusters would have burned 110lbs of propellant. The ZPM was a pre-planned trajectory used to command the CMG attitude hold controller to perform the maneuver between specified initial and final states while maintaining the CMGs within their operational limits. The trajectory was obtained from a PseudoSpectral solution to a new optimal attitude control problem. The flight test established the breakthrough capability to simultaneously perform a large angle attitude maneuver and momentum desaturation without the need to use thrusters. The flight implementation did not require any modifications to flight software. This approach is applicable to any spacecraft that are controlled by momentum storage devices.

Attitude control/momentum management of the Space Station Freedom for large angle torque-equilibrium-attitude configurations

NASA Technical Reports Server (NTRS)

Parlos, Alexander G.; Sunkel, John W.

1990-01-01

An attitude-control and momentum-management (ACMM) system for the Space Station in a large-angle torque-equilibrium-attitude (TEA) configuration is developed analytically and demonstrated by means of numerical simulations. The equations of motion for a rigid-body Space Station model are outlined; linearized equations for an arbitrary TEA (resulting from misalignment of control and body axes) are derived; the general requirements for an ACMM are summarized; and a pole-placement linear-quadratic regulator solution based on scheduled gains is proposed. Results are presented in graphs for (1) simulations based on configuration MB3 (showing the importance of accounting for the cross-inertia terms in the TEA estimate) and (2) simulations of a stepwise change from configuration MB3 to the 'assembly complete' stage over 130 orbits (indicating that the present ACCM scheme maintains sufficient control over slowly varying Space Station dynamics).

The spacecraft control laboratory experiment optical attitude measurement system

NASA Technical Reports Server (NTRS)

Welch, Sharon S.; Montgomery, Raymond C.; Barsky, Michael F.

1991-01-01

A stereo camera tracking system was developed to provide a near real-time measure of the position and attitude of the Spacecraft COntrol Laboratory Experiment (SCOLE). The SCOLE is a mockup of the shuttle-like vehicle with an attached flexible mast and (simulated) antenna, and was designed to provide a laboratory environment for the verification and testing of control laws for large flexible spacecraft. Actuators and sensors located on the shuttle and antenna sense the states of the spacecraft and allow the position and attitude to be controlled. The stereo camera tracking system which was developed consists of two position sensitive detector cameras which sense the locations of small infrared LEDs attached to the surface of the shuttle. Information on shuttle position and attitude is provided in six degrees-of-freedom. The design of this optical system, calibration, and tracking algorithm are described. The performance of the system is evaluated for yaw only.

Body checking and eating cognitions in Brazilian outpatients with eating disorders and non psychiatric controls.

PubMed

Kachani, Adriana Trejger; Barroso, Lucia Pereira; Brasiliano, Silvia; Cordás, Táki Athanássios; Hochgraf, Patrícia Brunfentrinker

2015-12-01

Compare inadequate eating behaviors and their relationship to body checking in three groups: patients with anorexia nervosa (AN), patients with bulimia nervosa (BN) and a control group (C). Eighty three outpatients with eating disorders (ED) and 40 controls completed eating attitudes and body checking questionnaires. The overall relationship between the eating attitude and body checking was statistically significant in all three groups. The worse the eating attitude, the greater the body checking behavior. However, when we look at each group individually, the relationship was only statistically significant in the AN group (r=.354, p=0.020). The lower the desired weight and the worse the eating attitude, the more people check themselves, although in the presence of an ED the relationship between body checking and food restrictions is greater. In patients displaying the AN subgroup, body checking is also related to continued dietary control. Copyright © 2015 Elsevier Ltd. All rights reserved.

Knowledge, attitudes and beliefs about tobacco use after an educative intervention in health sciences' students.

PubMed

Molina, Antonio J; Fernández, Tania; Fernández, Daniel; Delgado, Miguel; de Abajo, Serafín; Martín, Vicente

2012-11-01

To examine the effectiveness of a tobacco control course on the improvement of knowledge, attitudes and beliefs about smoking among health sciences' students. This was a quasi-experimental study of community intervention carried out during the years 2005-2008, at 2 university health science centres in northwest Spain. A total of 290 students on the intervention and 256 on the control campus took part in the study. The intervention consisted of a course on the prevention and control of tobacco use offered only on the intervention campus. Data were collected before the intervention and 6 months afterwards. After the course, significant differences between groups were observed in the improvement of knowledge, attitudes and perceived ability to act in tobacco control. The introduction of training concerning smoking through active methodologies had a positive impact on the knowledge, attitudes and beliefs about tobacco of students. Copyright © 2011 Elsevier Ltd. All rights reserved.

An examination of student attitudes and understanding of exponential functions using interactive instructional multimedia

NASA Astrophysics Data System (ADS)

Singleton, Cynthia M.

The purpose of this study was to examine students' attitudes and understanding of exponential functions using InterAct Math, a mathematics tutorial software. The researcher used a convenience sampling of a total of 78 students from two intact pre-calculus classes; the students in the experimental group totaled 41 and the control group totaled 37. The two groups were exposed to the same curriculum content taught by the same instructor, the researcher. The experimental group used the mathematics tutorial software as an integral part of the instructional delivery. The control group used traditional instruction without integration of the educational technology. Data were collected during a two week span using a mixed-methodology to address the major research questions: (1) Is there a statistically significant difference in the mean achievement test scores between the experimental and the control groups? (2) Is there a statistically significant difference in students' attitudes toward learning mathematics between the experimental group and the control group? The researcher utilized paired t-tests and independent t-tests as statistical methods to evaluate the effectiveness of the intervention and to establish whether there was a significant difference between the experimental and control groups. Based on the analyses of the quantitative data, it was established that the students who received the InterAct Math tutorial (experimental group) did not perform better than the control group on exponential functions, graphs and applications. However, the quantitative part of the study (Aiken-Dreger Mathematics Attitude Scale) revealed that, while students in the experimental and control groups started with similar attitudes about mathematics and the integration of technology, their attitudes were significantly different at the conclusion of the study. The fear of mathematics was reduced for the experimental group at the end of the study, and their enjoyment of the subject matter was increased as a result of the intervention. No significant difference was reported concerning attitudes toward fear and enjoyment of learning mathematics for the control group. The researcher concluded that the use of InterAct Math tutorial software as part of the instructional delivery was beneficial and contributed to a positive attitude change. Other qualitative data obtained from the unstructured interviews of the treatment group supported these findings and reported that the change in attitudes was attributable to the use of the InterAct software in the instructional delivery of the course. The researcher concluded that the results of the study did not provide evidence that InterAct Math software could be credited with producing better learning outcomes. However, it appears that the InterAct Math tutorial software is an effective tutorial tool in promoting positive change in students' attitudes toward learning mathematics; thus, it is an effective tool for mathematics instruction. Based on the above results, it was concluded that the InterAct Math tutorial is an effective tutorial tool in promoting positive attitude change in students toward learning mathematics.

Attitude control system of the Delfi-n3Xt satellite

NASA Astrophysics Data System (ADS)

Reijneveld, J.; Choukroun, D.

2013-12-01

This work is concerned with the development of the attitude control algorithms that will be implemented on board of the Delfi-n3xt nanosatellite, which is to be launched in 2013. One of the mission objectives is to demonstrate Sun pointing and three axis stabilization. The attitude control modes and the associated algorithms are described. The control authority is shared between three body-mounted magnetorquers (MTQ) and three orthogonal reaction wheels. The attitude information is retrieved from Sun vector measurements, Earth magnetic field measurements, and gyro measurements. The design of the control is achieved as a trade between simplicity and performance. Stabilization and Sun pointing are achieved via the successive application of the classical Bdot control law and a quaternion feedback control. For the purpose of Sun pointing, a simple quaternion estimation scheme is implemented based on geometric arguments, where the need for a costly optimal filtering algorithm is alleviated, and a single line of sight (LoS) measurement is required - here the Sun vector. Beyond the three-axis Sun pointing mode, spinning Sun pointing modes are also described and used as demonstration modes. The three-axis Sun pointing mode requires reaction wheels and magnetic control while the spinning control modes are implemented with magnetic control only. In addition, a simple scheme for angular rates estimation using Sun vector and Earth magnetic measurements is tested in the case of gyro failures. The various control modes performances are illustrated via extensive simulations over several orbits time spans. The simulated models of the dynamical space environment, of the attitude hardware, and the onboard controller logic are using realistic assumptions. All control modes satisfy the minimal Sun pointing requirements allowed for power generation.

Advanced Integrated Power and Attitude Control System (IPACS) study

NASA Technical Reports Server (NTRS)

Oglevie, R. E.; Eisenhaure, D. B.

1985-01-01

Integrated Power and Attitude Control System (IPACS) studies performed over a decade ago established the feasibility of simultaneously satisfying the demands of energy storage and attitude control through the use of rotating flywheels. It was demonstrated that, for a wide spectrum of applications, such a system possessed many advantages over contemporary energy storage and attitude control approaches. More recent technology advances in composite material rotors, magnetic suspension systems, and power control electronics have triggered new optimism regarding the applicability and merits of this concept. This study is undertaken to define an advanced IPACS and to evaluate its merits for a space station application. System and component designs are developed to establish the performance of this concept and system trade studies conducted to examine the viability of this approach relative to conventional candidate systems. It is clearly demonstrated that an advanced IPACS concept is not only feasible, but also offers substantial savings in mass and life-cycle cost for the space station mission.

Integrated Power and Attitude Control Systems for Space Station

NASA Technical Reports Server (NTRS)

Oglevie, R. E.; Eisenhaure, D. B.

1985-01-01

Integrated Power and Attitude Control Systems (IPACS) studies performed over a decade ago established the feasibility of simultaneously storing electrical energy in wheels and utilizing the resulting momentum for spacecraft attitude control. It was shown that such a system possessed many advantages over other contemporary energy storage and attitude control systems in many applications. More recent technology advances in composite rotors, magnetic bearings, and power control electronics have triggered new optimism regarding the feasibility and merits of such a system. The paper presents the results of a recent study whose focus was to define an advanced IPACS and to evaluate its merits for the Space Station application. A system and component design concept is developed to establish the system performance capability. A system level trade study, including life-cycle costing, is performed to define the merits of the system relative to two other candidate systems. It is concluded that an advanced IPACS concept is not only feasible, but offers substantial savings in mass, and life-cycle cost.

Anti-sway control of tethered satellite systems using attitude control of the main satellite

NASA Astrophysics Data System (ADS)

Yousefian, Peyman; Salarieh, Hassan

2015-06-01

In this study a new method is introduced to suppress libration of a tethered satellite system (TSS). It benefits from coupling between satellites and tether libration dynamics. The control concept uses the main satellite attitude maneuvers to suppress librational motion of the tether, and the main satellite's actuators for attitude control are used as the only actuation in the system. The study considers planar motion of a two body TSS system in a circular orbit and it is assumed that the tether's motion will not change it. Governing dynamic equations of motion are derived using the extended Lagrange method. Controllability of the system around the equilibrium state is studied and a linear LQG controller is designed to regulate libration of the system. Tether tension and satellite attitude are assumed as only measurable outputs of the system. The Extended Kalman Filter (EKF) is used to estimate states of the system to be used as feedback to the controller. The designed controller and observer are implemented to the nonlinear plant and simulations demonstrate that the controller lead to reduction of the tether libration propoerly. By the way, because the controller is linear, it is applicable only at low amplitudes in the vicinity of equilibrium point. To reach global stability, a nonlinear controller is demanded.

Effects of a mixed media education intervention program on increasing knowledge, attitude, and compliance with standard precautions among nursing students: A randomized controlled trial.

PubMed

Xiong, Peng; Zhang, Jun; Wang, Xiaohui; Wu, Tat Leong; Hall, Brian J

2017-04-01

Standard precautions (SPs) are considered fundamental protective measures to manage health care-associated infections and to reduce occupational health hazards. This study intended to assess the effectiveness of a mixed media education intervention to enhance nursing students' knowledge, attitude, and compliance with SPs. A randomized controlled trial with 84 nursing students was conducted in a teaching hospital in Hubei, China. The intervention group (n = 42) attended 3 biweekly mixed media education sessions, consisting of lectures, videos, role-play, and feedback with 15-20 minutes of individual online supervision and feedback sessions following each class. The control group learned the same material through self-directed readings. Pre- and posttest assessments of knowledge, attitudes, and compliance were assessed with the Knowledge with Standard Precautions Questionnaire, Attitude with Standard Precautions Scale, and the Compliance with Standard Precautions Scale, respectively. The Standard Bacterial Colony Index was used to assess handwashing effectiveness. At 6-week follow-up, performance on the Knowledge with Standard Precautions Questionnaire, Attitude with Standard Precautions Scale, and Compliance with Standard Precautions Scale were significantly improved in the intervention group compared with the control group (P < .01). The hand hygiene standard in the intervention group (38 passed) outperformed the control group (23 passed) (P < .01). A mixed media education intervention is effective in improving knowledge, attitude, and compliance with SPs. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

A novel body frame based approach to aerospacecraft attitude tracking.

PubMed

Ma, Carlos; Chen, Michael Z Q; Lam, James; Cheung, Kie Chung

2017-09-01

In the common practice of designing an attitude tracker for an aerospacecraft, one transforms the Newton-Euler rotation equations to obtain the dynamic equations of some chosen inertial frame based attitude metrics, such as Euler angles and unit quaternions. A Lyapunov approach is then used to design a controller which ensures asymptotic convergence of the attitude to the desired orientation. Although this design methodology is pretty standard, it usually involves singularity-prone coordinate transformations which complicates the analysis process and controller design. A new, singularity free error feedback method is proposed in the paper to provide simple and intuitive stability analysis and controller synthesis. This new body frame based method utilizes the concept of Euleraxis and angles to generate the smallest error angles from a body frame perspective, without coordinate transformations. Global tracking convergence is illustrated with the use of a feedback linearizing PD tracker, a sliding mode controller, and a model reference adaptive controller. Experimental results are also obtained on a quadrotor platform with unknown system parameters and disturbances, using a boundary layer approximated sliding mode controller, a PIDD controller, and a unit sliding mode controller. Significant tracking quality is attained. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

A New Approach to Attitude Stability and Control for Low Airspeed Vehicles

NASA Technical Reports Server (NTRS)

Lim, K. B.; Shin, Y-Y.; Moerder, D. D.; Cooper, E. G.

2004-01-01

This paper describes an approach for controlling the attitude of statically unstable thrust-levitated vehicles in hover or slow translation. The large thrust vector that characterizes such vehicles can be modulated to provide control forces and moments to the airframe, but such modulation is accompanied by significant unsteady flow effects. These effects are difficult to model, and can compromise the practical value of thrust vectoring in closed-loop attitude stability, even if the thrust vectoring machinery has sufficient bandwidth for stabilization. The stabilization approach described in this paper is based on using internal angular momentum transfer devices for stability, augmented by thrust vectoring for trim and other "outer loop" control functions. The three main components of this approach are: (1) a z-body axis angular momentum bias enhances static attitude stability, reducing the amount of control activity needed for stabilization, (2) optionally, gimbaled reaction wheels provide high-bandwidth control torques for additional stabilization, or agility, and (3) the resulting strongly coupled system dynamics are controlled by a multivariable controller. A flight test vehicle is described, and nonlinear simulation results are provided that demonstrate the efficiency of the approach.

Mariner Mars 1971 attitude control subsystem

NASA Technical Reports Server (NTRS)

Edmunds, R. S.

1974-01-01

The Mariner Mars 1971 attitude control subsystem (ACS) is discussed. It is comprised of a sun sensor set, a Canopus tracker, an inertial reference unit, two cold gas reaction control assemblies, two rocket engine gimbal actuators, and an attitude control electronics unit. The subsystem has the following eight operating modes: (1) launch, (2) sun acquisition, (3) roll search, (4) celestial cruise, (5) all-axes inertial, (6) roll inertial, (7) commanded turn, and (8) thrust vector control. In the celestial cruise mode, the position control is held to plus or minus 0.25 deg. Commanded turn rates are plus or minus 0.18 deg/s. The attitude control logic in conjunction with command inputs from other spacecraft subsystems establishes the ACS operating mode. The logic utilizes Sun and Canopus acquisition signals generated within the ACS to perform automatic mode switching so that dependence of ground control is minimized when operating in the sun acquisition, roll search, and celestial cruise modes. The total ACS weight is 65.7 lb, and includes 5.4 lb of nitrogen gas. Total power requirements vary from 9 W for the celestial cruise mode to 54 W for the commanded turn mode.

Thrusting maneuver control of a small spacecraft via only gimbaled-thruster scheme

NASA Astrophysics Data System (ADS)

Kabganian, Mansour; Kouhi, Hamed; Shahravi, Morteza; Fani Saberi, Farhad

2018-05-01

The thrust vector control (TVC) scheme is a powerful method in spacecraft attitude control. Since the control of a small spacecraft is being studied here, a solid rocket motor (SRM) should be used instead of a liquid propellant motor. Among the TVC methods, gimbaled-TVC as an efficient method is employed in this paper. The spacecraft structure is composed of a body and a gimbaled-SRM where common attitude control systems such as reaction control system (RCS) and spin-stabilization are not presented. A nonlinear two-body model is considered for the characterization of the gimbaled-thruster spacecraft where, the only control input is provided by a gimbal actuator. The attitude of the spacecraft is affected by a large exogenous disturbance torque which is generated by a thrust vector misalignment from the center of mass (C.M). A linear control law is designed to stabilize the spacecraft attitude while rejecting the mentioned disturbance torque. A semi-analytical formulation of the region of attraction (RoA) is developed to ensure the local stability and fast convergence of the nonlinear closed-loop system. Simulation results of the 3D maneuvers are included to show the applicability of this method for use in a small spacecraft.

An Evaluation of Teachers' Attitudes and Beliefs Levels on Classroom Control in Terms of Teachers' Sense of Efficacy (The Sample of Biology Teachers in Turkey)

ERIC Educational Resources Information Center

Kurt, Hakan

2014-01-01

The aim of this study is to evaluate biology teachers' attitudes and belief levels on classroom control in terms of teachers' sense of efficacy. The screening model was used in the study. The study group was comprised of 135 biology teachers. In this study, Teachers' Sense of Efficacy Scale (TSES) and The Attitudes and Beliefs on Classroom Control…

AAS/GSFC 13th International Symposium on Space Flight Dynamics. Volume 2

NASA Technical Reports Server (NTRS)

Stengle, Tom (Editor)

1998-01-01

This conference proceedings preprint includes papers and abstracts presented at the 13th International Symposium on Space Flight Dynamics, May 11-15, 1998. Co-sponsored by American Astronautical Society and the Guidance, Navigation and Control Center of the Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination, and control; attitude sensor calibration; attitude dynamics; and mission design.

The Attitudinal and Cognitive Effects of Planetarium Integration in Teaching Selected Astronomical Concepts to Fourth, Fifth, and Sixth-Grade Students

NASA Astrophysics Data System (ADS)

Twiest, Mark Gilbert

The purpose of this study was to investigate the attitudinal and cognitive differences among students in an astronomy curriculum which utilizes a planetarium in comparison to an astronomy curriculum which is presented solely in the classroom. The specific attitudes of interest in this study are those student attitudes toward science as a whole and toward astronomy in particular. Researcher developed attitude and astronomy achievement measures were developed and administered to 423 fourth, fifth, and sixth grade students in three schools. Pre and post test data were collected from students in this quasi-experimental design. Two way analysis of covariance techniques were used to analyze the independent variables of gender and treatment. Results revealed significant differences (p < .05) in student attitudes toward astronomy in the fourth grade favoring the control school students. No other significant differences in student attitudes were found with respect to treatment or gender. Achievement was analyzed at both the knowledge and comprehension levels. Significant differences (p <.05) in student achievement were found fourth and fifth grades with respect to knowledge level questions. In both instances these differences favored the control school setting. Significant differences (p <.05) in student achievement were found for comprehension level questions at every grade level. In this case the control school outperformed the experimental setting in the fourth and sixth grades. Fifth grade experimental setting students had significantly higher achievement on comprehension level questions. A significant interaction occurred between treatment and gender with respect to student attitudes toward astronomy in the fifth grade. A second significant interaction occurred between treatment and gender for knowledge level questions for sixth grade students. No other significant interactions were found between treatment and gender. Correlations between post test attitudes and achievement were also calculated for each grade level in both the control and experimental settings. Correlations remained below.2 in every instance except one. Post test correlations between attitudes overall and achievement in the control school's sixth grade were.54.

Smoking Behaviors and Attitudes During Adolescence Prospectively Predict Support for Tobacco Control Policies in Adulthood

PubMed Central

Chassin, Laurie; Presson, Clark C.

2012-01-01

Introduction: Several cross-sectional studies have examined factors associated with support for tobacco control policies. The current study utilized a longitudinal design to test smoking status and attitude toward smoking measured in adolescence as prospective predictors of support for tobacco control policies measured in adulthood. Methods: Participants (N = 4,834) were from a longitudinal study of a Midwestern community-based sample. Hierarchical multiple regression analyses tested adolescent smoking status and attitude toward smoking as prospective predictors (after controlling for sociodemographic factors, adult smoking status, and adult attitude toward smoking) of support for regulation of smoking in public places, discussion of the dangers of smoking in public schools, prohibiting smoking in bars, eliminating smoking on television and in movies, prohibiting smoking in restaurants, and increasing taxes on cigarettes. Results: Participants who smoked during adolescence demonstrated more support for discussion of the dangers of smoking in public schools and less support for increasing taxes on cigarettes but only among those who smoked as adults. Those with more positive attitudes toward smoking during adolescence demonstrated less support as adults for prohibiting smoking in bars and eliminating smoking on television and in movies. Moreover, a significant interaction indicated that those with more positive attitudes toward smoking as adolescents demonstrated less support as adults for prohibiting smoking in restaurants, but only if they became parents as adults. Conclusions: This study’s findings suggest that interventions designed to deter adolescent smoking may have future benefits in increasing support for tobacco control policies. PMID:22193576

Smoking behaviors and attitudes during adolescence prospectively predict support for tobacco control policies in adulthood.

PubMed

Macy, Jonathan T; Chassin, Laurie; Presson, Clark C

2012-07-01

Several cross-sectional studies have examined factors associated with support for tobacco control policies. The current study utilized a longitudinal design to test smoking status and attitude toward smoking measured in adolescence as prospective predictors of support for tobacco control policies measured in adulthood. Participants (N = 4,834) were from a longitudinal study of a Midwestern community-based sample. Hierarchical multiple regression analyses tested adolescent smoking status and attitude toward smoking as prospective predictors (after controlling for sociodemographic factors, adult smoking status, and adult attitude toward smoking) of support for regulation of smoking in public places, discussion of the dangers of smoking in public schools, prohibiting smoking in bars, eliminating smoking on television and in movies, prohibiting smoking in restaurants, and increasing taxes on cigarettes. Participants who smoked during adolescence demonstrated more support for discussion of the dangers of smoking in public schools and less support for increasing taxes on cigarettes but only among those who smoked as adults. Those with more positive attitudes toward smoking during adolescence demonstrated less support as adults for prohibiting smoking in bars and eliminating smoking on television and in movies. Moreover, a significant interaction indicated that those with more positive attitudes toward smoking as adolescents demonstrated less support as adults for prohibiting smoking in restaurants, but only if they became parents as adults. This study's findings suggest that interventions designed to deter adolescent smoking may have future benefits in increasing support for tobacco control policies.

The impact of group training about parenting styles on maternal attitudes toward parenting styles.

PubMed

Zandiyeh, Zahra; Zare, Elaheh; Hedayati, Batool

2015-01-01

Parenting style is one of the most important and effective factors in training and growth of children and adolescents and the method that parents communicate with their children is an effective factor on family contact models. The aim of this study was to determine the impact of group training about parenting styles on maternal attitudes that were admitted to Isfahan Imam Ali (AS) health care center in 2013. This was an experimental study, which was conducted on a random sample of 25 mothers referred to this health care center. They were divided into two groups (experimental and control). The experimental group received five sessions of group training, and the control group received a booklet about parenting styles. The used tool in this study was the Bamerind Parenting Style Questionnaire that was completed by the mothers before and after the intervention and finally, their obtained scores were compared with each other. The results of the present study showed that the mean score of attitude toward easy-going style in test group was less than the control group after intervention (P = 0.045). The mean score of attitude toward authoritative style in the experimental group was less than control group after intervention (P = 0.037) and the mean score of attitude toward authoritative style in the experimental group was more than the control group after intervention (P = 0.011). Group training can be an appropriate method in changing maternal attitudes toward parenting styles.

Perceived difficulty in the theory of planned behaviour: perceived behavioural control or affective attitude?

PubMed

Kraft, Pål; Rise, Jostein; Sutton, Stephen; Røysamb, Espen

2005-09-01

A study was conducted to explore (a) the dimensional structure of perceived behavioural control (PBC), (b) the conceptual basis of perceived difficulty items, and (c) how PBC components and instrumental and affective attitudes, respectively, relate to intention and behaviour. The material stemmed from a two-wave study of Norwegian graduate students (N = 227 for the prediction of intention and N = 110 for the prediction of behaviour). Data were analysed using confirmatory factor analysis (CFA) and multiple regression by the application of structural equation modelling (SEM). CFA suggested that PBC could be conceived of as consisting of three separate but interrelated factors (perceived control, perceived confidence and perceived difficulty), or as two separate but interrelated factors representing self-efficacy (measured by perceived difficulty and perceived confidence or by just perceived confidence) and perceived control. However, the perceived difficulty items also overlapped substantially with affective attitude. Perceived confidence was a strong predictor of exercise intention but not of recycling intention. Perceived control, however, was a strong predictor of recycling intention but not exercise intention. Affective attitudes but not instrumental attitudes were identified as substantial predictors of intentions. The findings suggest that at least under some circumstances it may be inadequate to measure PBC by means of perceived difficulty. One possible consequence may be that the role of PBC as a predictor of intention is somewhat overestimated, whereas the role of (affective) attitude may be similarly underestimated.

The Attitude Control System for the Wilkinson Microwave Anisotropy Probe

NASA Technical Reports Server (NTRS)

Markley, F. Landis; Andrews, Stephen F.; ODonnell, James R., Jr.; Ward, David K.

2003-01-01

The Wilkinson Microwave Anisotropy Probe mission produces a map of the cosmic microwave background radiation over the entire celestial sphere by executing a fast spin and a slow precession of its spin axis about the Sun line to obtain a highly interconnected set of measurements. The spacecraft attitude is sensed and controlled using an inertial reference unit, two star trackers, a digital sun sensor, twelve coarse sun sensors, three reaction wheel assemblies, and a propulsion system. Sufficient attitude knowledge is provided to yield instrument pointing to a standard deviation (l sigma) of 1.3 arc-minutes per axis. In addition, the spacecraft acquires and holds the sunline at initial acquisition and in the event of a failure, and slews to the proper orbit adjust orientations and to the proper off-sunline attitude to start the compound spin. This paper presents an overview of the design of the attitude control system to carry out this mission and presents some early flight experience.

Compensation of an attitude disturbance torque caused by magnetic substances in LEO satellites

NASA Astrophysics Data System (ADS)

Inamori, Takaya; Wang, Jihe; Saisutjarit, Phongsatorn; Ohsaki, Hiroyuki

This research considers an attitude disturbance torque caused by ferromagnetic substances in a LEO satellite. In most LEO satellite missions, a gravity gradient torque, solar pressure torque, aerodynamic torque, and magnetic dipole moment torque are considered for their attitude control systems, however, the effect of the ferromagnetic substances causing a disturbance torque in the geomagnetic field is not considered in previous satellite missions. The ferromagnetic substances such as iron cores of MTQs and a magnetic hysteresis damper for a passive attitude control system are used in various small satellites. These substances cause a disturbance torque which is almost the same magnitude of the dipole magnetic disturbance and the dominant disturbance in the worst cases. This research proposes a method to estimate and compensate for the effect of the ferromagnetic substances using an extended Kalman filter. From simulation results, the research concludes that the proposed method is useful and attractive for precise attitude control for LEO satellite missions.

Determination of the implementation of the 3-axis attitude motion simulator digital position controller

NASA Technical Reports Server (NTRS)

Magana, Mario E.

1989-01-01

The digital position controller implemented in the control computer of the 3-axis attitude motion simulator is mathematically reconstructed and documented, since the information supplied with the executable code of this controller was insufficient to make substantial modifications to it. Also developed were methodologies to introduce changes in the controller which do not require rewriting the software. Finally, recommendations are made on possible improvement to the control system performance.

North Carolina Tobacco Farmers' Changing Perceptions of Tobacco Control and Tobacco Manufacturers

ERIC Educational Resources Information Center

Crankshaw, Erik C.; Beach, Robert H.; Austin, W. David; Altman, David G.; Jones, Alison Snow

2009-01-01

Purpose: To examine tobacco farmers' attitudes toward tobacco control, public health, and tobacco manufacturers in order to determine the extent to which rapidly changing economic conditions have influenced North Carolina tobacco farmer attitudes in ways that may provide tobacco control advocates with new opportunities to promote tobacco control…

Weight Control: Attitudes of Dieters and Change Agents.

ERIC Educational Resources Information Center

Parham, Ellen S.; And Others

1991-01-01

Survey explores attitudes toward weight loss/weight control among 2 groups of change agents--40 dietitians and 42 fitness instructors--and among 96 people trying to lose weight. Significant differences were found in terms of importance in weight control of diet, drugs, exercise, religion, and will power; in importance of being of normal weight;…

Flight Mechanics Symposium 1997

NASA Technical Reports Server (NTRS)

Walls, Donna M. (Editor)

1997-01-01

This conference publication includes papers and abstracts presented at the Flight Mechanics Symposium. This symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination, and control; attitude sensor calibration; attitude determination error analysis; attitude dynamics; and orbit decay and maneuver strategy. Government, industry, and the academic community participated in the preparation and presentation of these papers.

Six Degrees-of-Freedom Ascent Control for Small-Body Touch and Go

NASA Technical Reports Server (NTRS)

Blackmore, Lars James C.

2011-01-01

A document discusses a method of controlling touch and go (TAG) of a spacecraft to correct attitude, while ensuring a safe ascent. TAG is a concept whereby a spacecraft is in contact with the surface of a small body, such as a comet or asteroid, for a few seconds or less before ascending to a safe location away from the small body. The report describes a controller that corrects attitude and ensures that the spacecraft ascends to a safe state as quickly as possible. The approach allocates a certain amount of control authority to attitude control, and uses the rest to accelerate the spacecraft as quickly as possible in the ascent direction. The relative allocation to attitude and position is a parameter whose optimal value is determined using a ground software tool. This new approach makes use of the full control authority of the spacecraft to correct the errors imparted by the contact, and ascend as quickly as possible. This is in contrast to prior approaches, which do not optimize the ascent acceleration.

How does locus of control and inflated sense of responsibility relate to obsessive-compulsive symptoms in Turkish adolescents?

PubMed

Altin, Müjgan; Karanci, A Nuray

2008-12-01

This study aimed to examine the effects of responsibility attitudes, locus of control and their interactions on the general obsessive-compulsive (OC) symptomatology and the dimensions of OC symptoms in a sample of Turkish adolescents (n=385), their ages varied from 16 to 20 with a mean of 17.23 (S.D.=.68). The results of the present study revealed a significantly positive relationship between responsibility attitudes and general OC symptomatology. However, locus of control did not appear as a significant predictor of general OC symptomatology. Furthermore, results revealed that there was a significant interaction effect of responsibility attitudes with locus of control on OC symptomatology. That is, an inflated sense of responsibility and the presence of an external locus of control produced the highest level of OC symptoms. Related to the dimensions of OC symptoms, responsibility was a weak predictor of obsessive thinking symptoms, and a moderate predictor of cleanliness and checking symptoms. Locus of control and its interaction with responsibility attitudes only significantly predicted obsessional thinking symptoms.

Design of the EO-1 Pulsed Plasma Thruster Attitude Control Experiment

NASA Technical Reports Server (NTRS)

Zakrzwski, Charles; Sanneman, Paul; Hunt, Teresa; Blackman, Kathie; Bauer, Frank H. (Technical Monitor)

2001-01-01

The Pulsed Plasma Thruster (PPT) Experiment on the Earth Observing 1 (EO-1) spacecraft has been designed to demonstrate the capability of a new generation PPT to perform spacecraft attitude control. The PPT is a small, self-contained pulsed electromagnetic Propulsion system capable of delivering high specific impulse (900-1200 s), very small impulse bits (10-1000 micro N-s) at low average power (less than 1 to 100 W). EO-1 has a single PPT that can produce torque in either the positive or negative pitch direction. For the PPT in-flight experiment, the pitch reaction wheel will be replaced by the PPT during nominal EO-1 nadir pointing. A PPT specific proportional-integral-derivative (PID) control algorithm was developed for the experiment. High fidelity simulations of the spacecraft attitude control capability using the PPT were conducted. The simulations, which showed PPT control performance within acceptable mission limits, will be used as the benchmark for on-orbit performance. The flight validation will demonstrate the ability of the PPT to provide precision pointing resolution. response and stability as an attitude control actuator.

The relationship between age-stereotypes and health locus of control across adult age-groups.

PubMed

Sargent-Cox, Kerry; Anstey, Kaarin J

2015-01-01

This study integrates healthy ageing and health psychology theories to explore the mechanisms underlying the relationship between health control expectancies and age-attitudes on the process of ageing well. Specifically, the aim of this study is to investigate the relationship between age-stereotypes and health locus of control. A population-based survey of 739 adults aged 20-97 years (mean = 57.3 years, SD = 13.66; 42% female) explored attitudes towards ageing and health attitudes. A path-analytical approach was used to investigate moderating effects of age and gender. Higher age-stereotype endorsement was associated with higher chance (β = 2.91, p < .001) and powerful other (β = 1.07, p = .012) health expectancies, after controlling for age, gender, education and self-rated health. Significant age and gender interactions were found to influence the relationship between age-stereotypes and internal health locus of control. Our findings suggest that the relationship between age-stereotypes and health locus of control dimensions must be considered within the context of age and gender. The findings point to the importance of targeting health promotion and interventions through addressing negative age-attitudes.

Attitude control system design using a flywheel suspended by two gimbals

NASA Astrophysics Data System (ADS)

Peres, R. W.; Ricci, M. C.

2015-10-01

This work presents the attitude control system design procedures for a three axis stabilized satellite in geostationary orbit, which contains a flywheel suspended by two gimbals. The use of a flywheel with two DOFs is an interesting option because with only one device it's possible to control the torques about vehicle's three axes; through the wheel speed control and gyrotorquing phenomenon with two DOFs. If the wheel size and speed are determined properly it's possible to cancel cyclic torques using gas jets only periodically to cancel secular disturbance torques. The system, based on a flywheel, takes only one pitch/roll (earth) sensor to maintain precise attitude, unlike mass expulsion based control systems, which uses propellants continuously, beyond roll, pitch and yaw sensors. It is considered the satellite is in nominal orbit and, therefore, that the attitude's acquisition phase has already elapsed. Control laws and system parameters are determined in order to cancel the solar pressure radiation disturbance torque and the torque due to misalignment of the thrusters. Stability is analyzed and step and cyclic responses are obtained.

Active control strategy for the running attitude of high-speed train under strong crosswind condition

NASA Astrophysics Data System (ADS)

Li, Decang; Meng, Jianjun; Bai, Huan; Xu, Ruxun

2018-07-01

This paper focuses on the safety of high-speed trains under strong crosswind conditions. A new active control strategy is proposed based on the adaptive predictive control theory. The new control strategy aims at adjusting the attitudes of a train by controlling the new-type intelligent giant magnetostrictive actuator (GMA). It combined adaptive control with dynamic matrix control; parameters of predictive controller was real-time adjusted by online distinguishing to enhance the robustness of the control algorithm. On this basis, a correction control algorithm is also designed to regulate the parameters of predictive controller based on the step response of a controlled objective. Finally, the simulation results show that the proposed control strategy can adjust the running attitudes of high-speed trains under strong crosswind conditions; they also indicate that the new active control strategy is effective and applicable in improving the safety performance of a train based on a host-target computer technology provided by Matlab/Simulink.

Proceedings of the 1997 Space Control Conference, Volume 2

DTIC Science & Technology

1997-03-27

of attitude information are used in our orbit determination. The attitude history buffer on MSX holds quaternions and time tags at 100-second...being able to use the attitude quaternions , DYNAMO can also compute the park-mode attitude of MSX if, for example, some of the raw on-board attitude ... used to aid the target discrimination process. THE MSX SPACECRAFT The SBV sensor was launched on the BMDO supported MSX spacecraft on 24 April

A Feasibility Study on the Control of a Generic Air Vehicle Using Control Moment Gyros

NASA Technical Reports Server (NTRS)

Lim, Kyong B.; Moerder, Daniel D.

2006-01-01

This paper examines feasibility and performance issues in using Control Moment Gyroscopes (CMGs) to control the attitude of a fixed-wing aircraft. The paper describes a control system structure that permits allocating control authority and bandwidth between a CMG system and conventional aerodynamic control surfaces to stabilize a vehicle with neutral aerodynamic stability. A simulation study explores the interplay between aerodynamic and CMG effects, and indicates desirable physical characteristics for a CMG system to be used for aircraft attitude control.

Attitude control/momentum management and payload pointing in advanced space vehicles

NASA Technical Reports Server (NTRS)

Parlos, Alexander G.; Jayasuriya, Suhada

1990-01-01

The design and evaluation of an attitude control/momentum management system for highly asymmetric spacecraft configurations are presented. The preliminary development and application of a nonlinear control system design methodology for tracking control of uncertain systems, such as spacecraft payload pointing systems are also presented. Control issues relevant to both linear and nonlinear rigid-body spacecraft dynamics are addressed, whereas any structural flexibilities are not taken into consideration. Results from the first task indicate that certain commonly used simplifications in the equations of motions result in unstable attitude control systems, when used for highly asymmetric spacecraft configurations. An approach is suggested circumventing this problem. Additionally, even though preliminary results from the second task are encouraging, the proposed nonlinear control system design method requires further investigation prior to its application and use as an effective payload pointing system design technique.

Changing attitudes toward disabilities through unified sports.

PubMed

Sullivan, Emma; Masters Glidden, Laraine

2014-10-01

A cognitive/affective/behavioral intervention was implemented to change attitudes of college students towards individuals with disabilities. College swim team members were randomly assigned to intervention (N  =  16), and no-intervention control groups (N  =  17), with intervention group students and 8 Special Olympics swimmers working together to pursue swimming-related goals in 4 sessions over a 6-week period. Results indicated that on a revision of the Symons, Fish, McGuigan, Fox, and Akl (2012) attitudes inventory, the intervention group participants displayed significant increases in positive attitudes from pre- to posttest, whereas the control group participants did not. Written participant comments corroborated this improvement. A key element in the improved attitudes was the increased comfort level experienced by the college swimmers in their interactions with the Special Olympics swimmers.

Flight Technology Improvement. [spaceborne optical radiometric instruments, attitude control, and electromechanical and power subsystems

NASA Technical Reports Server (NTRS)

1979-01-01

Shortcomings in spaceborne instrumentation technology are analyzed and recommendations are given for corrections and technology development. The technologies discussed are optical radiometric instruments and calibration, attitude control and determination, and electromechanical and power subsystems.

The Microwave Anisotropy Probe (MAP) Attitude Control System

NASA Technical Reports Server (NTRS)

Markley, F. Landis; Andrews, Stephen F.; ODonnell, James R., Jr.; Ward, David K.; Ericsson, Aprille J.; Bauer, Frank H. (Technical Monitor)

2002-01-01

The Microwave Anisotropy Probe mission is designed to produce a map of the cosmic microwave background radiation over the entire celestial sphere by executing a fast spin and a slow precession of its spin axis about the Sun line to obtain a highly interconnected set of measurements. The spacecraft attitude is sensed and controlled using an Inertial Reference Unit, two Autonomous Star Trackers, a Digital Sun Sensor, twelve Coarse Sun Sensors, three Reaction Wheel Assemblies, and a propulsion system. This paper describes the design of the attitude control system that carries out this mission and presents some early flight experience.

Precise attitude control of the Stanford relativity satellite.

NASA Technical Reports Server (NTRS)

Bull, J. S.; Debra, D. B.

1973-01-01

A satellite being designed by the Stanford University to measure (with extremely high precision) the effect of General Relativity is described. Specifically, the satellite will measure two relativistic precessions predicted by the theory: the geodetic effect (6.9 arcsec/yr), due solely to motion about the earth, and the motional effect (0.05 arcsec/yr), due to rotation of the earth. The gyro design requirements, including the requirement for precise attitude control and a dynamic model for attitude control synthesis, are discussed. Closed loop simulation of the satellite's natural dynamics on an analog computer is described.

Flight performance of Skylab attitude and pointing control system

NASA Technical Reports Server (NTRS)

Chubb, W. B.; Kennel, H. F.; Rupp, C. C.; Seltzer, S. M.

1975-01-01

The Skylab attitude and pointing control system (APCS) requirements are briefly reviewed and the way in which they became altered during the prelaunch phase of development is noted. The actual flight mission (including mission alterations during flight) is described. The serious hardware failures that occurred, beginning during ascent through the atmosphere, also are described. The APCS's ability to overcome these failures and meet mission changes are presented. The large around-the-clock support effort on the ground is discussed. Salient design points and software flexibility that should afford pertinent experience for future spacecraft attitude and pointing control system designs are included.

Psychological interventions influence patients' attitudes and beliefs about their chronic pain.

PubMed

Vanhaudenhuyse, Audrey; Gillet, Aline; Malaise, Nicole; Salamun, Irène; Grosdent, Stéphanie; Maquet, Didier; Nyssen, Anne-Sophie; Faymonville, Marie-Elisabeth

2018-04-01

Patients' changing attitudes and beliefs about pain are considered as improvements in the treatment of chronic pain. Multidisciplinary approaches to pain allow modifications of coping strategies of patients, from passive to active. We investigate how two therapeutic treatments impact patients' attitudes and beliefs regarding pain, as measured with the Survey of Pain Attitudes (SOPA). We allocated 415 patients with chronic pain either to psychoeducation combined with physiotherapy, self-hypnosis combined with self-care learning, or to control groups. Pain intensity, global impression of change, and beliefs and attitudes regarding pain were assessed before and after treatment. Our main results showed a significant effect of psychoeducation/physiotherapy on control, harm, and medical cure SOPA subscales; and a significant effect of self-hypnosis/self-care on control, disability and medical cure subscales. Correlation results showed that pain perception was negatively associated with control, while positively associated with disability, and a belief that hurt signifies harm. Patients' impression of improvement was associated with greater control, lower disability, and lower belief that hurt signifies harm. The present study showed that self-hypnosis/self-care and psychoeducation/physiotherapy were associated with patients' evolution of coping strategies from passive to active, allowing them to reduce pain perception and improve their global impression of treatment effectiveness.

From single-use to multi-use: Study of consumers' behavior toward consumption of reusable containers.

PubMed

Ertz, Myriam; Huang, Rong; Jo, Myung-Soo; Karakas, Fahri; Sarigöllü, Emine

2017-05-15

This study advances the theory of planned behavior (TPB) to identify the mechanism that underlies the consumption of reusable containers. A questionnaire including context, motivation, subjective norms, attitudes, perceived behavioral control, intentions and behavior items was developed and pre-tested on 180 students in a Canadian and a Chinese university respectively. Subsequently, the questionnaire was implemented in the form of an online survey and 1221 effective responses were collected from Western (n = 549) and Asian (n = 672) consumers. The findings revealed that the context and motivation variables are important antecedents to several TPB constructs. Context strongly impacts perceived behavioral control and motivations as well as attitudes. Motivation is clearly distinct from intentions and has a significant influence on both attitudes and intentions. In addition to the standard variables of perceived behavioral control, subjective norms and attitudes, motivation does have a significant impact on intentions. Furthermore, there are cultural differences in the way context impacts intentions and behavior in that Asians (Westerners) are influenced by context to increase reusable containers consumption through motivation (attitudes). Attitude is a significantly stronger predictor of intentions for Westerners than Asians. Copyright © 2017 Elsevier Ltd. All rights reserved.

Attitudes towards individuals with disabilities as measured by the implicit association test: a literature review.

PubMed

Wilson, Michelle Clare; Scior, Katrina

2014-02-01

Research investigating attitudes towards individuals with disabilities has largely focused on self-reported explicit attitudes. Given that factors such as social desirability may influence explicit attitudes, researchers have developed tools which instead assess less consciously controllable implicit attitudes. Considering research on implicit attitudes thus seems pertinent. A review of studies measuring implicit attitudes towards individuals with physical disabilities (visual, motor or hearing) or intellectual disabilities via the Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998) was carried out. Systematic searches of PsycINFO, CINAHL, EMBASE, ERIC, MEDLINE, PUBMED, Scopus and Web of Science databases identified relevant articles published between January 2000 and September 2012. Seventeen articles (reporting on 18 studies that employed the IAT) were identified. These investigated implicit attitudes towards individuals with; physical disabilities (N=13), intellectual disabilities (N=3), both physical and intellectual disabilities (N=1), and 'unspecified disabilities' (N=1). Across all studies, moderate to strong negative implicit attitudes were found and there was little to no association between explicit and implicit attitudes. Individuals' beliefs about the controllability of their future, sensitivity to the concept of disease, and contact with individuals with disabilities appear to be associated with implicit attitudes. A consistent pattern of moderate to strong negative implicit attitudes towards individuals with disabilities was evident. These studies provide a starting point, but methodological issues related to sampling and the employed IATs limit the generalizability of these results. Further research investigating implicit attitudes towards specific disability types, with a wider subject pool are necessary as well as further investigation of factors that contribute to these attitudes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Smoking behaviours and attitudes toward tobacco control among assistant environmental health officer trainees.

PubMed

Tee, G H; Gurpreet, K; Hairi, N N; Zarihah, Z; Fadzilah, K

2013-12-01

Assistant environmental health officers (AEHO) are health care providers (HCPs) who act as enforcers, educators and trusted role models for the public. This is the first study to explore smoking behaviour and attitudes toward tobacco control among future HCPs. Almost 30% of AEHO trainees did not know the role of AEHOs in counselling smokers to stop smoking, but 91% agreed they should not smoke before advising others not to do so. The majority agreed that tobacco control regulations may be used as a means of reducing the prevalence of smoking. Future AEHOs had positive attitudes toward tobacco regulations but lacked understanding of their responsibility in tobacco control measures.

Motor Control of Two Flywheels Enabling Combined Attitude Control and Bus Regulation

NASA Technical Reports Server (NTRS)

Kenny, Barbara H.

2004-01-01

This presentation discussed the flywheel technology development work that is ongoing at NASA GRC with a particular emphasis on the flywheel system control. The "field orientation" motor/generator control algorithm was discussed and explained. The position-sensorless angle and speed estimation algorithm was presented. The motor current response to a step change in command at low (10 kRPM) and high (60 kRPM) was discussed. The flywheel DC bus regulation control was explained and experimental results presented. Finally, the combined attitude control and energy storage algorithm that controls two flywheels simultaneously was presented. Experimental results were shown that verified the operational capability of the algorithm. shows high speed flywheel energy storage (60,000 RPM) and the successful implementation of an algorithm to simultaneously control both energy storage and a single axis of attitude with two flywheels. Overall, the presentation demonstrated that GRC has an operational facility that

Attractive manifold-based adaptive solar attitude control of satellites in elliptic orbits

NASA Astrophysics Data System (ADS)

Lee, Keum W.; Singh, Sahjendra N.

2011-01-01

The paper presents a novel noncertainty-equivalent adaptive (NCEA) control system for the pitch attitude control of satellites in elliptic orbits using solar radiation pressure (SRP). The satellite is equipped with two identical solar flaps to produce control moments. The adaptive law is based on the attractive manifold design using filtered signals for synthesis, which is a modification of the immersion and invariance (I&I) method. The control system has a modular controller-estimator structure and has separate tunable gains. A special feature of this NCEA law is that the trajectories of the satellite converge to a manifold in an extended state space, and the adaptive law recovers the performance of a deterministic controller. This recovery of performance cannot be obtained with certainty-equivalent adaptive (CEA) laws. Simulation results are presented which show that the NCEA law accomplishes precise attitude control of the satellite in an elliptic orbit, despite large parameter uncertainties.

An integrated power/attitude control system /IPACS/ for space vehicle application

NASA Technical Reports Server (NTRS)

Anderson, W. W.; Keckler, C. R.

1973-01-01

An integrated power and attitude control system (IPACS) concept with potential application to a broad class of space missions is discussed. The concept involves the storage and supply on demand of electrical energy in rotating flywheels while simultaneously providing control torques by controlled precession of the flywheels. The system is thus an alternative to the storage batteries used on present spacecraft while providing similar capability for attitude control as that represented by a control moment gyroscope (CMG) system. Potential IPACS configurations discussed include single- and double-rotor double-gimbal IPACS units. Typical sets of control laws which would manage the momentum and energy exchange between the IPACS and a typical space vehicle are discussed. Discussion of a simulation of a typical potential IPACS configuration and candidate mission concerned with pointing capability, power supply and demand flow, and discussion of the interactions between stabilization and control requirements and power flow requirements are presented.

Evaluation of Eating Attitude in Patients with Migraine

PubMed Central

DEMİRCİ, Kadir; DEMİRCİ, Seden; AKPINAR, Abdullah; DEMİRDAŞ, Arif; ATAY, İnci Meltem

2015-01-01

Introduction This study aimed to investigate the eating attitudes in patients with migraine. Methods Fifty-nine patients (mean age: 32.54±8.47 years) diagnosed with migraine according to the International Classification of Headache Disorder, 2004, and 47 age-, gender- and education-matched healthy controls (mean age: 31.85±7.14 years) were enrolled for this study. Sociodemographic data were recorded, and the body mass index was calculated as kilograms per meter squared. Data regarding the duration of illness and attack, frequency of migraine attacks, and the presence of aura were recorded. Migraine severity was assessed by Migraine Disability Assessment Score (MIDAS). Eating Attitudes Test (EAT), Beck Depression Inventory (BDI), and Beck Anxiety Inventory were applied to all participants. Results The patients with migraine had significantly higher EAT scores, levels of anxiety, and depression than controls (p<.01). Furthermore, 11.9% of patients with migraine had an EAT score of 30 or higher, which is suggestive of a disordered eating attitude, whereas this rate was 2.1% in healthy controls (p<.05). The scores of EAT and BDI had positive correlation with the scores of MIDAS in patients with migraine (r=.298, p<.05; r=.332, p=.01, respectively). Conclusion In our study, disordered eating attitudes and the levels of anxiety and depression were high in patients with migraine than controls. Our study is important to demonstrate the connection between migraine and disordered eating attitudes. PMID:28360741

Effect of levels of inquiry model of science teaching on scientific literacy domain attitudes

NASA Astrophysics Data System (ADS)

Achmad, Maulana; Suhandi, Andi

2017-05-01

The aim of this research was to obtain an overview of the increase scientific literacy attitudes domain in high school students as the effects of the Levels of Inquiry (LOI) model of science teaching. This research using a quasi-experimental methods and randomizedpretest-posttest control group design. The subject of this research was students of grade X in a senior high school in Purwakarta and it consists of two classes who were divided into experimental class (30 students) and control class (30 students). While experimental class was taught LOIand control class was taught Interactive Lecture Demonstration (ILD). Data were collected using an attitude scale scientific literacy test which is based on the Likert scale. Data were analyzed using normality test, homogeneity test, and t-test to the value of N-gain attitude of scientific literacy scale test. The result of percentage average N-gain experimental class and control are 49 and 31 that classified into medium improvement category. Based on the results of hypothesis testing on the N-gain value obtained by the Sig.(One-tailed) 0.000 < 0.050, it means that H1 was accepted. The results showed that scientific literacy domain attitude of students who got learning by LOI is higher than students who got learning by ILD. It can be concluded that the effect of LOI is better to improve scientific literacy domain attitudes significantly.

Micropulsed Plasma Thrusters for Attitude Control of a Low-Earth-Orbiting CubeSat

NASA Technical Reports Server (NTRS)

Gatsonis, Nikolaos A.; Lu, Ye; Blandino, John; Demetriou, Michael A.; Paschalidis, Nicholas

2016-01-01

This study presents a 3-Unit CubeSat design with commercial-off-the-shelf hardware, Teflon-fueled micropulsed plasma thrusters, and an attitude determination and control approach. The micropulsed plasma thruster is sized by the impulse bit and pulse frequency required for continuous compensation of expected maximum disturbance torques at altitudes between 400 and 1000 km, as well as to perform stabilization of up to 20 deg /s and slew maneuvers of up to 180 deg. The study involves realistic power constraints anticipated on the 3-Unit CubeSat. Attitude estimation is implemented using the q method for static attitude determination of the quaternion using pairs of the spacecraft-sun and magnetic-field vectors. The quaternion estimate and the gyroscope measurements are used with an extended Kalman filter to obtain the attitude estimates. Proportional-derivative control algorithms use the static attitude estimates in order to calculate the torque required to compensate for the disturbance torques and to achieve specified stabilization and slewing maneuvers or combinations. The controller includes a thruster-allocation method, which determines the optimal utilization of the available thrusters and introduces redundancy in case of failure. Simulation results are presented for a 3-Unit CubeSat under detumbling, pointing, and pointing and spinning scenarios, as well as comparisons between the thruster-allocation and the paired-firing methods under thruster failure.

Attributions and Attitudes of Mothers and Fathers in Thailand.

PubMed

Tapanya, Sombat

2011-07-01

OBJECTIVE: The present study examined similarities and differences between mothers' and fathers' attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes as well as correlations between mothers' and fathers' attributions and attitudes. DESIGN: Interviews were conducted with both mothers and fathers in 88 Thai families. RESULTS: Mothers and fathers did not differ in mean levels of attributions regarding successes and failures in caregiving situations or in authoritarian or progressive attitudes. Mothers' and fathers' perceived control over failure, authoritarian attitudes, progressive attitudes, and modernity of attitudes were significantly correlated. CONCLUSIONS: This work suggests high similarities between Thai mothers and fathers in their attributions and attitudes related to parenting.

Coupled Attitude and Orbit Dynamics and Control in Formation Flying Systems

NASA Technical Reports Server (NTRS)

Xu, Yun-Jun; Fitz-Coy, Norman; Mason, Paul

2003-01-01

Formation flying systems can range from global constellations offering extended service coverage to clusters of highly coordinated vehicles that perform distributed sensing. Recently, the use of groups of micro-satellites in the areas of near Earth explorations, deep space explorations, and military applications has received considerable attention by researchers and practitioners. To date, most proposed control strategies are based on linear models (e.g., Hill-Clohessy-Wiltshire equations) or nonlinear models that are restricted to circular reference orbits. Also, all models in the literature are uncoupled between relative position and relative attitude. In this paper, a generalized dynamic model is proposed. The reference orbit is not restricted to the circular case. In this formulation, the leader or follower satellite can be in either a circular or an elliptic orbit. In addition to maintaining a specified relative position, the satellites are also required to maintain specified relative attitudes. Thus the model presented couples vehicle attitude and orbit requirements. Orbit perturbations are also included. In particular, the J(sub 2) effects are accounted in the model. Finally, a sliding mode controller is developed and used to control the relative attitude of the formation and the simulation results are presented.

The Effects of Learning Strategy Instruction on Achievement, Attitude, and Achievement Motivation in a Physics Course

NASA Astrophysics Data System (ADS)

Sezgin Selçuk, Gamze; Sahin, Mehmet; Açıkgöz, Kamile Ün

2011-01-01

This article reports on the influence of learning strategy instruction on student teachers' physics achievement, attitude towards physics, and achievement motivation. A pre-test/post-test quasi-experimental design with matching control group was used in the study. Two groups of student teachers ( n = 75) who were enrolled in an introductory physics course participated in the study. In the experimental group, questioning, summarizing, and graphic organizers were taught. The control group did not receive any presentation on strategy learning. Data were collected via the pre- and post-administration of the Physics Course Achievement Test, the Scale of Attitudes towards Physics, and the Achievement Motivation Scale. Univariate and multivariate analyses of variance on the data revealed no significant differences in the attitude and achievement motivation between the strategy and control groups. However, the strategy group students were observed to have a tendency of more positive attitude and motivation than the control group students. Results also showed that explicit learning strategy instruction was more effective than traditional instruction in improving physics achievement of the participating students. The implications of these results for physics education are discussed.

[External and internal validity of a multidimensional Locus of control scale of eating attitudes for athletes (LOCSCAS)].

PubMed

Paquet, Y; Scoffier, S; d'Arripe-Longueville, F

2016-10-01

In the field of health psychology, the control has consistently been considered as a protective factor. This protective role has been also highlighted in eating attitudes' domain. However, current studies use the one-dimensional scale of Rotter or the multidimensional health locus of control scale, and no specific eating attitudes' scale in the sport context exists. Moreover, the social influence in previous scales is limited. According to recent works, the purpose of this study was to test the internal and external validity of a multidimensional locus of control scale of eating attitudes for athletes. One hundred and seventy-nine participants were solicited. A confirmatory factorial analysis was conducted in order to test the internal validity of the scale. The scale external validity was tested in relation to eating attitudes. The internal validity of the scale was verified as well as the external validity, which confirmed the importance of taking into consideration social influences. Indeed, the 2 subscales "Trainers, friends" and "Parents, family" are related respectively positively and negatively in eating disorders. Copyright © 2016 L'Encéphale, Paris. Published by Elsevier Masson SAS. All rights reserved.

A novel single thruster control strategy for spacecraft attitude stabilization

NASA Astrophysics Data System (ADS)

Godard; Kumar, Krishna Dev; Zou, An-Min

2013-05-01

Feasibility of achieving three axis attitude stabilization using a single thruster is explored in this paper. Torques are generated using a thruster orientation mechanism with which the thrust vector can be tilted on a two axis gimbal. A robust nonlinear control scheme is developed based on the nonlinear kinematic and dynamic equations of motion of a rigid body spacecraft in the presence of gravity gradient torque and external disturbances. The spacecraft, controlled using the proposed concept, constitutes an underactuated system (a system with fewer independent control inputs than degrees of freedom) with nonlinear dynamics. Moreover, using thruster gimbal angles as control inputs make the system non-affine (control terms appear nonlinearly in the state equation). This necessitates the control algorithms to be developed based on nonlinear control theory since linear control methods are not directly applicable. The stability conditions for the spacecraft attitude motion for robustness against uncertainties and disturbances are derived to establish the regions of asymptotic 3-axis attitude stabilization. Several numerical simulations are presented to demonstrate the efficacy of the proposed controller and validate the theoretical results. The control algorithm is shown to compensate for time-varying external disturbances including solar radiation pressure, aerodynamic forces, and magnetic disturbances; and uncertainties in the spacecraft inertia parameters. The numerical results also establish the robustness of the proposed control scheme to negate disturbances caused by orbit eccentricity.

Implicit attitudes towards homosexuality: reliability, validity, and controllability of the IAT.

PubMed

Banse, R; Seise, J; Zerbes, N

2001-01-01

Two experiments were conducted to investigate the psychometric properties of an Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998) that was adapted to measure implicit attitudes towards homosexuality. In a first experiment, the validity of the Homosexuality-IAT was tested using a known group approach. Implicit and explicit attitudes were assessed in heterosexual and homosexual men and women (N = 101). The results provided compelling evidence for the convergent and discriminant validity of the Homosexuality-IAT as a measure of implicit attitudes. No evidence was found for two alternative explanations of IAT effects (familiarity with stimulus material and stereotype knowledge). The internal consistency of IAT scores was satisfactory (alpha s > .80), but retest correlations were lower. In a second experiment (N = 79) it was shown that uninformed participants were able to fake positive explicit but not implicit attitudes. Discrepancies between implicit and explicit attitudes towards homosexuality could be partially accounted for by individual differences in the motivation to control prejudiced behavior, thus providing independent evidence for the validity of the implicit attitude measure. Neither explicit nor implicit attitudes could be changed by persuasive messages. The results of both experiments are interpreted as evidence for a single construct account of implicit and explicit attitudes towards homosexuality.

Design of a Control Moment Gyroscope Attitude Actuation System for the Attitude Control Subsystem Proving Ground

DTIC Science & Technology

2013-03-01

57 3.4.3 Rotor Bearing Selection . . . . . . . . . . . . . . . . . . . . . . . . . 60 3.4.4 Rotor Shaft Design ...66 3.5.2 Gimbal Bearing Selection . . . . . . . . . . . . . . . . . . . . . . . . 67 3.5.3 Gimbal Shaft Design ...63 3.14 Rotor Shaft Design

Hierarchical control of ride height system for electronically controlled air suspension based on variable structure and fuzzy control theory

NASA Astrophysics Data System (ADS)

Xu, Xing; Zhou, Kongkang; Zou, Nannan; Jiang, Hong; Cui, Xiaoli

2015-09-01

The current research of air suspension mainly focuses on the characteristics and design of the air spring. In fact, electronically controlled air suspension (ECAS) has excellent performance in flexible height adjustment during different driving conditions. However, the nonlinearity of the ride height adjusting system and the uneven distribution of payload affect the control accuracy of ride height and the body attitude. Firstly, the three-point measurement system of three height sensors is used to establish the mathematical model of the ride height adjusting system. The decentralized control of ride height and the centralized control of body attitude are presented to design the ride height control system for ECAS. The exact feedback linearization method is adopted for the nonlinear mathematical model of the ride height system. Secondly, according to the hierarchical control theory, the variable structure control (VSC) technique is used to design a controller that is able to adjust the ride height for the quarter-vehicle anywhere, and each quarter-vehicle height control system is independent. Meanwhile, the three-point height signals obtained by three height sensors are tracked to calculate the body pitch and roll attitude over time, and then by calculating the deviation of pitch and roll and its rates, the height control correction is reassigned based on the fuzzy algorithm. Finally, to verify the effectiveness and performance of the proposed combined control strategy, a validating test of ride height control system with and without road disturbance is carried out. Testing results show that the height adjusting time of both lifting and lowering is over 5 s, and the pitch angle and the roll angle of body attitude are less than 0.15°. This research proposes a hierarchical control method that can guarantee the attitude stability, as well as satisfy the ride height tracking system.

Orbiting Geophysical Observatory Attitude Control Subsystem Design Survey. NASA/ERC Design Criteria Program, Guidance and Control

NASA Technical Reports Server (NTRS)

Mc Kenna, K. J.; Schmeichel, H.

1968-01-01

This design survey summarizes the history of the Orbiting Geophysical Observatories' (OGO) Attitude Control Subsystem (ACS) from the proposal phase through current flight experience. Problems encountered in design, fabrication, test, and on orbit are discussed. It is hoped that the experiences of the OGO program related here will aid future designers.

The company they keep: drinking group attitudes and male bar aggression.

PubMed

Dumas, Tara M; Graham, Kathryn; Wells, Samantha

2015-05-01

The purpose of this study was to assess (a) similarities in self-reported bar-aggression-related attitudes and behaviors among members of young male groups recruited on their way to bars and (b) group-level variables associated with individual members' self-reported likelihood of perpetrating physical bar aggression in the past year, controlling for individual attitudes. Young, male, natural drinking groups recruited on their way to a bar district Thursday, Friday, and Saturday nights (n = 167, 53 groups) completed an online survey that measured whether they had perpetrated physical aggression at a bar in the past year and constructs associated with bar aggression, including attitudes toward male bar aggression and frequency of heavy episodic drinking in the past year. Intraclass correlations and chi-square tests demonstrated significant within-group similarity on bar-aggression-related attitudes and behaviors (ps < .01). Hierarchical linear modeling revealed that group attitudes toward bar aggression were significantly associated with individuals' likelihood of perpetrating physical bar aggression, controlling for individual attitudes (p < .01); however, the link between group heavy episodic drinking and self-reported bar aggression was nonsignificant in the full model. This study suggests that the most important group influence on young men's bar aggression is the attitudes of other group members. These attitudes were associated with group members' likelihood of engaging in bar aggression over and above individuals' own attitudes. A better understanding of how group attitudes and behavior affect the behavior of individual group members is needed to inform aggression-prevention programming.

Do implicit measures of attitudes incrementally predict snacking behaviour over explicit affect-related measures?

PubMed

Ayres, Karen; Conner, Mark T; Prestwich, Andrew; Smith, Paul

2012-06-01

Various studies have demonstrated an association between implicit measures of attitudes and dietary-related behaviours. However, no study has tested whether implicit measures of attitudes predict dietary behaviour after controlling for explicit measures of palatability. In a prospective design, two studies assessed the validity of measures of implicit attitude (Implicit Association Test, IAT) and explicit measures of palatability and health-related attitudes on self-reported (Studies 1 and 2) and objective food (fruit vs. chocolate) choice (Study 2). Following regression analyses, in both studies, implicit measures of attitudes were correlated with food choice but failed to significantly predict food choice when controlling specifically for explicit measures of palatability. These consistent relationships emerged despite using different category labels within the IAT in the two studies. The current research suggests implicit measures of attitudes may not predict dietary behaviours after taking into account the palatability of food. This is important in order to establish determinants that explain unique variance in dietary behaviours and to inform dietary change interventions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Performance of ground attitude determination procedures for HEAO-1

NASA Technical Reports Server (NTRS)

Fallon, L., III; Sturch, C. R.

1978-01-01

Ground attitude support for HEAO 1 provided at GSFC by the HEAO 1 Attitude Ground Support System (AGSS) is described. Information telemetered from Sun sensors, gyroscopes, star trackers, and an onboard computer are used by the AGSS to compute updates to the onboard attitude reference and gyro calibration parameters. The onboard computer utilizes these updates in providing continuous attitudes (accurate to 0.25degree) for use in the observatory's attitude control procedures. The relationship between HEAO 1 onboard and ground processing, the procedures used by the AGSS in computing attitude and gyro calibration updates, and the performance of these procedures in the HEAO 1 postlaunch environment is discussed.

An analysis of control reversal errors during unusual attitude recoveries using helmet-mounted display symbology.

PubMed

Liggett, Kristen K; Gallimore, Jennie J

2002-02-01

Spatial disorientation (SD) refers to pilots' inability to accurately interpret the attitude of their aircraft with respect to Earth. Unfortunately, SD statistics have held constant for the past few decades, through the transition from the head-down attitude indicator (Al) to the head-up display (HUD) as the attitude instrument. The newest attitude-indicating device to find its way into military cockpits is the helmet-mounted display (HMD). HMDs were initially introduced into the cockpit to enhance target location and weapon-pointing, but there is currently an effort to make HMDs attitude reference displays so pilots need not go head-down to obtain attitude information. However, unintuitive information or inappropriate implementation of on-boresight attitude symbology on the HMD may contribute to the SD problem. The occurrence of control reversal errors (CREs) during unusual attitude recovery tasks when using an HMD to provide attitude information was investigated. The effect of such errors was evaluated in terms of altitude changes during recovery and time to recover. There were 12 pilot-subjects who completed 8 unusual attitude recovery tasks. Results showed that CREs did occur, and there was a significant negative effect of these errors on absolute altitude change, but not on total recovery time. Results failed to show a decrease in the number of CREs occurring when using the HMD as compared with data from other studies that used an Al or a HUD. Results suggest that new HMD attitude symbology needs to be designed to help reduce CREs and, perhaps, SD incidences.

Pupillary Responses as a Biomarker of Diminished Effort Associated With Defeatist Attitudes and Negative Symptoms in Schizophrenia.

PubMed

Granholm, Eric; Ruiz, Ivan; Gallegos-Rodriguez, Yuliana; Holden, Jason; Link, Peter C

2016-10-15

The hypothesis that defeatist performance attitudes are associated with decreased goal-directed task effort and negative symptoms in consumers with schizophrenia was investigated by using pupillary responses as a biomarker of task effort. Pupillary dilation during cognitive tasks provides a biomarker of effort devoted to the task, with greater dilation indicating greater effort. Defeatist attitudes were assessed in 149 consumers with schizophrenia or schizoaffective disorder and 50 healthy control subjects, and consumers were divided into three groups (tertile split) with respect to severity of defeatist attitudes. Pupillary dilation responses were recorded during a digit-span task with three-, six-, and nine-digit spans. Effort allocation (pupillary responses) to the task increased as the processing load increased from low (three-digit) to moderate (six-digit) demands in healthy control subjects and consumers with schizophrenia with mild and moderate severity of defeatist attitudes. In contrast, consumers with severe defeatist attitudes did not increase their effort when processing demands increased from low to moderate loads. These consumers showed significantly less effort in the six-digit condition relative to consumers with mild defeatist attitudes. Moreover, consumers with severe defeatist attitudes showed significantly greater severity of negative symptoms relative to consumers with mild defeatist attitudes and negative symptoms were significantly correlated with defeatist attitudes. These results suggest a relationship between defeatist performance attitudes, goal-directed task effort indexed by pupillary responses, and negative symptoms in schizophrenia. The findings have implications for using cognitive therapy to reduce defeatist attitudes that may contribute to diminished effort and negative symptoms in schizophrenia. Published by Elsevier Inc.

GOES-R active vibration damping controller design, implementation, and on-orbit performance

NASA Astrophysics Data System (ADS)

Clapp, Brian R.; Weigl, Harald J.; Goodzeit, Neil E.; Carter, Delano R.; Rood, Timothy J.

2018-01-01

GOES-R series spacecraft feature a number of flexible appendages with modal frequencies below 3.0 Hz which, if excited by spacecraft disturbances, can be sources of undesirable jitter perturbing spacecraft pointing. To meet GOES-R pointing stability requirements, the spacecraft flight software implements an Active Vibration Damping (AVD) rate control law which acts in parallel with the nadir point attitude control law. The AVD controller commands spacecraft reaction wheel actuators based upon Inertial Measurement Unit (IMU) inputs to provide additional damping for spacecraft structural modes below 3.0 Hz which vary with solar wing angle. A GOES-R spacecraft dynamics and attitude control system identified model is constructed from pseudo-random reaction wheel torque commands and IMU angular rate response measurements occurring over a single orbit during spacecraft post-deployment activities. The identified Fourier model is computed on the ground, uplinked to the spacecraft flight computer, and the AVD controller filter coefficients are periodically computed on-board from the Fourier model. Consequently, the AVD controller formulation is based not upon pre-launch simulation model estimates but upon on-orbit nadir point attitude control and time-varying spacecraft dynamics. GOES-R high-fidelity time domain simulation results herein demonstrate the accuracy of the AVD identified Fourier model relative to the pre-launch spacecraft dynamics and control truth model. The AVD controller on-board the GOES-16 spacecraft achieves more than a ten-fold increase in structural mode damping for the fundamental solar wing mode while maintaining controller stability margins and ensuring that the nadir point attitude control bandwidth does not fall below 0.02 Hz. On-orbit GOES-16 spacecraft appendage modal frequencies and damping ratios are quantified based upon the AVD system identification, and the increase in modal damping provided by the AVD controller for each structural mode is presented. The GOES-16 spacecraft AVD controller frequency domain stability margins and nadir point attitude control bandwidth are presented along with on-orbit time domain disturbance response performance.

GOES-R Active Vibration Damping Controller Design, Implementation, and On-Orbit Performance

NASA Technical Reports Server (NTRS)

Clapp, Brian R.; Weigl, Harald J.; Goodzeit, Neil E.; Carter, Delano R.; Rood, Timothy J.

2017-01-01

GOES-R series spacecraft feature a number of flexible appendages with modal frequencies below 3.0 Hz which, if excited by spacecraft disturbances, can be sources of undesirable jitter perturbing spacecraft pointing. In order to meet GOES-R pointing stability requirements, the spacecraft flight software implements an Active Vibration Damping (AVD) rate control law which acts in parallel with the nadir point attitude control law. The AVD controller commands spacecraft reaction wheel actuators based upon Inertial Measurement Unit (IMU) inputs to provide additional damping for spacecraft structural modes below 3.0 Hz which vary with solar wing angle. A GOES-R spacecraft dynamics and attitude control system identified model is constructed from pseudo-random reaction wheel torque commands and IMU angular rate response measurements occurring over a single orbit during spacecraft post-deployment activities. The identified Fourier model is computed on the ground, uplinked to the spacecraft flight computer, and the AVD controller filter coefficients are periodically computed on-board from the Fourier model. Consequently, the AVD controller formulation is based not upon pre-launch simulation model estimates but upon on-orbit nadir point attitude control and time-varying spacecraft dynamics. GOES-R high-fidelity time domain simulation results herein demonstrate the accuracy of the AVD identified Fourier model relative to the pre-launch spacecraft dynamics and control truth model. The AVD controller on-board the GOES-16 spacecraft achieves more than a ten-fold increase in structural mode damping of the fundamental solar wing mode while maintaining controller stability margins and ensuring that the nadir point attitude control bandwidth does not fall below 0.02 Hz. On-orbit GOES-16 spacecraft appendage modal frequencies and damping ratios are quantified based upon the AVD system identification, and the increase in modal damping provided by the AVD controller for each structural mode is presented. The GOES-16 spacecraft AVD controller frequency domain stability margins and nadir point attitude control bandwidth are presented along with on-orbit time domain disturbance response performance.

Fuzzy based attitude controller for flexible spacecraft with on/off thrusters

NASA Astrophysics Data System (ADS)

Knapp, Roger G.; Adams, Neil J.

A fuzzy-based attitude controller is designed for attitude control of a generic spacecraft with on/off thrusters. The controller is comprised of packages of rules dedicated to addressing different objectives (e.g., disturbance rejection, low fuel consumption, avoiding the excitation of flexible appendages, etc.). These rule packages can be inserted or removed depending on the requirements of the particular spacecraft and are parameterized based on vehicle parameters such as inertia or operational parameters such as the maneuvering rate. Individual rule packages can be 'weighted' relative to each other to emphasize the importance of one objective relative to another. Finally, the fuzzy controller and rule packages are demonstrated using the high-fidelity Space Shuttle Interactive On-Orbit Simulator (IOS) while performing typical on-orbit operations and are subsequently compared with the existing shuttle flight control system performance.

Fuzzy based attitude controller for flexible spacecraft with on/off thrusters

NASA Astrophysics Data System (ADS)

Knapp, Roger Glenn

1993-05-01

A fuzzy-based attitude controller is designed for attitude control of a generic spacecraft with on/off thrusters. The controller is comprised of packages of rules dedicated to addressing different objectives (e.g., disturbance rejection, low fuel consumption, avoiding the excitation of flexible appendages, etc.). These rule packages can be inserted or removed depending on the requirements of the particular spacecraft and are parameterized based on vehicle parameters such as inertia or operational parameters such as the maneuvering rate. Individual rule packages can be 'weighted' relative to each other to emphasize the importance of one objective relative to another. Finally, the fuzzy controller and rule packages are demonstrated using the high-fidelity Space Shuttle Interactive On-Orbit Simulator (IOS) while performing typical on-orbit operations and are subsequently compared with the existing shuttle flight control system performance.

Robust adaptive relative position and attitude control for spacecraft autonomous proximity.

PubMed

Sun, Liang; Huo, Wei; Jiao, Zongxia

2016-07-01

This paper provides new results of the dynamical modeling and controller designing for autonomous close proximity phase during rendezvous and docking in the presence of kinematic couplings and model uncertainties. A globally defined relative motion mechanical model for close proximity operations is introduced firstly. Then, in spite of the kinematic couplings and thrust misalignment between relative rotation and relative translation, robust adaptive relative position and relative attitude controllers are designed successively. Finally, stability of the overall system is proved that the relative position and relative attitude are uniformly ultimately bounded, and the size of the ultimate bound can be regulated small enough by control system parameters. Performance of the controlled overall system is demonstrated via a representative numerical example. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

The influence of gender on the relationship between wildlife value orientations, beliefs, and the acceptability of lethal deer control in Cuyahoga Valley National Park

USGS Publications Warehouse

Dougherty, E.M.; Fulton, D.C.; Anderson, D.H.

2003-01-01

This study examines how wildlife value orientations, attitudes, and gender influence acceptance of lethal actions to control deer in Cuyahoga Valley National Park in Ohio. Data were collected from female and male residents (n = 659) in a nine-county area, the primary service area of the park. Females and males demonstrated significant differences in their wildlife value orientations, attitudes toward lethal deer control, beliefs about the outcome of lethal deer control, and perceived personal impacts of lethal deer control. Gender also acted as a moderator of the relationship between values, beliefs and attitudes. Results indicate that a focus on understanding differences between males and females is essential to public participation in decision making concerning this and similar issues.

On the Stability of Collocated Controllers in the Presence or Uncertain Nonlinearities and Other Perils

NASA Technical Reports Server (NTRS)

Joshi, S. M.

1985-01-01

Robustness properties are investigated for two types of controllers for large flexible space structures, which use collocated sensors and actuators. The first type is an attitude controller which uses negative definite feedback of measured attitude and rate, while the second type is a damping enhancement controller which uses only velocity (rate) feedback. It is proved that collocated attitude controllers preserve closed loop global asymptotic stability when linear actuator/sensor dynamics satisfying certain phase conditions are present, or monotonic increasing nonlinearities are present. For velocity feedback controllers, the global asymptotic stability is proved under much weaker conditions. In particular, they have 90 phase margin and can tolerate nonlinearities belonging to the (0,infinity) sector in the actuator/sensor characteristics. The results significantly enhance the viability of both types of collocated controllers, especially when the available information about the large space structure (LSS) parameters is inadequate or inaccurate.

Singularity-free backstepping controller for model helicopters.

PubMed

Zou, Yao; Huo, Wei

2016-11-01

This paper develops a backstepping controller for model helicopters to achieve trajectory tracking without singularity, which occurs in the attitude representation when the roll or pitch reaches ±π2. Based on a simplified model with unmodeled dynamics, backstepping technique is introduced to exploit the controller and hyperbolic tangent functions are utilized to compensate the unmodeled dynamics. Firstly, a position loop controller is designed for the position tracking, where an auxiliary dynamic system with suitable parameters is introduced to warrant the singularity-free requirement for the extracted command attitude. Then, a novel attitude loop controller is proposed to obviate singularity. It is demonstrated that, based on the established criteria for selecting controller parameters and desired trajectories, the proposed controller realizes the singularity-free trajectory tracking of the model helicopter. Simulations confirm the theoretical results. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

A view finder control system for an earth observation satellite

NASA Astrophysics Data System (ADS)

Steyn, H.

2004-11-01

A real time TV view finder is used on-board a low earth orbiting (LEO) satellite to manually select targets for imaging from a ground station within the communication footprint of the satellite. The attitude control system on the satellite is used to steer the satellite using commands from the groundstation and a television camera onboard the satellite will then downlink a television signal in real time to a monitor screen in the ground station. The operator in the feedback loop will be able to manually steer the boresight of the satellite's main imager towards interested target areas e.g. to avoid clouds or correct for any attitude pointing errors. Due to a substantial delay (in the order of a second) in the view finding feedback loop and the narrow field of view of the main imager, the operator has to be assisted by the onboard attitude control system to stabilise and track the target area visible on the monitor screen. This paper will present the extended Kalman filter used to estimate the satellite's attitude angles using quaternions and the bias vector component of the 3-axis inertial rate sensors (gyros). Absolute attitude sensors (i.e. sun, horizon and magnetic) are used to supply the measurement vectors to correct the filter states during the view finder manoeuvres. The target tracking and rate steering reaction wheel controllers to accurately point and stabilise the satellite will be presented. The reference generator for the satellite to target attitude and rate vectors as used by the reaction wheel controllers will be derived.

The impact of group training about parenting styles on maternal attitudes toward parenting styles

PubMed Central

Zandiyeh, Zahra; Zare, Elaheh; Hedayati, Batool

2015-01-01

Background: Parenting style is one of the most important and effective factors in training and growth of children and adolescents and the method that parents communicate with their children is an effective factor on family contact models. Objectives: The aim of this study was to determine the impact of group training about parenting styles on maternal attitudes that were admitted to Isfahan Imam Ali (AS) health care center in 2013. Materials and Methods: This was an experimental study, which was conducted on a random sample of 25 mothers referred to this health care center. They were divided into two groups (experimental and control). The experimental group received five sessions of group training, and the control group received a booklet about parenting styles. The used tool in this study was the Bamerind Parenting Style Questionnaire that was completed by the mothers before and after the intervention and finally, their obtained scores were compared with each other. Results: The results of the present study showed that the mean score of attitude toward easy-going style in test group was less than the control group after intervention (P = 0.045). The mean score of attitude toward authoritative style in the experimental group was less than control group after intervention (P = 0.037) and the mean score of attitude toward authoritative style in the experimental group was more than the control group after intervention (P = 0.011). Conclusions: Group training can be an appropriate method in changing maternal attitudes toward parenting styles. PMID:27462627

Attitudes Toward Obese Persons and Weight Locus of Control in Chinese Nurses: A Cross-sectional Survey.

PubMed

Wang, Yan; Ding, Ye; Song, Daoping; Zhu, Daqiao; Wang, Jianrong

2016-01-01

Obese individuals frequently experience weight-related bias or discrimination-even in healthcare settings. Although obesity bias has been associated with several demographic factors, little is known about the association of weight locus of control with bias against overweight persons or about weight bias among Chinese health professionals. The aim of the study was to examine attitudes toward obese patients in a sample of Chinese registered nurses (RNs) and the relationship between weight bias and nurses' weight locus of control. RNs working in nine community health service centers across Shanghai, China, answered three self-report questionnaires: The Attitudes Toward Obese Persons Scale (ATOP), the External Weight Locus of Control Subscale (eWLOC) from the Dieting Belief Scale, and a sociodemographic profile. Hierarchical, stepwise, multiple regression was used to predict ATOP scores. From among 385 invited, a total of 297 RNs took part in the study (77.1% response rate). Participants scored an average of 71.04 on the ATOP, indicating slightly positive attitudes toward obese persons, and 30.08 on the eWLOC, indicating a belief in the uncontrollability of body weight. Using hierarchical, stepwise, multiple regression, two predictors of ATOP scores were statistically significant (eWLOC scores and status as a specialist rather than generalist nurse), but explained variance was low. Chinese RNs seemed to have relatively neutral or even slightly positive attitudes toward obese persons. Those nurses who believed that obesity was beyond the individual's control or worked in specialties were more likely to have positive attitudes toward obese people. Improved understanding of the comprehensive etiology of obesity is needed.

Premarital Sexual Guilt and Contraceptive Attitudes and Behavior.

ERIC Educational Resources Information Center

Herold, Edward S.; Goodwin, Marilyn Shirley

1981-01-01

Studied the relationship between premarital sexual guilt and contraceptive attitudes and behavior among young single women. High-guilt subjects were significantly more embarrassed about coming to the birth control clinics and were more likely to believe that it was difficult to obtain birth control. (Author)

Using Automatic Code Generation in the Attitude Control Flight Software Engineering Process

NASA Technical Reports Server (NTRS)

McComas, David; O'Donnell, James R., Jr.; Andrews, Stephen F.

1999-01-01

This paper presents an overview of the attitude control subsystem flight software development process, identifies how the process has changed due to automatic code generation, analyzes each software development phase in detail, and concludes with a summary of our lessons learned.

Adaptive twisting sliding mode algorithm for hypersonic reentry vehicle attitude control based on finite-time observer.

PubMed

Guo, Zongyi; Chang, Jing; Guo, Jianguo; Zhou, Jun

2018-06-01

This paper focuses on the adaptive twisting sliding mode control for the Hypersonic Reentry Vehicles (HRVs) attitude tracking issue. The HRV attitude tracking model is transformed into the error dynamics in matched structure, whereas an unmeasurable state is redefined by lumping the existing unmatched disturbance with the angular rate. Hence, an adaptive finite-time observer is used to estimate the unknown state. Then, an adaptive twisting algorithm is proposed for systems subject to disturbances with unknown bounds. The stability of the proposed observer-based adaptive twisting approach is guaranteed, and the case of noisy measurement is analyzed. Also, the developed control law avoids the aggressive chattering phenomenon of the existing adaptive twisting approaches because the adaptive gains decrease close to the disturbance once the trajectories reach the sliding surface. Finally, numerical simulations on the attitude control of the HRV are conducted to verify the effectiveness and benefit of the proposed approach. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Use of a knowledge-attitude-behaviour education programme for Chinese adults undergoing maintenance haemodialysis: Randomized controlled trial.

PubMed

Liu, Li; Liu, Yue-Ping; Wang, Jing; An, Li-Wei; Jiao, Jian-Mei

2016-06-01

To investigate the effects of a knowledge-attitude-behaviour health education model on acquisition of disease-related knowledge and self-management behaviour by patients undergoing maintenance haemodialysis. Patients recently prescribed MHD were randomly assigned to a control group or an intervention group. Control group patients were treated with usual care and general education models. A specialist knowledge-attitude-behaviour health education model was applied to patients in the intervention group. Eighty-six patients were included (n = 43 per group). Before intervention, there were no significant between-group differences in disease knowledge and self-management behaviour. After 6 months' intervention, a significant between-group difference in acquisition of disease knowledge was observed. Self-management behaviour scores (control of body mass, reasonable diet, correct drug intake, physical activity, correct fistula care, disease condition monitoring, psychological and social behaviours) for the intervention group were also higher than those for the control group. These preliminary findings suggest that the knowledge-attitude-behaviour model appears to be a valuable tool for the health education of MHD patients. © The Author(s) 2016.

Use of a knowledge-attitude-behaviour education programme for Chinese adults undergoing maintenance haemodialysis: Randomized controlled trial

PubMed Central

Liu, Li; Wang, Jing; An, Li-Wei; Jiao, Jian-Mei

2016-01-01

Objective To investigate the effects of a knowledge-attitude-behaviour health education model on acquisition of disease-related knowledge and self-management behaviour by patients undergoing maintenance haemodialysis. Methods Patients recently prescribed MHD were randomly assigned to a control group or an intervention group. Control group patients were treated with usual care and general education models. A specialist knowledge-attitude-behaviour health education model was applied to patients in the intervention group. Results Eighty-six patients were included (n = 43 per group). Before intervention, there were no significant between-group differences in disease knowledge and self-management behaviour. After 6 months’ intervention, a significant between-group difference in acquisition of disease knowledge was observed. Self-management behaviour scores (control of body mass, reasonable diet, correct drug intake, physical activity, correct fistula care, disease condition monitoring, psychological and social behaviours) for the intervention group were also higher than those for the control group. Conclusion These preliminary findings suggest that the knowledge-attitude-behaviour model appears to be a valuable tool for the health education of MHD patients. PMID:26951842

Wheel configurations for combined energy storage and attitude control systems

NASA Technical Reports Server (NTRS)

Oglevie, R. E.

1985-01-01

Integrated power and attitude control system (IPACS) studies performed over a decade ago established the feasibility of simultaneously storing electrical energy in wheels and utilizing the resulting momentum for spacecraft attitude control. It was shown that such a system possessed many advantages over other contemporary energy storage and attitude control systems in many applications. More recent technology advances in composite rotors, magnetic bearings, and power control electronics have triggered new optimism regarding the feasibility and merits of such a system. This paper presents the results of a recent study whose focus was to define an advanced IPACS and to evaluate its merits for the Space Station application. Emphasis is given to the selection of the wheel configuration to perform the combined functions. A component design concept is developed to establish the system performance capability. A system-level trade study, including life-cycle costing, is performed to define the merits of the system relative to two other candidate systems. It is concluded that an advanced IPACS concept is not only feasible but offers substantial savings in mass and life-cycle cost.

Can teaching research methodology influence students' attitude toward science? Cohort study and nonrandomized trial in a single medical school.

PubMed

Vujaklija, Ana; Hren, Darko; Sambunjak, Dario; Vodopivec, Ivana; Ivanis, Ana; Marusić, Ana; Marusić, Matko

2010-02-01

Medical teaching aims to develop attitudes and behaviors underlying professional competence of future physicians. We investigated whether a mandatory course on scientific methodology in the second study year could affect students' attitudes toward science in medicine. In a longitudinal study, students (n = 241) enrolling in 2001-2002 academic year at a single medical school were followed up until graduation in 2006-2007. Each year, they filled out a Likert-type questionnaire of 18 statements evaluating attitude toward science. Direct influence of the course on students' attitudes was tested in a nonrandomized controlled trial with the 2006-2007 second year student cohort. Positive students' attitudes toward science increased during study years (mean [SD] score of the maximum score of 90): from 57.6 (6.0) in the first to 69.8 (10.4) in the sixth year. There was a significant trend of increase in attitudes with the years of study (cubic trend by polynomial contrasts analysis, P = 0.011). Attendance of a course on research methodology significantly increased positive attitudes (score, 67.0 [7.0] before and 70.8 [7.5] after course, P = 0.032 vs control group), regardless of grade point average. The intervention had an effect even when the influence of the initial attitude was accounted for (F1,140 = 9.25, P = 0.003; analysis of covariance). The attitude changes after the course was greatest in students with low initial attitude scores (Spearman rinitial score, score difference, -0.44). Medical students have positive attitudes toward science and scientific method in medicine. Attendance of a course on research methodology had positive short-term effect on students' attitudes toward science. This positive effect should be maintained by vertical integration of the course in the medical curriculum.

Techniques for monitoring and controlling yaw attitude of a GPS satellite

NASA Technical Reports Server (NTRS)

Lichten, Stephen M. (Inventor); Bar-Sever, Yoaz (Inventor); Zumberge, James (Inventor); Bertiger, William I. (Inventor); Muellerschoen, Ronald J. (Inventor); Wu, Sien-Chong (Inventor); Hurst, Kenneth (Inventor); Blewitt, Geoff (Inventor); Yunck, Thomas (Inventor); Thornton, Catherine (Inventor)

2001-01-01

Techniques for monitoring and controlling yawing of a GPS satellite in an orbit that has an eclipsing portion out of the sunlight based on the orbital conditions of the GPS satellite. In one embodiment, a constant yaw bias is generated in the attitude control system of the GPS satellite to control the yawing of the GPS satellite when it is in the shadow of the earth.

A Control Concept for Large Flexible Spacecraft Using Order Reduction Techniques

NASA Technical Reports Server (NTRS)

Thieme, G.; Roth, H.

1985-01-01

Results found during the investigation of control problems of large flexible spacecraft are given. A triple plate configuration of such a spacecraft is defined and studied. The model is defined by modal data derived from infinite element modeling. The order reduction method applied is briefly described. An attitude control concept with low and high authority control has been developed to design an attitude controller for the reduced model. The stability and response of the original system together with the reduced controller is analyzed.

Optimal Electrical Energy Slewing for Reaction Wheel Spacecraft

NASA Astrophysics Data System (ADS)

Marsh, Harleigh Christian

The results contained in this dissertation contribute to a deeper level of understanding to the energy required to slew a spacecraft using reaction wheels. This work addresses the fundamental manner in which spacecrafts are slewed (eigenaxis maneuvering), and demonstrates that this conventional maneuver can be dramatically improved upon in regards to reduction of energy, dissipative losses, as well as peak power. Energy is a fundamental resource that effects every asset, system, and subsystem upon a spacecraft, from the attitude control system which orients the spacecraft, to the communication subsystem to link with ground stations, to the payloads which collect scientific data. For a reaction wheel spacecraft, the attitude control system is a particularly heavy load on the power and energy resources on a spacecraft. The central focus of this dissertation is reducing the burden which the attitude control system places upon the spacecraft in regards to electrical energy, which is shown in this dissertation to be a challenging problem to computationally solve and analyze. Reducing power and energy demands can have a multitude of benefits, spanning from the initial design phase, to in-flight operations, to potentially extending the mission life of the spacecraft. This goal is approached from a practical standpoint apropos to an industry-flight setting. Metrics to measure electrical energy and power are developed which are in-line with the cost associated to operating reaction wheel based attitude control systems. These metrics are incorporated into multiple families of practical high-dimensional constrained nonlinear optimal control problems to reduce the electrical energy, as well as the instantaneous power burdens imposed by the attitude control system upon the spacecraft. Minimizing electrical energy is shown to be a problem in L1 optimal control which is nonsmooth in regards to state variables as well as the control. To overcome the challenge of nonsmoothness, a method is adopted in this dissertation to transform the nonsmooth minimum electrical energy problem into an equivalent smooth formulation, which then allows standard techniques in optimal control to solve and analyze the problem. Through numerically solving families of optimal control problems, the relationship between electrical energy and transfer time is identified and explored for both off-and on-eigenaxis maneuvering, under minimum dissipative losses as well as under minimum electrical energy. A trade space between on-and off-eigenaxis maneuvering is identified, from which is shown that agile near time optimal maneuvers exist within the energy budget associated with conventional eigenaxis maneuvering. Moreover, even for conventional eigenaxis maneuvering, energy requirements can be dramatically reduced by maneuvering off-eigenaxis. These results address one of the fundamental assumptions in the field of optimal path design verses conventional maneuver design. Two practical flight situations are addressed in this dissertation in regards to reducing energy and power: The case when the attitude of the spacecraft is predetermined, and the case where reaction wheels can not be directly controlled. For the setting where the attitude of spacecraft is on a predefined trajectory, it is demonstrated that reduced energy maneuvers are only attainable though the application of null-motions, which requires control of the reaction wheels. A computationally light formulation is developed minimizing the dissipative losses through the application of null motions. In the situation where the reaction wheels can not be directly controlled, it is demonstrated that energy consumption, dissipative losses, and peak-power loads, of the reaction-wheel array can each be reduced substantially by controlling the input to the attitude control system through attitude steering. It is demonstrated that the open loop trajectories correctly predict the closed loop response when tracked by an attitude control system which does not allow direct command of the reaction wheels.

77 FR 39990 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-06

...' Knowledge, Attitudes and Perceptions of Coral Reefs in Two Hawaii Priority Sites. OMB Control Number: None... this survey is to identify resident users' knowledge, attitudes, and perceptions regarding coral reef... and education. A representative study of resident users' knowledge, attitudes, and perceptions will...

Changing implicit attitudes toward smoking: results from a web-based approach-avoidance practice intervention.

PubMed

Macy, Jonathan T; Chassin, Laurie; Presson, Clark C; Sherman, Jeffrey W

2015-02-01

Implicit attitudes have been shown to predict smoking behaviors. Therefore, an important goal is the development of interventions to change these attitudes. This study assessed the effects of a web-based intervention on implicit attitudes toward smoking and receptivity to smoking-related information. Smokers (N = 284) were recruited to a two-session web-based study. In the first session, baseline data were collected. Session two contained the intervention, which consisted of assignment to the experimental or control version of an approach-avoidance task and assignment to an anti-smoking or control public service announcement (PSA), and post-intervention measures. Among smokers with less education and with plans to quit, implicit attitudes were more negative for those who completed the approach-avoidance task. Smokers with more education who viewed the anti-smoking PSA and completed the approach-avoidance task spent more time reading smoking-related information. An approach-avoidance task is a potentially feasible strategy for changing implicit attitudes toward smoking and increasing receptivity to smoking-related information.

Changing Implicit Attitudes toward Smoking: Results from a Web-Based Approach-Avoidance Practice Intervention

PubMed Central

Macy, Jonathan T.; Chassin, Laurie; Presson, Clark C.; Sherman, Jeffrey W.

2014-01-01

Implicit attitudes have been shown to predict smoking behaviors. Therefore, an important goal is the development of interventions to change these attitudes. This study assessed the effects of a web-based intervention on implicit attitudes toward smoking and receptivity to smoking-related information. Smokers (N=284) were recruited to a two-session web-based study. In the first session, baseline data were collected. Session two contained the intervention, which consisted of assignment to the experimental or control version of an approach-avoidance task and assignment to an anti-smoking or control public service announcement (PSA), and post-intervention measures. Among smokers with less education and with plans to quit, implicit attitudes were more negative for those who completed the approach-avoidance task. Smokers with more education who viewed the anti-smoking PSA and completed the approach-avoidance task spent more time reading smoking-related information. An approach-avoidance task is a potentially feasible strategy for changing implicit attitudes toward smoking and increasing receptivity to smoking-related information. PMID:25059750

Parental overprotection engenders dysfunctional attitudes about achievement and dependency in a gender-specific manner.

PubMed

Otani, Koichi; Suzuki, Akihito; Matsumoto, Yoshihiko; Shibuya, Naoshi; Sadahiro, Ryoichi; Enokido, Masanori

2013-12-24

It has been suggested that dysfunctional attitudes, cognitive vulnerability to depression, have developmental origins. The present study examined the effects of parental rearing on dysfunctional attitudes in three areas of life with special attention to gender specificity. The subjects were 665 Japanese healthy volunteers. Dysfunctional attitudes were assessed by the 24-item Dysfunctional Attitude Scale, which has the Achievement, Dependency and Self-control subscales. Perceived parental rearing was assessed by the Parental Bonding Instrument, which has the Care and Protection subscales. Higher scores of the Achievement (β = 0.293, p < 0.01) and Dependency (β = 0.224, p < 0.05) subscales were correlated with higher scores of the Protection subscale in the combination of mother and daughter, but not in other combinations of parents and recipients. Scores of the Self-control subscale were not correlated with paternal or maternal rearing scores. The present study suggests that parental overprotection engenders dysfunctional attitudes about achievement and dependency in a gender-specific manner.

Why does asking questions change health behaviours? The mediating role of attitude accessibility

PubMed Central

Wood, Chantelle; Conner, Mark; Sandberg, Tracy; Godin, Gaston; Sheeran, Paschal

2013-01-01

Objective The question-behaviour effect (QBE) refers to the finding that measuring behavioural intentions increases performance of the relevant behaviour. This effect has been used to change health behaviours. The present research asks why the QBE occurs and evaluates one possible mediator – attitude accessibility. Design University staff and students (N = 151) were randomly assigned to an intention measurement condition where they reported their intentions to eat healthy foods, or to one of two control conditions. Main outcome measures Participants completed a response latency measure of attitude accessibility, before healthy eating behaviour was assessed unobtrusively using an objective measure of snacking. Results Intention measurement participants exhibited more accessible attitudes towards healthy foods, and were more likely to choose a healthy snack, relative to control participants. Furthermore, attitude accessibility mediated the relationship between intention measurement and behaviour. Conclusion This research demonstrates that increased attitude accessibility may explain the QBE, extending the findings of previous research to the domain of health behaviour. PMID:24245778

Effects of Brain-Based Learning Approach on Students' Motivation and Attitudes Levels in Science Class

ERIC Educational Resources Information Center

Akyurek, Erkan; Afacan, Ozlem

2013-01-01

The purpose of the study was to examine the effect of brain-based learning approach on attitudes and motivation levels in 8th grade students' science classes. The main reason for examining attitudes and motivation levels, the effect of the short-term motivation, attitude shows the long-term effect. The pre/post-test control group research model…

Influencing Attitudes and Changing Behavior: A Basic Introduction to Relevant Methodology, Theory, and Applications. Revised Edition.

ERIC Educational Resources Information Center

Zimbardo, Philip; Ebbesen, Ebbe B.

In this introductory text to the field of attitude change, the emphasis is on one of the end products of research in social psychology--manipulation and control of attitudes and related behaviors. The text first defines the concept of attitude, then identifies ideas from the areas of history, literature, law, religion, and the social sciences that…

Attitude motion of a non-attitude-controlled cylindrical satellite

NASA Technical Reports Server (NTRS)

Wilkinson, C. K.

1988-01-01

In 1985, two non-attitude-controlled satellites were each placed in a low earth orbit by the Scout Launch Vehicle. The satellites were cylindrical in shape and contained reservoirs of hydrazine fuel. Three-axis magnetometer measurements, telemetered in real time, were used to derive the attitude motion of each satellite. Algorithms are generated to deduce possible orientations (and magnitudes) of each vehicle's angular momentum for each telemetry contact. To resolve ambiguities at each contact, a force model was derived to simulate the significant long-term effects of magnetic, gravity gradient, and aerodynamic torques on the angular momentum of the vehicles. The histories of the orientation and magnitude of the angular momentum are illustrated.

Intention for healthy eating among southern Appalachian teens.

PubMed

Wu, Tiejian; Snider, Jeromy Blake; Floyd, Michael R; Florence, James E; Stoots, James Michael; Makamey, Michael I

2009-01-01

To describe the intention for healthy eating and its correlates among southern Appalachian teens. Four hundred sixteen adolescents 14- to 16-years-old were surveyed with self-administered questionnaires. About 30% of the adolescents surveyed had definite intentions to eat healthfully during the next 2 weeks. The scales for perceived behavior control, attitude, perceived eating habits of significant others, and social support were shown to be fairly reliable (Cronbach's alpha=0.60 to 0.88). Perceived behavior control and attitude were positively associated with the intention for healthy eating. Better behavior control and more positive attitude may lead to a stronger intention for healthy eating.

Application of square-root filtering for spacecraft attitude control

NASA Technical Reports Server (NTRS)

Sorensen, J. A.; Schmidt, S. F.; Goka, T.

1978-01-01

Suitable digital algorithms are developed and tested for providing on-board precision attitude estimation and pointing control for potential use in the Landsat-D spacecraft. These algorithms provide pointing accuracy of better than 0.01 deg. To obtain necessary precision with efficient software, a six state-variable square-root Kalman filter combines two star tracker measurements to update attitude estimates obtained from processing three gyro outputs. The validity of the estimation and control algorithms are established, and the sensitivity of their performance to various error sources and software parameters are investigated by detailed digital simulation. Spacecraft computer memory, cycle time, and accuracy requirements are estimated.

ADRC for spacecraft attitude and position synchronization in libration point orbits

NASA Astrophysics Data System (ADS)

Gao, Chen; Yuan, Jianping; Zhao, Yakun

2018-04-01

This paper addresses the problem of spacecraft attitude and position synchronization in libration point orbits between a leader and a follower. Using dual quaternion, the dimensionless relative coupled dynamical model is derived considering computation efficiency and accuracy. Then a model-independent dimensionless cascade pose-feedback active disturbance rejection controller is designed to spacecraft attitude and position tracking control problems considering parameter uncertainties and external disturbances. Numerical simulations for the final approach phase in spacecraft rendezvous and docking and formation flying are done, and the results show high-precision tracking errors and satisfactory convergent rates under bounded control torque and force which validate the proposed approach.

Should different marketing communication strategies be used to promote healthy eating among male and female adolescents?

PubMed

Chan, Kara; Ng, Yu-Leung; Prendergast, Gerard

2014-01-01

A study was conducted to examine how interpersonal norms, media norms, attitudes, perceived behavioral control, perceived barriers, and self-efficacy had an influence on healthy eating intention among adolescents. A probability sample of 544 adolescents aged 12 to 18 was conducted. Results indicated that girls had a more favorable attitude and intention toward healthy eating than boys. Healthy eating intention among boys was predicted by attitude, perceived behavioral control, perceived barriers, and self-efficacy, and among girls was predicted by perceived behavioral control and self-efficacy. Different marketing strategies to promote healthy eating among adolescent boys and girls should be adopted.

Flight test evaluation of a separate surface attitude command control system on a Beech 99 airplane

NASA Technical Reports Server (NTRS)

Gee, S. W.; Jenks, G. E.; Roskam, J.; Stone, R. L.

1976-01-01

A joint NASA/university/industry program was conducted to flight evaluate a potentially low cost separate surface implementation of attitude command in a Beech 99 airplane. Saturation of the separate surfaces was the primary cause of many problems during development. Six experienced professional pilots made simulated instrument flight evaluations in light-to-moderate turbulence. They were favorably impressed with the system, particularly with the elimination of control force transients that accompanied configuration changes. For ride quality, quantitative data showed that the attitude command control system resulted in all cases of airplane motion being removed from the uncomfortable ride region.

Sexual Risk Attitudes and Intentions of Youth Aged 12-14 Years: Survey Comparisons of Parent-Teen Prevention and Control Groups

ERIC Educational Resources Information Center

Lederman, Regina P.; Chan, Wenyaw; Roberts-Gray, Cynthia

2004-01-01

In this study, the authors compared differences in sexual risk attitudes and intentions for three groups of youth (experimental program, n = 90; attention control, n = 80; and nonparticipant control, n = 634) aged 12-14 years. Two student groups participated with their parents in programs focused on strengthening family interaction and prevention…

Adaptive extended-state observer-based fault tolerant attitude control for spacecraft with reaction wheels

NASA Astrophysics Data System (ADS)

Ran, Dechao; Chen, Xiaoqian; de Ruiter, Anton; Xiao, Bing

2018-04-01

This study presents an adaptive second-order sliding control scheme to solve the attitude fault tolerant control problem of spacecraft subject to system uncertainties, external disturbances and reaction wheel faults. A novel fast terminal sliding mode is preliminarily designed to guarantee that finite-time convergence of the attitude errors can be achieved globally. Based on this novel sliding mode, an adaptive second-order observer is then designed to reconstruct the system uncertainties and the actuator faults. One feature of the proposed observer is that the design of the observer does not necessitate any priori information of the upper bounds of the system uncertainties and the actuator faults. In view of the reconstructed information supplied by the designed observer, a second-order sliding mode controller is developed to accomplish attitude maneuvers with great robustness and precise tracking accuracy. Theoretical stability analysis proves that the designed fault tolerant control scheme can achieve finite-time stability of the closed-loop system, even in the presence of reaction wheel faults and system uncertainties. Numerical simulations are also presented to demonstrate the effectiveness and superiority of the proposed control scheme over existing methodologies.

Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices

NASA Technical Reports Server (NTRS)

Munday, Jeremy

2016-01-01

Solar sails offer an opportunity for a CubeSatscale, propellant-free spacecraft technology that enables long-term and long-distance missions not possible with traditional methods. Solar sails operate using the transfer of linear momentum from photons of sunlight reflected from the surface of the sail. To propel the spacecraft, no mechanically moving parts, thrusters, or propellant are needed. However, attitude control, or orientation, is still performed using traditional methods involving reaction wheels and propellant ejection, which severely limit mission lifetime. For example, the current state of the art solutions employed by upcoming missions couple solar sails with a state of the art propellant ejection gas system. Here, the use of the gas thruster has limited the lifetime of the mission. To solve the limited mission lifetime problem, the Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices project team is working on propellantless attitude control using thin layers of material, an optical film, electrically switchable from transparent to reflective. The technology is based on a polymer-dispersed liquid crystal (PDLC), which allows this switch upon application of a voltage. This technology removes the need for propellant, which reduces weight and cost while improving performance and lifetime.

Precision Pointing Control to and Accurate Target Estimation of a Non-Cooperative Vehicle

NASA Technical Reports Server (NTRS)

VanEepoel, John; Thienel, Julie; Sanner, Robert M.

2006-01-01

In 2004, NASA began investigating a robotic servicing mission for the Hubble Space Telescope (HST). Such a mission would not only require estimates of the HST attitude and rates in order to achieve capture by the proposed Hubble Robotic Vehicle (HRV), but also precision control to achieve the desired rate and maintain the orientation to successfully dock with HST. To generalize the situation, HST is the target vehicle and HRV is the chaser. This work presents a nonlinear approach for estimating the body rates of a non-cooperative target vehicle, and coupling this estimation to a control scheme. Non-cooperative in this context relates to the target vehicle no longer having the ability to maintain attitude control or transmit attitude knowledge.

Attitude Control Working Group report

NASA Technical Reports Server (NTRS)

Reid, Daniel F.; Studer, Phillip A.

1986-01-01

The goals were to establish the Attitude Control System (ACS) requirements, constraints, technology assessment, technology shortfalls, expected in the year 2000. These were based upon all missions, military and civil, for LEO and GEO. The critical ACS technology issues were identified and ACS programs developed to address these critical issues.

Maternal reactions to a child with epilepsy: Depression, anxiety, parental attitudes and family functions.

PubMed

Pekcanlar Akay, Aynur; Hiz Kurul, Semra; Ozek, Handan; Cengizhan, Sevay; Emiroglu, Neslihan; Ellidokuz, Hulya

2011-08-01

The goal of this study was to investigate how the disease and treatment of epilepsy affected the psychological profile (depression and anxiety) of mothers whose children had epilepsy, as well as these mothers' attitudes towards their children and their family relationships. Both the case and control groups consisted of 50 children and their mothers. All mothers were asked to complete the Beck Depression Inventory, State-Trait Anxiety Inventory, Parental Attitude Research Instrument and Family Assessment Device. Mothers whose children had epilepsy scored significantly higher in depression and state anxiety compared to the mothers of the control group. The mothers of children diagnosed with epilepsy also failed to develop supportive and friendly relationships with their children. In addition, these mothers scored significantly higher in the Attitude of Hostility and Rejection, Marital Discordance and Authoritarian Attitude as compared to the mothers of the control group. This cross-sectional study demonstrated that, for the mothers of children who had epilepsy, the illness might have an adverse effect on their lives and their family relationships. Copyright © 2011 Elsevier B.V. All rights reserved.

Adaptive fuzzy logic controller with direct action type structures for InnoSAT attitude control system

NASA Astrophysics Data System (ADS)

Bakri, F. A.; Mashor, M. Y.; Sharun, S. M.; Bibi Sarpinah, S. N.; Abu Bakar, Z.

2016-10-01

This study proposes an adaptive fuzzy controller for attitude control system (ACS) of Innovative Satellite (InnoSAT) based on direct action type structure. In order to study new methods used in satellite attitude control, this paper presents three structures of controllers: Fuzzy PI, Fuzzy PD and conventional Fuzzy PID. The objective of this work is to compare the time response and tracking performance among the three different structures of controllers. The parameters of controller were tuned on-line by adjustment mechanism, which was an approach similar to a PID error that could minimize errors between actual and model reference output. This paper also presents a Model References Adaptive Control (MRAC) as a control scheme to control time varying systems where the performance specifications were given in terms of the reference model. All the controllers were tested using InnoSAT system under some operating conditions such as disturbance, varying gain, measurement noise and time delay. In conclusion, among all considered DA-type structures, AFPID controller was observed as the best structure since it outperformed other controllers in most conditions.

How to reduce the latent social risk of disease: the determinants of vaccination against rabies in Taiwan.

PubMed

Ku-Yuan, Lee; Li-Chi, Lan; Jiun-Hao, Wang; Chen-Ling, Fang; Kun-Sun, Shiao

2014-06-04

To control the latent social risk of disease, the government usually spreads accurate information and attempts to improve the public's attitude toward adopting prevention. However, these methods with the Knowledge, Attitudes, and Practices (KAP) model do not always work. Therefore, we used the theory of planned behavior (TPB) to understand dog owners' behavior and distinguished the knowledge effect as objective knowledge (OK) and subjective knowledge (SK). A total of 310 dog owners completed a questionnaire based on our model. We employed structural equation modeling to verify the structural relationships and found three main results. First, our model was fit, and each path was significant. People with better attitudes, stronger subjective norms, and more perceptive behavioral control have stronger behavioral intention. Second, perceived behavioral control, not attitude, was the best predictive index in this model. Finally, on perceived behavioral control, subjective knowledge showed more influence than objective knowledge. We successfully extended TPB to explain the behavioral intention of dog owners and presented more workable recommendations. To reduce the latent social risk of disease, the government should not only address dog owners' attitudes, but also their subjective norms and perceptive behavioral control. Indeed, perceptive behavioral control and SK showed the most influence in this model. It is implied that the self-efficacy of dog owners is the most important factor in such a behavior. Therefore, the government should focus on enhancing dog owners' self-efficacy first while devoted to prevention activities.

How to Reduce the Latent Social Risk of Disease: The Determinants of Vaccination against Rabies in Taiwan

PubMed Central

Ku-Yuan, Lee; Li-Chi, Lan; Jiun-Hao, Wang; Chen-Ling, Fang; Kun-Sun, Shiao

2014-01-01

To control the latent social risk of disease, the government usually spreads accurate information and attempts to improve the public’s attitude toward adopting prevention. However, these methods with the Knowledge, Attitudes, and Practices (KAP) model do not always work. Therefore, we used the theory of planned behavior (TPB) to understand dog owners’ behavior and distinguished the knowledge effect as objective knowledge (OK) and subjective knowledge (SK). A total of 310 dog owners completed a questionnaire based on our model. We employed structural equation modeling to verify the structural relationships and found three main results. First, our model was fit, and each path was significant. People with better attitudes, stronger subjective norms, and more perceptive behavioral control have stronger behavioral intention. Second, perceived behavioral control, not attitude, was the best predictive index in this model. Finally, on perceived behavioral control, subjective knowledge showed more influence than objective knowledge. We successfully extended TPB to explain the behavioral intention of dog owners and presented more workable recommendations. To reduce the latent social risk of disease, the government should not only address dog owners’ attitudes, but also their subjective norms and perceptive behavioral control. Indeed, perceptive behavioral control and SK showed the most influence in this model. It is implied that the self-efficacy of dog owners is the most important factor in such a behavior. Therefore, the government should focus on enhancing dog owners’ self-efficacy first while devoted to prevention activities. PMID:24901413

Attitude dynamics and control of a spacecraft like a robotic manipulator when implementing on-orbit servicing

NASA Astrophysics Data System (ADS)

Da Fonseca, Ijar M.; Goes, Luiz C. S.; Seito, Narumi; da Silva Duarte, Mayara K.; de Oliveira, Élcio Jeronimo

2017-08-01

In space the manipulators working space is characterized by the microgravity environment. In this environment the spacecraft floats and its rotational/translational motion may be excited by any internal and external disturbances. The complete system, i.e., the spacecraft and the associated robotic manipulator, floats and is sensitive to any reaction force and torque related to the manipulator's operation. In this sense the effort done by the robot may result in torque about the system center of mass and also in forces changing its translational motion. This paper analyzes the impact of the robot manipulator dynamics on the attitude motion and the associated control effort to keep the attitude stable during the manipulator's operation. The dynamics analysis is performed in the close proximity phase of rendezvous docking/berthing operation. In such scenario the linear system equations for the translation and attitude relative motions are appropriate. The computer simulations are implemented for the relative translational and rotational motion. The equations of motion have been simulated through computer by using the MatLab software. The LQR and the PID control laws are used for linear and nonlinear control, respectively, aiming to keep the attitude stable while the robot is in and out of service. The gravity-gradient and the residual magnetic torque are considered as external disturbances. The control efforts are analyzed for the manipulator in and out of service. The control laws allow the system stabilization and good performance when the manipulator is in service.

The efficacy of a modified Theory of Reasoned Action to explain gambling behavior in college students.

PubMed

Thrasher, Robert G; Andrew, Damon P S; Mahony, Daniel F

2011-09-01

Recently, Thrasher et al. (College Student Affairs Journal 27(1): 57-75, 2007) explored the efficacy of the Theory of Reasoned Action (TRA; Ajzen and Fishbein, Attitudes, personality, and behavior, 1980) in explaining gambling behavior of college students. However, their study found the TRA only predicted small amounts of variance in gambling intentions. Heeding their call to enhance the efficacy of the TRA through the addition of explanatory variables to the model, the present study incorporated gambling motivations and locus of control as moderating variables within the TRA to test the potential of a modified TRA in explaining gambling behavior of college students. A total of 345 students at a major metropolitan research university in the Midwest volunteered to participate in the study. A series of hierarchical linear regressions indicated intrinsic motivation to accomplish (p = .002) significantly moderated the relationship between gambling attitudes and gambling intentions. Further, internal locus of control (p < .001), chance locus of control (p < .001), and powerful others locus of control (p < .001) also significantly moderated the relationship between gambling attitudes and gambling intentions. The significant impact of the moderating variables on the relationship between gambling attitudes and intentions suggests intrinsic motivation and locus of control can alter the impact of the relationship between gambling attitudes and gambling intentions.

Cassini at Saturn Proximal Orbits - Attitude Control Challenges

NASA Technical Reports Server (NTRS)

Burk, Thomas A.

2013-01-01

The Cassini mission at Saturn will come to an end in the spring and summer of 2017 with a series of 22 orbits that will dip inside the rings of Saturn. These are called proximal orbits and will conclude with spacecraft disposal into the atmosphere of the ringed world on September 15, 2017. These unique orbits that cross the ring plane only a few thousand kilometers above the cloud tops of the planet present new attitude control challenges for the Cassini operations team. Crossing the ring plane so close to the inner edge of the rings means that the Cassini orientation during the crossing will be tailored to protect the sensitive electronics bus of the spacecraft. This orientation will put the sun sensors at some extra risk so this paper discusses how the team prepares for dust hazards. Periapsis is so close to the planet that spacecraft controllability with RCS thrusters needs to be evaluated because of the predicted atmospheric torque near closest approach to Saturn. Radiation during the ring plane crossings will likely trigger single event transients in some attitude control sensors. This paper discusses how the attitude control team deals with radiation hazards. The angular size and unique geometry of the rings and Saturn near periapsis means that star identification will be interrupted and this paper discusses how the safe mode attitude is selected to best deal with these large bright bodies during the proximal orbits.

Changing the Sexual Aggression-Supportive Attitudes of Men: A Psychoeducational Intervention.

ERIC Educational Resources Information Center

Gilbert, Barbara J.; And Others

1991-01-01

Assessed psychoeducational intervention designed to change attitudes of men found to be associated with sexual aggression toward women. College men receiving elaboration likelihood model-based intervention showed significantly more attitude change than did control group. One month later, in unrelated naturalistic context, intervention subjects…

78 FR 19490 - Disease, Disability, and Injury Prevention and Control Special Emphasis Panel (SEP): Initial Review

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-01

... announced below concerns Attitudes Towards Cognitive Health, Cognitive Impairment, and Caregiving--Identifying Attitude Questions and Measures for Public Health Practice, Special Interest Project (SIP)13-071... review, discussion, and evaluation of ``Attitudes Towards Cognitive Health, Cognitive Impairment, and...

Community knowledge, attitudes and practices in relation to tuberculosis in Cameroon.

PubMed

Kwedi Nolna, S; Kammogne, I D; Ndzinga, R; Afanda, B; Ntonè, R; Boum, Y; Nolna, D

2016-09-01

With 15 080 new cases in 2013, Cameroon is a country with high tuberculosis (TB) incidence and prevalence. Understanding the community's knowledge, attitude and practice (KAP) about TB is key to TB control in such endemic settings. To assess TB-related KAP in Cameroon by describing the sociodemographics of respondents, to identify barriers to seeking care and to explore attitudes and experiences of stigma and discrimination related to TB in communities. We conducted a cross-sectional descriptive study using structured questionnaires to assess and compare TB KAP in the entire territory. The results showed that Cameroonians have insufficient understanding of TB, numerous erroneous health assumptions and beliefs concerning TB, and erroneous information about the symptoms and mode of transmission of the disease. Negative attitudes and poor practices are obstacles to elimination and control efforts. The National Tuberculosis Control Programme should generate more effective strategies to reach the populations, paying particular attention to rural populations.

Hypothalamic-pituitary-adrenal axis functioning and dysfunctional attitude in depressed patients with and without childhood neglect.

PubMed

Peng, Hongjun; Long, Ying; Li, Jie; Guo, Yangbo; Wu, Huawang; Yang, YuLing; Ding, Yi; He, Jianfei; Ning, Yuping

2014-02-18

To date, the relationships between childhood neglect, hypothalamic-pituitary-adrenal (HPA) axis functioning and dysfunctional attitude in depressed patients are still obscure. The Childhood Trauma Questionnaire (CTQ) was used to assess childhood emotional neglect and physical neglect. Twenty-eight depressed patients with childhood neglect and 30 depressed patients without childhood neglect from Guangzhou Psychiatric Hospital were compared with 29 age- and gender-matched control subjects without childhood neglect and 22 control subjects with childhood neglect. Cortisol awakening response, the difference between the cortisol concentrations at awakening and 30 minutes later, provided a measure of HPA axis functioning. The Dysfunctional Attitude Scale measured cognitive schema. HPA axis functioning was significantly increased in depressed patients with childhood neglect compared with depressed patients without childhood neglect (p < 0.001). HPA axis activity in the control group with childhood neglect was significantly higher than in the depressed group without childhood neglect (p < 0.001). Total scores of childhood neglect were positively correlated with HPA axis functioning and dysfunctional attitude scores, but not with severity of depression. We did not find correlations with HPA axis functioning and dysfunctional attitude or with the Hamilton Rating Scale for Depression scores. Childhood neglect may cause hyperactivity of the HPA axis functioning and dysfunctional attitude, but does not affect depression severity.

Attitudes without Objects: Evidence for a Dispositional Attitude, its Measurement, and its Consequences

PubMed Central

Hepler, Justin; Albarracin, Dolores

2013-01-01

We hypothesized that individuals may differ in the dispositional tendency to have positive versus negative attitudes, a trait termed the Dispositional Attitude. Across four studies, we developed a 16-item Dispositional Attitude Measure (DAM) and investigated its internal consistency, test-retest reliability, factor structure, convergent validity, discriminant validity, and predictive validity. DAM scores were (a) positively correlated with positive affect traits, curiosity-related traits, and individual pre-existing attitudes, (b) negatively correlated with negative affect traits, and (c) uncorrelated with theoretically unrelated traits. Dispositional attitudes also significantly predicted the valence of novel attitudes while controlling for theoretically relevant traits (such as the big-five and optimism). The dispositional attitude construct represents a new perspective in which attitudes are not simply a function of the properties of the stimuli under consideration, but are also a function of the properties of the evaluator. We discuss the intriguing implications of dispositional attitudes for many areas of research, including attitude formation, persuasion, and behavior prediction. PMID:23586409

Attitudes without objects: evidence for a dispositional attitude, its measurement, and its consequences.

PubMed

Hepler, Justin; Albarracín, Dolores

2013-06-01

We hypothesized that individuals may differ in the dispositional tendency to have positive vs. negative attitudes, a trait termed the dispositional attitude. Across 4 studies, we developed a 16-item Dispositional Attitude Measure (DAM) and investigated its internal consistency, test-retest reliability, factor structure, convergent validity, discriminant validity, and predictive validity. DAM scores were (a) positively correlated with positive affect traits, curiosity-related traits, and individual preexisting attitudes; (b) negatively correlated with negative affect traits; and (c) uncorrelated with theoretically unrelated traits. Dispositional attitudes also significantly predicted the valence of novel attitudes while controlling for theoretically relevant traits (such as the Big 5 and optimism). The dispositional attitude construct represents a new perspective in which attitudes are not simply a function of the properties of the stimuli under consideration, but are also a function of the properties of the evaluator. We discuss the intriguing implications of dispositional attitudes for many areas of research, including attitude formation, persuasion, and behavior prediction. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Engines-only flight control system

NASA Technical Reports Server (NTRS)

Burcham, Frank W. (Inventor); Gilyard, Glenn B (Inventor); Conley, Joseph L. (Inventor); Stewart, James F. (Inventor); Fullerton, Charles G. (Inventor)

1994-01-01

A backup flight control system for controlling the flightpath of a multi-engine airplane using the main drive engines is introduced. The backup flight control system comprises an input device for generating a control command indicative of a desired flightpath, a feedback sensor for generating a feedback signal indicative of at least one of pitch rate, pitch attitude, roll rate and roll attitude, and a control device for changing the output power of at least one of the main drive engines on each side of the airplane in response to the control command and the feedback signal.

Nature and operation of attitudes.

PubMed

Ajzen, I

2001-01-01

This survey of attitude theory and research published between 1996 and 1999 covers the conceptualization of attitude, attitude formation and activation, attitude structure and function, and the attitude-behavior relation. Research regarding the expectancy-value model of attitude is considered, as are the roles of accessible beliefs and affective versus cognitive processes in the formation of attitudes. The survey reviews research on attitude strength and its antecedents and consequences, and covers progress made on the assessment of attitudinal ambivalence and its effects. Also considered is research on automatic attitude activation, attitude functions, and the relation of attitudes to broader values. A large number of studies dealt with the relation between attitudes and behavior. Research revealing additional moderators of this relation is reviewed, as are theory and research on the link between intentions and actions. Most work in this context was devoted to issues raised by the theories of reasoned action and planned behavior. The present review highlights the nature of perceived behavioral control, the relative importance of attitudes and subjective norms, the utility of adding more predictors, and the roles of prior behavior and habit.

A description of the thruster attitude control simulation and its application to the HEAO-C study

NASA Technical Reports Server (NTRS)

Brandon, L. B.

1971-01-01

During the design and evaluation of a reaction control system (RCS), it is desirable to have a digital computer program simulating vehicle dynamics, disturbance torques, control torques, and RCS logic. The thruster attitude control simulation (TACS) is just such a computer program. The TACS is a relatively sophisticated digital computer program that includes all the major parameters involved in the attitude control of a vehicle using an RCS for control. It includes the effects of gravity gradient torques and HEAO-C aerodynamic torques so that realistic runs can be made in the areas of fuel consumption and engine actuation rates. Also, the program is general enough that any engine configuration and logic scheme can be implemented in a reasonable amount of time. The results of the application of the TACS in the HEAO-C study are included.

Self-control, self-regulation, and doping in sport: a test of the strength-energy model.

PubMed

Chan, Derwin K; Lentillon-Kaestner, Vanessa; Dimmock, James A; Donovan, Robert J; Keatley, David A; Hardcastle, Sarah J; Hagger, Martin S

2015-04-01

We applied the strength-energy model of self-control to understand the relationship between self-control and young athletes' behavioral responses to taking illegal performance-enhancing substances, or "doping." Measures of trait self-control, attitude and intention toward doping, intention toward, and adherence to, doping-avoidant behaviors, and the prevention of unintended doping behaviors were administered to 410 young Australian athletes. Participants also completed a "lollipop" decision-making protocol that simulated avoidance of unintended doping. Hierarchical linear multiple regression analyses revealed that self-control was negatively associated with doping attitude and intention, and positively associated with the intention and adherence to doping-avoidant behaviors, and refusal to take or eat the unfamiliar candy offered in the "lollipop" protocol. Consistent with the strength-energy model, athletes with low self-control were more likely to have heightened attitude and intention toward doping, and reduced intention, behavioral adherence, and awareness of doping avoidance.

Fuzzy based attitude controller for flexible spacecraft with on/off thrusters. M.S. Thesis - M.I.T., 1993

NASA Technical Reports Server (NTRS)

Knapp, Roger Glenn

1993-01-01

A fuzzy-based attitude controller is designed for attitude control of a generic spacecraft with on/off thrusters. The controller is comprised of packages of rules dedicated to addressing different objectives (e.g., disturbance rejection, low fuel consumption, avoiding the excitation of flexible appendages, etc.). These rule packages can be inserted or removed depending on the requirements of the particular spacecraft and are parameterized based on vehicle parameters such as inertia or operational parameters such as the maneuvering rate. Individual rule packages can be 'weighted' relative to each other to emphasize the importance of one objective relative to another. Finally, the fuzzy controller and rule packages are demonstrated using the high-fidelity Space Shuttle Interactive On-Orbit Simulator (IOS) while performing typical on-orbit operations and are subsequently compared with the existing shuttle flight control system performance.

The influence of the guided constructivist instructional model on attitudes toward secondary-level physics

NASA Astrophysics Data System (ADS)

Dallal, Kamel Salim

The effect of guided constructivism (bridging analogies) and expository instructional methods on the attitudes of students toward physics was investigated. A nonrandomize nonequivalent pretest-posttest control group quasi- experimental design was employed. The sample consisted of 127 eleventh-grade and twelfth-grade students from five selected classes from two private high schools in Beirut, Lebanon. Two intact classes were assigned to the control group and three classes to the experimental group. The experimental group was exposed to the bridging analogies instructional method, and the control group was taught using the traditional expository method. A Likert-type instrument, the Physics Attitude Index, was used to measure attitudes on four dimensions. The 40-item Physics Attitude Index (PAI) is a questionnaire using a five response scale. Performance in the assigned topics in physics, cognitive developmental levels, and gender were used as covariants and to examine interaction effects. The experimental groups had significantly higher means than the control groups on all criterion variables. A significant interaction was found between groups and performance levels in the following cases: (a) criterion variable of attitude toward physics; (b) views toward physics learning; and (c) enjoyment of physics. This result indicated that the low performing students among the experimental group had greater gain in attitude toward physics than the high performing students in same group. On the other hand, no interaction occurred between treatment groups and gender, which shows that in this study gender has no significant effect on attitude toward physics. Significant interactions between the treatment groups and cognitive levels were found on the criterion variable of beliefs about physics as a process of learning and enjoyment of physics. In both cases, the difference between the group means were widely different among students at the concrete and transitional levels, but narrowly different among students at the formal level.

Summary of the Flight Technology Improvement Workshop. [spaceborne optical radiometric instruments, attitude control, and electromechanical and power subsystems

NASA Technical Reports Server (NTRS)

1979-01-01

Spaceborne instrumentation technology deficiencies are summarized. Recommendations are given for technology development, improvements in existing technology, and policy changes needed to facilitate the use of improved technology. Optical radiometric instruments, attitude control, and electromechanical and power subsystems are considered.

Community Involvement, Perceived Control, and Attitudes toward Aging among Lesbians and Gay Men

ERIC Educational Resources Information Center

Hostetler, Andrew J.

2012-01-01

A person-environment approach was used to explore the relationship between community involvement and attitudes toward aging among middle-age and older lesbians and gay men. Specifically, this study investigated the relationships between participation in gay community activities, perceived control, and aging-related concerns among two…

Black Family Planning: Attitudes of Leaders and a General Sample.

ERIC Educational Resources Information Center

Harris, William G.; And Others

Attitudes of black leaders and a general black population sample toward birth control and family planning issues were "Pro Birth Control" and "Genocide Fears." The leaders questioned held positions in twenty national black organizations, while the general population samples were taken from Philadelphia, Pennsylvania, and Charlotte, North Carolina.…

Acquisition and cruise sensing for attitude control

NASA Technical Reports Server (NTRS)

Pace, G. D., Jr.; Schmidt, L. F.

1977-01-01

Modified wideangle analog cruise sun sensor coupled with changes in optic attitude correction capabilities, eliminate need of acquisition and sun gate sensors, making on-course navigation of spacecraft flying interplanetary missions less risky and costly. Operational characteristics potentially make system applicable to guidance and control of solar energy collection systems.

Skylab

NASA Image and Video Library

1972-09-01

This photograph shows the Skylab Orbital Workshop (OWS) assembled, with its Thruster Attitude Control System (TACS) and radiator, ready for placing on the transporter. Twenty-two titanium spheres above the radiator housed the nitrogen required for operation of the TACS. At one end of the OWS, the TACS provided short-term control of the attitude of the Skylab.

Effects of news media messages about mass shootings on attitudes toward persons with serious mental illness and public support for gun control policies.

PubMed

McGinty, Emma E; Webster, Daniel W; Barry, Colleen L

2013-05-01

In recent years, mass shootings by persons with serious mental illness have received extensive news media coverage. The authors test the effects of news stories about mass shootings on public attitudes toward persons with serious mental illness and support for gun control policies. They also examine whether news coverage of proposals to prevent persons with serious mental illness from having guns exacerbates the public's negative attitudes toward this group. The authors conducted a survey-embedded randomized experiment using a national sample (N=1,797) from an online panel. Respondents were randomly assigned to groups instructed to read one of three news stories or to a no-exposure control group. The news stories described, respectively, a mass shooting by a person with serious mental illness, the same mass shooting and a proposal for gun restrictions for persons with serious mental illness, and the same mass shooting and a proposal to ban large-capacity magazines. Outcome measures included attitudes toward working with or living near a person with serious mental illness, perceived dangerousness of persons with serious mental illness, and support for gun restrictions for persons with serious mental illness and for a ban on large-capacity magazines. Compared with the control group, the story about a mass shooting heightened respondents' negative attitudes toward persons with serious mental illness and raised support for gun restrictions for this group and for a ban on large-capacity magazines. Including information about the gun restriction policy in a story about a mass shooting did not heighten negative attitudes toward persons with serious mental illness or raise support for the restrictions. The aftermath of mass shootings is often viewed as a window of opportunity to garner support for gun control policies, but it also exacerbates negative attitudes toward persons with serious mental illness.

Hardware and software implementation of a low power attitude control and determination system for cubesats

NASA Astrophysics Data System (ADS)

Frey, Jesse

In recent years there has been a growing interest in smaller satellites. Smaller satellites are cheaper to build and launch than larger satellites. One form factor, the CubeSat, is especially popular with universities and is a 10~cm cube. Being smaller means that the mass and power budgets are tighter and as such new ways must be developed to cope with these constraints. Traditional attitude control systems often use reaction wheels with gas thrusters which present challenges on a CubeSat. Many CubeSats use magnetic attitude control which uses the Earth's magnetic field to torque the satellite into the proper orientation. Magnetic attitude control systems fall into two main categories: active and passive. Active control is often achieved by running current through a coil to produce a dipole moment, while passive control uses the dipole moment from permanent magnets that consume no power. This thesis describes a system that uses twelve hard magnetic torquers along with a magnetometer. The torquers only consume current when their dipole moment is flipped, thereby significantly reducing power requirements compared with traditional active control. The main focus of this thesis is on the design, testing and fabrication of CubeSat hardware and software in preparation for launch.

Evidence that attitude accessibility augments the relationship between speeding attitudes and speeding behavior: a test of the MODE model in the context of driving.

PubMed

Elliott, Mark A; Lee, Emme; Robertson, Jamie S; Innes, Rhona

2015-01-01

According to the MODE model of attitude-to-behavior processes, attitude accessibility augments attitude-behavior correspondence, reflecting an automatic influence of attitudes on behavior. We therefore tested whether attitude accessibility moderates the attitude-behavior relationship in a context that is governed by characteristically automatic behavior, namely driving. In study 1 (correlational design), participants (N=130) completed online questionnaire measures of the valences and accessibilities of their attitudes towards speeding. Two weeks later, online questionnaire measures of subsequent speeding behavior were obtained. Attitude valence was a significantly better predictor of behavior at high (mean+1SD) versus low (mean-1SD) levels of attitude accessibility. In study 2 (experimental design), attitude accessibility was manipulated with a repeated attitude expression task. Immediately after the manipulation, participants (N=122) completed online questionnaire measures of attitude valence and accessibility, and two weeks later, subsequent speeding behavior. Increased attitude accessibility in the experimental (versus control) condition generated an increase in attitude-behavior correspondence. The findings are consistent with the MODE model's proposition that attitudes can exert an automatic influence on behavior. Interventions to reduce speeding could usefully increase the accessibility of anti-speeding attitudes and reduce the accessibility of pro-speeding attitudes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessing the reliability and validity of anti-tobacco attitudes/beliefs in the context of a campaign strategy.

PubMed

Arheart, Kristopher L; Sly, David F; Trapido, Edward J; Rodriguez, Richard D; Ellestad, Amy J

2004-11-01

To identify multi-item attitude/belief scales associated with the theoretical foundations of an anti-tobacco counter-marketing campaign and assess their reliability and validity. The data analyzed are from two state-wide, random, cross-sectional telephone surveys [n(S1)=1,079, n(S2)=1,150]. Items forming attitude/belief scales are identified using factor analysis. Reliability is assessed with Chronbach's alpha. Relationships among scales are explored using Pearson correlation. Validity is assessed by testing associations derived from the Centers for Disease Control and Prevention's (CDC) logic model for tobacco control program development and evaluation linking media exposure to attitudes/beliefs, and attitudes/beliefs to smoking-related behaviors. Adjusted odds ratios are employed for these analyses. Three factors emerged: traditional attitudes/beliefs about tobacco and tobacco use, tobacco industry manipulation and anti-tobacco empowerment. Reliability coefficients are in the range of 0.70 and vary little between age groups. The factors are correlated with one-another as hypothesized. Associations between media exposure and the attitude/belief scales and between these scales and behaviors are consistent with the CDC logic model. Using reliable, valid multi-item scales is theoretically and methodologically more sound than employing single-item measures of attitudes/beliefs. Methodological, theoretical and practical implications are discussed.

A spacecraft integrated power/attitude control system

NASA Technical Reports Server (NTRS)

Keckler, C. R.; Jacobs, K. L.

1974-01-01

A study to determine the viability and application of a system capable of performing the dual function of power storage/generation and attitude control has been conducted. Results from the study indicate that an integrated power/attitude control system (IPACS) can satisfy future mission requirements while providing significant savings in weight, volume, and cost over conventional systems. A failure-mode configuration of an IPACS was applied to a shuttle-launched RAM free-flyer and simulated using make-do hardware linked to a hybrid computer. Data from the simulation runs indicate that control interactions resulting from heavy power demands have minimal effect on system control effectiveness. The system was shown to be capable of meeting the stringent pointing requirements of 1 arc-second while operating under the influence of an orbital disturbance environment and during periods of momentum variations imposed by energy transfer requirements.

Attitude orientation control for a spinning satellite

NASA Astrophysics Data System (ADS)

Frost, Gerald

The Department of the Air Force, Headquarters Space Systems Division, and the National Aeronautics and Space Administration (NASA) are currently involved in litigation with Hughes Aircraft Company over the alledged infringement of the 'Williams patent,' which describes a method for attitude control of a spin-stabilized vehicle. Summarized here is pre-1960 RAND work on this subject and information obtained from RAND personnel knowledgeable on this subject. It was concluded that there is no RAND documentation that directly parallels the 'Williams patent' concept. Also, the TIROS II magnetic torque attitude control method is reviewed. The TIROS II meteorological satellite, launched on November 23, 1960, incorporated a magnetic actuation system for spin axis orientation control. The activation system was ground controlled to orient the satellite spin axis to obtain the desired pointing direction for optical and infrared sensor subsystems.

Planar rigid-flexible coupling spacecraft modeling and control considering solar array deployment and joint clearance

NASA Astrophysics Data System (ADS)

Li, Yuanyuan; Wang, Zilu; Wang, Cong; Huang, Wenhu

2018-01-01

Based on Nodal Coordinate Formulation (NCF) and Absolute Nodal Coordinate Formulation (ANCF), this paper establishes rigid-flexible coupling dynamic model of the spacecraft with large deployable solar arrays and multiple clearance joints to analyze and control the satellite attitude under deployment disturbance. Considering torque spring, close cable loop (CCL) configuration and latch mechanisms, a typical spacecraft composed of a rigid main-body described by NCF and two flexible panels described by ANCF is used as a demonstration case. Nonlinear contact force model and modified Coulomb friction model are selected to establish normal contact force and tangential friction model, respectively. Generalized elastic force are derived and all generalized forces are defined in the NCF-ANCF frame. The Newmark-β method is used to solve system equations of motion. The availability and superiority of the proposed model is verified through comparing with numerical co-simulations of Patran and ADAMS software. The numerical results reveal the effects of panel flexibility, joint clearance and their coupling on satellite attitude. The effects of clearance number, clearance size and clearance stiffness on satellite attitude are investigated. Furthermore, a proportional-differential (PD) attitude controller of spacecraft is designed to discuss the effect of attitude control on the dynamic responses of the whole system.

Long-term stability of GOES-8 and -9 attitude control

NASA Astrophysics Data System (ADS)

Carr, James L.

1996-10-01

An independent audit of the in-orbit behavior of the GOES-8 and GOES-9 satellites has been conducted for the NASA/GSFC. This audit utilized star and landmark observations from the GOES imager to determine long-term histories for spacecraft attitude, orbital position, and instrument internal misalignments. The paper presents results from this audit. Long-term drifts are found in the attitude histories, whereas the misalignment histories are shown to be diurnally stable. The GOES image navigation and registration system is designed to compensate for instrument internal misalignments, and both the diurnally repeatable and drift components of the attitude. Correlations between GOES-8 and GOES-9 long-term roll and pitch drifts implicate the Earth sensor as the origin of these observed drifts. This results clearly demonstrates the enhanced registration stability to be obtained with stellar inertial attitude determination replacing or supplementing Earth sensor control on future GOES missions.

Satellite attitude prediction by multiple time scales method

NASA Technical Reports Server (NTRS)

Tao, Y. C.; Ramnath, R.

1975-01-01

An investigation is made of the problem of predicting the attitude of satellites under the influence of external disturbing torques. The attitude dynamics are first expressed in a perturbation formulation which is then solved by the multiple scales approach. The independent variable, time, is extended into new scales, fast, slow, etc., and the integration is carried out separately in the new variables. The theory is applied to two different satellite configurations, rigid body and dual spin, each of which may have an asymmetric mass distribution. The disturbing torques considered are gravity gradient and geomagnetic. Finally, as multiple time scales approach separates slow and fast behaviors of satellite attitude motion, this property is used for the design of an attitude control device. A nutation damping control loop, using the geomagnetic torque for an earth pointing dual spin satellite, is designed in terms of the slow equation.

The Motherhood Inventory: A Questionnaire for Studying Attitudes Toward Motherhood.

ERIC Educational Resources Information Center

Hare-Mustin, Rachel T.; Broderick, Patricia C.

The Motherhood Inventory (MI) is a 40-item questionnaire developed to study attitudes toward motherhood and the motherhood myth. It includes items related to the control of reproduction, abortion, adoption, single motherhood, male-female relationships, and idealized and punitive attitudes toward mothers. The MI was investigated using 301 subjects…

Opportunity and Attitudes toward Job Advancement in a Manufacturing Firm.

ERIC Educational Resources Information Center

Harlan, Sharon L.

1989-01-01

Examines the relation between opportunity for promotion in work organizations and promotion attitudes. Reveals that effects of opportunity variables on promotion attitudes are significant even when age, education, and gender are controlled. Argues that one dimension of opportunity is embodied in workers perceptions of fairness and accessibility of…

Drug Use and Attitudes Toward Social and Legal Aspects of Marijuana in a Large Metropolitan University

ERIC Educational Resources Information Center

Martino, Edward R.; Truss, Carroll V.

1973-01-01

Attitude toward marijuana shifted from strongly negative to strongly positive as frequency of marijuana use increased. With frequency of use controlled, attitude toward marijuana was even more favorable when other drugs had been tried, and also among students who were religiously inactive. (Author)

Flight Mechanics/Estimation Theory Symposium, 1991

NASA Technical Reports Server (NTRS)

Stengle, Thomas (Editor)

1991-01-01

Twenty-six papers and abstracts are presented. A wide range of issues related to orbit attitude prediction, orbit determination, and orbit control are examined including attitude sensor calibration, attitude dynamics, and orbit decay and maneuver strategy. Government, industry, and the academic community participated in the preparation and presentation of these papers.

Initial Position, Personal Control, and Attributional Augmentation of Persuasive Communication on Nuclear Disarmament.

ERIC Educational Resources Information Center

Fleming, John H.; Shaver, Kelly G.

The effectiveness of two alternative attitude change strategies--a traditional persuasive strategy and a combined attributional/persuasive strategy--in altering attitudes toward nuclear disarmament were compared. Seventeen male and 39 female undergraduate students at a small university participated. A nuclear disarmament attitude pretest was…

Attitude and vibration control of a satellite containing flexible solar arrays by using reaction wheels, and piezoelectric transducers as sensors and actuators

NASA Astrophysics Data System (ADS)

da Fonseca, Ijar M.; Rade, Domingos A.; Goes, Luiz C. S.; de Paula Sales, Thiago

2017-10-01

The primary purpose of this paper is to provide insight into control-structure interaction for satellites comprising flexible appendages and internal moving components. The physical model considered herein aiming to attend such purpose is a rigid-flexible satellite consisting of a rigid platform containing two rotating flexible solar panels. The solar panels rotation is assumed to be in a sun-synchronous configuration mode. The panels contain surface-bonded piezoelectric patches that can be used either as sensors for the elastic displacements or as actuators to counteract the vibration motion. It is assumed that in the normal mode operation the satellite platform points towards the Earth while the solar arrays rotate so as to follow the Sun. The vehicle moves in a low Earth polar orbit. The technique used to obtain the mathematical model combines the Lagrangian formulation with the Finite Elements Method used to describe the dynamics of the solar panel. The gravity-gradient torque as well as the torque due to the interaction of the Earth magnetic field and the satellite internal residual magnetic moment is included as environmental perturbations. The actuators are three reaction wheels for attitude control and piezoelectric actuators to control the flexible motion of the solar arrays. Computer simulations are performed using the MATLAB® software package. The following on-orbit satellite operating configurations are object of analysis: i) Satellite pointing towards the Earth (Earth acquisition maneuver) by considering the initial conditions in the elastic displacement equal to zero, aiming the assessment of the flexible modes excitation by the referred maneuver; ii) the satellite pointing towards the Earth with the assumption of an initial condition different from zero for the flexible motion such that the attitude alterations are checked against the elastic motion disturbance; and iii) attitude acquisition accomplished by taking into account initial conditions different from zero for both attitude and elastic vibrations. Additionally, the control efforts for the three cases are compared. Results indicate that the attitude control is able to excite the solar panels' vibration modes and vice-versa. The piezoelectric vibration control shows significant performance improvement when compared to contributions of the attitude control to the vibration damping.

Reusable Launch Vehicle Attitude Control Using a Time-Varying Sliding Mode Control Technique

NASA Technical Reports Server (NTRS)

Shtessel, Yuri B.; Zhu, J. Jim; Daniels, Dan; Jackson, Scott (Technical Monitor)

2002-01-01

In this paper we present a time-varying sliding mode control (TVSMC) technique for reusable launch vehicle (RLV) attitude control in ascent and entry flight phases. In ascent flight the guidance commands Euler roll, pitch and yaw angles, and in entry flight it commands the aerodynamic angles of bank, attack and sideslip. The controller employs a body rate inner loop and the attitude outer loop, which are separated in time-scale by the singular perturbation principle. The novelty of the TVSMC is that both the sliding surface and the boundary layer dynamics can be varied in real time using the PD-eigenvalue assignment technique. This salient feature is used to cope with control command saturation and integrator windup in the presence of severe disturbance or control effector failure, which enhances the robustness and fault tolerance of the controller. The TV-SMC ascent and descent designs are currently being tested with high fidelity, 6-DOF dispersion simulations. The test results will be presented in the final version of this paper.

Simulation of Flywheel Energy Storage System

DTIC Science & Technology

2006-01-01

currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 02/11/06 2. REPORT TYPE...Government Purpose Rights 14. ABSTRACT Presented is a comprehensive power model for the Flywheel Attitude Control , Energy Transmission, and Storage...flywheel units and the Agile Multi-Purpose Satellite Simulator (AMPSS). The purpose of FACETS is to demonstrate integrated attitude control maneuvers

Robust integral variable structure controller and pulse-width pulse-frequency modulated input shaper design for flexible spacecraft with mismatched uncertainty/disturbance.

PubMed

Hu, Qinglei

2007-10-01

This paper presents a dual-stage control system design method for the flexible spacecraft attitude maneuvering control by use of on-off thrusters and active vibration control by input shaper. In this design approach, attitude control system and vibration suppression were designed separately using lower order model. As a stepping stone, an integral variable structure controller with the assumption of knowing the upper bounds of the mismatched lumped perturbation has been designed which ensures exponential convergence of attitude angle and angular velocity in the presence of bounded uncertainty/disturbances. To reconstruct estimates of the system states for use in a full information variable structure control law, an asymptotic variable structure observer is also employed. In addition, the thruster output is modulated in pulse-width pulse-frequency so that the output profile is similar to the continuous control histories. For actively suppressing the induced vibration, the input shaping technique is used to modify the existing command so that less vibration will be caused by the command itself, which only requires information about the vibration frequency and damping of the closed-loop system. The rationale behind this hybrid control scheme is that the integral variable structure controller can achieve good precision pointing, even in the presence of uncertainties/disturbances, whereas the shaped input attenuator is applied to actively suppress the undesirable vibrations excited by the rapid maneuvers. Simulation results for the spacecraft model show precise attitude control and vibration suppression.

Effect of pain neurophysiology education on physiotherapy students' understanding of chronic pain, clinical recommendations and attitudes towards people with chronic pain: a randomised controlled trial.

PubMed

Colleary, G; O'Sullivan, K; Griffin, D; Ryan, C G; Martin, D J

2017-12-01

To investigate the effect of pain neurophysiology education (PNE) on student physiotherapists': (1) knowledge of chronic pain; (2) attitudes towards patients with chronic pain; and (3) clinical recommendations for patients with chronic pain. Multicentre single-blind randomised controlled trial. One UK and one Irish university. Seventy-two student physiotherapists. Participants received either PNE (intervention) or a control education. Both were delivered in a 70-minute group lecture. (1) The Revised Pain Neurophysiology Quiz to assess knowledge; (2) the Health Care Pain Attitudes and Impairment Relationship Scale (HC-PAIRS) to assess attitudes; and (3) a case vignette to assess the appropriateness of clinical recommendations. Post education, the PNE group had a greater increase in pain neurophysiology knowledge [mean difference 4.0 (95% confidence interval 3.2 to 4.7), P<0.01] and more improved attitudes [-17.5 (95% confidence interval -22.1 to -12.9), P<0.01] compared with the control group. Post education, students in the PNE group were more likely to make appropriate recommendations regarding work (94% vs 56%), exercise (92% vs 56%), activity (94% vs 67%) and bed rest (69% vs 33%) compared with those in the control group (P<0.05). The improvements in knowledge, attitudes and recommendations for pain management show that PNE is a potentially valuable part of the education of physiotherapy students, and could be used on a more widespread basis. There is a need to investigate whether these findings can be replicated in other healthcare professions, and how well these reported changes lead to changes in actual clinical behaviour and the clinical outcomes of patients. Copyright © 2017 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

A randomized prospective pilot trial of Web-delivered epilepsy stigma reduction communications in young adults.

PubMed

Sajatovic, Martha; Herrmann, Lynn K; Van Doren, Jamie R; Tatsuoka, Curtis; Welter, Elisabeth; Perzynski, Adam T; Bukach, Ashley; Needham, Kelley; Liu, Hongyan; Berg, Anne T

2017-11-01

Epilepsy is a common neurological condition that is often associated with stigmatizing attitudes and negative stereotypes among the general public. This randomized controlled trial (RCT) tested two new communication approaches targeting epilepsy stigma versus an education-alone approach. Two brief stigma-reduction videos were developed, informed by community stakeholder input; one highlighted role competency in people with epilepsy; the other highlighted social inclusion of people with epilepsy. A control video was also developed. A Web-based survey using a prospective RCT design compared effects of experimental videos and control on acceptability, perceived impact, epilepsy knowledge, and epilepsy stigma. Epilepsy knowledge and stigma were measured with the Epilepsy Knowledge Questionnaire (EKQ) and Attitudes and Beliefs about Living with Epilepsy (ABLE), respectively. A total of 295 participants completed the study. Mean age was 23.1 (standard deviation = 3.27) years; 59.0% were male, and 71.4% were white. Overall, respondents felt videos impacted their epilepsy attitudes. EKQ scores were similar across videos, with a trend for higher knowledge in experimental videos versus control (p = 0.06). The role competency and control videos were associated with slightly better perceived impact on attitudes. There were no differences between videos on ABLE scores (p = 0.568). There were subgroup differences suggesting that men, younger individuals, whites, and those with personal epilepsy experience had more stigmatizing attitudes. This RCT tested communication strategies to improve knowledge and attitudes about epilepsy. Although this initial effort will require follow-up, we have demonstrated the acceptability, feasibility, and potential of novel communication strategies to target epilepsy stigma, and a Web-based approach for assessing them. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

Attitude and Intention Regarding Pain Management among Chinese Nursing Students: A Cross-Sectional Questionnaire Survey.

PubMed

Fang, Liang-Yu; Xu, Yin-Chuan; Lin, Dan-Ni; Jin, Jing-Feng; Yan, Min

2017-08-01

Optimal pain management is a priority in effective nursing care. Lack of sufficient pain knowledge associated with inadequate pain management has been proved. However, the intention, defined as the predictor of behavior, regarding pain management remains unknown. Therefore, the study was to determine the attitude and intention regarding pain management among Chinese nursing students and investigate the underlying determinants and their interactions in terms of intention toward pain management. The Pain Management Survey Questionnaire, comprising the key determinants of the theory of planned behavior-that is, direct attitude, belief-based intention, subjective norm, direct control, and indirect control-was used to collect data from 512 nursing students who undertook clinical rotation in an affiliated hospital of a medical college in China. Data were analyzed using descriptive statistics, independent sample t test, Pearson correlation analysis, or structural equation modeling analysis. Chinese nursing students reported negative attitudes and behavioral intentions toward pain management. Direct control, subjective norm, belief-based attitude, and indirect control independently predicted nursing students' intention to treat patients with pain. Direct control was the strongest predictor. Structural equation modeling analysis further revealed 39.84% of the variance associated with intention that could be explained by determinants of the theory of planned behavior. Additionally, educational school level and previous pain management training had great effects on pain management intention. Overall, this study identified intention as an important factor in effective pain treatment. Chinese nursing students have negative attitudes and insufficient intention to pain management. Therefore, hospitals and universities in China should manage these factors to improve nursing students' practice regarding pain management. Copyright © 2017 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

The effect of family climate on risky driving of young novices: the moderating role of attitude and locus of control.

PubMed

Carpentier, Aline; Brijs, Kris; Declercq, Katrien; Brijs, Tom; Daniels, Stijn; Wets, Geert

2014-12-01

The aim of the study was to examine the relative importance of young novice drivers' family climate on their driving behavior. A sample of young novice drivers (N=171) between the age of 17 and 24, who held their permanent (or temporary) driver's license for no longer than one year, participated. The questionnaire included items related to the participants' family climate, 3 socio-cognitive determinants (i.e., attitude, locus of control and social norm), and risky driving behaviors. We expected both family climate and the socio-cognitive determinants to exert a direct effect on risky driving. Furthermore we hypothesized that the socio-cognitive determinants would moderate the impact of family climate on risky driving. The results showed that the effect of family climate on risky driving only originated from one single factor (i.e., noncommitment). Besides that, the results confirmed the importance of the three socio-cognitive determinants to the degree that attitude, locus of control, and social norm significantly predicted the self-reported risky driving. In line of what we hypothesized, attitude moderated the relationship between noncommitment and risky driving. Lastly, we found an unexpected three-way interaction which indicated that locus of control moderated the relation between noncommitment and risky driving only when young drivers' attitude was risk-supportive. We recommend scholars and practitioners to take into account the interaction between external sources of influence (such as an individual's family climate) and more personally oriented dispositions (such as an individual's attitude, social norm and locus of control) when trying to explain and change young novices' risky driving. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of Joyful Learning on Elementary School Students’ Attitudes Toward Science

NASA Astrophysics Data System (ADS)

Anggoro, S.; Sopandi, W.; Sholehuddin, M.

2017-02-01

This study investigated the effects of joyful learning approach on elementary school students’ attitudes toward science. The method used is quasy experiment with the participants were divided into two groups. Thirty three of 4th grade students volunteered as an experimental group, and the other forty two act as a control group. The data was collected by questionnaire that are given before and after the lesson, observation sheet, and interview. The effect of joyful learning on students’ attitude was obtained by determining the n-gain and independent t-test. Observation and interview results were used to triangulate and support the quantitative findings. The data showed that the gain scores of the experimental group students’ attitudes toward science were significantly higher than the gain scores of control group. In addition, the experimental group made significantly greater progress in their cognitive, affective and conative experiences. Interviews and observations indicated that their attitude toward science changed over the intervention. This indicated that joyful learning approach can enhance the elementary school students’ attitudes toward science. According to these findings, it can be concluded that joyful learning approach can be used as an alternative approach to improve student’s attitude toward science.

Attitude Dynamics and Control of Solar Sails

NASA Astrophysics Data System (ADS)

Sperber, Evan

Solar sails are space vehicles that rely on solar radiation pressure in order to generate forces for thrust and attitude control torques. They exhibit characteristics such as large moments of inertia, fragility of various system components, and long mission durations that make attitude control a particularly difficult engineering problem. Thrust vector control (TVC) is a family of sailcraft attitude control techniques that is on a short list of strategies thought to be suitable for the primary attitude control of solar sails. Every sailcraft TVC device functions by manipulating the relative locations of the composite mass center (cm) of the sailcraft and the center of pressure (cp) of at least one of its reflectors. Relative displacement of these two points results in body torques that can be used to steer the sailcraft. This dissertation presents a strategy for the large-angle reorientation of a sailcraft using TVC. Two forms of TVC, namely the panel and ballast mass translation methods are well represented in the literature, while rigorous studies regarding a third form, gimballed mass rotation, are conspicuously absent. The gimballed mass method is physically realized by placing a ballast mass, commonly the sailcraft's scientific payload, at the tip of a gimballed boom that has its base fixed at some point on the sailcraft. A TVC algorithm will then strategically manipulate the payload boom's gimbal angles, thereby changing the projection of the sailcraft cm in the plane of the sail. This research demonstrates effective three-axis attitude control of a model sailcraft using numerical simulation of its nonlinear equations of motion. The particular TVC algorithm developed herein involves two phases---the first phase selects appropriate gimbal rates with the objective that the sailcraft be placed in the neighborhood of its target orientation. It was discovered, however that concomitantly minimizing attitude error as well as residual body rate was not possible using soley this method. By solving the one-dimensional Euler's equation, a single gimbal angle can be found that will cause simultaneous convergence of both these quantities to their respective target values. The second phase of control consists of calculating such an angle, and then setting and maintaining this configuration until the maneuver is completed. iiOnce the validity of the approach is confirmed via simulation for a model sailcraft, it is demonstrated that three-axis attitude control can be performed using this approach by executing a sequence of maneuvers about principal axes. The algorithm is implemented directly inline with the nonlinear equations of motion and simulations are conducted for sailcraft of various sizes that are representative of the dimensions proposed in the literature for future missions.

The effects of contextual learning instruction on science achievement of male and female tenth-grade students

NASA Astrophysics Data System (ADS)

Ingram, Samantha Jones

The purpose of this study was to investigate the effects of the contextual learning method on science performance, attitudes toward science, and motivational factors that influence high school students to learn science. Gender differences in science performance and attitudes toward science were also investigated. The sample included four tenth-grade classes of African-American students enrolled in Chemistry I. All students were required to review for the Alabama High School Graduation Exam in Science. Students were administered a science pretest and posttest to measure science performance. A two-way analysis of covariance was performed on the test data. The results showed a main effect of contextual learning instruction on science achievement and no significant differences between females' and males' performance in science. The Science Attitude and the Alabama High School Graduation Exam (AHSGE) Review Class Surveys were administered to assess students' beliefs and attitudes toward science. The Science Attitude Survey results indicated a control effect in three subscales: perception of guardian's attitude, attitude toward success in science, and perception of teacher's attitude. No significant differences resulted between males and females in their beliefs about science from the attitude survey. However, students' attitudes toward science were more favorable in the contextual learning classes based on the results of the Review Class Survey. The survey data revealed that both males and females in the contextual classes had positive attitudes toward science and toward being active participants in the learning process. Qualitative data on student motivation were collected to examine the meaningfulness of the contextual learning content and materials. The majority of the students in the treatment (96%) and the control groups (86%) reported high interest in the lesson on Newton's three laws of motion. Both the treatment and the control groups indicated their interest ratings were a result of their prior experiences. This study shows that contextual learning instruction positively influences student motivation, interest, and achievement in science. Student achievement in science improved in the contextual learning classes as a result of increased interest due to learning that emphasized relevancy and purposeful meaning.

Online purchases in an Infocomm sophisticated society.

PubMed

Goby, Valerie Priscilla

2006-08-01

This paper presents a preliminary investigation of attitude and intention in relation to online shopping in Singapore. Singaporeans display high levels of Infocomm proficiency, the result of many intense government initiatives to transform the country into an Intelligent Community. Does this Internet embracing environment enhance attitude and intention to online shopping? This study considers the links between personal consequences, subjective norms, behavioral control, and personal innovativeness with attitude and intention among Singaporeans. It uses a model based on the Theory of Planned Behavior and makes some initial comparisons of its findings with those of existing studies. The effects of behavioral control and intention on actual purchase behavior are not investigated. Findings permit the tentative proposition that level of Infocomm knowledge impacts on attitude and intention.

Knowledge, attitudes and practices regarding smoking cessation among Chinese affiliates of women's organisations in Hong Kong.

PubMed

Leung, Doris Y P; Chan, Sophia S C; Fu, Idy C Y; Lam, Tai-hing

2011-03-01

Volunteers and staff of women's organisations who are highly active in engaging and providing community service can be recruited to motivate female smokers to quit. We described the knowledge and attitudes regarding tobacco control and smoking cessation among these affiliates in Hong Kong and identified factors associated with the practices of cessation interventions. Eight of 14 women's organisations joining the Women Against Tobacco Taskforce agreed to participate. All staff, volunteers, and members of the eight organisations were invited to complete a self-administered anonymous questionnaire during July and August 2006. A total of 623 out of 771 (80.8%) affiliates responded. Their knowledge on smoking and health (mean = 3.91, SD = 1.44 on a range of 0-7), smoking related diseases (mean = 2.91, SD = 0.97 on a range of 0-4), and women-specific diseases (mean = 2.93, SD = 1.87 on a range of 0-6), was considered to be inadequate. They had positive attitudes towards tobacco control (mean = 3.31, SD = 0.55) and their own role in smoking cessation counselling (mean = 3.19, SD = 0.56) on a 4-point Likert scale and 39.3% reported had attempted to offer quitting advice. Logistic regression analysis found that participants having direct contact with smokers who had a positive attitude towards their own role in smoking cessation counselling (OR = 2.57; 95% CI = 1.67-3.95) and better knowledge of smoking and smoking-related diseases (OR = 1.35; 95% CI = 1.06-1.71) were more likely to provide cessation counselling after controlling for gender; knowledge on smoking and health, and women-specific diseases; attitude towards tobacco control, negative and positive attitudes towards female smokers, and perceived self-efficacy in smoking cessation counselling. Women's organisations showed limited support towards tobacco control and their affiliates had a limited knowledge on smoking and health but had positive attitudes. Appropriate training, capacity building and establishing rapport with women's organisations are needed to promote smoking cessation and to support tobacco control in the community. © 2010 Blackwell Publishing Ltd.

A controller design approach for large flexible space structures

NASA Technical Reports Server (NTRS)

Joshi, S. M.

1981-01-01

A controller design approach for large space structures is presented, which consists of a primary attitude controller and a secondary or damping enhancement controller. The secondary controller, which uses several Annular Momentum Control Device (AMCD's), is shown to make the closed loop system asymptotically stable under relatively simple conditions. The primary controller using torque actuators (or AMCD's) and colocated attitude and rate sensors is shown to be stable. It is shown that the same AMCD's can be used for simultaneous actuation of primary and secondary controllers. Numerical results are obtained for a large, thin, completely free plate model.

Attitudes towards smoking and tobacco control among pre-clinical medical students in Malaysia.

PubMed

Tee, G H; Hairi, N N; Hairi, F

2012-08-01

Physicians should play a leading role in combatting smoking; information on attitudes of future physicians towards tobacco control measures in a middle-income developing country is limited. Of 310 future physicians surveyed in a medical school in Malaysia, 50% disagreed that it was a doctor's duty to advise smokers to stop smoking; 76.8% agreed that physicians should not smoke before advising others not to smoke; and 75% agreed to the ideas of restricting the sale of cigarettes to minors, making all public places smoke-free and banning advertising of tobacco-related merchandise. Future physicians had positive attitudes towards tobacco regulations but had not grasped their responsibilities in tobacco control measures.

Integrated Power and Attitude Control System (IPACS) technology developments

NASA Technical Reports Server (NTRS)

Eisenhaure, David B.; Bechtel, Robert; Hockney, Richard; Oglevie, Ron; Olszewski, Mitch

1990-01-01

Integrated Power and Attitude Control System (IPACS) studies performed over a decade ago established the feasibility of storing electrical energy in flywheels and utilizing the resulting angular momentum for spacecraft attitude control. Such a system has been shown to have numerous attractive features relative to more contemporary technology, and is appropriate to many applications (including high-performance slewing actuators). Technology advances over the last two decades in composite rotors, motor/generator/electronics, and magnetic bearings are found to support the use of IPACS for increasingly sophisticated applications. It is concluded that the concept offers potential performance advantages as well as savings in mass and life-cycle cost. Viewgraphs and discussion on IPACS are included.

Dual-spin attitude control for outer planet missions

NASA Technical Reports Server (NTRS)

Ward, R. S.; Tauke, G. J.

1977-01-01

The applicability of dual-spin technology to a Jupiter orbiter with probe mission was investigated. Basic mission and system level attitude control requirements were established and preliminary mechanization and control concepts developed. A comprehensive 18-degree-of-freedom digital simulation was utilized extensively to establish control laws, study dynamic interactions, and determined key sensitivities. Fundamental system/subsystem constraints were identified, and the applicability of dual-spin technology to a Jupiter orbiter with probe mission was validated.

An Artificial Neural Network Control System for Spacecraft Attitude Stabilization

DTIC Science & Technology

1990-06-01

NAVAL POSTGRADUATE SCHOOL Monterey, California ’-DTIC 0 ELECT f NMARO 5 191 N S, U, THESIS B . AN ARTIFICIAL NEURAL NETWORK CONTROL SYSTEM FOR...NO. NO. NO ACCESSION NO 11. TITLE (Include Security Classification) AN ARTIFICIAL NEURAL NETWORK CONTROL SYSTEM FOR SPACECRAFT ATTITUDE STABILIZATION...obsolete a U.S. G v pi.. iim n P.. oiice! toog-eo.5s43 i Approved for public release; distribution is unlimited. AN ARTIFICIAL NEURAL NETWORK CONTROL

Observing Mode Attitude Controller for the Lunar Reconnaissance Orbiter

NASA Technical Reports Server (NTRS)

Calhourn, Philip C.; Garrick, Joseph C.

2007-01-01

The Lunar Reconnaissance Orbiter (LRO) mission is the first of a series of lunar robotic spacecraft scheduled for launch in Fall 2008. LRO will spend at least one year in a low altitude polar orbit around the Moon, collecting lunar environment science and mapping data to enable future human exploration. The LRO employs a 3-axis stabilized attitude control system (ACS) whose primary control mode, the "Observing mode", provides Lunar Nadir, off-Nadir, and Inertial fine pointing for the science data collection and instrument calibration. The controller combines the capability of fine pointing with that of on-demand large angle full-sky attitude reorientation into a single ACS mode, providing simplicity of spacecraft operation as well as maximum flexibility for science data collection. A conventional suite of ACS components is employed in this mode to meet the pointing and control objectives. This paper describes the design and analysis of the primary LRO fine pointing and attitude re-orientation controller function, known as the "Observing mode" of the ACS subsystem. The control design utilizes quaternion feedback, augmented with a unique algorithm that ensures accurate Nadir tracking during large angle yaw maneuvers in the presence of high system momentum and/or maneuver rates. Results of system stability analysis and Monte Carlo simulations demonstrate that the observing mode controller can meet fine pointing and maneuver performance requirements.

Design Considerations for Attitude State Awareness and Prevention of Entry into Unusual Attitudes

NASA Technical Reports Server (NTRS)

Ellis, Kyle K. E.; Prinzel, Lawrence J., III; Arthur, Jarvis J.; Nicholas, Stephanie N.; Kiggins, Daniel; Verstynen, Harry; Hubbs, Clay; Wilkerson, James

2017-01-01

Loss of control - inflight (LOC-I) has historically represented the largest category of commercial aviation fatal accidents. A review of the worldwide transport airplane accidents (2001-2010) evinced that loss of attitude or energy state awareness was responsible for a large majority of the LOC-I events. A Commercial Aviation Safety Team (CAST) study of 18 worldwide loss-of-control accidents and incidents determined that flight crew loss of attitude awareness or energy state awareness due to lack of external visual reference cues was a significant causal factor in 17 of the 18 reviewed flights. CAST recommended that "Virtual Day-Visual Meteorological Condition" (Virtual Day-VMC) displays be developed to provide the visual cues necessary to prevent loss-of-control resulting from flight crew spatial disorientation and loss of energy state awareness. Synthetic vision or equivalent systems (SVS) were identified for a design "safety enhancement" (SE-200). Part of this SE involves the conduct of research for developing minimum aviation system performance standards (MASPS) for these flight deck display technologies to aid flight crew attitude and energy state awareness similar to that of a virtual day-VMC-like environment. This paper will describe a novel experimental approach to evaluating a flight crew's ability to maintain attitude awareness and to prevent entry into unusual attitudes across several SVS optical flow design considerations. Flight crews were subjected to compound-event scenarios designed to elicit channelized attention and startle/surprise within the crew. These high-fidelity scenarios, designed from real-world events, enable evaluation of the efficacy of SVS at improving flight crew attitude awareness to reduce the occurrence of LOC-I incidents in commercial flight operations.

Impact of Family Planning Health Education on the Knowledge and Attitude among Yasoujian Women

PubMed Central

Mahamed, Fariba; Parhizkar, Saadat; Shirazi, Alireza Raygan

2012-01-01

The aim of this study was to determine the effect of health education on the knowledge and attitude regarding family planning and contraception’s method among the women who obligatory attended the Premarital Counseling Center in Yasouj city, Iran. An experimental study was carried out and a total of 200 women were selected for the study using convenience sampling method among women who attended in the health centre in order to utilize the necessary premarital actions. Respondents were divided by two experimental and control groups randomly. A pre-evaluation was done on the knowledge and attitude on family planning using a structured questionnaire. After which, the health education for experimental group was done within four educational sessions during 4 consecutive weeks and control group underwent traditional education method. Post evaluation was utilized for any changes regarding their knowledge and attitude among the respondents immediately after the intervention. Independent and paired t-test was used to evaluate the mean knowledge and attitude scores differences among both groups. Results showed that there was a significant improvement in respondents’ knowledge and attitude after educational program in experimental group (p<0.001), while no significant difference was observed in knowledge and attitude of control group. The finding also indicated that age was significantly associated with the level of respondents’ knowledge. These results deal the effectiveness of the educational method. In conclusion, the educational method is effective in increasing the knowledge and improving the attitude of women regarding family planning in Yasouj compared to current used educational method. Future educational programs need to incorporate the features that have been associated with successful interventions in the past, as well as including their own evaluation procedures. PMID:22980158

Relationships between attitudes toward and achievement in science for rural middle school students: Patterns across gender

NASA Astrophysics Data System (ADS)

Mattern, Nancy Page Garland

Four causal models describing the relationships between attitudes and achievement have been proposed in the literature. The cross-effects, or reciprocal effects, model highlights the effects of prior attitudes on later achievement (over and above the effect of previous achievement) and of prior achievement on later attitudes (above the effect of previous attitudes). In the achievement predominant model, the effect of prior achievement on later attitudes is emphasized, controlling for the effect of previous attitudes. The effect of prior attitudes on later achievement, controlling for the effect of previous achievement, is emphasized in the attitudes predominant model. In the no cross-effects model there are no significant cross paths from prior attitudes to later achievement or from prior achievement to later attitudes. To determine the best-fitting model for rural seventh and eighth grade science girls and boys, the causal relationships over time between attitudes toward science and achievement in science were examined by gender using structural equation modeling. Data were collected in two waves, over one school year. A baseline measurement model was estimated in simultaneous two-group solutions and was a good fit to the data. Next, the four structural models were estimated and model fits compared. The three models nested within the structural cross-effects model showed significant decay of fit when compared to the fit of the cross-effects model. The cross-effects model was the best fit overall for middle school girls and boys. The cross-effects model was then tested for invariance across gender. There was significant decay of fit when model form, factor path loadings, and structural paths were constrained to be equal for girls and boys. Two structural paths, the path from prior achievement to later attitudes, and the path from prior attitudes to later attitudes, were the sources of gender non-invariance. Separate models were estimated for girls and boys, and the fits of nested models were compared. The no cross-effects model was the best-fitting model for rural middle school girls. The new no attitudes-path model was the best-fitting model for boys. Implications of these findings for teaching middle school students were discussed.

The effect of disability empathy activity on the attitude of nursing students towards disabled people: a pilot study.

PubMed

Geçkil, Emine; Kaleci, Elanur; Cingil, Dilek; Hisar, Filiz

2017-02-01

Nurses care for disabled people in society. The aim of this experimental study was to investigate the effect of disability empathy activities on strengthening the positive attitudes of nursing students towards disabled people. An experimental study. Pretest-Posttest control group arrangement was used. This research has been conducted with 116 nursing students (53 experimental and 63 control). The data were collected with "Attitudes Towards Disabled Persons Scale" (ATDP). Before the experiment, there was no significant difference between ATDP scores of experimental and control groups (p > 0.05). After the experiment, second ATDP scores of experimental group (66.81 ± 14.27) were found to be significantly higher than the scores of control group (59.02 ± 11.71) (p = 0.002). After six months, third ATDP scores of experimental group (63.58 ± 13.46) were also found to be higher than the scores of control group (58.43 ± 11.03) (p = 0.025). Empathy activities applied to understand disabled people affected the attitudes of student nurses towards disabled people positively.

Inertial attitude control of a bat-like morphing-wing air vehicle.

PubMed

Colorado, J; Barrientos, A; Rossi, C; Parra, C

2013-03-01

This paper presents a novel bat-like unmanned aerial vehicle inspired by the morphing-wing mechanism of bats. The goal of this paper is twofold. Firstly, a modelling framework is introduced for analysing how the robot should manoeuvre by means of changing wing morphology. This allows the definition of requirements for achieving forward and turning flight according to the kinematics of the wing modulation. Secondly, an attitude controller named backstepping+DAF is proposed. Motivated by biological evidence about the influence of wing inertia on the production of body accelerations, the attitude control law incorporates wing inertia information to produce desired roll (ϕ) and pitch (θ) acceleration commands (desired angular acceleration function (DAF)). This novel control approach is aimed at incrementing net body forces (F(net)) that generate propulsion. Simulations and wind-tunnel experimental results have shown an increase of about 23% in net body force production during the wingbeat cycle when the wings are modulated using the DAF as a part of the backstepping control law. Results also confirm accurate attitude tracking in spite of high external disturbances generated by aerodynamic loads at airspeeds up to 5 ms⁻¹.

Peer group socialization of homophobic attitudes and behavior during adolescence.

PubMed

Poteat, V Paul

2007-01-01

A social developmental framework was applied to test for the socialization of homophobic attitudes and behavior within adolescent peer groups (Grades 7-11; aged 12-17 years). Substantial similarity within and differences across groups were documented. Multilevel models identified a group socializing contextual effect, predicting homophobic attitudes and behavior of individuals within the group 8 months later, even after controlling for the predictive effect of individuals' own previously reported attitudes and behavior. Several group characteristics moderated the extent to which individuals' previously reported attitudes predicted later attitudes. Findings indicate the need to integrate the concurrent assessment of individual and social factors to inform the construction of more comprehensive models of how prejudiced attitudes and behaviors develop and are perpetuated.

Attitudes toward Nutrition, Locus of Control and Smoking Behavior.

ERIC Educational Resources Information Center

Corfield, V. Kilian; And Others

Research has shown that many behaviors previously thought to be purely psychological in origin do, in fact, have a physiological basis. To examine the relationship of smoking behavior to locus of control, and to attitudes toward, knowledge about, and behavior with respect to nutrition, 116 Canadian undergraduate students completed the Nutrition…

Two Classes and One Vision? Managers' and Workers' Attitudes toward Workplace Democracy.

ERIC Educational Resources Information Center

Collom, Ed

2003-01-01

Analyses of national survey data on workplace democracy found both managers and workers support worker participation in manager selection and worker control of production processes. Experience of class-related practices strongly predicts attitudes; location in the class hierarchy does not. Once workers gain some control, they seek to broaden it to…

Working Memory and Attitudes

ERIC Educational Resources Information Center

Jung, Eun Sook; Reid, Norman

2009-01-01

Working memory capacity has been shown to be an important factor in controlling understanding in the sciences. Attitudes related to studies in the sciences are also known to be important in relation to success in learning. It might be argued that if working memory capacity is a rate controlling feature of learning and success in understanding…

Older Latinos' Attitudes toward and Comfort with End-of-Life Planning

ERIC Educational Resources Information Center

Heyman, Janna C.; Gutheil, Irene A.

2010-01-01

The purpose of this study was to determine which of two educational interventions delivered in Spanish would influence Latino elders' attitudes toward and comfort with end-of-life planning in comparison with a control group receiving only standard information routinely provided. Using a posttest-only control group design, elders receiving home…

MSFC Skylab Orbital Workshop, volume 2. [design and development of electrical systems and attitude control system

NASA Technical Reports Server (NTRS)

1974-01-01

The design and development of the Skylab Orbital Workshop are discussed. The subjects considered are: (1) thrust attitude control system, (2) solar array system, (3) electrical power distribution system, (4) communication and data acquisition system, (5) illumination system, and (6) caution and warning system.

The Effects of Using Dynamic Geometry on Eighth Grade Students' Achievement and Attitude towards Triangles

ERIC Educational Resources Information Center

Turk, Halime Samur; Akyuz, Didem

2016-01-01

This study investigates the effects of dynamic geometry based computer instruction on eighth grade students' achievement in geometry and their attitudes toward geometry and technology compared to traditional instruction. Central to the study was a controlled experiment, which contained experimental and control groups both instructed by the same…

Control techniques to improve Space Shuttle solid rocket booster separation

NASA Technical Reports Server (NTRS)

Tomlin, D. D.

1983-01-01

The present Space Shuttle's control system does not prevent the Orbiter's main engines from being in gimbal positions that are adverse to solid rocket booster separation. By eliminating the attitude error and attitude rate feedback just prior to solid rocket booster separation, the detrimental effects of the Orbiter's main engines can be reduced. In addition, if angular acceleration feedback is applied, the gimbal torques produced by the Orbiter's engines can reduce the detrimental effects of the aerodynamic torques. This paper develops these control techniques and compares the separation capability of the developed control systems. Currently with the worst case initial conditions and each Shuttle system dispersion aligned in the worst direction (which is more conservative than will be experienced in flight), the solid rocket booster has an interference with the Shuttle's external tank of 30 in. Elimination of the attitude error and attitude rate feedback reduces that interference to 19 in. Substitution of angular acceleration feedback reduces the interference to 6 in. The two latter interferences can be eliminated by atess conservative analysis techniques, that is, by using a root sum square of the system dispersions.

Optical tools and techniques for aligning solar payloads with the SPARCS control system. [Solar Pointing Aerobee Rocket Control System

NASA Technical Reports Server (NTRS)

Thomas, N. L.; Chisel, D. M.

1976-01-01

The success of a rocket-borne experiment depends not only on the pointing of the attitude control system, but on the alignment of the attitude control system to the payload. To ensure proper alignment, special optical tools and alignment techniques are required. Those that were used in the SPARCS program are described and discussed herein. These tools include theodolites, autocollimators, a 38-cm diameter solar simulator, a high-performance 1-m heliostat to provide a stable solar source during the integration of the rocket payload, a portable 75-cm sun tracker for use at the launch site, and an innovation called the Solar Alignment Prism. Using the real sun as the primary reference under field conditions, the Solar Alignment Prism facilitates the coalignment of the attitude sun sensor with the payload. The alignment techniques were developed to ensure the precise alignment of the solar payloads to the SPARCS attitude sensors during payload integration and to verify the required alignment under field conditions just prior to launch.

Attitude guidance and simulation with animation of a land-survey satellite motion

NASA Astrophysics Data System (ADS)

Somova, Tatyana

2017-01-01

We consider problems of synthesis of the vector spline attitude guidance laws for a land-survey satellite and an in-flight support of the satellite attitude control system with the use of computer animation of its motion. We have presented the results on the efficiency of the developed algorithms.

Initial Communications with the Parents of Emotionally Disturbed University Students.

ERIC Educational Resources Information Center

Rockwell, W. J. Kenneth

This paper discusses attitudes that may come into play when a parent enters the treatment picture with a disturbed student. The attitudes of therapists toward parents, including sources of bias, and reasons for controlling it, are presented. The attitudes of parents toward their emotionally disturbed child, toward treatment, and toward therapists…

Primary Teachers Conducting Inquiry Projects: Effects on Attitudes towards Teaching Science and Conducting Inquiry

ERIC Educational Resources Information Center

van Aalderen-Smeets, Sandra I.; Walma van der Molen, Juliette H.; van Hest, Erna G. W. C. M.; Poortman, Cindy

2017-01-01

This study used an experimental, pretest-posttest control group design to investigate whether participation in a large-scale inquiry project would improve primary teachers' attitudes towards teaching science and towards conducting inquiry. The inquiry project positively affected several elements of teachers' attitudes. Teachers felt less anxious…

Incorporating E-Mail into the Learning Process: Its Impact on Student Academic Achievement and Attitudes.

ERIC Educational Resources Information Center

Yu, Fu-Yun; Yu, Hsin-Jin Jessy

2002-01-01

Describes a study of Taiwan university students that investigated the impacts of incorporating email into the classroom on student achievement and attitudes using a posttest-only control-group design. Results showed a statistically significant difference in academic performance but not in student attitudes toward computers. (Author/LRW)

A Case for Ubiquitous, Integrated Computing in Teacher Education

ERIC Educational Resources Information Center

Kay, Robin H.; Knaack, Liesel

2005-01-01

The purpose of this study was to evaluate the effect of an integrated, laptop-based approach on pre-service teachers' computer attitudes, ability and use. Pre-post program analysis revealed significant differences in behavioural attitudes and perceived control (self-efficacy), but not in affective and cognitive attitudes. In addition, there was a…

An Examination of Gender Differences in Mexican-American Attitudes toward Family and Career Roles.

ERIC Educational Resources Information Center

Gowan, Mary; Trevino, Melanie

1998-01-01

Examined attitudes of 76 Mexican-American females and 62 Mexican-American males about the role of the woman in the workplace and child care responsibility of working parents. Controlling for age, marital status, number of children, and acculturation, males were more likely to hold traditional attitudes than women. (SLD)

Parental overprotection engenders dysfunctional attitudes about achievement and dependency in a gender-specific manner

PubMed Central

2013-01-01

Background It has been suggested that dysfunctional attitudes, cognitive vulnerability to depression, have developmental origins. The present study examined the effects of parental rearing on dysfunctional attitudes in three areas of life with special attention to gender specificity. Methods The subjects were 665 Japanese healthy volunteers. Dysfunctional attitudes were assessed by the 24-item Dysfunctional Attitude Scale, which has the Achievement, Dependency and Self-control subscales. Perceived parental rearing was assessed by the Parental Bonding Instrument, which has the Care and Protection subscales. Results Higher scores of the Achievement (β = 0.293, p < 0.01) and Dependency (β = 0.224, p < 0.05) subscales were correlated with higher scores of the Protection subscale in the combination of mother and daughter, but not in other combinations of parents and recipients. Scores of the Self-control subscale were not correlated with paternal or maternal rearing scores. Conclusions The present study suggests that parental overprotection engenders dysfunctional attitudes about achievement and dependency in a gender-specific manner. PMID:24365104

Correlates of attitudes towards mood stabilizers in individuals with bipolar disorder.

PubMed

Chang, Ching-Wen; Sajatovic, Martha; Tatsuoka, Curtis

2015-02-01

Attitudes towards medication are believed to be important for medication adherence and social factors are believed to have effects on attitudes. Only a limited literature has focused on how attitudes to medication may correlate with social factors relevant to medication adherence among individuals with bipolar disorder (BPD). This secondary analysis of baseline data from a longitudinal study examined the relationships between attitudes towards mood stabilizers and psychosocial variables. Community mental health clinic patients (n = 122) were assessed on the outcome variable of medication attitudes as measured by the Attitudes towards Mood Stabilizers Questionnaire (AMSQ). Independent variables included education as well as standardized measures of psychiatric symptom severity, alcohol and drug problem severity, health locus of control (the belief that one's health is self-determined versus determined by factors outside of one's own control), and psychosocial support. A hierarchical multiple regression model evaluated the relationship between AMSQ and these variables. More positive medication attitudes were seen in individuals with higher levels of social support and in those who held a stronger belief that their health outcomes are determined by others, such as family or clinicians. Education, symptom severity, alcohol problem severity and drug problem severity were not significant attitudinal correlates. Attitudes towards mood stabilizers are correlated with both the support a person receives from others in their social network and how much a person believes others can influence his or her health. Clinicians need to be aware of the importance of the social environment as it relates to medication attitudes and more research is needed on how treatment attitudes may actually translate into medication adherence behavior. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Variable structure control of spacecraft reorientation maneuvers

NASA Technical Reports Server (NTRS)

Sira-Ramirez, H.; Dwyer, T. A. W., III

1986-01-01

A Variable Structure Control (VSC) approach is presented for multi-axial spacecraft reorientation maneuvers. A nonlinear sliding surface is proposed which results in an asymptotically stable, ideal linear sliding motion of Cayley-Rodriques attitude parameters. By imposing a desired equivalent dynamics on the attitude parameters, the approach is devoid of optimal control considerations. The single axis case provides a design scheme for the multiple axes design problem. Illustrative examples are presented.

Attitude and Translation Control of a Solar Sail Vehicle

NASA Technical Reports Server (NTRS)

Singh, Gurkirpal

2008-01-01

A report discusses the ability to control the attitude and translation degrees-of-freedom of a solar sail vehicle by changing its center of gravity. A movement of the spacecraft s center of mass causes solar-pressure force to apply a torque to the vehicle. At the compact core of the solar-sail vehicle lies the spacecraft bus which is a large fraction of the total vehicle mass. In this concept, the bus is attached to the spacecraft by two single degree-of-freedom linear tracks. This allows relative movement of the bus in the sail plane. At the null position, the resulting solar pressure applies no torque to the vehicle. But any deviation of the bus from the null creates an offset between the spacecraft center of mass and center of solar radiation pressure, resulting in a solar-pressure torque on the vehicle which changes the vehicle attitude. Two of the three vehicle degrees of freedom can be actively controlled in this manner. The third, the roll about the sunline, requires a low-authority vane/propulsive subsystem. Translation control of the vehicle is achieved by directing the solar-pressure-induced force in the proper inertial direction. This requires attitude control. Attitude and translation degrees-of-freedom are therefore coupled. A guidance law is proposed, which allows the vehicle to stationkeep at an appropriate point on the inertially-rotating Sun-Earth line. Power requirements for moving the bus are minimal. Extensive software simulations have been performed to demonstrate the feasibility of this concept.

Solar Anomalous and Magnetospheric Particle Explorer attitude control electronics box design and performance

NASA Technical Reports Server (NTRS)

Chamberlin, K.; Clagett, C.; Correll, T.; Gruner, T.; Quinn, T.; Shiflett, L.; Schnurr, R.; Wennersten, M.; Frederick, M.; Fox, S. M.

1993-01-01

The attitude Control Electronics (ACE) Box is the center of the Attitude Control Subsystem (ACS) for the Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) satellite. This unit is the single point interface for all of the Attitude Control Subsystem (ACS) related sensors and actuators. Commands and telemetry between the SAMPEX flight computer and the ACE Box are routed via a MIL-STD-1773 bus interface, through the use of an 80C85 processor. The ACE Box consists of the flowing electronic elements: power supply, momentum wheel driver, electromagnet driver, coarse sun sensor interface, digital sun sensor interface, magnetometer interface, and satellite computer interface. In addition, the ACE Box also contains an independent Safehold electronics package capable of keeping the satellite pitch axis pointing towards the sun. The ACE Box has dimensions of 24 x 31 x 8 cm, a mass of 4.3 kg, and an average power consumption of 10.5 W. This set of electronics was completely designed, developed, integrated, and tested by personnel at NASA GSFC. SAMPEX was launched on July 3, 1992, and the initial attitude acquisition was successfully accomplished via the analog Safehold electronics in the ACE Box. This acquisition scenario removed the excess body rates via magnetic control and precessed the satellite pitch axis to within 10 deg of the sun line. The performance of the SAMPEX ACS in general and the ACE Box in particular has been quite satisfactory.

Attitude control compensator for flexible spacecraft

NASA Technical Reports Server (NTRS)

Goodzeit, Neil E. (Inventor); Linder, David M. (Inventor)

1991-01-01

An attitude control loop for a spacecraft uses a proportional-integral-derivative (PID) controller for control about an axis. The spacecraft body has at least a primary mechanical resonance. The attitude sensors are collocated, or both on the rigid portion of the spacecraft. The flexure attributable to the resonance may result in instability of the system. A compensator for the control loop has an amplitude response which includes a component which rolls off beginning at frequencies below the resonance, and which also includes a component having a notch at a notch frequency somewhat below the resonant frequency. The phase response of the compensator tends toward zero at low frequencies, and tends toward -180.degree. as frequency increases toward the notch frequency. At frequencies above the notch frequency, the phase decreases from +180.degree., becoming more negative, and tending toward -90.degree. at frequencies far above the resonance frequency. Near the resonance frequency, the compensator phase is near zero.

Voyager Saturn encounter attitude and articulation control experience

NASA Technical Reports Server (NTRS)

Carlisle, G.; Hill, M.

1981-01-01

The Voyager attitude and articulation control system is designed for a three-axis stabilized spacecraft; it uses a biasable sun sensor and a Canopus Star Tracker (CST) for celestial control, as well as a dry inertial reference unit, comprised of three dual-axis dry gryos, for inertial control. A series of complex maneuvers was required during the first of two Voyager spacecraft encounters with Saturn (November 13, 1980); these maneuvers involved rotating the spacecraft simultaneously about two or three axes while maintaining accurate pointing of the scan platform. Titan and Saturn earth occulation experiments and a ring scattering experiment are described. Target motion compensation and the effects of celestial sensor interference are also considered. Failure of the CST, which required an extensive reevaluation of the star reference and attitude control mode strategy, is discussed. Results analyzed thus far show that the system performed with high accuracy, gathering data deeper into Saturn's atmosphere than on any previous planetary encounter.

Information fusion based optimal control for large civil aircraft system.

PubMed

Zhen, Ziyang; Jiang, Ju; Wang, Xinhua; Gao, Chen

2015-03-01

Wind disturbance has a great influence on landing security of Large Civil Aircraft. Through simulation research and engineering experience, it can be found that PID control is not good enough to solve the problem of restraining the wind disturbance. This paper focuses on anti-wind attitude control for Large Civil Aircraft in landing phase. In order to improve the riding comfort and the flight security, an information fusion based optimal control strategy is presented to restrain the wind in landing phase for maintaining attitudes and airspeed. Data of Boeing707 is used to establish a nonlinear mode with total variables of Large Civil Aircraft, and then two linear models are obtained which are divided into longitudinal and lateral equations. Based on engineering experience, the longitudinal channel adopts PID control and C inner control to keep longitudinal attitude constant, and applies autothrottle system for keeping airspeed constant, while an information fusion based optimal regulator in the lateral control channel is designed to achieve lateral attitude holding. According to information fusion estimation, by fusing hard constraint information of system dynamic equations and the soft constraint information of performance index function, optimal estimation of the control sequence is derived. Based on this, an information fusion state regulator is deduced for discrete time linear system with disturbance. The simulation results of nonlinear model of aircraft indicate that the information fusion optimal control is better than traditional PID control, LQR control and LQR control with integral action, in anti-wind disturbance performance in the landing phase. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

A comparison of beliefs about exercise during pregnancy between Chinese and Australian pregnant women.

PubMed

Guelfi, Kym J; Wang, Chen; Dimmock, James A; Jackson, Ben; Newnham, John P; Yang, Huixia

2015-12-22

Despite the well-established benefits of exercise during pregnancy, many women remain inactive. This may be related, in part, to women's beliefs about exercise in pregnancy, which are likely influenced by cultural background. Accordingly, the aim of this study was to compare attitudes, subjective norms, and perceived behavioural control toward exercise, together with current levels of exercise participation between Chinese and Australian women during pregnancy. A second aim was to determine the extent to which these factors predict intention to exercise within a Theory of Planned Behaviour framework. Pregnant women (22 ± 2 weeks of gestation) living in China (n = 240) and Australia (n = 215) completed a questionnaire designed to assess a) maternal beliefs regarding the importance of exercise in relation to other health behaviours, b) attitudes, subjective norms, perceived behavioural control and intentions toward exercise, and c) current levels of physical activity. One-way analyses of variance were used to compare the demographics, maternal beliefs, attitudes, subjective norms, perceived behavioural control, intentions to exercise, and current physical activity levels between the Chinese and Australian samples. Structural equation modelling was used to determine which factors predicted intention to exercise in the two samples. Australian women reported higher levels of current exercise and intentions to exercise in the next four weeks of pregnancy compared with Chinese women. These observations were associated with higher instrumental attitudes, ratings of subjective norm, and perceived behavioural control toward exercise in the Australian women. Instrumental attitudes and perceived behavioural control predicted intention to exercise in the Australian women, while perceived behavioural control was the only predictor of intentions to exercise in the Chinese sample. Beliefs, attitudes, barriers and intentions towards exercise during pregnancy differ between cultures. Understanding these differences may assist in the design of exercise interventions to maximise exercise adherence and lifelong physical activity patterns.

3-Axis magnetic control: flight results of the TANGO satellite in the PRISMA mission

NASA Astrophysics Data System (ADS)

Chasset, C.; Noteborn, R.; Bodin, P.; Larsson, R.; Jakobsson, B.

2013-09-01

PRISMA implements guidance, navigation and control strategies for advanced formation flying and rendezvous experiments. The project is funded by the Swedish National Space Board and run by OHB-Sweden in close cooperation with DLR, CNES and the Danish Technical University. The PRISMA test bed consists of a fully manoeuvrable MANGO satellite as well as a 3-axis controlled TANGO satellite without any Δ V capability. PRISMA was launched on the 15th of June 2010 on board DNEPR. The TANGO spacecraft is the reference satellite for the experiments performed by MANGO, either with a "cooperative" or "non-cooperative" behaviour. Small, light and low-cost were the keywords for the TANGO design. The attitude determination is based on Sun sensors and magnetometers, and the active attitude control uses magnetic torque rods only. In order to perform the attitude manoeuvres required to fulfil the mission objectives, using any additional gravity gradient boom to passively stabilize the spacecraft was not allowed. After a two-month commissioning phase, TANGO separated from MANGO on the 11th of August 2010. All operational modes have been successfully tested, and the pointing performance in flight is in accordance with expectations. The robust Sun Acquisition mode reduced the initial tip-off rate and placed TANGO into a safe attitude in <30 min. The Manual Pointing mode was commissioned, and the spacecraft demonstrated the capability to follow or maintain different sets of attitudes. In Sun/Zenith Pointing mode, TANGO points its GPS antenna towards zenith with sufficient accuracy to track as many GPS satellites as MANGO. At the same time, it points its solar panel towards the Sun, and all payload equipments can be switched on without any restriction. This paper gives an overview of the TANGO Attitude Control System design. It then presents the flight results in the different operating modes. Finally, it highlights the key elements at the origin of the successful 3-axis magnetic control strategy on the TANGO satellite.

Enhancing computer self-efficacy and attitudes in multi-ethnic older adults: a randomised controlled study

PubMed Central

Laganà, Luciana; Oliver, Taylor; Ainsworth, Andrew; Edwards, Marc

2014-01-01

Several studies have documented the health-related benefits of older adults' use of computer technology, but before they can be realised, older individuals must be positively inclined and confident in their ability to engage in computer-based environments. To facilitate the assessment of computer technology attitudes, one aim of the longitudinal study reported in this paper was to test and refine a new 22-item measure of computer technology attitudes designed specifically for older adults, as none such were available.1 Another aim was to replicate, on a much larger scale, the successful findings of a preliminary study that tested a computer technology training programme for older adults (Laganà 2008). Ninety-six older men and women, mainly from non-European-American backgrounds, were randomly assigned to the waitlist/control or the experimental group. The same six-week one-on-one training was administered to the control subjects at the completion of their post-test. The revised (17-item) version of the Older Adults' Computer Technology Attitudes Scale (OACTAS) showed strong reliability: the results of a factor analysis were robust, and two analyses of covariance demonstrated that the training programme induced significant changes in attitudes and self-efficacy. Such results encourage the recruitment of older persons into training programmes aimed at increasing computer technology attitudes and self-efficacy. PMID:25512679

Torque equilibrium attitudes for the Space Station

NASA Technical Reports Server (NTRS)

Thompson, Roger C.

1993-01-01

All spacecraft orbiting in a low earth orbit (LEO) experience external torques due to environmental effects. Examples of these torques include those induced by aerodynamic, gravity-gradient, and solar forces. It is the gravity-gradient and aerodynamic torques that produce the greatest disturbances to the attitude of a spacecraft in LEO, and large asymmetric spacecraft, such as the space station, are affected to a greater degree because the magnitude of the torques will, in general, be larger in proportion to the moments of inertia. If left unchecked, these torques would cause the attitude of the space station to oscillate in a complex manner and the resulting motion would destroy the micro-gravity environment as well as prohibit the orbiter from docking. The application of control torques will maintain the proper attitude, but the controllers have limited momentum capacity. When any controller reaches its limit, propellant must then be used while the device is reset to a zero or negatively-biased momentum state. Consequently, the rate at which momentum is accumulated is a significant factor in the amount of propellant used and the frequency of resupply necessary to operate the station. A torque profile in which the area curve for a positive torque is not equal to the area under the curve for a negative torque is 'biased,' and the consequent momentum build-up about that axis is defined as secular momentum because it continues to grow with time. Conversely, when the areas are equal, the momentum is cyclic and bounded. A Torque Equilibrium Attitude (TEA) is thus defined as an attitude at which the external torques 'balance' each other as much as possible, and which will result in lower momentum growth in the controllers. Ideally, the positive and negative external moments experienced by a spacecraft at the TEA would exactly cancel each other out and small cyclic control torques would be required only for precise attitude control. Over time, the only momentum build-up in the controllers would be due to electro-mechanical losses within the device. However, the atmospheric torques are proportional to the density of the atmosphere and the density varies with the orbital position, time of day, time of year, and the solar cycle. In addition, there are unmodeled disturbances and uncertainties in the mass and inertias. Therefore, there is no constant attitude that will completely balance the environmental torques and the dynamic TEA cannot be solved in closed form. The objective of this research was to determine a method to calculate a dynamic TEA such that the rate of momentum build-up in the controllers would be minimized and to implement this method in the MATRIX(x) simulation software by Integrated Systems, Inc.

Control of Crazyflie nano quadcopter using Simulink

NASA Astrophysics Data System (ADS)

Gopabhat Madhusudhan, Meghana

This thesis focuses on developing a mathematical model in Simulink to Crazyflie, an open source platform. Attitude, altitude and position controllers of a Crazyflie are designed in the mathematical model. The mathematical model is developed based on the quadcopter system dynamics using a non-linear approach. The parameters of translational and rotational dynamics of the quadcopter system are linearized and tuned individually. The tuned attitude and altitude controllers from the mathematical model are implemented on real time Crazyflie Simulink model to achieve autonomous and controlled flight.

Attitude control system for a lightweight flapping wing MAV.

PubMed

Tijmons, Sjoerd; Karásek, Matěj; de Croon, G C H E

2018-03-14

Robust attitude control is an essential aspect of research on autonomous flight of flapping wing Micro Air Vehicles. The mechanical solutions by which the necessary control moments are realised come at the price of extra weight and possible loss of aerodynamic efficiency. Stable flight of these vehicles has been shown by several designs using a conventional tail, but also by tailless designs that use active control of the wings. In this study a control mechanism is proposed that provides active control over the wings. The mechanism improves vehicle stability and agility by generation of control moments for roll, pitch and yaw. Its effectiveness is demonstrated by static measurements around all the three axes. Flight test results confirm that the attitude of the test vehicle, including a tail, can be successfully controlled in slow forward flight conditions. Furthermore, the flight envelope is extended with robust hovering and the ability to reverse the flight direction using a small turn space. This capability is very important for autonomous flight capabilities such as obstacle avoidance. Finally, it is demonstrated that the proposed control mechanism allows for tailless hovering flight. © 2018 IOP Publishing Ltd.

Flight Mechanics/Estimation Theory Symposium, 1992

NASA Technical Reports Server (NTRS)

Stengle, Thomas H. (Editor)

1993-01-01

This conference publication includes 40 papers and abstracts presented at the Flight Mechanics/Estimation Theory Symposium on May 5-7, 1992. Sponsored by the Flight Dynamics Division of Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination, and control; attitude sensor calibration; attitude determination error analysis; attitude dynamics; and orbit decay and maneuver strategy. Government, industry, and the academic community participated in the preparation and presentation of these papers.

Flight Mechanics/Estimation Theory Symposium 1996

NASA Technical Reports Server (NTRS)

Greatorex, Scott (Editor)

1996-01-01

This conference publication includes 34 papers and abstracts presented at the Flight Mechanics/ Estimation Theory Symposium on May 14-16, 1996. Sponsored by the Flight Dynamics Division of Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination, and control; attitude sensor calibration; attitude determination error analysis; attitude dynamics; and orbit decay and maneuver strategy. Government, industry, and the academic community participated in the preparation and presentation of these papers.

Return-to-launch-site three degree of freedom analysis, constant inertial attitude during the fuel dissipation phase

NASA Technical Reports Server (NTRS)

Bown, R. L.; Winans, L. C.

1975-01-01

Results are presented of a study to show the effect of selecting a constant inertial attitude during the fuel dissipation phase of a return-to-launch-site abort. Results are also presented which show that the selection of the constant inertial attitude will affect the arrival point on the range-velocity target line. An alternate selection of the inertial attitude will provide control over the trajectory shape.

Flight Mechanics/Estimation Theory Symposium, 1994

NASA Technical Reports Server (NTRS)

Hartman, Kathy R. (Editor)

1994-01-01

This conference publication includes 41 papers and abstracts presented at the Flight Mechanics/Estimation Theory Symposium on May 17-19, 1994. Sponsored by the Flight Dynamics Division of Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination and control; attitude sensor calibration; attitude determination error analysis; attitude dynamics; and orbit decay and maneuver strategy. Government, industry, and the academic community participated in the preparation and presentation of these papers.

Flight Mechanics/Estimation Theory Symposium, 1990

NASA Technical Reports Server (NTRS)

Stengle, Thomas (Editor)

1990-01-01

This conference publication includes 32 papers and abstracts presented at the Flight Mechanics/Estimation Theory Symposium on May 22-25, 1990. Sponsored by the Flight Dynamics Division of Goddard Space Flight Center, this symposium features technical papers on a wide range of issues related to orbit-attitude prediction, determination and control; attitude sensor calibration; attitude determination error analysis; attitude dynamics; and orbit decay and maneuver strategy. Government, industry, and the academic community participated in the preparation and presentation of these papers.

Flight Mechanics/Estimation Theory Symposium 1995

NASA Technical Reports Server (NTRS)

Hartman, Kathy R. (Editor)

1995-01-01

This conference publication includes 41 papers and abstracts presented at the Flight Mechanics/ Estimation Theory Symposium on May 16-18, 1995. Sponsored by the Flight Dynamics Division of Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination, and control; attitude sensor calibration; attitude determination error analysis; attitude dynamics; and orbit decay and maneuver strategy. Government, industry, and the academic community participated in the preparation and presentation of these papers.

SPS attitude control and stationkeeping: Requirements and tradeoffs

NASA Technical Reports Server (NTRS)

Oglevie, R. E.

1980-01-01

The dominant control requirements of solar power satellites change appreciably relative to small contemporary spacecraft. Trade studies and analyses illustrated preferred control approaches. It was found that the geosynchronous equatorial orbit is preferred over the alternative orbits considered, that the solar pressure orbit perturbation dominates stationkeeping propulsion requirements and that a combined AC and SK system using ion electric propulsion can satisfy the attitude control requirements. It was also found that control system/structural dynamic interaction stability can be obtained through frequency separation with reasonable structural dynamic requirements and simplify spacecraft design.

A comparison of three strategies for reducing the public stigma associated with stuttering.

PubMed

Boyle, Michael P; Dioguardi, Lauren; Pate, Julie E

2016-12-01

The effects of three anti-stigma strategies for stuttering-contact (hearing personal stories from an individual who stutters), education (replacing myths about stuttering with facts), and protest (condemning negative attitudes toward people who stutter)-were examined on attitudes, emotions, and behavioral intentions toward people who stutter. Two hundred and twelve adults recruited from a nationwide survey in the United States were randomly assigned to one of the three anti-stigma conditions or a control condition. Participants completed questionnaires about stereotypes, negative emotional reactions, social distance, discriminatory intentions, and empowerment regarding people who stutter prior to and after watching a video for the assigned condition, and reported their attitude changes about people who stutter. Some participants completed follow-up questionnaires on the same measures one week later. All three anti-stigma strategies were more effective than the control condition for reducing stereotypes, negative emotions, and discriminatory intentions from pretest to posttest. Education and protest effects for reducing negative stereotypes were maintained at one-week follow-up. Contact had the most positive effect for increasing affirming attitudes about people who stutter from pretest to posttest and pretest to follow-up. Participants in the contact and education groups, but not protest, self-reported significantly more positive attitude change about people who stutter as a result of watching the video compared to the control group. Advocates in the field of stuttering can use education and protest strategies to reduce negative attitudes about people who stutter, and people who stutter can increase affirming attitudes through interpersonal contact with others. Copyright © 2016 Elsevier Inc. All rights reserved.

The effects of traditional learning and a learning cycle inquiry learning strategy on students' science achievement and attitudes toward elementary science

NASA Astrophysics Data System (ADS)

Ebrahim, Ali

The purpose of this study is to examine the impact of two instructional methods on students' academic achievement and attitudes toward elementary science in the State of Kuwait: traditional teaching method and the 4-E learning cycle inquiry teaching method. The subjects were 111 students from four intact 4th grade classes. The experiment group (n = 56) received the learning cycle instruction while the control group (n = 55) received a more traditional approach over a four week period. The same female teacher taught the experimental and control groups for boys and a different female teacher taught experimental and control groups for girls. The dependent variables were measured through the use of: (1) a science achievement test to assess student achievement; and (2) an attitude survey to measure students' attitudes toward science. Quantitative data were collected on students' pre- and post-treatment achievement and attitudes measures. The two way MANOVA reveals that: the 4-E learning cycle instructional method produces significantly greater achievement and attitudes among fourth grade science students than the traditional teaching approach F (2, 93) = 19.765, (P = .000), corresponding to Wilks' Lambda = .702 with an effect size of .298 and a power of 1. In light of these findings, it is therefore suggested that students can achieve greater and have higher science attitudes when the 4-E learning cycle is used. In addition, these findings support the notion that effective instruction in teaching science, such as the 4-E learning cycle instruction, should be proposed and implemented in elementary schools.

A multi-site controlled trial of a cognitive skills program for mentally disordered offenders.

PubMed

Rees-Jones, Angharad; Gudjonsson, Gisli; Young, Susan

2012-05-18

The effectiveness of offending behaviour programs in forensic mental health settings is not well established. Thus this study aimed to evaluate the Reasoning and Rehabilitation Mental Health program (R&R2 MHP) among a mentally disordered offender (MDO) population. A sample of 121 adult males drawn from 10 forensic mental health sites completed questionnaires at baseline and post-treatment to assess violent attitudes, locus of control, social problem-solving and anger. An informant measure of social and psychological functioning, including disruptive behaviour, was completed by unit staff at the same time. At three month follow-up patients completed again the violent attitudes and locus of control questionnaires. The data of 67 patients who participated in the group condition were compared with 54 waiting-list controls who received treatment as usual. 78% of group participants completed the program. In contrast to controls, significant treatment effects were found at outcome on self-reported measures of violent attitudes, rational problem-solving and anger cognitions. Improvements were endorsed by informant ratings of social and psychological functioning within the establishments. At follow-up significant treatment effects were found for both violent attitudes and locus of control. R&R2 MHP was effective in a sample of MDOs and had a comparatively low drop-out rate. Future research should use a randomized controlled design.

Older African American Homeless-Experienced Smokers' Attitudes Toward Tobacco Control Policies-Results from the HOPE HOME Study.

PubMed

Vijayaraghavan, Maya; Olsen, Pamela; Weeks, John; McKelvey, Karma; Ponath, Claudia; Kushel, Margot

2018-02-01

To examine attitudes toward tobacco control policies among older African American homeless-experienced smokers. A qualitative study. Oakland, California. Twenty-two African American older homeless-experienced smokers who were part of a longitudinal study on health and health-related outcomes (Health Outcomes of People Experiencing Homelessness in Older Middle Age Study). We conducted in-depth, semistructured interviews with each participant to explore beliefs and attitudes toward tobacco use and cessation, barriers to smoking cessation, and attitudes toward current tobacco control strategies including raising cigarette prices, smoke-free policies, and graphic warning labels. We used a grounded theory approach to analyze the transcripts. Community social norms supportive of cigarette smoking and co-use of tobacco with other illicit substances were strong motivators of initiation and maintenance of tobacco use. Self-reported barriers to cessation included nicotine dependence, the experience of being homeless, fatalistic attitudes toward smoking cessation, substance use, and exposure to tobacco industry marketing. While participants were cognizant of current tobacco control policies and interventions for cessation, they felt that they were not specific enough for African Americans experiencing homelessness. Participants expressed strong support for strategies that de-normalized tobacco use and advertised the harmful effects of tobacco. Older African American homeless-experienced smokers face significant barriers to smoking cessation. Interventions that advertise the harmful effects of tobacco may be effective in stimulating smoking cessation among this population.

How do medical students engaging in elective courses on acupuncture and homeopathy differ from unselected students? A survey.

PubMed

Jocham, Alexandra; Kriston, Levente; Berberat, Pascal O; Schneider, Antonius; Linde, Klaus

2017-03-09

We aimed to investigate whether students at German medical schools participating in elective courses on acupuncture and homeopathy differ from an unselected group of students regarding attitudes and personality traits. Elective courses on acupuncture and homeopathy in the academic half-year 2013/14 all over Germany were identified and participants invited to fill in a questionnaire including nineteen questions on attitudes towards Complementary and Alternative Medicine (CAM), orientation towards science, care and status orientation, and a short validated instrument (Big-Five-Inventory-10) to measure personality traits (extraversion, neuroticism, openness, conscientiousness, and agreeableness). Participants of a mandatory family medicine course at one university served as unselected control group. Two hundred twenty and 113 students from elective courses on acupuncture and homeopathy, respectively, and 315 control students participated (response rate 93%). Students participating in elective courses had much more positive attitudes towards CAM, somewhat lower science and status orientation, and somewhat higher care orientation than control group students (all p-values for three-group comparisons < 0.001). There were no differences between the three groups regarding personality traits with the exception of lower values for agreeableness in controls (p = 0.009). The findings of this study show that attitudes of students participating in elective courses on acupuncture or homeopathy at German medical schools differ to a considerable degree from the attitudes of unselected students.

An assessment of a pilot asthma education program for childcare workers in a high-prevalence county.

PubMed

Saville, Suzanne K; Wetta-Hall, Ruth; Hawley, Suzanne R; Molgaard, Craig A; St Romain, Theresa; Hart, Traci A

2008-12-01

To assess changes in knowledge, attitudes, and intentions among childcare workers before and after an asthma-management-education session. Between May and August 2004 five asthma-education sessions were provided for childcare workers from Sonoma County, California. A total of 71 childcare workers came to the sessions. Before and after each session we assessed the participants' knowledge, attitudes, and intentions about asthma. Participant knowledge of asthma causes (eg, air quality, common cold) and interventions (eg, bronchodilators), asthma trigger control plans, ability to identify a child who needs medical attention for asthma, and comfort level with caring for a child with asthma increased significantly. Their knowledge about asthma triggers, early warning signs, and asthma control plans was high before and after the asthma education intervention. Their stated intentions to utilize their asthma knowledge were high before and after the training, which may indicate willingness to implement knowledge and attitude change. Asthma education can improve childcare workers' knowledge about asthma-control strategies and attitudes toward asthma interventions.

MAP Attitude Control System Design and Flight Performance

NASA Technical Reports Server (NTRS)

Andrews, S. F.; ODonnell, J. R.; Bauer, Frank H. (Technical Monitor)

2002-01-01

The Microwave Anisotropy Probe (MAP) is a follow-on to the Differential Microwave Radiometer (DMR) instrument on the Cosmic Background Explorer (COBE) spacecraft. To make a full-sky map of cosmic microwave background fluctuations, a combination fast spin and slow precession motion will be used that will cover the entire celestial sphere in six months. The spin rate should be an order of magnitude higher than the precession rate, and each rate should be tightly controlled. The sunline angle should be 22.5 +/- 0.25 deg. Sufficient attitude knowledge must be provided to yield instrument pointing to a standard deviation of 1.3 arc-minutes RSS three axes. In addition, the spacecraft must be able to acquire and hold the sunline at initial acquisition, and in the event of a failure. Finally. the spacecraft must be able to slew to the proper burn orientations and to the proper off-sunline attitude to start the compound spin. The design and flight performance of the Attitude Control System on MAP that meets these requirements will be discussed.

In-orbit performance of the ITOS improved attitude control system with Hall generator brushless motor and earth-splitting technique

NASA Technical Reports Server (NTRS)

Peacock, W. M.

1973-01-01

The National Aeronautics and Space Administration (NASA), launched ITOS-D with an improved attitude control system. A Hall generator brushless dc torque motor replaced the brush dc torque motor on Tiros-M and ITOS-A. Two CO2 attitude horizon sensors and one mirror replaced the four wideband horizon sensors and two mirrors on ITOS-1 and NOAA-1. Redundant pitch-control electronic boxes containing additional electronic circuitry for earth-splitting and brushless motor electronics were used. A method of generating a spacecraft earth-facing side reference for comparison to the time occurrence of the earth-splitting pulse was used to automatically correct pitch-attitude error. A single rotating flywheel, supported by a single bearing, provided gyroscopic stability and the required momentum interchange to keep one side of the satellite facing the earth. Magnetic torquing against the earth's magnetic field eliminated the requirement for expendable propellants which would limit satellite life in orbit.

Effectiveness of Case-Based Learning Instruction on Epistemological Beliefs and Attitudes Toward Chemistry

NASA Astrophysics Data System (ADS)

Çam, Aylin; Geban, Ömer

2011-02-01

The purpose of the study was to investigate the effectiveness of case-based learning instruction over traditionally designed chemistry instruction on eleventh grade students' epistemological beliefs and their attitudes toward chemistry as a school subject. The subjects of this study consisted of 63 eleventh grade students from two intact classes of an urban high school instructed with same teacher. Each teaching method was randomly assigned to one class. The experimental group received case-based learning and the control group received traditional instruction. At the experimental group, life cases were presented with small group format; at the control group, lecturing and discussion was carried out. The results showed that there was a significant difference between the experimental and control group with respect to their epistemological beliefs and attitudes toward chemistry as a school subject in favor of case-based learning method group. Thus, case base learning is helpful for development of students' epistemological beliefs and attitudes toward chemistry.

WMAP C&DH Software

NASA Technical Reports Server (NTRS)

Cudmore, Alan; Leath, Tim; Ferrer, Art; Miller, Todd; Walters, Mark; Savadkin, Bruce; Wu, Ji-Wei; Slegel, Steve; Stagmer, Emory

2007-01-01

The command-and-data-handling (C&DH) software of the Wilkinson Microwave Anisotropy Probe (WMAP) spacecraft functions as the sole interface between (1) the spacecraft and its instrument subsystem and (2) ground operations equipment. This software includes a command-decoding and -distribution system, a telemetry/data-handling system, and a data-storage-and-playback system. This software performs onboard processing of attitude sensor data and generates commands for attitude-control actuators in a closed-loop fashion. It also processes stored commands and monitors health and safety functions for the spacecraft and its instrument subsystems. The basic functionality of this software is the same of that of the older C&DH software of the Rossi X-Ray Timing Explorer (RXTE) spacecraft, the main difference being the addition of the attitude-control functionality. Previously, the C&DH and attitude-control computations were performed by different processors because a single RXTE processor did not have enough processing power. The WMAP spacecraft includes a more-powerful processor capable of performing both computations.

A study of attitude control concepts for precision-pointing non-rigid spacecraft

NASA Technical Reports Server (NTRS)

Likins, P. W.

1975-01-01

Attitude control concepts for use onboard structurally nonrigid spacecraft that must be pointed with great precision are examined. The task of determining the eigenproperties of a system of linear time-invariant equations (in terms of hybrid coordinates) representing the attitude motion of a flexible spacecraft is discussed. Literal characteristics are developed for the associated eigenvalues and eigenvectors of the system. A method is presented for determining the poles and zeros of the transfer function describing the attitude dynamics of a flexible spacecraft characterized by hybrid coordinate equations. Alterations are made to linear regulator and observer theory to accommodate modeling errors. The results show that a model error vector, which evolves from an error system, can be added to a reduced system model, estimated by an observer, and used by the control law to render the system less sensitive to uncertain magnitudes and phase relations of truncated modes and external disturbance effects. A hybrid coordinate formulation using the provided assumed mode shapes, rather than incorporating the usual finite element approach is provided.

ATTDES: An Expert System for Satellite Attitude Determination and Control. 2

NASA Technical Reports Server (NTRS)

Mackison, Donald L.; Gifford, Kevin

1996-01-01

The design, analysis, and flight operations of satellite attitude determintion and attitude control systems require extensive mathematical formulations, optimization studies, and computer simulation. This is best done by an analyst with extensive education and experience. The development of programs such as ATTDES permit the use of advanced techniques by those with less experience. Typical tasks include the mission analysis to select stabilization and damping schemes, attitude determination sensors and algorithms, and control system designs to meet program requirements. ATTDES is a system that includes all of these activities, including high fidelity orbit environment models that can be used for preliminary analysis, parameter selection, stabilization schemes, the development of estimators covariance analyses, and optimization, and can support ongoing orbit activities. The modification of existing simulations to model new configurations for these purposes can be an expensive, time consuming activity that becomes a pacing item in the development and operation of such new systems. The use of an integrated tool such as ATTDES significantly reduces the effort and time required for these tasks.

Sex-role attitudes as predictors of contraceptive use among unmarried university students.

PubMed

Fox, G L

1977-06-01

A survey of the literature led to 3 propositions: 1) the most usual response of young women when deciding whether to use a contraceptive is to avoid the decision by not using any or by leaving it to the male, 2) contraceptive inertia is reinforced by the joint operation of external locus of control and traditional sex-role attitudes, and 3) contraceptive use is facilitated by nontraditional sex-role attitudes in conjunction with a positive sense of personal control. A stratified random sample of 1009 male and female students at a large Midwestern university provided survey research data. Findings indicate a majority of students do not use contraceptive protection at 1st intercourse but increase usage. 22% of the females and 31% of the males did not use contraceptives at their last sexual encounter. The results suggest that nontraditional sex-role-related attitudes in conjunction with an internal locus of control orientation are predictive of effective contraception for women respondents. Neither variable alone or jointly explained contraceptive behavior of men respondents.

Solar Array Disturbances to Spacecraft Pointing During the Lunar Reconnaissance Orbiter (LRO) Mission

NASA Technical Reports Server (NTRS)

Calhoun, Philip

2010-01-01

The Lunar Reconnaissance Orbiter (LRO), the first spacecraft to support NASA s return to the Moon, launched on June 18, 2009 from the Cape Canaveral Air Force Station aboard an Atlas V launch vehicle. It was initially inserted into a direct trans-lunar trajectory to the Moon. After a five day transit to the Moon, LRO was inserted into the Lunar orbit and successfully lowered to a low altitude elliptical polar orbit for spacecraft commissioning. Successful commissioning was completed in October 2009 when LRO was placed in its near circular mission orbit with an approximate altitude of 50km. LRO will spend at least one year orbiting the Moon, collecting lunar environment science and mapping data, utilizing a suite of seven instruments to enable future human exploration. The objective is to provide key science data necessary to facilitate human return to the Moon as well as identification of opportunities for future science missions. LRO's instrument suite will provide the high resolution imaging data with sub-meter accuracy, highly accurate lunar cartographic maps, mineralogy mapping, amongst other science data of interest. LRO employs a 3-axis stabilized attitude control system (ACS) whose primary control mode, the "Observing Mode", provides Lunar nadir, off-nadir, and inertial fine pointing for the science data collection and instrument calibration. This controller combines the capability of fine pointing with on-demand large angle full-sky attitude reorientation. It provides simplicity of spacecraft operation as well as additional flexibility for science data collection. A conventional suite of ACS components is employed in the Observing Mode to meet the pointing and control objectives. Actuation is provided by a set of four reaction wheels developed in-house at NASA Goddard Space Flight Center (GSFC). Attitude feedback is provided by a six state Kalman filter which utilizes two SELEX Galileo Star Trackers for attitude updates, and a single Honeywell Miniature Inertial Measurement Unit (MIMU) to provide body rates for attitude propagation. Rate is computed by differentiating accumulated angle provided by the MIMU. The Observing Mode controller is required to maintain fine pointing while a large fully-articulated solar array (SA) maintains its panel normal to the solar incidence. This paper describes the disturbances to the attitude control resulting from the SA articulation. Observing Mode performance in the presence of this disturbance was assessed while the spacecraft was in an initial elliptical low altitude orbit during the commissioning phase, which started about two weeks after launch and lasted for 90 days. LRO demonstrated excellent pointing performance during Observing Mode nadir and inertial attitude target operations during this phase. Transient LRO attitude errors observed during commissioning resulted primarily from three sources, Diviner instrument calibrations, RW zero crossings, and SA articulation. Even during times of considerable disturbance from SA articulation, the attitude errors were maintained below the statistical attitude error requirement level of 15 arc-sec (3 sigma).

Gravity Probe B spacecraft description

NASA Astrophysics Data System (ADS)

Bennett, Norman R.; Burns, Kevin; Katz, Russell; Kirschenbaum, Jon; Mason, Gary; Shehata, Shawky

2015-11-01

The Gravity Probe B spacecraft, developed, integrated, and tested by Lockheed Missiles & Space Company and later Lockheed Martin Corporation, consisted of structures, mechanisms, command and data handling, attitude and translation control, electrical power, thermal control, flight software, and communications. When integrated with the payload elements, the integrated system became the space vehicle. Key requirements shaping the design of the spacecraft were: (1) the tight mission timeline (17 months, 9 days of on-orbit operation), (2) precise attitude and translational control, (3) thermal protection of science hardware, (4) minimizing aerodynamic, magnetic, and eddy current effects, and (5) the need to provide a robust, low risk spacecraft. The spacecraft met all mission requirements, as demonstrated by dewar lifetime meeting specification, positive power and thermal margins, precision attitude control and drag-free performance, reliable communications, and the collection of more than 97% of the available science data.

[Comparison of knowledge, attitude and practice of students left at home or not on schistosomiasis prevention and control].

PubMed

Zhang, Gang-Gang; Zhao, An; Tang, Qi-Qiang; Zhu, Jing; Huang, Chao-Qing

2012-02-01

The questionnaire survey on knowledge, attitude and practice (KAP)of students left at home or not about schistosomiasis prevention and control showed that there were no statistically significant differences of the scores of KAP between the two groups of students (all P values were above 0.05).

Children's Eating Attitudes and Behaviour: A Study of the Modelling and Control Theories of Parental Influence

ERIC Educational Resources Information Center

Brown, Rachael; Ogden, Jane

2004-01-01

The present study compared the modelling and control theories of parental influence on children's eating attitudes and behaviour with a focus on snack foods. Matched questionnaires describing reported snack intake, eating motivations and body dissatisfaction were completed by 112 parent/child pairs. Parents completed additional items relating to…

The Attitudes & Beliefs on Classroom Control Inventory-Revised and Revisited: A Continuation of Construct Validation

ERIC Educational Resources Information Center

Martin, Nancy K.; Yin, Zenong; Mayall, Hayley

2008-01-01

The purpose of this study was to report the psychometric properties of the revised Attitudes and Beliefs of Classroom Control Inventory (ABCC-R). Data were collected from 489 participants via the ABCC-R, Teacher Efficacy Scale, Problems in School Questionnaire, and a demographic questionnaire. Results were in keeping with the construct. The…

Educating Students about Parents: Husbands' Versus Wives' Attitudes about Self.

ERIC Educational Resources Information Center

Arena, Jordan; Black, Aimee; Dantonio, Kelley; Farrell, Debi; Fleming, Hillary; Fontanez, Mary; Gelband, Amy; Sosnowski, Jane; McCauley, Joy; Nyce, Susan; Chambliss, Catherine

This study assessed the attitudes of both males and females regarding their perceptions of themselves, spouse and locus of control, and the role that children may play in that assessment. To determine if men and women view themselves differently subsequent to having children, the Rosenberg self concept scale, the Ferguson Locus of Control scale,…

Effect of Ethnochemistry Practices on Secondary School Students' Attitude towards Chemistry

ERIC Educational Resources Information Center

Singh, Indra Sen; Chibuye, Bitwell

2016-01-01

The main purpose of the study was to find out the effect of ethnochemistry practices on secondary school students' attitude towards Chemistry. The design of the study was pre-test post-test control group quasiexperimental design. Two grade 11 intact classes were assigned into experimental and control groups randomly. The total sample size…

Improving Senior Secondary School Students' Attitude towards Mathematics through Self and Cooperative-Instructional Strategies

ERIC Educational Resources Information Center

Ifamuyiwa, S. A.; Akinsola, M. K.

2008-01-01

This study investigated the effects of self and cooperative-instructional strategies on senior secondary school students' attitude towards Mathematics. The moderating effects of locus of control and gender were also investigated. The study adopted pre-test and post-test, control group quasi-experimental design using a 3 x 2 x 2 factorial matrix…

Tobacco Control Policy Advocacy Attitudes and Self-Efficacy among Ethnically Diverse High School Students

ERIC Educational Resources Information Center

Ramirez, Amelie G.; Velez, Luis F.; Chalela, Patricia; Grussendorf, Jeannie; McAlister, Alfred L.

2006-01-01

This study applied self-efficacy theory to assess empowerment to advocate on behalf of tobacco control policies. The Youth Tobacco Survey with added policy advocacy self-efficacy, attitudes, and outcome expectations scales was given to 9,177 high school students in Texas. Asians showed the lowest prevalence of experimentation and current smoking,…

78 FR 31836 - Special Conditions: Embraer S.A., Model EMB-550 Airplane, Dive Speed Definition With Speed...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-28

... attitudes; or that the airplane is protected by the flight control laws from getting into non-symmetric...-symmetric attitudes, unless the airplane is protected by the flight control laws from getting into non... equivalent to that established by the existing airworthiness standards. DATES: Effective Date: June 27, 2013...

The Effects of Value Confrontation and Reinforcement Counseling on the Career Planning Attitudes and Behavior of Adolescent Males.

ERIC Educational Resources Information Center

Young, Richard A.

1979-01-01

Post-tests show that the value confrontation procedure resulted in significantly greater frequency of information seeking for internally controlled subjects when compared to the reinforcement counseling and control procedures. Examines two procedures designed to enhance the career planning attitudes and behavior of rural adolescent males.…

Attitudes to Gun Control in an American Twin Sample: Sex Differences in the Causes of Variation.

PubMed

Eaves, Lindon J; Silberg, Judy L

2017-10-01

The genetic and social causes of individual differences in attitudes to gun control are estimated in a sample of senior male and female twin pairs in the United States. Genetic and environmental parameters were estimated by weighted least squares applied to polychoric correlations for monozygotic (MZ) and dizygotic (DZ) twins of both sexes. The analysis suggests twin similarity for attitudes to gun control in men is entirely genetic while that in women is purely social. Although the volunteer sample is small, the analysis illustrates how the well-tested concepts and methods of genetic epidemiology may be a fertile resource for deepening our scientific understanding of biological and social pathways that affect individual risk to gun violence.

Thermal elastic shock and its effect on TOPEX spacecraft attitude control

NASA Technical Reports Server (NTRS)

Zimbelman, Darrell F.

1991-01-01

Thermal elastic shock (TES) is a twice per orbit impulsive disturbance torque experienced by low-Earth orbiting spacecraft. The fundamental equations used to model the TES disturbance torque for typical spacecraft appendages (e.g., solar arrays and antenna booms) are derived in detail. In particular, the attitude-pointing performance of the TOPEX spacecraft, when subjected to the TES disturbance, is analyzed using a three-axis nonlinear time-domain simulation. Results indicate that the TOPEX spacecraft could exceed its roll-axis attitude-control requirement during penumbral transitions, and remain in violation for approximately 150 sec each orbit until the umbra collapses. A localized active-control system is proposed as a solution to minimize and/or eliminate the degrading effects of the TES disturbance.

Inertial vestibular coding of motion: concepts and evidence

NASA Technical Reports Server (NTRS)

Hess, B. J.; Angelaki, D. E.

1997-01-01

Central processing of inertial sensory information about head attitude and motion in space is crucial for motor control. Vestibular signals are coded relative to a non-inertial system, the head, that is virtually continuously in motion. Evidence for transformation of vestibular signals from head-fixed sensory coordinates to gravity-centered coordinates have been provided by studies of the vestibulo-ocular reflex. The underlying central processing depends on otolith afferent information that needs to be resolved in terms of head translation related inertial forces and head attitude dependent pull of gravity. Theoretical solutions have been suggested, but experimental evidence is still scarce. It appears, along these lines, that gaze control systems are intimately linked to motor control of head attitude and posture.