Speed control for a mobile robot

NASA Astrophysics Data System (ADS)

Kolli, Kaylan C.; Mallikarjun, Sreeram; Kola, Krishnamohan; Hall, Ernest L.

1997-09-01

Automated guided vehicles (AGVs) have many potential applications in manufacturing, medicine, space and defense. The purpose of this paper is to describe exploratory research on the design of a speed control for a modular autonomous mobile robot controller. The speed control of the traction motor is essential for safe operation of a mobile robot. The challenges of autonomous operation of a vehicle require safe, runaway and collision free operation. A mobile robot test-bed has been constructed using a golf cart base. The computer controlled speed control has been implemented and works with guidance provided by vision system and obstacle avoidance using ultrasonic sensors systems. A 486 computer through a 3- axis motion controller supervises the speed control. The traction motor is controlled via the computer by an EV-1 speed control. Testing of the system was done both in the lab and on an outside course with positive results. This design is a prototype and suggestions for improvements are also given. The autonomous speed controller is applicable for any computer controlled electric drive mobile vehicle.

Asymmetry of short-term control of spatio-temporal gait parameters during treadmill walking

NASA Astrophysics Data System (ADS)

Kozlowska, Klaudia; Latka, Miroslaw; West, Bruce J.

2017-03-01

Optimization of energy cost determines average values of spatio-temporal gait parameters such as step duration, step length or step speed. However, during walking, humans need to adapt these parameters at every step to respond to exogenous and/or endogenic perturbations. While some neurological mechanisms that trigger these responses are known, our understanding of the fundamental principles governing step-by-step adaptation remains elusive. We determined the gait parameters of 20 healthy subjects with right-foot preference during treadmill walking at speeds of 1.1, 1.4 and 1.7 m/s. We found that when the value of the gait parameter was conspicuously greater (smaller) than the mean value, it was either followed immediately by a smaller (greater) value of the contralateral leg (interleg control), or the deviation from the mean value decreased during the next movement of ipsilateral leg (intraleg control). The selection of step duration and the selection of step length during such transient control events were performed in unique ways. We quantified the symmetry of short-term control of gait parameters and observed the significant dominance of the right leg in short-term control of all three parameters at higher speeds (1.4 and 1.7 m/s).

Control of Walking Speed in Children With Cerebral Palsy.

PubMed

Davids, Jon R; Cung, Nina Q; Chen, Suzy; Sison-Williamson, Mitell; Bagley, Anita M

2017-03-21

Children's ability to control the speed of gait is important for a wide range of activities. It is thought that the ability to increase the speed of gait for children with cerebral palsy (CP) is common. This study considered 3 hypotheses: (1) most ambulatory children with CP can increase gait speed, (2) the characteristics of free (self-selected) and fast walking are related to motor impairment level, and (3) the strategies used to increase gait speed are distinct among these levels. A retrospective review of time-distance parameters (TDPs) for 212 subjects with CP and 34 typically developing subjects walking at free and fast speeds was performed. Only children who could increase their gait speed above the minimal clinically important difference were defined as having a fast walk. Analysis of variance was used to compare TDPs of children with CP, among Gross Motor Function Classification System (GMFCS) levels, and children in typically developing group. Eight-five percent of the CP group (GMFCS I, II, III; 96%, 99%, and 34%, respectively) could increase gait speed on demand. At free speed, children at GMFCS I and II were significantly faster than children at GMFCS level III. At free speed, children at GMFCS I and II had significantly greater stride length than those at GMFCS levels III. At free speed, children at GMFCS level III had significantly lower cadence than those at GMFCS I and II. There were no significant differences in cadence among GMFCS levels at fast speeds. There were no significant differences among GMFCS levels for percent change in any TDP between free and fast walking. Almost all children with CP at GMFCS levels I and II can control the speed of gait, however, only one-third at GMFCS III level have this ability. This study suggests that children at GMFCS III level can be divided into 2 groups based on their ability to control gait speed; however, the prognostic significance of such categorization remains to be determined. Diagnostic level II.

Model-free adaptive speed control on travelling wave ultrasonic motor

NASA Astrophysics Data System (ADS)

Di, Sisi; Li, Huafeng

2018-01-01

This paper introduced a new data-driven control (DDC) method for the speed control of ultrasonic motor (USM). The model-free adaptive control (MFAC) strategy was presented in terms of its principles, algorithms, and parameter selection. To verify the efficiency of the proposed method, a speed-frequency-time model, which contained all the measurable nonlinearity and uncertainties based on experimental data was established for simulation to mimic the USM operation system. Furthermore, the model was identified using particle swarm optimization (PSO) method. Then, the control of the simulated system using MFAC was evaluated under different expectations in terms of overshoot, rise time and steady-state error. Finally, the MFAC results were compared with that of proportion iteration differentiation (PID) to demonstrate its advantages in controlling general random system.

14 CFR 23.373 - Speed control devices.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Speed control devices. 23.373 Section 23....373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are incorporated....441 and 23.443, with the device extended at speeds up to the placard device extended speed; and (b) If...

14 CFR 23.373 - Speed control devices.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Speed control devices. 23.373 Section 23....373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are incorporated....441 and 23.443, with the device extended at speeds up to the placard device extended speed; and (b) If...

Research on speed control of secondary regulation lifting system of parking equipment

NASA Astrophysics Data System (ADS)

Zang, Faye

2005-12-01

Hydrostatic transmission with secondary regulation is a new kind of hydrostatic transmission that can regenerate inertial and gravitational energy of load. On the basis of an in-depth analysis of the working principles and energy-saving mechanisms of the parking equipment lifting systems with, secondary regulating technology, this paper proposes a method of regenerating a lifting system's inertial energy by controlling rotational speed and reclaiming the gravitational energy by use of a constant rotational speed. Considering large changes of the parameters of lifting systems and then non-linearity, a fuzzy control was adopted to control the lifting system, and a mathematical model of the system was established. By simulation and experiment of the lifting system, the conclusion was reached a lifting system's braking achieved by controlling rotational speed is reliable and stable at a definite speed. It also permits changing the efficiency of recovery by changing the rotational speed. The design power of the lifting system can be chosen in terms of the system's average power, so the system's power can be reduced and energy savings achieved.

14 CFR 25.149 - Minimum control speed.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Minimum control speed. 25.149 Section 25... Minimum control speed. (a) In establishing the minimum control speeds required by this section, the method... prevent a heading change of more than 20 degrees. (e) VMCG, the minimum control speed on the ground, is...

14 CFR 25.149 - Minimum control speed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 25.149 Section 25... Minimum control speed. (a) In establishing the minimum control speeds required by this section, the method... prevent a heading change of more than 20 degrees. (e) VMCG, the minimum control speed on the ground, is...

Robust adaptive cruise control of high speed trains.

PubMed

Faieghi, Mohammadreza; Jalali, Aliakbar; Mashhadi, Seyed Kamal-e-ddin Mousavi

2014-03-01

The cruise control problem of high speed trains in the presence of unknown parameters and external disturbances is considered. In particular a Lyapunov-based robust adaptive controller is presented to achieve asymptotic tracking and disturbance rejection. The system under consideration is nonlinear, MIMO and non-minimum phase. To deal with the limitations arising from the unstable zero-dynamics we do an output redefinition such that the zero-dynamics with respect to new outputs becomes stable. Rigorous stability analyses are presented which establish the boundedness of all the internal states and simultaneously asymptotic stability of the tracking error dynamics. The results are presented for two common configurations of high speed trains, i.e. the DD and PPD designs, based on the multi-body model and are verified by several numerical simulations. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

PSO-based PID Speed Control of Traveling Wave Ultrasonic Motor under Temperature Disturbance

NASA Astrophysics Data System (ADS)

Arifin Mat Piah, Kamal; Yusoff, Wan Azhar Wan; Azmi, Nur Iffah Mohamed; Romlay, Fadhlur Rahman Mohd

2018-03-01

Traveling wave ultrasonic motors (TWUSMs) have a time varying dynamics characteristics. Temperature rise in TWUSMs remains a problem particularly in sustaining optimum speed performance. In this study, a PID controller is used to control the speed of TWUSM under temperature disturbance. Prior to developing the controller, a linear approximation model which relates the speed to the temperature is developed based on the experimental data. Two tuning methods are used to determine PID parameters: conventional Ziegler-Nichols(ZN) and particle swarm optimization (PSO). The comparison of speed control performance between PSO-PID and ZN-PID is presented. Modelling, simulation and experimental work is carried out utilizing Fukoku-Shinsei USR60 as the chosen TWUSM. The results of the analyses and experimental work reveal that PID tuning using PSO-based optimization has the advantage over the conventional Ziegler-Nichols method.

Control of variable speed variable pitch wind turbine based on a disturbance observer

NASA Astrophysics Data System (ADS)

Ren, Haijun; Lei, Xin

2017-11-01

In this paper, a novel sliding mode controller based on disturbance observer (DOB) to optimize the efficiency of variable speed variable pitch (VSVP) wind turbine is developed and analyzed. Due to the highly nonlinearity of the VSVP system, the model is linearly processed to obtain the state space model of the system. Then, a conventional sliding mode controller is designed and a DOB is added to estimate wind speed. The proposed control strategy can successfully deal with the random nature of wind speed, the nonlinearity of VSVP system, the uncertainty of parameters and external disturbance. Via adding the observer to the sliding mode controller, it can greatly reduce the chattering produced by the sliding mode switching gain. The simulation results show that the proposed control system has the effectiveness and robustness.

Nonlinear engine model for idle speed control

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

Livshiz, M.; Sanvido, D.J.; Stiles, S.D.

1994-12-31

This paper describes a nonlinear model of an engine used for the design of idle speed control and prediction in a broad range of idle speeds and operational conditions. Idle speed control systems make use of both spark advance and the idle air actuator to control engine speed for improved response relative to variations in the target idle speed due to load disturbances. The control system at idle can be presented by a multiple input multiple output (MIMO) nonlinear model. Information of nonlinearities helps to improve performance of the system over the whole range of engine speeds. A proposed simplemore » nonlinear model of the engine at idle was applied for design of optimal controllers and predictors for improved steady state, load rejection and transition from and to idle. This paper describes vehicle results of engine speed prediction based on the described model.« less

Commercial motor vehicle speed control devices

DOT National Transportation Integrated Search

This report reviews the problem of heavy vehicle speeding (in particular, speeding at greater than 65 mph) : and speeding-related crash involvements. The report describes and assesses devices available to control : truck speed, and addresses the ques...

Neural control and modulation of swimming speed in the larval zebrafish

PubMed Central

Marques, João C.; O'Malley, Donald M.; Orger, Michael B.; Engert, Florian

2014-01-01

Summary Vertebrate locomotion at different speeds is driven by descending excitatory connections to central pattern generators in the spinal cord. To investigate how these inputs determine locomotor kinematics, we used whole-field visual motion to drive zebrafish to swim at different speeds. Larvae match the stimulus speed by utilizing more locomotor events, or modifying kinematic parameters such as the duration and speed of swimming bouts, the tail-beat frequency, and choice of gait. We used laser ablations, electrical stimulation, and activity recordings in descending neurons of the nucleus of the medial longitudinal fasciculus (nMLF) to dissect their contribution to controlling forward movement. We found that the activity of single identified neurons within the nMLF is correlated with locomotor kinematics, and modulates both the duration and oscillation frequency of tail movements. By identifying the contribution of individual supraspinal circuit elements to locomotion kinematics we build a better understanding of how the brain controls movement. PMID:25066084

Neural control and modulation of swimming speed in the larval zebrafish.

PubMed

Severi, Kristen E; Portugues, Ruben; Marques, João C; O'Malley, Donald M; Orger, Michael B; Engert, Florian

2014-08-06

Vertebrate locomotion at different speeds is driven by descending excitatory connections to central pattern generators in the spinal cord. To investigate how these inputs determine locomotor kinematics, we used whole-field visual motion to drive zebrafish to swim at different speeds. Larvae match the stimulus speed by utilizing more locomotor events, or modifying kinematic parameters such as the duration and speed of swimming bouts, the tail-beat frequency, and the choice of gait. We used laser ablations, electrical stimulation, and activity recordings in descending neurons of the nucleus of the medial longitudinal fasciculus (nMLF) to dissect their contribution to controlling forward movement. We found that the activity of single identified neurons within the nMLF is correlated with locomotor kinematics, and modulates both the duration and oscillation frequency of tail movements. By identifying the contribution of individual supraspinal circuit elements to locomotion kinematics, we build a better understanding of how the brain controls movement. Copyright © 2014 Elsevier Inc. All rights reserved.

Speed control for synchronous motors

NASA Technical Reports Server (NTRS)

Packard, H.; Schott, J.

1981-01-01

Feedback circuit controls fluctuations in speed of synchronous ac motor. Voltage proportional to phase angle is developed by phase detector, rectified, amplified, compared to threshold, and reapplied positively or negatively to motor excitation circuit. Speed control reduces wow and flutter of audio turntables and tape recorders, and enhances hunting in gyroscope motors.

Universal Parameter Measurement and Sensorless Vector Control of Induction and Permanent Magnet Synchronous Motors

NASA Astrophysics Data System (ADS)

Yamamoto, Shu; Ara, Takahiro

Recently, induction motors (IMs) and permanent-magnet synchronous motors (PMSMs) have been used in various industrial drive systems. The features of the hardware device used for controlling the adjustable-speed drive in these motors are almost identical. Despite this, different techniques are generally used for parameter measurement and speed-sensorless control of these motors. If the same technique can be used for parameter measurement and sensorless control, a highly versatile adjustable-speed-drive system can be realized. In this paper, the authors describe a new universal sensorless control technique for both IMs and PMSMs (including salient pole and nonsalient pole machines). A mathematical model applicable for IMs and PMSMs is discussed. Using this model, the authors derive the proposed universal sensorless vector control algorithm on the basis of estimation of the stator flux linkage vector. All the electrical motor parameters are determined by a unified test procedure. The proposed method is implemented on three test machines. The actual driving test results demonstrate the validity of the proposed method.

14 CFR 23.1513 - Minimum control speed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 23.1513 Section 23.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1513 Minimum control speed. The minimum control speed V MC, determined under § 23.149, must...

14 CFR 23.1513 - Minimum control speed.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Minimum control speed. 23.1513 Section 23.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1513 Minimum control speed. The minimum control speed V MC, determined under § 23.149, must...

Variable current speed controller for eddy current motors

DOEpatents

Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.

1982-03-12

A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

14 CFR 25.373 - Speed control devices.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Speed control devices. 25.373 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are installed for use in en route...

14 CFR 25.373 - Speed control devices.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Speed control devices. 25.373 Section 25... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Supplementary Conditions § 25.373 Speed control devices. If speed control devices (such as spoilers and drag flaps) are installed for use in en route...

14 CFR 25.1513 - Minimum control speed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 25.1513 Section 25.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1513 Minimum control speed. The minimum control speed V MC determined under § 25.149 must be...

14 CFR 25.1513 - Minimum control speed.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Minimum control speed. 25.1513 Section 25.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1513 Minimum control speed. The minimum control speed V MC determined under § 25.149 must be...

Innovation Analysis Approach to Design Parameters of High Speed Train Carriage and Their Intrinsic Complexity Relationships

NASA Astrophysics Data System (ADS)

Xiao, Shou-Ne; Wang, Ming-Meng; Hu, Guang-Zhong; Yang, Guang-Wu

2017-09-01

In view of the problem that it's difficult to accurately grasp the influence range and transmission path of the vehicle top design requirements on the underlying design parameters. Applying directed-weighted complex network to product parameter model is an important method that can clarify the relationships between product parameters and establish the top-down design of a product. The relationships of the product parameters of each node are calculated via a simple path searching algorithm, and the main design parameters are extracted by analysis and comparison. A uniform definition of the index formula for out-in degree can be provided based on the analysis of out-in-degree width and depth and control strength of train carriage body parameters. Vehicle gauge, axle load, crosswind and other parameters with higher values of the out-degree index are the most important boundary conditions; the most considerable performance indices are the parameters that have higher values of the out-in-degree index including torsional stiffness, maximum testing speed, service life of the vehicle, and so on; the main design parameters contain train carriage body weight, train weight per extended metre, train height and other parameters with higher values of the in-degree index. The network not only provides theoretical guidance for exploring the relationship of design parameters, but also further enriches the application of forward design method to high-speed trains.

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.

A wind-tunnel investigation of parameters affecting helicopter directional control at low speeds in ground effect

NASA Technical Reports Server (NTRS)

Yeager, W. T., Jr.; Young, W. H., Jr.; Mantay, W. R.

1974-01-01

An investigation was conducted in the Langley full-scale tunnel to measure the performance of several helicopter tail-rotor/fin configurations with regard to directional control problems encountered at low speeds in ground effect. Tests were conducted at wind azimuths of 0 deg to 360 deg in increments of 30 deg and 60 deg and at wind speeds from 0 to 35 knots. The results indicate that at certain combinations of wind speed and wind azimuth, large increases in adverse fin force require correspondingly large increases in the tail-rotor thrust, collective pitch, and power required to maintain yaw trim. Changing the tail-rotor direction of rotation to top blade aft for either a pusher tail rotor (tail-rotor wake blowing away from fin) or a tractor tail rotor (tail-rotor wake blowing against fin) will alleviate this problem. For a pusher tail rotor at 180 deg wind azimuth, increases in the fin/tail-rotor gap were not found to have any significant influence on the overall vehicle directional control capability. Changing the tail rotor to a higher position was found to improve tail-rotor performance for a fin-off configuration at a wind azimuth of 180 deg. A V-tail configuration with a pusher tail rotor with top blade aft direction of rotation was found to be the best configuration with regard to overall directional control capability.

Linear parameter varying representations for nonlinear control design

NASA Astrophysics Data System (ADS)

Carter, Lance Huntington

Linear parameter varying (LPV) systems are investigated as a framework for gain-scheduled control design and optimal hybrid control. An LPV system is defined as a linear system whose dynamics depend upon an a priori unknown but measurable exogenous parameter. A gain-scheduled autopilot design is presented for a bank-to-turn (BTT) missile. The method is novel in that the gain-scheduled design does not involve linearizations about operating points. Instead, the missile dynamics are brought to LPV form via a state transformation. This idea is applied to the design of a coupled longitudinal/lateral BTT missile autopilot. The pitch and yaw/roll dynamics are separately transformed to LPV form, where the cross axis states are treated as "exogenous" parameters. These are actually endogenous variables, so such a plant is called "quasi-LPV." Once in quasi-LPV form, a family of robust controllers using mu synthesis is designed for both the pitch and yaw/roll channels, using angle-of-attack and roll rate as the scheduling variables. The closed-loop time response is simulated using the original nonlinear model and also using perturbed aerodynamic coefficients. Modeling and control of engine idle speed is investigated using LPV methods. It is shown how generalized discrete nonlinear systems may be transformed into quasi-LPV form. A discrete nonlinear engine model is developed and expressed in quasi-LPV form with engine speed as the scheduling variable. An example control design is presented using linear quadratic methods. Simulations are shown comparing the LPV based controller performance to that using PID control. LPV representations are also shown to provide a setting for hybrid systems. A hybrid system is characterized by control inputs consisting of both analog signals and discrete actions. A solution is derived for the optimal control of hybrid systems with generalized cost functions. This is shown to be computationally intensive, so a suboptimal strategy is proposed that

Preliminary Experiments with a Unified Controller for a Powered Knee-Ankle Prosthetic Leg Across Walking Speeds

PubMed Central

Villarreal, Dario J.; Gregg, Robert D.

2016-01-01

This paper presents the experimental validation of a novel control strategy that unifies the entire gait cycle of a powered knee-ankle prosthetic leg without the need to switch between controllers for different periods of gait. Current control methods divide the gait cycle into several sequential periods each with independent controllers, resulting in many patient-specific control parameters and switching rules that must be tuned for a specific walking speed. The single controller presented is speed-invariant with a minimal number of control parameters to be tuned. A single, periodic virtual constraint is derived that exactly characterizes the desired actuated joint motion as a function of a mechanical phase variable across walking cycles. A single sensor was used to compute a phase variable related to the residual thigh angle’s phase plane, which was recently shown to robustly represent the phase of non-steady human gait. This phase variable allows the prosthesis to synchronize naturally with the human user for intuitive, biomimetic behavior. A custom powered knee-ankle prosthesis was designed and built to implement the control strategy and validate its performance. A human subject experiment was conducted across multiple walking speeds (1 to 3 miles/hour) in a continuous sequence with the single phase-based controller, demonstrating its adaptability to the user’s intended speed. PMID:28392969

Treadmill based reference running data for healthy subjects is dependent on speed and morphological parameters.

PubMed

Schulze, Stephan; Schwesig, René; Edel, Melanie; Fieseler, Georg; Delank, Karl-Stefan; Hermassi, Souhail; Laudner, Kevin G

2017-10-01

To obtain spatiotemporal and dynamic running parameters of healthy participants and to identify relationships between running parameters, speed, and physical characteristics. A dynamometric treadmill was used to collect running data among 417 asymptomatic subjects during speeds ranging from 10 to 24km/h. Spatiotemporal and dynamic running parameters were calculated and measured. Results of the analyses showed that assessing running parameters is dependent on running speed. Body height correlated with stride length (r=0.5), cadence (r=-0.5) and plantar forefoot force (r=0.6). Body mass also had a strong relationship to plantar forefoot forces at 14 and 24km/h and plantar midfoot forces at 14 and 24km/h. This reference data base can be used in the kinematic and kinetic evaluation of running under a wide range of speeds. Copyright © 2017 Elsevier B.V. All rights reserved.

Variable speed controller

NASA Technical Reports Server (NTRS)

Estes, Christa; Spiggle, Charles; Swift, Shannon; Vangeffen, Stephen; Younger, Frank

1992-01-01

This report details a new design for a variable speed controller which can be used to operate lunar machinery without the astronaut using his or her upper body. In order to demonstrate the design, a treadle for an industrial sewing machine was redesigned to be used by a standing operator. Since the invention of an electrically powered sewing machine, the operator has been seated. Today, companies are switching from sit down to stand up operation involving modular stations. The old treadle worked well with a sitting operator, but problems have been found when trying to use the same treadle with a standing operator. Emphasis is placed on the ease of use by the operator along with the ergonomics involved. Included with the design analysis are suggestions for possible uses for the speed controller in other applications.

Embodied linearity of speed control in Drosophila melanogaster.

PubMed

Medici, V; Fry, S N

2012-12-07

Fruitflies regulate flight speed by adjusting their body angle. To understand how low-level posture control serves an overall linear visual speed control strategy, we visually induced free-flight acceleration responses in a wind tunnel and measured the body kinematics using high-speed videography. Subsequently, we reverse engineered the transfer function mapping body pitch angle onto flight speed. A linear model is able to reproduce the behavioural data with good accuracy. Our results show that linearity in speed control is realized already at the level of body posture-mediated speed control and is therefore embodied at the level of the complex aerodynamic mechanisms of body and wings. Together with previous results, this study reveals the existence of a linear hierarchical control strategy, which can provide relevant control principles for biomimetic implementations, such as autonomous flying micro air vehicles.

Embodied linearity of speed control in Drosophila melanogaster

PubMed Central

Medici, V.; Fry, S. N.

2012-01-01

Fruitflies regulate flight speed by adjusting their body angle. To understand how low-level posture control serves an overall linear visual speed control strategy, we visually induced free-flight acceleration responses in a wind tunnel and measured the body kinematics using high-speed videography. Subsequently, we reverse engineered the transfer function mapping body pitch angle onto flight speed. A linear model is able to reproduce the behavioural data with good accuracy. Our results show that linearity in speed control is realized already at the level of body posture-mediated speed control and is therefore embodied at the level of the complex aerodynamic mechanisms of body and wings. Together with previous results, this study reveals the existence of a linear hierarchical control strategy, which can provide relevant control principles for biomimetic implementations, such as autonomous flying micro air vehicles. PMID:22933185

High-speed monodisperse droplet generation by ultrasonically controlled micro-jet breakup

NASA Astrophysics Data System (ADS)

Frommhold, Philipp Erhard; Lippert, Alexander; Holsteyns, Frank Ludwig; Mettin, Robert

2014-04-01

A liquid jet that is ejected from a nozzle into air will disintegrate into drops via the well-known Plateau-Rayleigh instability within a certain range of Ohnesorge and Reynolds numbers. With the focus on the micrometer scale, we investigate the control of this process by superimposing a suitable ultrasonic signal, which causes the jet to break up into a very precise train of monodisperse droplets. The jet leaves a pressurized container of liquid via a small orifice of about 20 μm diameter. The break-up process and the emerging droplets are recorded via high-speed imaging. An extended parameter study of exit speed and ultrasonic frequency is carried out for deionized water to evaluate the jet's state and the subsequent generation of monodisperse droplets. Maximum exit velocities obtained reach almost 120 m s-1, and frequencies have been applied up to 1.8 MHz. Functionality of the method is confirmed for five additional liquids for moderate jet velocities 38 m s-1. For the uncontrolled jet disintegration, the drop size spectra revealed broad distributions and downstream drop growth by collision, while the acoustic control generated monodisperse droplets with a standard deviation less than 0.5 %. By adjustment of the acoustic excitation frequency, drop diameters could be tuned continuously from about 30 to 50 μm for all exit speeds. Good agreement to former experiments and theoretical approaches is found for the relation of overpressure and jet exit speed, and for the observed stability regions of monodisperse droplet generation in the parameter plane of jet speed and acoustic excitation frequency. Fitting of two free parameters of the general theory to the liquids and nozzles used is found to yield an even higher precision. Furthermore, the high-velocity instability limit of regular jet breakup described by von Ohnesorge has been superseded by more than a factor of two without entering the wind-induced instability regime, and monodisperse droplet generation was

Engine control system having speed-based timing

DOEpatents

Willi, Martin L [Dunlap, IL; Fiveland, Scott B [Metamora, IL; Montgomery, David T [Edelstein, IL; Gong, Weidong [Dunlap, IL

2012-02-14

A control system for an engine having a cylinder is disclosed having an engine valve movable to regulate a fluid flow of the cylinder and an actuator associated with the engine valve. The control system also has a controller in communication with the actuator. The controller is configured to receive a signal indicative of engine speed and compare the engine speed signal with a desired engine speed. The controller is also configured to selectively regulate the actuator to adjust a timing of the engine valve to control an amount of air/fuel mixture delivered to the cylinder based on the comparison.

14 CFR 23.149 - Minimum control speed.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Minimum control speed. 23.149 Section 23... Maneuverability § 23.149 Minimum control speed. (a) VMC is the calibrated airspeed at which, when the critical... still inoperative, and thereafter maintain straight flight at the same speed with an angle of bank of...

14 CFR 23.149 - Minimum control speed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 23.149 Section 23... Maneuverability § 23.149 Minimum control speed. (a) VMC is the calibrated airspeed at which, when the critical... still inoperative, and thereafter maintain straight flight at the same speed with an angle of bank of...

Wheel speed management control system for spacecraft

NASA Technical Reports Server (NTRS)

Goodzeit, Neil E. (Inventor); Linder, David M. (Inventor)

1991-01-01

A spacecraft attitude control system uses at least four reaction wheels. In order to minimize reaction wheel speed and therefore power, a wheel speed management system is provided. The management system monitors the wheel speeds and generates a wheel speed error vector. The error vector is integrated, and the error vector and its integral are combined to form a correction vector. The correction vector is summed with the attitude control torque command signals for driving the reaction wheels.

Digital phase-locked-loop speed sensor for accuracy improvement in analog speed controls. [feedback control and integrated circuits

NASA Technical Reports Server (NTRS)

Birchenough, A. G.

1975-01-01

A digital speed control that can be combined with a proportional analog controller is described. The stability and transient response of the analog controller were retained and combined with the long-term accuracy of a crystal-controlled integral controller. A relatively simple circuit was developed by using phase-locked-loop techniques and total error storage. The integral digital controller will maintain speed control accuracy equal to that of the crystal reference oscillator.

21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class II...

21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class II...

Behavioural system identification of visual flight speed control in Drosophila melanogaster

PubMed Central

Rohrseitz, Nicola; Fry, Steven N.

2011-01-01

Behavioural control in many animals involves complex mechanisms with intricate sensory-motor feedback loops. Modelling allows functional aspects to be captured without relying on a description of the underlying complex, and often unknown, mechanisms. A wide range of engineering techniques are available for modelling, but their ability to describe time-continuous processes is rarely exploited to describe sensory-motor control mechanisms in biological systems. We performed a system identification of visual flight speed control in the fruitfly Drosophila, based on an extensive dataset of open-loop responses previously measured under free flight conditions. We identified a second-order under-damped control model with just six free parameters that well describes both the transient and steady-state characteristics of the open-loop data. We then used the identified control model to predict flight speed responses after a visual perturbation under closed-loop conditions and validated the model with behavioural measurements performed in free-flying flies under the same closed-loop conditions. Our system identification of the fruitfly's flight speed response uncovers the high-level control strategy of a fundamental flight control reflex without depending on assumptions about the underlying physiological mechanisms. The results are relevant for future investigations of the underlying neuromotor processing mechanisms, as well as for the design of biomimetic robots, such as micro-air vehicles. PMID:20525744

Behavioural system identification of visual flight speed control in Drosophila melanogaster.

PubMed

Rohrseitz, Nicola; Fry, Steven N

2011-02-06

Behavioural control in many animals involves complex mechanisms with intricate sensory-motor feedback loops. Modelling allows functional aspects to be captured without relying on a description of the underlying complex, and often unknown, mechanisms. A wide range of engineering techniques are available for modelling, but their ability to describe time-continuous processes is rarely exploited to describe sensory-motor control mechanisms in biological systems. We performed a system identification of visual flight speed control in the fruitfly Drosophila, based on an extensive dataset of open-loop responses previously measured under free flight conditions. We identified a second-order under-damped control model with just six free parameters that well describes both the transient and steady-state characteristics of the open-loop data. We then used the identified control model to predict flight speed responses after a visual perturbation under closed-loop conditions and validated the model with behavioural measurements performed in free-flying flies under the same closed-loop conditions. Our system identification of the fruitfly's flight speed response uncovers the high-level control strategy of a fundamental flight control reflex without depending on assumptions about the underlying physiological mechanisms. The results are relevant for future investigations of the underlying neuromotor processing mechanisms, as well as for the design of biomimetic robots, such as micro-air vehicles.

Design of permanent magnet synchronous motor speed loop controller based on sliding mode control algorithm

NASA Astrophysics Data System (ADS)

Qiang, Jiang; Meng-wei, Liao; Ming-jie, Luo

2018-03-01

Abstract.The control performance of Permanent Magnet Synchronous Motor will be affected by the fluctuation or changes of mechanical parameters when PMSM is applied as driving motor in actual electric vehicle,and external disturbance would influence control robustness.To improve control dynamic quality and robustness of PMSM speed control system, a new second order integral sliding mode control algorithm is introduced into PMSM vector control.The simulation results show that, compared with the traditional PID control,the modified control scheme optimized has better control precision and dynamic response ability and perform better with a stronger robustness facing external disturbance,it can effectively solve the traditional sliding mode variable structure control chattering problems as well.

Idling speed control system of an internal combustion engine

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

Miyazaki, M.; Ishii, M.; Kako, H.

1986-09-16

This patent describes an idling speed control system of an internal combustion engine comprising: a valve device which controls the amount of intake air for the engine; an actuator which includes an electric motor for variably controlling the opening of the value device; rotation speed detector means for detecting the rotation speed of the engine; idling condition detector means for detecting the idling condition of the engine; feedback control means responsive to the detected output of the idling condition detector means for generating feedback control pulses to intermittently drive the electric motor so that the detected rotation speed of themore » engine under the idling condition may converge into a target idling rotation speed; and control means responsive to the output of detector means that detects an abnormally low rotation speed of the engine detected by the rotation speed detector means for generating control pulses that do not overlap the feedback control pulses to drive the electric motor in a predetermined direction.« less

Low speed phaselock speed control system. [for brushless dc motor

NASA Technical Reports Server (NTRS)

Fulcher, R. W.; Sudey, J. (Inventor)

1975-01-01

A motor speed control system for an electronically commutated brushless dc motor is provided which includes a phaselock loop with bidirectional torque control for locking the frequency output of a high density encoder, responsive to actual speed conditions, to a reference frequency signal, corresponding to the desired speed. The system includes a phase comparator, which produces an output in accordance with the difference in phase between the reference and encoder frequency signals, and an integrator-digital-to-analog converter unit, which converts the comparator output into an analog error signal voltage. Compensation circuitry, including a biasing means, is provided to convert the analog error signal voltage to a bidirectional error signal voltage which is utilized by an absolute value amplifier, rotational decoder, power amplifier-commutators, and an arrangement of commutation circuitry.

Automated section speed control on motorways: an evaluation of the effect on driving speed.

PubMed

De Pauw, Ellen; Daniels, Stijn; Brijs, Tom; Hermans, Elke; Wets, Geert

2014-12-01

Automated section speed control is a fairly new traffic safety measure that is increasingly applied to enforce speed limits. The advantage of this enforcement system is the registration of the average speed at an entire section, which would lead to high speed limit compliances and subsequently to a reduction in the vehicle speed variability, increased headway, more homogenised traffic flow and increased traffic capacity. However, the number of studies that analysed these effects are limited. The present study evaluates the speed effect of two section speed control systems in Flanders, Belgium. Both sections are located in the opposite direction of a three-lane motorway with a posted speed limit of 120 km/h. Speed data were collected at different points: from 6 km before the entrance of the section to 6 km downstream from the section. The effect was analysed through a before- and after comparison of travel speeds. General time trends and fluctuations were controlled through the analysis of speeds at comparison locations. On the enforced sections considerable decreases were found of about 5.84 km/h in the average speed, 74% in the odds of drivers exceeding the speed limit and 86% in the odds of drivers exceeding the speed limit by more than 10%. At the locations up- and downstream from the section also favourable effects were found for the three outcomes. Furthermore a decrease in the speed variability could be observed at all these data points. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fuzzy – PI controller to control the velocity parameter of Induction Motor

NASA Astrophysics Data System (ADS)

Malathy, R.; Balaji, V.

2018-04-01

The major application of Induction motor includes the usage of the same in industries because of its high robustness, reliability, low cost, highefficiency and good self-starting capability. Even though it has the above mentioned advantages, it also have some limitations: (1) the standard motor is not a true constant-speed machine, itsfull-load slip varies less than 1 % (in high-horsepower motors).And (2) it is not inherently capable of providing variable-speedoperation. In order to solve the above mentioned problem smart motor controls and variable speed controllers are used. Motor applications involve non linearity features, which can be controlled by Fuzzy logic controller as it is capable of handling those features with high efficiency and it act similar to human operator. This paper presents individuality of the plant modelling. The fuzzy logic controller (FLC)trusts on a set of linguistic if-then rules, a rule-based Mamdani for closed loop Induction Motor model. Themotor model is designed and membership functions are chosenaccording to the parameters of the motor model. Simulation results contains non linearity in induction motor model. A conventional PI controller iscompared practically to fuzzy logic controller using Simulink.

Nonlinear adaptive control system design with asymptotically stable parameter estimation error

NASA Astrophysics Data System (ADS)

Mishkov, Rumen; Darmonski, Stanislav

2018-01-01

The paper presents a new general method for nonlinear adaptive system design with asymptotic stability of the parameter estimation error. The advantages of the approach include asymptotic unknown parameter estimation without persistent excitation and capability to directly control the estimates transient response time. The method proposed modifies the basic parameter estimation dynamics designed via a known nonlinear adaptive control approach. The modification is based on the generalised prediction error, a priori constraints with a hierarchical parameter projection algorithm, and the stable data accumulation concepts. The data accumulation principle is the main tool for achieving asymptotic unknown parameter estimation. It relies on the parametric identifiability system property introduced. Necessary and sufficient conditions for exponential stability of the data accumulation dynamics are derived. The approach is applied in a nonlinear adaptive speed tracking vector control of a three-phase induction motor.

14 CFR 23.149 - Minimum control speed.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Minimum control speed. 23.149 Section 23... Maneuverability § 23.149 Minimum control speed. (a) VMC is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine...

14 CFR 25.1149 - Propeller speed and pitch controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and... synchronization of all propellers. (d) The propeller speed and pitch controls must be to the right of, and at...

14 CFR 25.1149 - Propeller speed and pitch controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and... synchronization of all propellers. (d) The propeller speed and pitch controls must be to the right of, and at...

14 CFR 23.1149 - Propeller speed and pitch controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller speed or pitch controls, they must be grouped and arranged to allow— (1) Separate control of each...

14 CFR 23.1149 - Propeller speed and pitch controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller speed or pitch controls, they must be grouped and arranged to allow— (1) Separate control of each...

14 CFR 25.1149 - Propeller speed and pitch controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and pitch control for each propeller. (b) The controls must be grouped and arranged to allow— (1) Separate...

14 CFR 25.1149 - Propeller speed and pitch controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and pitch control for each propeller. (b) The controls must be grouped and arranged to allow— (1) Separate...

14 CFR 25.1149 - Propeller speed and pitch controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller speed and pitch controls. 25.1149... Accessories § 25.1149 Propeller speed and pitch controls. (a) There must be a separate propeller speed and pitch control for each propeller. (b) The controls must be grouped and arranged to allow— (1) Separate...

49 CFR 236.501 - Forestalling device and speed control.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Forestalling device and speed control. 236.501... Train Stop, Train Control and Cab Signal Systems Standards § 236.501 Forestalling device and speed... the following features: (1) Low-speed restriction, requiring the train to proceed under slow speed...

49 CFR 236.501 - Forestalling device and speed control.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Forestalling device and speed control. 236.501... Train Stop, Train Control and Cab Signal Systems Standards § 236.501 Forestalling device and speed... the following features: (1) Low-speed restriction, requiring the train to proceed under slow speed...

A Mathematical Model of Marine Diesel Engine Speed Control System

NASA Astrophysics Data System (ADS)

Sinha, Rajendra Prasad; Balaji, Rajoo

2018-02-01

Diesel engine is inherently an unstable machine and requires a reliable control system to regulate its speed for safe and efficient operation. Also, the diesel engine may operate at fixed or variable speeds depending upon user's needs and accordingly the speed control system should have essential features to fulfil these requirements. This paper proposes a mathematical model of a marine diesel engine speed control system with droop governing function. The mathematical model includes static and dynamic characteristics of the control loop components. Model of static characteristic of the rotating fly weights speed sensing element provides an insight into the speed droop features of the speed controller. Because of big size and large time delay, the turbo charged diesel engine is represented as a first order system or sometimes even simplified to a pure integrator with constant gain which is considered acceptable in control literature. The proposed model is mathematically less complex and quick to use for preliminary analysis of the diesel engine speed controller performance.

Quadrupedal galloping control for a wide range of speed via vertical impulse scaling.

PubMed

Park, Hae-Won; Kim, Sangbae

2015-03-25

This paper presents a bio-inspired quadruped controller that allows variable-speed galloping. The controller design is inspired by observations from biological runners. Quadrupedal animals increase the vertical impulse that is generated by ground reaction forces at each stride as running speed increases and the duration of each stance phase reduces, whereas the swing phase stays relatively constant. Inspired by this observation, the presented controller estimates the required vertical impulse at each stride by applying the linear momentum conservation principle in the vertical direction and prescribes the ground reaction forces at each stride. The design process begins with deriving a planar model from the MIT Cheetah 2 robot. A baseline periodic limit cycle is obtained by optimizing ground reaction force profiles and the temporal gait pattern (timing and duration of gait phases). To stabilize the optimized limit cycle, the obtained limit cycle is converted to a state feedback controller by representing the obtained ground reaction force profiles as functions of the state variable, which is monotonically increasing throughout the gait, adding impedance control around the height and pitch trajectories of the obtained limit cycle and introducing a finite state machine and a pattern stabilizer to enforce the optimized gait pattern. The controller that achieves a stable 3 m s(-1) gallop successfully adapts the speed change by scaling the vertical ground reaction force to match the momentum lost by gravity and adding a simple speed controller that controls horizontal speed. Without requiring additional gait optimization processes, the controller achieves galloping at speeds ranging from 3 m s(-1) to 14.9 m s(-1) while respecting the torque limit of the motor used in the MIT Cheetah 2 robot. The robustness of the controller is verified by demonstrating stable running during various disturbances, including 1.49 m step down and 0.18 m step up, as well as random ground

A novel robust speed controller scheme for PMBLDC motor.

PubMed

Thirusakthimurugan, P; Dananjayan, P

2007-10-01

The design of speed and position controllers for permanent magnet brushless DC motor (PMBLDC) drive remains as an open problem in the field of motor drives. A precise speed control of PMBLDC motor is complex due to nonlinear coupling between winding currents and rotor speed. In addition, the nonlinearity present in the developed torque due to magnetic saturation of the rotor further complicates this issue. This paper presents a novel control scheme to the conventional PMBLDC motor drive, which aims at improving the robustness by complete decoupling of the design besides minimizing the mutual influence among the speed and current control loops. The interesting feature of this robust control scheme is its suitability for both static and dynamic aspects. The effectiveness of the proposed robust speed control scheme is verified through simulations.

Implementation of Temperature Sequential Controller on Variable Speed Drive

NASA Astrophysics Data System (ADS)

Cheong, Z. X.; Barsoum, N. N.

2008-10-01

There are many pump and motor installations with quite extensive speed variation, such as Sago conveyor, heating, ventilation and air conditioning (HVAC) and water pumping system. A common solution for these applications is to run several fixed speed motors in parallel, with flow control accomplish by turning the motors on and off. This type of control method causes high in-rush current, and adds a risk of damage caused by pressure transients. This paper explains the design and implementation of a temperature speed control system for use in industrial and commercial sectors. Advanced temperature speed control can be achieved by using ABB ACS800 variable speed drive-direct torque sequential control macro, programmable logic controller and temperature transmitter. The principle of direct torque sequential control macro (DTC-SC) is based on the control of torque and flux utilizing the stator flux field orientation over seven preset constant speed. As a result of continuous comparison of ambient temperature to the references temperatures; electromagnetic torque response is particularly fast to the motor state and it is able maintain constant speeds. Experimental tests have been carried out by using ABB ACS800-U1-0003-2, to validate the effectiveness and dynamic respond of ABB ACS800 against temperature variation, loads, and mechanical shocks.

Using Simulation Speeds to Differentiate Controller Interface Concepts

NASA Technical Reports Server (NTRS)

Trujillo, Anna; Pope, Alan

2008-01-01

This study investigated two concepts: (1) whether speeding a human-in-the-loop simulation (or the subject's "world") scales time stress in such a way as to cause primary task performance to reveal workload differences between experimental conditions and (2) whether using natural hand motions to control the attitude of an aircraft makes controlling the aircraft easier and more intuitive. This was accomplished by having pilots and non-pilots make altitude and heading changes using three different control inceptors at three simulation speeds. Results indicate that simulation speed does affect workload and controllability. The bank and pitch angle error was affected by simulation speed but not by a simulation speed by controller type interaction; this may have been due to the relatively easy flying task. Results also indicate that pilots could control the bank and pitch angle of an aircraft about equally as well with the glove as with the sidestick. Non-pilots approached the pilots ability to control the bank and pitch angle of an aircraft using the positional glove - where the hand angle is directly proportional to the commanded aircraft angle. Therefore, (1) changing the simulation speed lends itself to objectively indexing a subject s workload and may also aid in differentiating among interface concepts based upon performance if the task being studied is sufficiently challenging and (2) using natural body movements to mimic the movement of an airplane for attitude control is feasible.

Design and control of a novel two-speed Uninterrupted Mechanical Transmission for electric vehicles

NASA Astrophysics Data System (ADS)

Fang, Shengnan; Song, Jian; Song, Haijun; Tai, Yuzhuo; Li, Fei; Sinh Nguyen, Truong

2016-06-01

Conventional all-electric vehicles (EV) adopt single-speed transmission due to its low cost and simple construction. However, with the adoption of this type of driveline system, development of EV technology leads to the growing performance requirements of drive motor. Introducing a multi-speed or two-speed transmission to EV offers the possibility of efficiency improvement of the whole powertrain. This paper presents an innovative two-speed Uninterrupted Mechanical Transmission (UMT), which consists of an epicyclic gearing system, a centrifugal clutch and a brake band, allowing the seamless shifting between two gears. Besides, driver's intention is recognized by the control system which is based on fuzzy logic controller (FLC), utilizing the signals of vehicle velocity and accelerator pedal position. The novel UMT shows better dynamic and comfort performance in compare with the optimized AMT with the same gear ratios. Comparison between the control strategy with recognition of driver intention and the conventional two-parameter gear shifting strategy is presented. And the simulation and analysis of the middle layer of optimal gearshift control algorithm is detailed. The results indicate that the UMT adopting FLC and optimal control method provides a significant improvement of energy efficiency, dynamic performance and shifting comfort for EV.

Speed isn’t everything: Complex processing speed measures mask individual differences and developmental changes in executive control

PubMed Central

Cepeda, Nicholas J.; Blackwell, Katharine A.; Munakata, Yuko

2012-01-01

The rate at which people process information appears to influence many aspects of cognition across the lifespan. However, many commonly accepted measures of “processing speed” may require goal maintenance, manipulation of information in working memory, and decision-making, blurring the distinction between processing speed and executive control and resulting in overestimation of processing-speed contributions to cognition. This concern may apply particularly to studies of developmental change, as even seemingly simple processing speed measures may require executive processes to keep children and older adults on task. We report two new studies and a re-analysis of a published study, testing predictions about how different processing speed measures influence conclusions about executive control across the life span. We find that the choice of processing speed measure affects the relationship observed between processing speed and executive control, in a manner that changes with age, and that choice of processing speed measure affects conclusions about development and the relationship among executive control measures. Implications for understanding processing speed, executive control, and their development are discussed. PMID:23432836

Direct Torque Control of a Small Wind Turbine with a Sliding-Mode Speed Controller

NASA Astrophysics Data System (ADS)

Sri Lal Senanayaka, Jagath; Karimi, Hamid Reza; Robbersmyr, Kjell G.

2016-09-01

In this paper. the method of direct torque control in the presence of a sliding-mode speed controller is proposed for a small wind turbine being used in water heating applications. This concept and control system design can be expanded to grid connected or off-grid applications. Direct torque control of electrical machines has shown several advantages including very fast dynamics torque control over field-oriented control. Moreover. the torque and flux controllers in the direct torque control algorithms are based on hvsteretic controllers which are nonlinear. In the presence of a sliding-mode speed control. a nonlinear control system can be constructed which is matched for AC/DC conversion of the converter that gives fast responses with low overshoots. The main control objectives of the proposed small wind turbine can be maximum power point tracking and soft-stall power control. This small wind turbine consists of permanent magnet synchronous generator and external wind speed. and rotor speed measurements are not required for the system. However. a sensor is needed to detect the rated wind speed overpass events to activate proper speed references for the wind turbine. Based on the low-cost design requirement of small wind turbines. an available wind speed sensor can be modified. or a new sensor can be designed to get the required measurement. The simulation results will be provided to illustrate the excellent performance of the closed-loop control system in entire wind speed range (4-25 m/s).

An Anaylsis of Control Requirements and Control Parameters for Direct-Coupled Turbojet Engines

NASA Technical Reports Server (NTRS)

Novik, David; Otto, Edward W.

1947-01-01

Requirements of an automatic engine control, as affected by engine characteristics, have been analyzed for a direct-coupled turbojet engine. Control parameters for various conditions of engine operation are discussed. A hypothetical engine control is presented to illustrate the use of these parameters. An adjustable speed governor was found to offer a desirable method of over-all engine control. The selection of a minimum value of fuel flow was found to offer a means of preventing unstable burner operation during steady-state operation. Until satisfactory high-temperature-measuring devices are developed, air-fuel ratio is considered to be a satisfactory acceleration-control parameter for the attainment of the maximum acceleration rates consistent with safe turbine temperatures. No danger of unstable burner operation exists during acceleration if a temperature-limiting acceleration control is assumed to be effective. Deceleration was found to be accompanied by the possibility of burner blow-out even if a minimum fuel-flow control that prevents burner blow-out during steady-state operation is assumed to be effective. Burner blow-out during deceleration may be eliminated by varying the value of minimum fuel flow as a function of compressor-discharge pressure, but in no case should the fuel flow be allowed to fall below the value required for steady-state burner operation.

Speed tracking control of pneumatic motor servo systems using observation-based adaptive dynamic sliding-mode control

NASA Astrophysics Data System (ADS)

Chen, Syuan-Yi; Gong, Sheng-Sian

2017-09-01

This study aims to develop an adaptive high-precision control system for controlling the speed of a vane-type air motor (VAM) pneumatic servo system. In practice, the rotor speed of a VAM depends on the input mass air flow, which can be controlled by the effective orifice area (EOA) of an electronic throttle valve (ETV). As the control variable of a second-order pneumatic system is the integral of the EOA, an observation-based adaptive dynamic sliding-mode control (ADSMC) system is proposed to derive the differential of the control variable, namely, the EOA control signal. In the ADSMC system, a proportional-integral-derivative fuzzy neural network (PIDFNN) observer is used to achieve an ideal dynamic sliding-mode control (DSMC), and a supervisor compensator is designed to eliminate the approximation error. As a result, the ADSMC incorporates the robustness of a DSMC and the online learning ability of a PIDFNN. To ensure the convergence of the tracking error, a Lyapunov-based analytical method is employed to obtain the adaptive algorithms required to tune the control parameters of the online ADSMC system. Finally, our experimental results demonstrate the precision and robustness of the ADSMC system for highly nonlinear and time-varying VAM pneumatic servo systems.

Measurement of whole-body vibration exposure from speed control humps

NASA Astrophysics Data System (ADS)

Khorshid, E.; Alkalby, F.; Kamal, H.

2007-07-01

The main objective of speed control humps is to introduce shocks and high vibration levels when a car passes over them if its speed is higher than the allowable limit. Hump geometry is a major factor in altering the level of these shocks and specifying the speed limit. However, there is no study of the relationship between whole body vibration due to passing over a speed control hump and lower back pain or occupational diseases. In this study, an experimental investigation is conducted to evaluate health risks associated with different geometry speed control humps. Vibration levels and shocks are measured by a seat pad accelerometer placed under the driver's seat to evaluate hazard risks on the human body's lower back. The assessment is based on two standard methods of measuring whole body vibration: the British standard BS 6841 and the new ISO/DIS standard 2631-5. These methods are used to assess the effects of vehicle type, passenger location in the vehicle, vehicle speed, and speed control hump geometry. It was found that circular speed control humps currently installed on many public roads should be modified in order to eliminate hazards. Two newly designed speed humps were proved to be less hazardous than circular speed control humps.

Speed control system for an access gate

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

Bzorgi, Fariborz M

2012-03-20

An access control apparatus for an access gate. The access gate typically has a rotator that is configured to rotate around a rotator axis at a first variable speed in a forward direction. The access control apparatus may include a transmission that typically has an input element that is operatively connected to the rotator. The input element is generally configured to rotate at an input speed that is proportional to the first variable speed. The transmission typically also has an output element that has an output speed that is higher than the input speed. The input element and the outputmore » element may rotate around a common transmission axis. A retardation mechanism may be employed. The retardation mechanism is typically configured to rotate around a retardation mechanism axis. Generally the retardation mechanism is operatively connected to the output element of the transmission and is configured to retard motion of the access gate in the forward direction when the first variable speed is above a control-limit speed. In many embodiments the transmission axis and the retardation mechanism axis are substantially co-axial. Some embodiments include a freewheel/catch mechanism that has an input connection that is operatively connected to the rotator. The input connection may be configured to engage an output connection when the rotator is rotated at the first variable speed in a forward direction and configured for substantially unrestricted rotation when the rotator is rotated in a reverse direction opposite the forward direction. The input element of the transmission is typically operatively connected to the output connection of the freewheel/catch mechanism.« less

The influence of cooling parameters on the speed of continuous steel casting

NASA Astrophysics Data System (ADS)

Tirian, G. O.; Gheorghiu, C. A.; Hepuţ, T.; Chioncel, C. P.

2018-01-01

This paper analyzes the cooling parameters of the continuous casting speed. In the researches carried out we aimed to establish some correlation equations between the parameters characterizing the continuous casting process, the temperature of the steel at the entrance to the crystallizer, the superheating of the steel and the flow of the cooling water in the crystallizer and different zones of the secondary cooling. Parallel to these parameters were also the values for the casting speed. The research was made for the casting of round ϕ270mm semi-finished steel products. The steel was developed in an electric EBT furnace with a capacity of 100t, treated in L.F. (Ladle - Furnace) and VD (Vacuum-Degassing) and poured in a 5-wire continuous casting plant. The obtained data was processed in MATLAB using three types of correlation equations. The obtained results are presented both in the analytical and graphical form, each correlation being analyzed from the technological point of view, indicating the optimal values for the independent parameters monitored. In the analysis we present a comparison between the results obtained after the three types of equations for each correlation.

High-Speed Photography with Computer Control.

ERIC Educational Resources Information Center

Winters, Loren M.

1991-01-01

Describes the use of a microcomputer as an intervalometer for the control and timing of several flash units to photograph high-speed events. Applies this technology to study the oscillations of a stretched rubber band, the deceleration of high-speed projectiles in water, the splashes of milk drops, and the bursts of popcorn kernels. (MDH)

Cavity parameters identification for TESLA control system development

NASA Astrophysics Data System (ADS)

Czarski, Tomasz; Pozniak, Krysztof T.; Romaniuk, Ryszard S.; Simrock, Stefan

2005-08-01

Aim of the control system development for TESLA cavity is a more efficient stabilization of the pulsed, accelerating EM field inside resonator. Cavity parameters identification is an essential task for the comprehensive control algorithm. TESLA cavity simulator has been successfully implemented using high-speed FPGA technology. Electromechanical model of the cavity resonator includes Lorentz force detuning and beam loading. The parameters identification is based on the electrical model of the cavity. The model is represented by state space equation for envelope of the cavity voltage driven by current generator and beam loading. For a given model structure, the over-determined matrix equation is created covering long enough measurement range with the solution according to the least-squares method. A low-degree polynomial approximation is applied to estimate the time-varying cavity detuning during the pulse. The measurement channel distortion is considered, leading to the external cavity model seen by the controller. The comprehensive algorithm of the cavity parameters identification was implemented in the Matlab system with different modes of operation. Some experimental results were presented for different cavity operational conditions. The following considerations have lead to the synthesis of the efficient algorithm for the cavity control system predicted for the potential FPGA technology implementation.

Fractional order PIλ controller synthesis for steam turbine speed governing systems.

PubMed

Chen, Kai; Tang, Rongnian; Li, Chuang; Lu, Junguo

2018-06-01

The current state of the art of fractional order stability theory is hardly to build connection between the time domain analysis and frequency domain synthesis. The existing tuning methodologies for fractional order PI λ D μ are not always satisfy the given gain crossover frequency and phase margin simultaneously. To overcome the drawbacks in the existing synthesis of fractional order controller, the synthesis of optimal fractional order PI λ controller for higher-order process is proposed. According to the specified phase margin, the corresponding upper boundary of gain crossover frequency and stability surface in parameter space are obtained. Sweeping the order parameter over λ∈(0,2), the complete set of stabilizing controller which guarantees both pre-specifying phase frequency characteristic can be collected. Whereafter, the optimal fractional order PI λ controller is applied to the speed governing systems of steam turbine generation units. The numerical simulation and hardware-in-the-loop simulation demonstrate the effectiveness and satisfactory closed-loop performance of obtained fractional order PI λ controller. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

14 CFR 23.1149 - Propeller speed and pitch controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller... propeller; and (2) Simultaneous control of all propellers. (b) The controls must allow ready synchronization...

14 CFR 23.1149 - Propeller speed and pitch controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller... propeller; and (2) Simultaneous control of all propellers. (b) The controls must allow ready synchronization...

14 CFR 23.1149 - Propeller speed and pitch controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Propeller speed and pitch controls. 23.1149... Powerplant Controls and Accessories § 23.1149 Propeller speed and pitch controls. (a) If there are propeller... propeller; and (2) Simultaneous control of all propellers. (b) The controls must allow ready synchronization...

Speeding in highway work zone: An Evaluation of methods of speed control.

PubMed

Ravani, Bahram; Wang, Chao

2018-04-01

Highway workers frequently work in close proximity of live traffic in highway work zones, traffic accidents therefore have devastating effects on worker safety. In order to reduce the potential for such accidents, methods involving use of advisory signs and police presence have been used to mitigate accident risks and improve safety for highway workers. This research evaluates the magnitude of the speeding problem in highway work zones and the effects of four levels of police presence on improving work zone safety. Speed data were collected in six different work zone locations in northern and southern California and used to determine the magnitude and nature of speeding problem in highway work zones. In addition data were collected over 11 test-days in four work zones with four levels of police presence: radar speed display with police decal and lighting, passive use of a police vehicle with radar speed display, passive use of a police vehicle without radar speed display, and active police speed enforcement near work zones. This paper analyzes this data using statistical methods to evaluate the effectiveness of these different methods of speed control on the safety of the work zone. Four Measures of Effectiveness (MOE) were used in this evaluation consisting of average speed reduction, speed variance, 85th percentile speed, and proportion of high speed vehicles. The results indicate that all levels of police presence provided statistically significant improvements in one or more of the MOEs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Type-2 fuzzy logic control based MRAS speed estimator for speed sensorless direct torque and flux control of an induction motor drive.

PubMed

Ramesh, Tejavathu; Kumar Panda, Anup; Shiva Kumar, S

2015-07-01

In this research study, a model reference adaptive system (MRAS) speed estimator for speed sensorless direct torque and flux control (DTFC) of an induction motor drive (IMD) using two adaptation mechanism schemes are proposed to replace the conventional proportional integral controller (PIC). The first adaptation mechanism scheme is based on Type-1 fuzzy logic controller (T1FLC), which is used to achieve high performance sensorless drive in both transient as well as steady state conditions. However, the Type-1 fuzzy sets are certain and unable to work effectively when higher degree of uncertainties presents in the system which can be caused by sudden change in speed or different load disturbances, process noise etc. Therefore, a new Type-2 fuzzy logic controller (T2FLC) based adaptation mechanism scheme is proposed to better handle the higher degree of uncertainties and improves the performance and also robust to various load torque and sudden change in speed conditions, respectively. The detailed performances of various adaptation mechanism schemes are carried out in a MATLAB/Simulink environment with a speed sensor and speed sensorless modes of operation when an IMD is operating under different operating conditions, such as, no-load, load and sudden change in speed, respectively. To validate the different control approaches, the system also implemented on real-time system and adequate results are reported for its validation. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Active control system for high speed windmills

DOEpatents

Avery, D.E.

1988-01-12

A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed. 4 figs.

Active control system for high speed windmills

DOEpatents

Avery, Don E.

1988-01-01

A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed.

Controllable High-Speed Rotation of Nanowires

NASA Astrophysics Data System (ADS)

Fan, D. L.; Zhu, F. Q.; Cammarata, R. C.; Chien, C. L.

2005-06-01

We report a versatile method for executing controllable high-speed rotation of nanowires by ac voltages applied to multiple electrodes. The rotation of the nanowires can be instantly switched on or off with precisely controlled rotation speed (to at least 1800 rpm), definite chirality, and total angle of rotation. We have determined the torque due to the fluidic drag force on nanowire of different lengths. We also demonstrate a micromotor using a rotating nanowire driving a dust particle into circular motion. This method has been used to rotate magnetic and nonmagnetic nanowires as well as carbon nanotubes.

Idle speed and fuel vapor recovery control system

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

Orzel, D.V.

1993-06-01

A method for controlling idling speed of an engine via bypass throttle connected in parallel to a primary engine throttle and for controlling purge flow through a vapor recovery system into an air/fuel intake of the engine is described, comprising the steps of: positioning the bypass throttle to decrease any difference between a desired engine idle speed and actual engine idle speed; and decreasing the purge flow when said bypass throttle position is less than a preselected fraction of a maximum bypass throttle position.

Hunting stability analysis of high-speed train bogie under the frame lateral vibration active control

NASA Astrophysics Data System (ADS)

Yao, Yuan; Wu, Guosong; Sardahi, Yousef; Sun, Jian-Qiao

2018-02-01

In this paper, we study a multi-objective optimal design of three different frame vibration control configurations and compare their performances in improving the lateral stability of a high-speed train bogie. The existence of the time-delay in the control system and its impact on the bogie hunting stability are also investigated. The continuous time approximation method is used to approximate the time-delay system dynamics and then the root locus curves of the system before and after applying control are depicted. The analysis results show that the three control cases could improve the bogie hunting stability effectively. But the root locus of low- frequency hunting mode of bogie which determinates the system critical speed is different, thus affecting the system stability with the increasing of speed. Based on the stability analysis at different bogie dynamics parameters, the robustness of the control case (1) is the strongest. However, the case (2) is more suitable for the dynamic performance requirements of bogie. For the case (1), the time-delay over 10 ms may lead to instability of the control system which will affect the bogie hunting stability seriously. For the case (2) and (3), the increasing time-delay reduces the hunting stability gradually over the high-speed range. At a certain speed, such as 200 km/h, an appropriate time-delay is favourable to the bogie hunting stability. The mechanism is proposed according to the root locus analysis of time-delay system. At last, the nonlinear bifurcation characteristics of the bogie control system are studied by the numerical integration methods to verify the effects of these active control configurations and the delay on the bogie hunting stability.

A Sequential Shifting Algorithm for Variable Rotor Speed Control

NASA Technical Reports Server (NTRS)

Litt, Jonathan S.; Edwards, Jason M.; DeCastro, Jonathan A.

2007-01-01

A proof of concept of a continuously variable rotor speed control methodology for rotorcraft is described. Variable rotor speed is desirable for several reasons including improved maneuverability, agility, and noise reduction. However, it has been difficult to implement because turboshaft engines are designed to operate within a narrow speed band, and a reliable drive train that can provide continuous power over a wide speed range does not exist. The new methodology proposed here is a sequential shifting control for twin-engine rotorcraft that coordinates the disengagement and engagement of the two turboshaft engines in such a way that the rotor speed may vary over a wide range, but the engines remain within their prescribed speed bands and provide continuous torque to the rotor; two multi-speed gearboxes facilitate the wide rotor speed variation. The shifting process begins when one engine slows down and disengages from the transmission by way of a standard freewheeling clutch mechanism; the other engine continues to apply torque to the rotor. Once one engine disengages, its gear shifts, the multi-speed gearbox output shaft speed resynchronizes and it re-engages. This process is then repeated with the other engine. By tailoring the sequential shifting, the rotor may perform large, rapid speed changes smoothly, as demonstrated in several examples. The emphasis of this effort is on the coordination and control aspects for proof of concept. The engines, rotor, and transmission are all simplified linear models, integrated to capture the basic dynamics of the problem.

Differential effects of absent visual feedback control on gait variability during different locomotion speeds.

PubMed

Wuehr, M; Schniepp, R; Pradhan, C; Ilmberger, J; Strupp, M; Brandt, T; Jahn, K

2013-01-01

Healthy persons exhibit relatively small temporal and spatial gait variability when walking unimpeded. In contrast, patients with a sensory deficit (e.g., polyneuropathy) show an increased gait variability that depends on speed and is associated with an increased fall risk. The purpose of this study was to investigate the role of vision in gait stabilization by determining the effects of withdrawing visual information (eyes closed) on gait variability at different locomotion speeds. Ten healthy subjects (32.2 ± 7.9 years, 5 women) walked on a treadmill for 5-min periods at their preferred walking speed and at 20, 40, 70, and 80 % of maximal walking speed during the conditions of walking with eyes open (EO) and with eyes closed (EC). The coefficient of variation (CV) and fractal dimension (α) of the fluctuations in stride time, stride length, and base width were computed and analyzed. Withdrawing visual information increased the base width CV for all walking velocities (p < 0.001). The effects of absent visual information on CV and α of stride time and stride length were most pronounced during slow locomotion (p < 0.001) and declined during fast walking speeds. The results indicate that visual feedback control is used to stabilize the medio-lateral (i.e., base width) gait parameters at all speed sections. In contrast, sensory feedback control in the fore-aft direction (i.e., stride time and stride length) depends on speed. Sensory feedback contributes most to fore-aft gait stabilization during slow locomotion, whereas passive biomechanical mechanisms and an automated central pattern generation appear to control fast locomotion.

Adaptive two-degree-of-freedom PI for speed control of permanent magnet synchronous motor based on fractional order GPC.

PubMed

Qiao, Wenjun; Tang, Xiaoqi; Zheng, Shiqi; Xie, Yuanlong; Song, Bao

2016-09-01

In this paper, an adaptive two-degree-of-freedom (2Dof) proportional-integral (PI) controller is proposed for the speed control of permanent magnet synchronous motor (PMSM). Firstly, an enhanced just-in-time learning technique consisting of two novel searching engines is presented to identify the model of the speed control system in a real-time manner. Secondly, a general formula is given to predict the future speed reference which is unavailable at the interval of two bus-communication cycles. Thirdly, the fractional order generalized predictive control (FOGPC) is introduced to improve the control performance of the servo drive system. Based on the identified model parameters and predicted speed reference, the optimal control law of FOGPC is derived. Finally, the designed 2Dof PI controller is auto-tuned by matching with the optimal control law. Simulations and real-time experimental results on the servo drive system of PMSM are provided to illustrate the effectiveness of the proposed strategy. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Simulation of parameters of hydraulic drive with volumetric type controller

NASA Astrophysics Data System (ADS)

Mulyukin, V. L.; Boldyrev, A. V.; Karelin, D. L.; Belousov, A. M.

2017-09-01

The article presents a mathematical model of volumetric type hydraulic drive controller that allows to calculate the parameters of forward and reverse motion. According to the results of simulation static characteristics of rod’s speed and the force of the hydraulic cylinder rod were built and the influence of the angle of swash plate of the controller at the characteristics profile is shown. The results analysis showed that the proposed controller allows steplessly adjust the speed□ц of hydraulic cylinder’s rod motion and the force developed on the rod without the use of flow throttling.

Speed limiter integrated fatigue analyzer (SLIFA) for speed and fatigue control on diesel engine truck and bus

NASA Astrophysics Data System (ADS)

Wahyudi, Haris; Pranoto, Hadi; Leman, A. M.; Sebayang, Darwin; Baba, I.

2017-09-01

Every second, the number of road traffic deaths is increased globally with millions more sustaining severe injuries and living with long-term adverse health consequences. Jakarta alone in year 2015 had recorded 556 people died due to road accidents, approximately reached 6.231 road accident cases. The identified major contributory factors of such unfortunate events are both driver fatigue and over speeding habit especially related to the driving of truck and bus. This paper presents the idea on how to control the electronic system from input fuel system of injection pump and the combustion chamber engine will control the valve solenoid in injection pump which can lock and fuel will stop for moment, and speed limit can be success, by using sensor heart rate we can input reduce speed limit when fatigue detection driver. Integration process this tool can be relevant when Speed Limiter Integrated Fatigue Analyser (SLIFA) trial in the diesel engine for truck and bus, the result of this research Speed Limiter Integrated Fatigue Analyser (SLIFA) able to control speed of diesel engine for truck and bus almost 30km/h, 60km/h, and until 70 km/h. The installation of the sensor heart rate as the input speed limit SLIFA would work when the driver is detected to be in the fatigue condition. We make Speed Limiter Integrated Fatigue Analyser (SLIFA) for control and monitoring system for diesel engine in truck and bus. Speed Limiter Integrated Fatigue Analyser (SLIFA) system can save the historical of the speed record, fatigue, rpm, and body temperature of the driver.

An Auto-Tuning PI Control System for an Open-Circuit Low-Speed Wind Tunnel Designed for Greenhouse Technology

PubMed Central

Espinoza, Karlos; Valera, Diego L.; Torres, José A.; López, Alejandro; Molina-Aiz, Francisco D.

2015-01-01

Wind tunnels are a key experimental tool for the analysis of airflow parameters in many fields of application. Despite their great potential impact on agricultural research, few contributions have dealt with the development of automatic control systems for wind tunnels in the field of greenhouse technology. The objective of this paper is to present an automatic control system that provides precision and speed of measurement, as well as efficient data processing in low-speed wind tunnel experiments for greenhouse engineering applications. The system is based on an algorithm that identifies the system model and calculates the optimum PI controller. The validation of the system was performed on a cellulose evaporative cooling pad and on insect-proof screens to assess its response to perturbations. The control system provided an accuracy of <0.06 m·s−1 for airflow speed and <0.50 Pa for pressure drop, thus permitting the reproducibility and standardization of the tests. The proposed control system also incorporates a fully-integrated software unit that manages the tests in terms of airflow speed and pressure drop set points. PMID:26274962

An Auto-Tuning PI Control System for an Open-Circuit Low-Speed Wind Tunnel Designed for Greenhouse Technology.

PubMed

Espinoza, Karlos; Valera, Diego L; Torres, José A; López, Alejandro; Molina-Aiz, Francisco D

2015-08-12

Wind tunnels are a key experimental tool for the analysis of airflow parameters in many fields of application. Despite their great potential impact on agricultural research, few contributions have dealt with the development of automatic control systems for wind tunnels in the field of greenhouse technology. The objective of this paper is to present an automatic control system that provides precision and speed of measurement, as well as efficient data processing in low-speed wind tunnel experiments for greenhouse engineering applications. The system is based on an algorithm that identifies the system model and calculates the optimum PI controller. The validation of the system was performed on a cellulose evaporative cooling pad and on insect-proof screens to assess its response to perturbations. The control system provided an accuracy of <0.06 m·s(-1) for airflow speed and <0.50 Pa for pressure drop, thus permitting the reproducibility and standardization of the tests. The proposed control system also incorporates a fully-integrated software unit that manages the tests in terms of airflow speed and pressure drop set points.

Digital phase-locked loop speed control for a brushless dc motor

NASA Astrophysics Data System (ADS)

Wise, M. G.

1985-06-01

Speed control of d.c. motors by phase-locked loops (PLL) is becoming increasingly popular. Primary interest has been in employing PLL for constant speed control. This thesis investigates the theory and techniques of digital PLL to speed control of a brushless d.c. motor with a variable speed of operation. Addition of logic controlled count enable/disable to a synchronous up/down counter, used as a phase-frequency detector, is shown to improve the performance of previously proposed PLL control schemes.

Novel Observer Scheme of Fuzzy-MRAS Sensorless Speed Control of Induction Motor Drive

NASA Astrophysics Data System (ADS)

Chekroun, S.; Zerikat, M.; Mechernene, A.; Benharir, N.

2017-01-01

This paper presents a novel approach Fuzzy-MRAS conception for robust accurate tracking of induction motor drive operating in a high-performance drives environment. Of the different methods for sensorless control of induction motor drive the model reference adaptive system (MRAS) finds lot of attention due to its good performance. The analysis of the sensorless vector control system using MRAS is presented and the resistance parameters variations and speed observer using new Fuzzy Self-Tuning adaptive IP Controller is proposed. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. The present approach helps to achieve a good dynamic response, disturbance rejection and low to plant parameter variations of the induction motor. In order to verify the performances of the proposed observer and control algorithms and to test behaviour of the controlled system, numerical simulation is achieved. Simulation results are presented and discussed to shown the validity and the performance of the proposed observer.

30 CFR 56.9101 - Operating speeds and control of equipment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Operating speeds and control of equipment. 56... Loading, Hauling, and Dumping Traffic Safety § 56.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility, and...

30 CFR 56.9101 - Operating speeds and control of equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Operating speeds and control of equipment. 56... Loading, Hauling, and Dumping Traffic Safety § 56.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility, and...

30 CFR 57.9101 - Operating speeds and control of equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Operating speeds and control of equipment. 57... Loading, Hauling, and Dumping Traffic Safety § 57.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility, and...

30 CFR 57.9101 - Operating speeds and control of equipment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Operating speeds and control of equipment. 57... Loading, Hauling, and Dumping Traffic Safety § 57.9101 Operating speeds and control of equipment.... Operating speeds shall be consistent with conditions of roadways, tracks, grades, clearance, visibility, and...

Effect of Different Training Methods on Stride Parameters in Speed Maintenance Phase of 100-m Sprint Running.

PubMed

Cetin, Emel; Hindistan, I Ethem; Ozkaya, Y Gul

2018-05-01

Cetin, E, Hindistan, IE, Ozkaya, YG. Effect of different training methods on stride parameters in speed maintenance phase of 100-m sprint running. J Strength Cond Res 32(5): 1263-1272, 2018-This study examined the effects of 2 different training methods relevant to sloping surface on stride parameters in speed maintenance phase of 100-m sprint running. Twenty recreationally active students were assigned into one of 3 groups: combined training (Com), horizontal training (H), and control (C) group. Com group performed uphill and downhill training on a sloping surface with an angle of 4°, whereas H group trained on a horizontal surface, 3 days a week for 8 weeks. Speed maintenance and deceleration phases were divided into distances with 10-m intervals, and running time (t), running velocity (RV), step frequency (SF), and step length (SL) were measured at preexercise, and postexercise period. After 8 weeks of training program, t was shortened by 3.97% in Com group, and 2.37% in H group. Running velocity also increased for totally 100 m of running distance by 4.13 and 2.35% in Com, and H groups, respectively. At the speed maintenance phase, although t and maximal RV (RVmax) found to be statistically unaltered during overall phase, t was found to be decreased, and RVmax was preceded by 10 m in distance in both training groups. Step length was increased at 60-70 m, and SF was decreased at 70-80 m in H group. Step length was increased with concomitant decrease in SF at 80-90 m in Com group. Both training groups maintained the RVmax with a great percentage at the speed maintenance phase. In conclusion, although both training methods resulted in an increase in running time and RV, Com training method was more prominently effective method in improving RV, and this improvement was originated from the positive changes in SL during the speed maintaining phase.

Stability control for high speed tracked unmanned vehicles

NASA Astrophysics Data System (ADS)

Pape, Olivier; Morillon, Joel G.; Houbloup, Philippe; Leveque, Stephane; Fialaire, Cecile; Gauthier, Thierry; Ropars, Patrice

2005-05-01

The French Military Robotic Study Program (introduced in Aerosense 2003), sponsored by the French Defense Procurement Agency and managed by Thales as the prime contractor, focuses on about 15 robotic themes which can provide an immediate "operational add-on value". The paper details the "automatic speed adjustment" behavior (named SYR4), developed by Giat Industries Company, which main goal is to secure the teleoperated mobility of high speed tracked vehicles on rough grounds; more precisely, the validated low level behavior continuously adjusts the vehicle speed taking into account the teleperator wish AND the maximum speed that the vehicle can manage safely according to the commanded radius of curvature. The algorithm is based on a realistic physical model of the ground-tracks relation, taking into account many vehicle and ground parameters (such as ground adherence and dynamic specificities of tracked vehicles). It also deals with the teleoperator-machine interface, providing a balanced strategy between both extreme behaviors: a) maximum speed reduction before initiating the commanded curve; b) executing the minimum possible radius without decreasing the commanded speed. The paper presents the results got from the military acceptance tests performed on tracked SYRANO vehicle (French Operational Demonstrator).

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.

Redundant speed control for brushless Hall effect motor

NASA Technical Reports Server (NTRS)

Nola, F. J. (Inventor)

1973-01-01

A speed control system for a brushless Hall effect device equipped direct current (D.C.) motor is described. Separate windings of the motor are powered by separate speed responsive power sources. A change in speed, upward or downward, because of the failure of a component of one of the power sources results in a corrective signal being generated in the other power source to supply an appropriate power level and polarity to one winding to cause the motor to be corrected in speed.

Controlling the Temperature and Speed of the Phase Transition of VO 2 Microcrystals

DOE PAGES

Yoon, Joonseok; Kim, Howon; Chen, Xian; ...

2015-12-29

Here, we investigated the control of two important parameters of vanadium dioxide (VO 2 ) microcrystals, the phase transition temperature and speed, by varying microcrystal width. By using the reflectivity change between insulating and metallic phases, phase transition temperature is measured by optical microscopy. As the width of square cylinder-shaped microcrystals decreases from ~70 to ~1 μm, the phase transition temperature (67 °C for bulk) varied as much as 26.1 °C (19.7 °C) during heating (cooling). In addition, the propagation speed of phase boundary in the microcrystal, i.e., phase transition speed, is monitored at the onset of phase transition bymore » using the high-speed resistance measurement. The phase transition speed increases from 4.6 × 10 2 to 1.7 × 10 4 μm/s as the width decreases from ~50 to ~2 μm. While the statistical description for a heterogeneous nucleation process explains the size dependence on phase transition temperature of VO 2 , the increase of effective thermal exchange process is responsible for the enhancement of phase transition speed of small VO 2 microcrystals. These findings not only enhance the understanding of VO 2 intrinsic properties but also contribute to the development of innovative electronic devices.« less

Controlling the Temperature and Speed of the Phase Transition of VO 2 Microcrystals

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

Yoon, Joonseok; Kim, Howon; Chen, Xian

Here, we investigated the control of two important parameters of vanadium dioxide (VO 2 ) microcrystals, the phase transition temperature and speed, by varying microcrystal width. By using the reflectivity change between insulating and metallic phases, phase transition temperature is measured by optical microscopy. As the width of square cylinder-shaped microcrystals decreases from ~70 to ~1 μm, the phase transition temperature (67 °C for bulk) varied as much as 26.1 °C (19.7 °C) during heating (cooling). In addition, the propagation speed of phase boundary in the microcrystal, i.e., phase transition speed, is monitored at the onset of phase transition bymore » using the high-speed resistance measurement. The phase transition speed increases from 4.6 × 10 2 to 1.7 × 10 4 μm/s as the width decreases from ~50 to ~2 μm. While the statistical description for a heterogeneous nucleation process explains the size dependence on phase transition temperature of VO 2 , the increase of effective thermal exchange process is responsible for the enhancement of phase transition speed of small VO 2 microcrystals. These findings not only enhance the understanding of VO 2 intrinsic properties but also contribute to the development of innovative electronic devices.« less

Variable speed control in wells turbine-based oscillating water column devices: optimum rotational speed

NASA Astrophysics Data System (ADS)

Lekube, J.; Garrido, A. J.; Garrido, I.

2018-03-01

The effects of climate change and global warming reveal the need to find alternative sources of clean energy. In this sense, wave energy power plants, and in particular Oscillating Water Column (OWC) devices, offer a huge potential of energy harnessing. Nevertheless, the conversion systems have not reached a commercially mature stage yet so as to compete with conventional power plants. At this point, the use of new control methods over the existing technology arises as a doable way to improve the efficiency of the system. Due to the non-uniform response that the turbine shows to the rotational speed variation, the speed control of the turbo-generator may offer a feasible solution for efficiency improvement during the energy conversion. In this context, a novel speed control approach for OWC systems is presented in this paper, demonstrating its goodness and affording promising results when particularized to the Mutriku’s wave power plant.

Shelter Index and a simple wind speed parameter to characterize vegetation control of sand transport threshold and Flu

NASA Astrophysics Data System (ADS)

Gillies, J. A.; Nield, J. M.; Nickling, W. G.; Furtak-Cole, E.

2014-12-01

Wind erosion and dust emissions occur in many dryland environments from a range of surfaces with different types and amounts of vegetation. Understanding how vegetation modulates these processes remains a research challenge. Here we present results from a study that examines the relationship between an index of shelter (SI=distance from a point to the nearest upwind vegetation/vegetation height) and particle threshold expressed as the ratio of wind speed measured at 0.45 times the mean plant height divided by the wind speed at 17 m when saltation commences, and saltation flux. The results are used to evaluate SI as a parameter to characterize the influence of vegetation on local winds and sediment transport conditions. Wind speed, wind direction, saltation activity and point saltation flux were measured at 35 locations in defined test areas (~13,000 m2) in two vegetation communities: mature streets of mesquite covered nebkhas and incipient nebkhas dominated by low mesquite plants. Measurement positions represent the most open areas, and hence those places most susceptible to wind erosion among the vegetation elements. Shelter index was calculated for each measurement position for each 10° wind direction bin using digital elevation models for each site acquired using terrestrial laser scanning. SI can show the susceptibility to wind erosion at different time scales, i.e., event, seasonal, or annual, but in a supply-limited system it can fail to define actual flux amounts due to a lack of knowledge of the distribution of sediment across the surface of interest with respect to the patterns of SI.

Influences of Cutting Speed and Material Mechanical Properties on Chip Deformation and Fracture during High-Speed Cutting of Inconel 718.

PubMed

Wang, Bing; Liu, Zhanqiang; Hou, Xin; Zhao, Jinfu

2018-03-21

The paper aims to investigate the influences of material constitutive and fracture parameters in addition to cutting speed on chip formation during high-speed cutting of Inconel 718. Finite element analyses for chip formation are conducted with Johnson-Cook constitutive and fracture models. Meanwhile, experiments of high-speed orthogonal cutting are performed to verify the simulation results with cutting speeds ranging from 50 m/min to 7000 m/min. The research indicates that the chip morphology transforms from serrated to fragmented at the cutting speed of 7000 m/min due to embrittlement of the workpiece material under ultra-high cutting speeds. The parameter of shear localization sensitivity is put forward to describe the influences of material mechanical properties on serrated chip formation. The results demonstrate that the effects of initial yield stress and thermal softening coefficient on chip shear localization are much more remarkable than the other constitutive parameters. For the material fracture parameters, the effects of initial fracture strain and exponential factor of stress state on chip shear localization are more much prominent. This paper provides guidance for controlling chip formation through the adjustment of material mechanical properties and the selection of appropriate cutting parameters.

Influences of Cutting Speed and Material Mechanical Properties on Chip Deformation and Fracture during High-Speed Cutting of Inconel 718

PubMed Central

Hou, Xin; Zhao, Jinfu

2018-01-01

The paper aims to investigate the influences of material constitutive and fracture parameters in addition to cutting speed on chip formation during high-speed cutting of Inconel 718. Finite element analyses for chip formation are conducted with Johnson–Cook constitutive and fracture models. Meanwhile, experiments of high-speed orthogonal cutting are performed to verify the simulation results with cutting speeds ranging from 50 m/min to 7000 m/min. The research indicates that the chip morphology transforms from serrated to fragmented at the cutting speed of 7000 m/min due to embrittlement of the workpiece material under ultra-high cutting speeds. The parameter of shear localization sensitivity is put forward to describe the influences of material mechanical properties on serrated chip formation. The results demonstrate that the effects of initial yield stress and thermal softening coefficient on chip shear localization are much more remarkable than the other constitutive parameters. For the material fracture parameters, the effects of initial fracture strain and exponential factor of stress state on chip shear localization are more much prominent. This paper provides guidance for controlling chip formation through the adjustment of material mechanical properties and the selection of appropriate cutting parameters. PMID:29561770

Selective Use of Optical Variables to Control Forward Speed

NASA Technical Reports Server (NTRS)

Johnson, Walter W.; Awe, Cynthia A.; Hart, Sandra G. (Technical Monitor)

1994-01-01

Previous work on the perception and control of simulated vehicle speed has examined the contributions of optical flow rate (angular visual speed) and texture, or edge rate (frequency of passing terrain objects or markings) on the perception and control of forward speed. However, these studies have not examined the ability to selectively use edge rate or flow rate. The two studies reported here show that subjects found it very difficult to arbitrarily direct attention to one or the other of these variables; but that the ability to selectively use these variables is linked to the visual contextual information about the relative validity (linkage with speed) of the two variables. The selectivity also resulted in different velocity adaptation levels for events in which flow rate and edge rate specified forward speed. Finally, the role of visual context in directing attention was further buttressed by the finding that the incorrect perception of changes in ground texture density tended to be coupled with incorrect perceptions of changes in forward speed.

Experimental Comparison of Speed : Fuel-flow and Speed-area Controls on a Turbojet Engine for Small Step Disturbances

NASA Technical Reports Server (NTRS)

Wenzel, L M; Hart, C E; Craig, R T

1957-01-01

Optimum proportional-plus-integral control settings for speed - fuel-flow control, determined by minimization of integral criteria, correlated well with analytically predicted optimum settings. Engine response data are given for a range of control settings around the optimum. An inherent nonlinearity in the speed-area loop necessitated the use of nonlinear controls. Response data for two such nonlinear control schemes are presented.

Innovations in Rheometer Controlled-Rate Control Loop Design: Ultra Low Angular Speed Control and New Applications

NASA Astrophysics Data System (ADS)

Schulz, Ulrich; Sierro, Philippe; Nijman, Jint

2008-07-01

The design and implementation of an angular speed control loop for a universal rheometer is not a trivial task. The combination of a highly dynamic, very low inertia (drag cup) motor (motor inertia is 10-5 kg m2) with samples which can range in viscosity from 10-3 Pas to 108 Pas, which can be between purely viscous and higly viscoelastic, which can exhibit yield-stresses, etc. asks for a highly adaptive digital control loop. For the HAAKE MARS rotational rheometer a new adaptive control loop was developed which allows the control of angular speeds as low 5×10-9 rad/s and response times a short as 10 ms. The adaptation of the control loop to "difficult" samples is performed by analysing the response of the complete system to a short pre-test. In this paper we will show that the (very) short response times at (very) low angular speeds are not only achieved with ideal samples, but due to the adaptable control loop, also with "difficult" samples. We will show measurement results on "difficult" samples like cosmetic creams and emulsions, a laponite gel, etc. to proof that angular speeds down to 10-4 rad/s are reached within 10 ms to 20 ms and angular speeds down to 10-7 rad/s within 1 s to 2 s. The response times for reaching ultra low angular speeds down to 5×10-9 rad/s are in the order of 10 s to 30 s. With this new control loop it is, for the first time, possible to measure yield stresses by applying a very low constant shear-rate to the sample and measuring the torque response as a function of time.

Integrated High-Speed Torque Control System for a Robotic Joint

NASA Technical Reports Server (NTRS)

Davis, Donald R. (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Valvo, Michael C. (Inventor); Askew, R. Scott (Inventor)

2013-01-01

A control system for achieving high-speed torque for a joint of a robot includes a printed circuit board assembly (PCBA) having a collocated joint processor and high-speed communication bus. The PCBA may also include a power inverter module (PIM) and local sensor conditioning electronics (SCE) for processing sensor data from one or more motor position sensors. Torque control of a motor of the joint is provided via the PCBA as a high-speed torque loop. Each joint processor may be embedded within or collocated with the robotic joint being controlled. Collocation of the joint processor, PIM, and high-speed bus may increase noise immunity of the control system, and the localized processing of sensor data from the joint motor at the joint level may minimize bus cabling to and from each control node. The joint processor may include a field programmable gate array (FPGA).

Scale Control and Quality Management of Printed Image Parameters

NASA Astrophysics Data System (ADS)

Novoselskaya, O. A.; Kolesnikov, V. L.; Solov'eva, T. V.; Nagornova, I. V.; Babluyk, E. B.; Trapeznikova, O. V.

2017-06-01

The article provides a comparison of the main valuation techniques for a regulated parameter of printability of the offset paper by current standards GOST 24356 and ISO 3783: 2006. The results of development and implementation of a complex test scale for management and control the quality of printed production are represented. The estimation scale is introduced. It includes normalized parameters of print optical density, print uniformity, picking out speed, the value of dot gain, print contrast with the added criteria of minimizing microtexts, a paper slip, resolution threshold and effusing ability of paper surface. The results of analysis allow directionally form surface properties of the substrate to facilitate achieving the required quality of the printed image parameters, i. e. optical density of a print at a predetermined level not less than 1.3, the print uniformity with minimal deviation of dot gain about the order of 10 per cents.

Railroad classification yard technology : assessment of car speed control systems

DOT National Transportation Integrated Search

1980-12-01

The scope of this study has encompassed an evaluation of fourteen yard speed : control devices, an identification of four generic speed control systems, a : qualitative assessment of the four systems, and finally a quantitative analysis : of three hy...

Variable-speed controller provides flexibility to electrical submersible pumps

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

Butlin, D.

1986-06-09

The performance of an electric submersible pump (ESP) is dramatically modified by a variable speed controller (VSC). Variable frequency power directly controls pump speed and thus the hydraulic performance of the pump. Even though the ESP is the primary form of artificial lift for high volume, deep oil wells (particularly where gas is unavailable), the biggest disadvantage has been the pump's inflexibility when run at a constant speed, i.e., the unit is limited to a fixed head output at each rate. The VSC has rapidly gained acceptance as a valuable ESP accessory to alleviate this restriction. By allowing the pumpmore » speed to be varied, the rate and head, or both, can be adjusted with no modification of the downhole unit. There are now over 700 VSCs running with ESPs on every continent of the world. Pumping flexibility was the main purpose of applying the VSC to the ESP, but several other benefits have become apparent. Of particular interest are those that can extend downhole equipment life, e.g., soft start, automatically controlled speed, line-transient suppression, and elimination of surface chokes.« less

Induction motor speed control using varied duty cycle terminal voltage via PI controller

NASA Astrophysics Data System (ADS)

Azwin, A.; Ahmed, S.

2018-03-01

This paper deals with the PI speed controller for the three-phase induction motor using PWM technique. The PWM generated signal is utilized for voltage source inverter with an optimal duty cycle on a simplified induction motor model. A control algorithm for generating PWM control signal is developed. Obtained results shows that the steady state error and overshoot of the developed system is in the limit under different speed and load condition. The robustness of the control performance would be potential for induction motor performance improvement.

High-speed tracking control of piezoelectric actuators using an ellipse-based hysteresis model.

PubMed

Gu, Guoying; Zhu, Limin

2010-08-01

In this paper, an ellipse-based mathematic model is developed to characterize the rate-dependent hysteresis in piezoelectric actuators. Based on the proposed model, an expanded input space is constructed to describe the multivalued hysteresis function H[u](t) by a multiple input single output (MISO) mapping Gamma:R(2)-->R. Subsequently, the inverse MISO mapping Gamma(-1)(H[u](t),H[u](t);u(t)) is proposed for real-time hysteresis compensation. In controller design, a hybrid control strategy combining a model-based feedforward controller and a proportional integral differential (PID) feedback loop is used for high-accuracy and high-speed tracking control of piezoelectric actuators. The real-time feedforward controller is developed to cancel the rate-dependent hysteresis based on the inverse hysteresis model, while the PID controller is used to compensate for the creep, modeling errors, and parameter uncertainties. Finally, experiments with and without hysteresis compensation are conducted and the experimental results are compared. The experimental results show that the hysteresis compensation in the feedforward path can reduce the hysteresis-caused error by up to 88% and the tracking performance of the hybrid controller is greatly improved in high-speed tracking control applications, e.g., the root-mean-square tracking error is reduced to only 0.34% of the displacement range under the input frequency of 100 Hz.

Control of airplanes at low speeds

NASA Technical Reports Server (NTRS)

Wood, R Mckinnon

1923-01-01

Loss of control over the orientation of an airplane as the incidence approaches and enters the region of stalled flight is a prolific cause of serious accidents. This report discusses methods of landing at slow speeds approaching stall.

An RFID-based intelligent vehicle speed controller using active traffic signals.

PubMed

Pérez, Joshué; Seco, Fernando; Milanés, Vicente; Jiménez, Antonio; Díaz, Julio C; de Pedro, Teresa

2010-01-01

These days, mass-produced vehicles benefit from research on Intelligent Transportation System (ITS). One prime example of ITS is vehicle Cruise Control (CC), which allows it to maintain a pre-defined reference speed, to economize on fuel or energy consumption, to avoid speeding fines, or to focus all of the driver's attention on the steering of the vehicle. However, achieving efficient Cruise Control is not easy in roads or urban streets where sudden changes of the speed limit can happen, due to the presence of unexpected obstacles or maintenance work, causing, in inattentive drivers, traffic accidents. In this communication we present a new Infrastructure to Vehicles (I2V) communication and control system for intelligent speed control, which is based upon Radio Frequency Identification (RFID) technology for identification of traffic signals on the road, and high accuracy vehicle speed measurement with a Hall effect-based sensor. A fuzzy logic controller, based on sensor fusion of the information provided by the I2V infrastructure, allows the efficient adaptation of the speed of the vehicle to the circumstances of the road. The performance of the system is checked empirically, with promising results.

An RFID-Based Intelligent Vehicle Speed Controller Using Active Traffic Signals

PubMed Central

Pérez, Joshué; Seco, Fernando; Milanés, Vicente; Jiménez, Antonio; Díaz, Julio C.; de Pedro, Teresa

2010-01-01

These days, mass-produced vehicles benefit from research on Intelligent Transportation System (ITS). One prime example of ITS is vehicle Cruise Control (CC), which allows it to maintain a pre-defined reference speed, to economize on fuel or energy consumption, to avoid speeding fines, or to focus all of the driver’s attention on the steering of the vehicle. However, achieving efficient Cruise Control is not easy in roads or urban streets where sudden changes of the speed limit can happen, due to the presence of unexpected obstacles or maintenance work, causing, in inattentive drivers, traffic accidents. In this communication we present a new Infrastructure to Vehicles (I2V) communication and control system for intelligent speed control, which is based upon Radio Frequency Identification (RFID) technology for identification of traffic signals on the road, and high accuracy vehicle speed measurement with a Hall effect-based sensor. A fuzzy logic controller, based on sensor fusion of the information provided by the I2V infrastructure, allows the efficient adaptation of the speed of the vehicle to the circumstances of the road. The performance of the system is checked empirically, with promising results. PMID:22219692

Ride performance of a high speed rail vehicle using controlled semi active suspension system

NASA Astrophysics Data System (ADS)

Sharma, Sunil Kumar; Kumar, Anil

2017-05-01

The rail-wheel interaction in a rail vehicle running at high speed results in large amplitude vibration of carbody that deteriorates the ride comfort of travellers. The role of suspension system is crucial to provide an acceptable level of ride performance. In this context, an existing rail vehicle is modelled in vertical, pitch and roll motions of carbody and bogies. Additionally, nonlinear stiffness and damping parameters of passive suspension system are defined based on experimental data. In the secondary vertical suspension system, a magneto-rheological (MR) damper is included to improve the ride quality and comfort. The parameters of MR damper depend on the current, amplitude and frequency of excitations. At different running speeds, three semi-active suspension strategies with MR damper are analysed for periodic track irregularity and the resulting performance indices are juxtaposed with the nonlinear passive suspension system. The disturbance rejection and force tracking damper controller algorithms are applied to control the desired force of MR damper. This study reveals that the vertical vibrations of a vehicle can be reduced significantly by using the proposed semi-active suspension strategies. Moreover, it naturally results in improved ride quality and passenger’s comfort in comparison to the existing passive system.

Adaptive estimation of nonlinear parameters of a nonholonomic spherical robot using a modified fuzzy-based speed gradient algorithm

NASA Astrophysics Data System (ADS)

Roozegar, Mehdi; Mahjoob, Mohammad J.; Ayati, Moosa

2017-05-01

This paper deals with adaptive estimation of the unknown parameters and states of a pendulum-driven spherical robot (PDSR), which is a nonlinear in parameters (NLP) chaotic system with parametric uncertainties. Firstly, the mathematical model of the robot is deduced by applying the Newton-Euler methodology for a system of rigid bodies. Then, based on the speed gradient (SG) algorithm, the states and unknown parameters of the robot are estimated online for different step length gains and initial conditions. The estimated parameters are updated adaptively according to the error between estimated and true state values. Since the errors of the estimated states and parameters as well as the convergence rates depend significantly on the value of step length gain, this gain should be chosen optimally. Hence, a heuristic fuzzy logic controller is employed to adjust the gain adaptively. Simulation results indicate that the proposed approach is highly encouraging for identification of this NLP chaotic system even if the initial conditions change and the uncertainties increase; therefore, it is reliable to be implemented on a real robot.

An adaptive nonlinear internal-model control for the speed control of homopolar salient-pole BLDC motor

NASA Astrophysics Data System (ADS)

CheshmehBeigi, Hassan Moradi

2018-05-01

In this paper, a novel speed control method for Homopolar Brushless DC (HBLDC) motor based on the adaptive nonlinear internal-model control (ANIMC) is presented. Rotor position information is obtained online by the Hall-Effect sensors placed on the motor's shaft, and is used to calculate the accurate model and accurate inverse model of the HBLDC motor. The online inverse model of the motor is used in the controller structure. To suppress the reference ? error, the negative feedback of difference between the motor speed and its model output ? is applied in the proposed controller. An appropriate signal is the output of the controller, which drives the power switches to converge the motor speed to the constant desired speed. Simulations and experiments are carried out on a ? three-phase HBLDC motor. The proposed drive system operates well in the speed response and has good robustness with respect to the disturbances. To validate the theoretical analysis, several experimental results are discussed in this paper.

UDE-based control of variable-speed wind turbine systems

NASA Astrophysics Data System (ADS)

Ren, Beibei; Wang, Yeqin; Zhong, Qing-Chang

2017-01-01

In this paper, the control of a PMSG (permanent magnet synchronous generator)-based variable-speed wind turbine system with a back-to-back converter is considered. The uncertainty and disturbance estimator (UDE)-based control approach is applied to the regulation of the DC-link voltage and the control of the RSC (rotor-side converter) and the GSC (grid-side converter). For the rotor-side controller, the UDE-based vector control is developed for the RSC with PMSG control to facilitate the application of the MPPT (maximum power point tracking) algorithm for the maximum wind energy capture. For the grid-side controller, the UDE-based vector control is developed to control the GSC with the power reference generated by a UDE-based DC-link voltage controller. Compared with the conventional vector control, the UDE-based vector control can achieve reliable current decoupling control with fast response. Moreover, the UDE-based DC-link voltage regulation can achieve stable DC-link voltage under model uncertainties and external disturbances, e.g. wind speed variations. The effectiveness of the proposed UDE-based control approach is demonstrated through extensive simulation studies in the presence of coupled dynamics, model uncertainties and external disturbances under varying wind speeds. The UDE-based control is able to generate more energy, e.g. by 5% for the wind profile tested.

A new ball launching system with controlled flight parameters for catching experiments.

PubMed

d'Avella, A; Cesqui, B; Portone, A; Lacquaniti, F

2011-03-30

Systematic investigations of sensorimotor control of interceptive actions in naturalistic conditions, such as catching or hitting a ball moving in three-dimensional space, requires precise control of the projectile flight parameters and of the associated visual stimuli. Such control is challenging when air drag cannot be neglected because the mapping of launch parameters into flight parameters cannot be computed analytically. We designed, calibrated, and experimentally validated an actuated launching apparatus that can control the average spatial position and flight duration of a ball at a given distance from a fixed launch location. The apparatus was constructed by mounting a ball launching machine with adjustable delivery speed on an actuated structure capable of changing the spatial orientation of the launch axis while projecting balls through a hole in a screen hiding the apparatus. The calibration procedure relied on tracking the balls with a motion capture system and on approximating the mapping of launch parameters into flight parameters by means of polynomials functions. Polynomials were also used to estimate the variability of the flight parameters. The coefficients of these polynomials were obtained using the launch and flight parameters of 660 launches with 65 different initial conditions. The relative accuracy and precision of the apparatus were larger than 98% for flight times and larger than 96% for ball heights at a distance of 6m from the screen. Such novel apparatus, by reliably and automatically controlling desired ball flight characteristics without neglecting air drag, allows for a systematic investigation of naturalistic interceptive tasks. Copyright © 2011 Elsevier B.V. All rights reserved.

Suction prevention and physiologic control of continuous flow left ventricular assist devices using intrinsic pump parameters.

PubMed

Wang, Yu; Koenig, Steven C; Slaughter, Mark S; Giridharan, Guruprasad A

2015-01-01

The risk for left ventricular (LV) suction during left ventricular assist devices (LVAD) support has been a clinical concern. Current development efforts suggest LVAD suction prevention and physiologic control algorithms may require chronic implantation of pressure or flow sensors, which can be unreliable because of baseline drift and short lifespan. To overcome this limitation, we designed a sensorless suction prevention and physiologic control (eSPPC) algorithm that only requires LVAD intrinsic parameters (pump speed and power). Two gain-scheduled, proportional-integral controllers maintain a differential pump speed (ΔRPM) above a user-defined threshold to prevent LV suction while maintaining an average reference differential pressure (ΔP) between the LV and aorta. ΔRPM is calculated from noisy pump speed measurements that are low-pass filtered, and ΔP is estimated using an extended Kalman filter. Efficacy and robustness of the eSPPC algorithm were evaluated in silico during simulated rest and exercise test conditions for 1) excessive ΔP setpoint (ES); 2) rapid eightfold increase in pulmonary vascular resistance (PVR); and 3) ES and PVR. Simulated hemodynamic waveforms (LV pressure and volume; aortic pressure and flow) using only intrinsic pump parameters showed the feasibility of our proposed eSPPC algorithm in preventing LV suction for all test conditions.

Sensitivity of turbine-height wind speeds to parameters in planetary boundary-layer and surface-layer schemes in the weather research and forecasting model

DOE PAGES

Yang, Ben; Qian, Yun; Berg, Larry K.; ...

2016-07-21

We evaluate the sensitivity of simulated turbine-height wind speeds to 26 parameters within the Mellor–Yamada–Nakanishi–Niino (MYNN) planetary boundary-layer scheme and MM5 surface-layer scheme of the Weather Research and Forecasting model over an area of complex terrain. An efficient sampling algorithm and generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of simulated turbine-height wind speeds. The results indicate that most of the variability in the ensemble simulations is due to parameters related to the dissipation of turbulent kinetic energy (TKE), Prandtl number, turbulent length scales, surface roughness, and the von Kármán constant. Themore » parameter associated with the TKE dissipation rate is found to be most important, and a larger dissipation rate produces larger hub-height wind speeds. A larger Prandtl number results in smaller nighttime wind speeds. Increasing surface roughness reduces the frequencies of both extremely weak and strong airflows, implying a reduction in the variability of wind speed. All of the above parameters significantly affect the vertical profiles of wind speed and the magnitude of wind shear. Lastly, the relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability.« less

Sensitivity of turbine-height wind speeds to parameters in planetary boundary-layer and surface-layer schemes in the weather research and forecasting model

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

Yang, Ben; Qian, Yun; Berg, Larry K.

We evaluate the sensitivity of simulated turbine-height wind speeds to 26 parameters within the Mellor–Yamada–Nakanishi–Niino (MYNN) planetary boundary-layer scheme and MM5 surface-layer scheme of the Weather Research and Forecasting model over an area of complex terrain. An efficient sampling algorithm and generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of simulated turbine-height wind speeds. The results indicate that most of the variability in the ensemble simulations is due to parameters related to the dissipation of turbulent kinetic energy (TKE), Prandtl number, turbulent length scales, surface roughness, and the von Kármán constant. Themore » parameter associated with the TKE dissipation rate is found to be most important, and a larger dissipation rate produces larger hub-height wind speeds. A larger Prandtl number results in smaller nighttime wind speeds. Increasing surface roughness reduces the frequencies of both extremely weak and strong airflows, implying a reduction in the variability of wind speed. All of the above parameters significantly affect the vertical profiles of wind speed and the magnitude of wind shear. Lastly, the relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability.« less

Characterization of material parameters for high speed forming and cutting via experiment and inverse simulation

NASA Astrophysics Data System (ADS)

Scheffler, Christian; Psyk, Verena; Linnemann, Maik; Tulke, Marc; Brosius, Alexander; Landgrebe, Dirk

2018-05-01

High speed velocity effects in production technology provide a broad range of technological and economic advantages [1, 2]. However, exploiting them necessitates the knowledge of strain rate dependent material behavior in process modelling. In general, high speed material data characterization features several difficulties and requires sophisticated approaches in order to provide reliable material data. This paper proposes two innovative concepts with electromagnetic and pneumatic drive and an approach for material characterization in terms of strain rate dependent flow curves and parameters of failure or damage models. The test setups have been designed for investigations of strain rates up to 105 s-1. In principle, knowledge about the temporary courses and local distributions of stress and strain in the specimen is essential for identifying material characteristics, but short process times, fast changes of the measurement values, small specimen size and frequently limited accessibility of the specimen during the test hinder directly measuring these parameters at high-velocity testing. Therefore, auxiliary test parameters, which are easier to measure, are recorded and used as input data for an inverse numerical simulation that provides the desired material characteristics, e.g. the Johnson-Cook parameters, as a result. These parameters are a force equivalent strain signal on a measurement body and the displacement of the upper specimen edge.

Guidance and Control Design for High-Speed Rollout and Turnoff (ROTO)

NASA Technical Reports Server (NTRS)

Goldthorpe, S. H.; Dangaran, R. D.; Dwyer, J. P.; McBee, L. S.; Norman, R. M.; Shannon, J. H.; Summers, L. G.

1996-01-01

A ROTO architecture, braking and steering control law and display designs for a research high speed Rollout and Turnoff (ROTO) system applicable to transport class aircraft are described herein. Minimum surface friction and FMS database requirements are also documented. The control law designs were developed with the aid of a non-real time simulation program incorporating airframe and gear dynamics as well as steering and braking guidance algorithms. An attainable objective of this ROTO system, as seen from the results of this study, is to assure that the studied aircraft can land with runway occupancy times less then 53 seconds. Runway occupancy time is measured from the time the aircraft crosses the runway threshold until its wing tip clears the near side of the runway. Turnoff ground speeds of 70 knots onto 30 degree exits are allowed with dry and wet surface conditions. Simulation time history and statistical data are documented herein. Parameters which were treated as variables in the simulation study include aircraft touchdown weight/speed/location, aircraft CG, runway friction, sensor noise and winds. After further design and development of the ROTO control system beyond the system developed earlier, aft CG MD-11 aircraft no longer require auto-asymmetric braking (steering) and fly-by-wire nose gear steering. However, the auto ROTO nose gear hysteresis must be less than 2 degrees. The 2 sigma dispersion certified for MD-11 CATIIIB is acceptable. Using this longitudinal dispersion, three ROTO exits are recommended at 3300, 4950 and 6750 feet past the runway threshold. The 3300 foot exit is required for MD-81 class aircraft. Designs documented in this report are valid for the assumptions/models used in this simulation. It is believed that the results will apply to the general class of transport aircraft; however further effort is required to validate this assumption for the general case.

Influence of coronal mass ejections on parameters of high-speed solar wind: a case study

NASA Astrophysics Data System (ADS)

Shugay, Yulia; Slemzin, Vladimir; Rodkin, Denis; Yermolaev, Yuri; Veselovsky, Igor

2018-05-01

We investigate the case of disagreement between predicted and observed in-situ parameters of the recurrent high-speed solar wind streams (HSSs) existing for Carrington rotation (CR) 2118 (December 2011) in comparison with CRs 2117 and 2119. The HSSs originated at the Sun from a recurrent polar coronal hole (CH) expanding to mid-latitudes, and its area in the central part of the solar disk increased with the rotation number. This part of the CH was responsible for the equatorial flank of the HSS directed to the Earth. The time and speed of arrival for this part of the HSS to the Earth were predicted by the hierarchical empirical model based on EUV-imaging and the Wang-Sheeley-Arge ENLIL semi-empirical replace model and compared with the parameters measured in-situ by model. The predicted parameters were compared with those measured in-situ. It was found, that for CR 2117 and CR 2119, the predicted HSS speed values agreed with the measured ones within the typical accuracy of ±100 km s-1. During CR 2118, the measured speed was on 217 km s-1 less than the value predicted in accordance with the increased area of the CH. We suppose that at CR 2118, the HSS overtook and interacted with complex ejecta formed from three merged coronal mass ejections (CMEs) with a mean speed about 400 km s-1. According to simulations of the Drag-based model, this complex ejecta might be created by several CMEs starting from the Sun in the period between 25 and 27 December 2011 and arriving to the Earth simultaneously with the HSS. Due to its higher density and magnetic field strength, the complex ejecta became an obstacle for the equatorial flank of the HSS and slowed it down. During CR 2117 and CR 2119, the CMEs appeared before the arrival of the HSSs, so the CMEs did not influence on the HSSs kinematics.

The research of automatic speed control algorithm based on Green CBTC

NASA Astrophysics Data System (ADS)

Lin, Ying; Xiong, Hui; Wang, Xiaoliang; Wu, Youyou; Zhang, Chuanqi

2017-06-01

Automatic speed control algorithm is one of the core technologies of train operation control system. It’s a typical multi-objective optimization control algorithm, which achieve the train speed control for timing, comfort, energy-saving and precise parking. At present, the train speed automatic control technology is widely used in metro and inter-city railways. It has been found that the automatic speed control technology can effectively reduce the driver’s intensity, and improve the operation quality. However, the current used algorithm is poor at energy-saving, even not as good as manual driving. In order to solve the problem of energy-saving, this paper proposes an automatic speed control algorithm based on Green CBTC system. Based on the Green CBTC system, the algorithm can adjust the operation status of the train to improve the efficient using rate of regenerative braking feedback energy while ensuring the timing, comfort and precise parking targets. Due to the reason, the energy-using of Green CBTC system is lower than traditional CBTC system. The simulation results show that the algorithm based on Green CBTC system can effectively reduce the energy-using due to the improvement of the using rate of regenerative braking feedback energy.

Computational modeling of driver speed control with its applications in developing intelligent transportation system to prevent speeding-related accidents.

DOT National Transportation Integrated Search

2013-08-01

Speeding is the leading contributing factor in fatal accidents in NY state, according to NY State Department of Motor : Vehicle Accidents Statistical Summary (2009). Understanding and modeling speeding and speed control is one of major : challenges i...

Speed control with end cushion for high speed air cylinder

DOEpatents

Stevens, Wayne W.; Solbrig, Charles W.

1991-01-01

A high speed air cylinder in which the longitudinal movement of the piston within the air cylinder tube is controlled by pressurizing the air cylinder tube on the accelerating side of the piston and releasing pressure at a controlled rate on the decelerating side of the piston. The invention also includes a method for determining the pressure required on both the accelerating and decelerating sides of the piston to move the piston with a given load through a predetermined distance at the desired velocity, bringing the piston to rest safely without piston bounce at the end of its complete stroke.

Speed tracking and synchronization of multiple motors using ring coupling control and adaptive sliding mode control.

PubMed

Li, Le-Bao; Sun, Ling-Ling; Zhang, Sheng-Zhou; Yang, Qing-Quan

2015-09-01

A new control approach for speed tracking and synchronization of multiple motors is developed, by incorporating an adaptive sliding mode control (ASMC) technique into a ring coupling synchronization control structure. This control approach can stabilize speed tracking of each motor and synchronize its motion with other motors' motion so that speed tracking errors and synchronization errors converge to zero. Moreover, an adaptive law is exploited to estimate the unknown bound of uncertainty, which is obtained in the sense of Lyapunov stability theorem to minimize the control effort and attenuate chattering. Performance comparisons with parallel control, relative coupling control and conventional PI control are investigated on a four-motor synchronization control system. Extensive simulation results show the effectiveness of the proposed control scheme. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

A Taguchi approach on optimal process control parameters for HDPE pipe extrusion process

NASA Astrophysics Data System (ADS)

Sharma, G. V. S. S.; Rao, R. Umamaheswara; Rao, P. Srinivasa

2017-06-01

High-density polyethylene (HDPE) pipes find versatile applicability for transportation of water, sewage and slurry from one place to another. Hence, these pipes undergo tremendous pressure by the fluid carried. The present work entails the optimization of the withstanding pressure of the HDPE pipes using Taguchi technique. The traditional heuristic methodology stresses on a trial and error approach and relies heavily upon the accumulated experience of the process engineers for determining the optimal process control parameters. This results in setting up of less-than-optimal values. Hence, there arouse a necessity to determine optimal process control parameters for the pipe extrusion process, which can ensure robust pipe quality and process reliability. In the proposed optimization strategy, the design of experiments (DoE) are conducted wherein different control parameter combinations are analyzed by considering multiple setting levels of each control parameter. The concept of signal-to-noise ratio ( S/ N ratio) is applied and ultimately optimum values of process control parameters are obtained as: pushing zone temperature of 166 °C, Dimmer speed at 08 rpm, and Die head temperature to be 192 °C. Confirmation experimental run is also conducted to verify the analysis and research result and values proved to be in synchronization with the main experimental findings and the withstanding pressure showed a significant improvement from 0.60 to 1.004 Mpa.

Multivariable Techniques for High-Speed Research Flight Control Systems

NASA Technical Reports Server (NTRS)

Newman, Brett A.

1999-01-01

This report describes the activities and findings conducted under contract with NASA Langley Research Center. Subject matter is the investigation of suitable multivariable flight control design methodologies and solutions for large, flexible high-speed vehicles. Specifically, methodologies are to address the inner control loops used for stabilization and augmentation of a highly coupled airframe system possibly involving rigid-body motion, structural vibrations, unsteady aerodynamics, and actuator dynamics. Design and analysis techniques considered in this body of work are both conventional-based and contemporary-based, and the vehicle of interest is the High-Speed Civil Transport (HSCT). Major findings include: (1) control architectures based on aft tail only are not well suited for highly flexible, high-speed vehicles, (2) theoretical underpinnings of the Wykes structural mode control logic is based on several assumptions concerning vehicle dynamic characteristics, and if not satisfied, the control logic can break down leading to mode destabilization, (3) two-loop control architectures that utilize small forward vanes with the aft tail provide highly attractive and feasible solutions to the longitudinal axis control challenges, and (4) closed-loop simulation sizing analyses indicate the baseline vane model utilized in this report is most likely oversized for normal loading conditions.

Influence of simulation parameters on the speed and accuracy of Monte Carlo calculations using PENEPMA

NASA Astrophysics Data System (ADS)

Llovet, X.; Salvat, F.

2018-01-01

The accuracy of Monte Carlo simulations of EPMA measurements is primarily determined by that of the adopted interaction models and atomic relaxation data. The code PENEPMA implements the most reliable general models available, and it is known to provide a realistic description of electron transport and X-ray emission. Nonetheless, efficiency (i.e., the simulation speed) of the code is determined by a number of simulation parameters that define the details of the electron tracking algorithm, which may also have an effect on the accuracy of the results. In addition, to reduce the computer time needed to obtain X-ray spectra with a given statistical accuracy, PENEPMA allows the use of several variance-reduction techniques, defined by a set of specific parameters. In this communication we analyse and discuss the effect of using different values of the simulation and variance-reduction parameters on the speed and accuracy of EPMA simulations. We also discuss the effectiveness of using multi-core computers along with a simple practical strategy implemented in PENEPMA.

Optimal supplementary frequency controller design using the wind farm frequency model and controller parameters stability region.

PubMed

Toulabi, Mohammadreza; Bahrami, Shahab; Ranjbar, Ali Mohammad

2018-03-01

In most of the existing studies, the frequency response in the variable speed wind turbines (VSWTs) is simply realized by changing the torque set-point via appropriate inputs such as frequency deviations signal. However, effective dynamics and systematic process design have not been comprehensively discussed yet. Accordingly, this paper proposes a proportional-derivative frequency controller and investigates its performance in a wind farm consisting of several VSWTs. A band-pass filter is deployed before the proposed controller to avoid responding to either steady state frequency deviations or high rate of change of frequency. To design the controller, the frequency model of the wind farm is first characterized. The proposed controller is then designed based on the obtained open loop system. The stability region associated with the controller parameters is analytically determined by decomposing the closed-loop system's characteristic polynomial into the odd and even parts. The performance of the proposed controller is evaluated through extensive simulations in MATLAB/Simulink environment in a power system comprising a high penetration of VSWTs equipped with the proposed controller. Finally, based on the obtained feasible area and appropriate objective function, the optimal values associated with the controller parameters are determined using the genetic algorithm (GA). Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Neural rotational speed control for wave energy converters

NASA Astrophysics Data System (ADS)

Amundarain, M.; Alberdi, M.; Garrido, A. J.; Garrido, I.

2011-02-01

Among the benefits arising from an increasing use of renewable energy are: enhanced security of energy supply, stimulation of economic growth, job creation and protection of the environment. In this context, this study analyses the performance of an oscillating water column device for wave energy conversion in function of the stalling behaviour in Wells turbines, one of the most widely used turbines in wave energy plants. For this purpose, a model of neural rotational speed control system is presented, simulated and implemented. This scheme is employed to appropriately adapt the speed of the doubly-fed induction generator coupled to the turbine according to the pressure drop entry, so as to avoid the undesired stalling behaviour. It is demonstrated that the proposed neural rotational speed control design adequately matches the desired relationship between the slip of the doubly-fed induction generator and the pressure drop input, improving the power generated by the turbine generator module.

Low speed hybrid generalized predictive control of a gasoline-propelled car.

PubMed

Romero, M; de Madrid, A P; Mañoso, C; Milanés, V

2015-07-01

Low-speed driving in traffic jams causes significant pollution and wasted time for commuters. Additionally, from the passengers׳ standpoint, this is an uncomfortable, stressful and tedious scene that is suitable to be automated. The highly nonlinear dynamics of car engines at low-speed turn its automation in a complex problem that still remains as unsolved. Considering the hybrid nature of the vehicle longitudinal control at low-speed, constantly switching between throttle and brake pedal actions, hybrid control is a good candidate to solve this problem. This work presents the analytical formulation of a hybrid predictive controller for automated low-speed driving. It takes advantage of valuable characteristics supplied by predictive control strategies both for compensating un-modeled dynamics and for keeping passengers security and comfort analytically by means of the treatment of constraints. The proposed controller was implemented in a gas-propelled vehicle to experimentally validate the adopted solution. To this end, different scenarios were analyzed varying road layouts and vehicle speeds within a private test track. The production vehicle is a commercial Citroën C3 Pluriel which has been modified to automatically act over its throttle and brake pedals. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Speed Sensorless Induction Motor Drives for Electrical Actuators: Schemes, Trends and Tradeoffs

NASA Technical Reports Server (NTRS)

Elbuluk, Malik E.; Kankam, M. David

1997-01-01

For a decade, induction motor drive-based electrical actuators have been under investigation as potential replacement for the conventional hydraulic and pneumatic actuators in aircraft. Advantages of electric actuator include lower weight and size, reduced maintenance and operating costs, improved safety due to the elimination of hazardous fluids and high pressure hydraulic and pneumatic actuators, and increased efficiency. Recently, the emphasis of research on induction motor drives has been on sensorless vector control which eliminates flux and speed sensors mounted on the motor. Also, the development of effective speed and flux estimators has allowed good rotor flux-oriented (RFO) performance at all speeds except those close to zero. Sensorless control has improved the motor performance, compared to the Volts/Hertz (or constant flux) controls. This report evaluates documented schemes for speed sensorless drives, and discusses the trends and tradeoffs involved in selecting a particular scheme. These schemes combine the attributes of the direct and indirect field-oriented control (FOC) or use model adaptive reference systems (MRAS) with a speed-dependent current model for flux estimation which tracks the voltage model-based flux estimator. Many factors are important in comparing the effectiveness of a speed sensorless scheme. Among them are the wide speed range capability, motor parameter insensitivity and noise reduction. Although a number of schemes have been proposed for solving the speed estimation, zero-speed FOC with robustness against parameter variations still remains an area of research for speed sensorless control.

High speed turning of compacted graphite iron using controlled modulation

NASA Astrophysics Data System (ADS)

Stalbaum, Tyler Paul

Compacted graphite iron (CGI) is a material which emerged as a candidate material to replace cast iron (CI) in the automotive industry for engine block castings. Its thermal and mechanical properties allow the CGI-based engines to operate at higher cylinder pressures and temperatures than CI-based engines, allowing for lower fuel emissions and increased fuel economy. However, these same properties together with the thermomechanical wear mode in the CGI-CBN system result in poor machinability and inhibit CGI from seeing wide spread use in the automotive industry. In industry, machining of CGI is done only at low speeds, less than V = 200 m/min, to avoid encountering rapid wear of the cutting tools during cutting. Studies have suggested intermittent cutting operations such as milling suffer less severe tool wear than continuous cutting. Furthermore, evidence that a hard sulfide layer which forms over the cutting edge in machining CI at high speeds is absent during machining CGI is a major factor in the difference in machinability of these material systems. The present study addresses both of these issues by modification to the conventional machining process to allow intermittent continuous cutting. The application of controlled modulation superimposed onto the cutting process -- modulation-assisted machining (MAM) -- is shown to be quite effective in reducing the wear of cubic boron nitride (CBN) tools when machining CGI at high machining speeds (> 500 m/min). The tool life is at least 20 times greater than found in conventional machining of CGI. This significant reduction in wear is a consequence of reduction in the severity of the tool-work contact conditions with MAM. The propensity for thermochemical wear of CBN is thus reduced. It is found that higher cutting speed (> 700 m/min) leads to lower tool wear with MAM. The MAM configuration employing feed-direction modulation appears feasible for implementation at high speeds and offers a solution to this challenging

Control of a High Speed Flywheel System for Energy Storage in Space Applications

NASA Technical Reports Server (NTRS)

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

2004-01-01

A novel control algorithm for the charge and discharge modes of operation of a flywheel energy storage system for space applications is presented. The motor control portion of the algorithm uses sensorless field oriented control with position and speed estimates determined from a signal injection technique at low speeds and a back EMF technique at higher speeds. The charge and discharge portion of the algorithm use command feed-forward and disturbance decoupling, respectively, to achieve fast response with low gains. Simulation and experimental results are presented demonstrating the successful operation of the flywheel control up to the rated speed of 60,000 rpm.

Functional integration of vertical flight path and speed control using energy principles

NASA Technical Reports Server (NTRS)

Lambregts, A. A.

1984-01-01

A generalized automatic flight control system was developed which integrates all longitudinal flight path and speed control functions previously provided by a pitch autopilot and autothrottle. In this design, a net thrust command is computed based on total energy demand arising from both flight path and speed targets. The elevator command is computed based on the energy distribution error between flight path and speed. The engine control is configured to produce the commanded net thrust. The design incorporates control strategies and hierarchy to deal systematically and effectively with all aircraft operational requirements, control nonlinearities, and performance limits. Consistent decoupled maneuver control is achieved for all modes and flight conditions without outer loop gain schedules, control law submodes, or control function duplication.

Adaptive Neuro-Fuzzy Determination of the Effect of Experimental Parameters on Vehicle Agent Speed Relative to Vehicle Intruder.

PubMed

Shamshirband, Shahaboddin; Banjanovic-Mehmedovic, Lejla; Bosankic, Ivan; Kasapovic, Suad; Abdul Wahab, Ainuddin Wahid Bin

2016-01-01

Intelligent Transportation Systems rely on understanding, predicting and affecting the interactions between vehicles. The goal of this paper is to choose a small subset from the larger set so that the resulting regression model is simple, yet have good predictive ability for Vehicle agent speed relative to Vehicle intruder. The method of ANFIS (adaptive neuro fuzzy inference system) was applied to the data resulting from these measurements. The ANFIS process for variable selection was implemented in order to detect the predominant variables affecting the prediction of agent speed relative to intruder. This process includes several ways to discover a subset of the total set of recorded parameters, showing good predictive capability. The ANFIS network was used to perform a variable search. Then, it was used to determine how 9 parameters (Intruder Front sensors active (boolean), Intruder Rear sensors active (boolean), Agent Front sensors active (boolean), Agent Rear sensors active (boolean), RSSI signal intensity/strength (integer), Elapsed time (in seconds), Distance between Agent and Intruder (m), Angle of Agent relative to Intruder (angle between vehicles °), Altitude difference between Agent and Intruder (m)) influence prediction of agent speed relative to intruder. The results indicated that distance between Vehicle agent and Vehicle intruder (m) and angle of Vehicle agent relative to Vehicle Intruder (angle between vehicles °) is the most influential parameters to Vehicle agent speed relative to Vehicle intruder.

Speed adaptation in a powered transtibial prosthesis controlled with a neuromuscular model.

PubMed

Markowitz, Jared; Krishnaswamy, Pavitra; Eilenberg, Michael F; Endo, Ken; Barnhart, Chris; Herr, Hugh

2011-05-27

Control schemes for powered ankle-foot prostheses would benefit greatly from a means to make them inherently adaptive to different walking speeds. Towards this goal, one may attempt to emulate the intact human ankle, as it is capable of seamless adaptation. Human locomotion is governed by the interplay among legged dynamics, morphology and neural control including spinal reflexes. It has been suggested that reflexes contribute to the changes in ankle joint dynamics that correspond to walking at different speeds. Here, we use a data-driven muscle-tendon model that produces estimates of the activation, force, length and velocity of the major muscles spanning the ankle to derive local feedback loops that may be critical in the control of those muscles during walking. This purely reflexive approach ignores sources of non-reflexive neural drive and does not necessarily reflect the biological control scheme, yet can still closely reproduce the muscle dynamics estimated from biological data. The resulting neuromuscular model was applied to control a powered ankle-foot prosthesis and tested by an amputee walking at three speeds. The controller produced speed-adaptive behaviour; net ankle work increased with walking speed, highlighting the benefits of applying neuromuscular principles in the control of adaptive prosthetic limbs.

Self-tuning control algorithm design for vehicle adaptive cruise control system through real-time estimation of vehicle parameters and road grade

NASA Astrophysics Data System (ADS)

Marzbanrad, Javad; Tahbaz-zadeh Moghaddam, Iman

2016-09-01

The main purpose of this paper is to design a self-tuning control algorithm for an adaptive cruise control (ACC) system that can adapt its behaviour to variations of vehicle dynamics and uncertain road grade. To this aim, short-time linear quadratic form (STLQF) estimation technique is developed so as to track simultaneously the trend of the time-varying parameters of vehicle longitudinal dynamics with a small delay. These parameters are vehicle mass, road grade and aerodynamic drag-area coefficient. Next, the values of estimated parameters are used to tune the throttle and brake control inputs and to regulate the throttle/brake switching logic that governs the throttle and brake switching. The performance of the designed STLQF-based self-tuning control (STLQF-STC) algorithm for ACC system is compared with the conventional method based on fixed control structure regarding the speed/distance tracking control modes. Simulation results show that the proposed control algorithm improves the performance of throttle and brake controllers, providing more comfort while travelling, enhancing driving safety and giving a satisfactory performance in the presence of different payloads and road grade variations.

The selective use of functional optical variables in the control of forward speed

NASA Technical Reports Server (NTRS)

Johnson, Walter W.; Awe, Cynthia A.

1994-01-01

Previous work on the perception and control of simulated vehicle speed has examined the contributions of optical flow rate (angular visual speed) and texture, or edge rate (frequency of passing terrain objects or markings) on the perception and control of forward speed. However, these studies have not examined the ability to selectively use edge rate or flow rate. The two studies presented here show that this ability is far greater for pilots than non-pilots, as would be expected since pilots must control vehicular speed over a variety of altitudes where flow rates change independently of forward speed. These studies also show that this ability to selectively use these variables is linked to the visual contextual information about the relative validity (linkage with speed) of the two variables. Subjective judgment data also indicated that awareness of altitude and ground texture density did not mediate ground speed awareness.

Measuring the Speed of Newborn Object Recognition in Controlled Visual Worlds

ERIC Educational Resources Information Center

Wood, Justin N.; Wood, Samantha M. W.

2017-01-01

How long does it take for a newborn to recognize an object? Adults can recognize objects rapidly, but measuring object recognition speed in newborns has not previously been possible. Here we introduce an automated controlled-rearing method for measuring the speed of newborn object recognition in controlled visual worlds. We raised newborn chicks…

Precision electronic speed controller for an alternating-current motor

DOEpatents

Bolie, V.W.

A high precision controller for an alternating-current multi-phase electrical motor that is subject to a large inertial load. The controller was developed for controlling, in a neutron chopper system, a heavy spinning rotor that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal having a meandering line frequency. The controller includes a shaft revolution sensor which provides a feedback pulse train representative of the actual speed of the motor. An internal digital timing signal generator provides a reference signal which is compared with the feedback signal in a computing unit to provide a motor control signal. The motor control signal is a weighted linear sum of a speed error voltage, a phase error voltage, and a drift error voltage, each of which is computed anew with each revolution of the motor shaft. The speed error signal is generated by a novel vernier-logic circuit which is drift-free and highly sensitive to small speed changes. The phase error is also computed by digital logic, with adjustable sensitivity around a 0 mid-scale value. The drift error signal, generated by long-term counting of the phase error, is used to compensate for any slow changes in the average friction drag on the motor. An auxillary drift-byte status sensor prevents any disruptive overflow or underflow of the drift-error counter. An adjustable clocked-delay unit is inserted between the controller and the source of the reference pulse train to permit phase alignment of the rotor to any desired offset angle. The stator windings of the motor are driven by two amplifiers which are provided with input signals having the proper quadrature relationship by an exciter unit consisting of a voltage controlled oscillator, a binary counter, a pair of read-only memories, and a pair of digital-to-analog converters.

Speed of processing and strategic control of attention after traumatic brain injury.

PubMed

Dymowski, Alicia Rhian; Owens, Jacqueline Anne; Ponsford, Jennie Louise; Willmott, Catherine

2015-01-01

Slowed information processing speed has consistently been documented after traumatic brain injury (TBI). Debate continues as to whether deficits in strategic control are proportionate to, or remain after controlling for, reduced speed of processing. The study aim was to investigate the association of speed of processing and strategic control of attention with working memory, selective attention, response inhibition, and mental flexibility task performance after TBI using traditional and novel clinical measures. Twenty-five individuals with complicated mild to severe TBI (post-traumatic amnesia duration, M = 39.52 days, SD = 38.34; worst Glasgow Coma Scale score, M = 7.33, SD = 4.35; time post-injury, M = 392.64 days, SD = 537.19) and 25 matched healthy controls completed assessment of attentional and executive functioning. Measures included the Symbol Digit Modalities Test (SDMT), the computerized Selective Attention Task (SAT), the Ruff 2&7 Selective Attention Test (2&7), the visual n-back, Digit Span, Hayling Test, and Trail Making Test (TMT). t tests revealed that individuals with TBI demonstrated reduced processing speed on the SDMT, n-back, SAT, 2&7, Hayling Test, and TMT-A (p ≤ .002 for all). Digit Span performance did not differ between groups. Mixed-model ANOVAs revealed that individuals with TBI demonstrated a disproportionate increase in reaction time with complexity, which was accounted for by speed on the SAT but remained on the Hayling Inhibition Test after controlling for speed in ANCOVAs. Mann-Whitney U tests revealed that individuals with TBI also made more errors on the Hayling Test, missed responses on the n-back and were unable to benefit from the automatic condition of the 2&7. While slowed speed of information processing was pervasive across tasks after TBI, residual difficulties in response inhibition remained after controlling for slowness, which suggests impaired strategic control. These findings support targeted intervention for slowed

High-speed wavefront control using MEMS micromirrors

NASA Astrophysics Data System (ADS)

Bifano, T. G.; Stewart, J. B.

2005-08-01

Over the past decade, a number of electrostatically-actuated MEMS deformable mirror devices have been used for adaptive control in beam-forming and imaging applications. One architecture that has been widely used is the silicon device developed by Boston University, consisting of a continuous or segmented mirror supported by post attachments to an array of parallel plate electrostatic actuators. MEMS deformable mirrors and segmented mirrors with up to 1024 of these actuators have been used in open loop and closed loop control systems to control wavefront errors. Frame rates as high as 11kHz have been demonstrated. Mechanically, the actuators used in this device exhibit a first-mode resonant frequency that is in the range of many tens of kilohertz up to a few hundred kilohertz. Viscous air damping has been found to limit operation at such high frequencies in air at standard pressure. Some applications in high-speed tracking and beam-forming could benefit from increased speed. In this paper, several approaches to achieving critically-damped performance with such MEMS DMs are detailed, and theoretical and experimental results are presented. One approach is to seal the MEMS DM in a full or partial vacuum environment, thereby affecting air damping. After vacuum sealing the device's predicted resonant behavior at tens of kilohertz was observed. In vacuum, the actuator's intrinsic material damping is quite small, resulting in considerable oscillation in step response. To alleviate this problem, a two-step actuation algorithm was employed. Precise control of a single actuator frequencies up to 100kHz without overshoot was demonstrated using this approach. Another approach to increasing actuation speed was to design actuators that reduce air damping effects. This is also demonstrated in the paper.

Data-based fault-tolerant control of high-speed trains with traction/braking notch nonlinearities and actuator failures.

PubMed

Song, Qi; Song, Yong-Duan

2011-12-01

This paper investigates the position and velocity tracking control problem of high-speed trains with multiple vehicles connected through couplers. A dynamic model reflecting nonlinear and elastic impacts between adjacent vehicles as well as traction/braking nonlinearities and actuation faults is derived. Neuroadaptive fault-tolerant control algorithms are developed to account for various factors such as input nonlinearities, actuator failures, and uncertain impacts of in-train forces in the system simultaneously. The resultant control scheme is essentially independent of system model and is primarily data-driven because with the appropriate input-output data, the proposed control algorithms are capable of automatically generating the intermediate control parameters, neuro-weights, and the compensation signals, literally producing the traction/braking force based upon input and response data only--the whole process does not require precise information on system model or system parameter, nor human intervention. The effectiveness of the proposed approach is also confirmed through numerical simulations.

Muscular control of a learned movement: the speed control system hypothesis.

PubMed

Enoka, R M

1983-01-01

The "speed control system" hypothesis, which represents an attempt to identify an invariant characteristic of learned movements, postulates that movements of variable extent are controlled by regulating the intensity of muscle contractions such that the contraction duration remains constant. The contingency set originally utilized to develop this hypothesis was expanded by examining a movement that was multidirectional and multiarticular, and executed by large muscle groups generating near maximum torques. The investigation focused on the techniques utilized by weightlifters to control lower extremity displacement during the initial phase of the double knee bend execution of the "clean" in Olympic weightlifting. The combination of the quantified muscle activity and the angular velocity, both about the knee joint, revealed a sequence of shortening-lengthening muscle contractions throughout the movement. The first two periods of net muscular activity, one extensor and the other flexor, were utilized to examine the movement for invariant characteristics. As predicted by the speed control system hypothesis, the duration of the first period of net muscle torque activity (extensor) did not vary significantly, for either group of subjects, over the relative loads examined. The duration of the second period of activity (resultant flexor muscle torque), however, was not constant across loads, and further, the direction of the change depended upon the level of expertise. The more capable lifters tended to increase the duration of the resultant flexor involvement while the less skilled athletes utilized the reverse strategy when the load was increased. Conversely, the intensity of the muscle activity for both groups of subjects and both the extensor and flexor periods covaried with load, as predicted by the hypothesis. The speed control system hypothesis, therefore, provided an appropriate explanation for the first component of the movement, the period of extensor dominated

Robust/optimal temperature profile control of a high-speed aerospace vehicle using neural networks.

PubMed

Yadav, Vivek; Padhi, Radhakant; Balakrishnan, S N

2007-07-01

An approximate dynamic programming (ADP)-based suboptimal neurocontroller to obtain desired temperature for a high-speed aerospace vehicle is synthesized in this paper. A 1-D distributed parameter model of a fin is developed from basic thermal physics principles. "Snapshot" solutions of the dynamics are generated with a simple dynamic inversion-based feedback controller. Empirical basis functions are designed using the "proper orthogonal decomposition" (POD) technique and the snapshot solutions. A low-order nonlinear lumped parameter system to characterize the infinite dimensional system is obtained by carrying out a Galerkin projection. An ADP-based neurocontroller with a dual heuristic programming (DHP) formulation is obtained with a single-network-adaptive-critic (SNAC) controller for this approximate nonlinear model. Actual control in the original domain is calculated with the same POD basis functions through a reverse mapping. Further contribution of this paper includes development of an online robust neurocontroller to account for unmodeled dynamics and parametric uncertainties inherent in such a complex dynamic system. A neural network (NN) weight update rule that guarantees boundedness of the weights and relaxes the need for persistence of excitation (PE) condition is presented. Simulation studies show that in a fairly extensive but compact domain, any desired temperature profile can be achieved starting from any initial temperature profile. Therefore, the ADP and NN-based controllers appear to have the potential to become controller synthesis tools for nonlinear distributed parameter systems.

A model predictive speed tracking control approach for autonomous ground vehicles

NASA Astrophysics Data System (ADS)

Zhu, Min; Chen, Huiyan; Xiong, Guangming

2017-03-01

This paper presents a novel speed tracking control approach based on a model predictive control (MPC) framework for autonomous ground vehicles. A switching algorithm without calibration is proposed to determine the drive or brake control. Combined with a simple inverse longitudinal vehicle model and adaptive regulation of MPC, this algorithm can make use of the engine brake torque for various driving conditions and avoid high frequency oscillations automatically. A simplified quadratic program (QP) solving algorithm is used to reduce the computational time, and the approach has been applied in a 16-bit microcontroller. The performance of the proposed approach is evaluated via simulations and vehicle tests, which were carried out in a range of speed-profile tracking tasks. With a well-designed system structure, high-precision speed control is achieved. The system can robustly model uncertainty and external disturbances, and yields a faster response with less overshoot than a PI controller.

The effect of changing disk parameters on whirling frequency of high speed rotor system

NASA Astrophysics Data System (ADS)

Wahab, A. M. Abdul; Rasid, Z. A.; Abu, A.; Rudin, N. F. Mohd Noor; Yakub, F.

2017-12-01

The requirement for efficiency improvement of machines has caused machine rotor to be designed to rotate at high speeds. It is known that whirling natural frequency of a shaft changes with the change of shaft speed and the design needs to avoid points of resonance where the whirling frequency equals the shaft speed. At high speeds, a shaft may have to carry a huge torque along and this torsional effect has been neglected in past shaft analyses. Whirling behaviour of high speed rotating shaft is investigated in this study with consideration of the torsional effect of the shaft. The shaft system under study consists of a shaft, discs and two bearings, and the focus is on the effect of the disc parameters. A finite element formulation is developed based on Nelson’s 5 degrees of freedom (DOF) per node element that includes the torsional degree of freedom. Bolotin’s method is applied to the derived Mathieu-Hill type of equation to get quadratic eigenvalues problem that gives the forward and backward frequencies of the shaft. Campbell’s diagrams are drawn in studying the effect of discs on the whirling behaviour of the shaft. It is found that the addition of disks on the shaft decreases the whirling frequency of the shaft and the frequency is lower for mass located at the centre of the shaft compared to the one located near to the end. The effect of torsional motion is found to be significant where the difference between critical speed of 4DOF and 5DOF models can be as high as 15%.

Effectiveness of changeable message signs in controlling vehicle speeds in work zones.

DOT National Transportation Integrated Search

1994-01-01

Work zone speeds have customarily been regulated by standard regulatory or advisory speed signs. However, most drivers do not slow down in response to these static speed control measures. The changeable message sign (CMS) with radar unit has dynamic ...

Low-Speed Stability-and-Control and Ground-Effects Measurements on the Industry Reference High Speed Civil Transport

NASA Technical Reports Server (NTRS)

Kemmerly, Guy T.; Campbell, Bryan A.; Banks, Daniel W.; Yaros, Steven F.

1999-01-01

As a part of a national effort to develop an economically feasible High Speed Civil Transport (HSCT), a single configuration has been accepted as the testing baseline by the organizations working in the High Speed Research (HSR) program. The configuration is based on a design developed by the Boeing Company and is referred to as the Reference H (Ref H). The data contained in this report are low-speed stability-and-control and ground-effect measurements obtained on a 0.06 scale model of the Ref H in a subsonic tunnel.

Precision electronic speed controller for an alternating-current

DOEpatents

Bolie, Victor W.

1988-01-01

A high precision controller for an alternating-current multi-phase electrical motor that is subject to a large inertial load. The controller was developed for and is particularly suitable for controlling, in a neutron chopper system, a heavy spinning rotor that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal having a meandering line frequency. The controller includes a shaft revolution sensor which provides a feedback pulse train representative of the actual speed of the motor. An internal digital timing signal generator provides a reference signal which is compared with the feedback signal in a computing unit to provide a motor control signal. In the preferred embodiment, the motor control signal is a weighted linear sum of a speed error voltage, a phase error voltage, and a drift error voltage, each of which is computed anew with each revolution of the motor shaft. The stator windings of the motor are driven by two amplifiers which are provided with input signals having the proper quadrature relationship by an exciter unit consisting of a voltage controlled oscillator, a binary counter, a pair of readonly memories, and a pair of digital-to-analog converters.

Controlled Speed Accessory Drive demonstration program

NASA Technical Reports Server (NTRS)

Hoehn, F. W.

1981-01-01

A Controlled Speed Accessory Drive System was examined in an effort to improve the fuel economy of passenger cars. Concept feasibility and the performance of a typical system during actual road driving conditions were demonstrated. The CSAD system is described as a mechanical device which limits engine accessory speeds, thereby reducing parasitic horsepower losses and improving overall vehicle fuel economy. Fuel consumption data were compiled for fleets of GSA vehicles. Various motor pool locations were selected, each representing different climatic conditions. On the basis of a total accumulated fleet usage of nearly three million miles, an overall fuel economy improvement of 6 percent to 7 percent was demonstrated. Coincident chassis dynamometer tests were accomplished on selected vehicles to establish the effect of different accessory drive systems on exhaust emissions, and to evaluate the magnitude of the mileage benefits which could be derived.

Hardware Evolution of Analog Speed Controllers for a DC Motor

NASA Technical Reports Server (NTRS)

Gwaltney, David A.; Ferguson, Michael I.

2003-01-01

This viewgraph presentation provides information on the design of analog speed controllers for DC motors on aerospace systems. The presentation includes an overview of controller evolution, evolvable controller configuration, an emphasis on proportion integral (PI) controllers, schematic diagrams, and experimental results.

Dependencies and Ill-designed Parameters Within High-speed Videoendoscopy and Acoustic Signal Analysis.

PubMed

Schlegel, Patrick; Stingl, Michael; Kunduk, Melda; Kniesburges, Stefan; Bohr, Christopher; Döllinger, Michael

2018-05-31

The phonatory process is often judged during sustained phonation by analyzing the acoustic voice signal and the vocal fold vibrations. Many formulas and parameters have been suggested for qualifying the characteristics of the acoustic signal and the vocal fold vibrations during sustained phonation. These parameters are directly computed from the acoustic signal and the endoscopic glottal area waveform (GAW). The GAW is calculated from laryngeal high-speed videoendoscopy (HSV) recordings and describes the increase and decrease of the glottal area during the phonation process, that is, the opening and closing of the two oscillating vocal folds over time. However, some of the parameters have strong mathematical dependencies with one another and some are ill-defined. The purpose of this study is to identify mathematical dependencies between parameters with the aim of reducing their numbers and suggesting which parameters may best describe the properties of the GAW and the acoustical signal. In this preliminary investigation, 20 frequently used parameters are examined: 10 GAW only and 10 both GAW and acoustic parameters. In total 13 parameters can be neglected because of mathematical dependencies. In addition, nine of these parameters show problematic features that range from unexpected behavior to ill definition. Reducing the number of parameters appears to be necessary to standardize vocal fold function analysis. This may lead to better comparability of research results from different studies. Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Speed And Power Control Of An Engine By Modulation Of The Load Torque

DOEpatents

Ziph, Benjamin; Strodtman, Scott; Rose, Thomas K

1999-01-26

A system and method of speed and power control for an engine in which speed and power of the engine is controlled by modulation of the load torque. The load torque is manipulated in order to cause engine speed, and hence power to be changed. To accomplish such control, the load torque undergoes a temporary excursion in the opposite direction of the desired speed and power change. The engine and the driven equipment will accelerate or decelerate accordingly as the load torque is decreased or increased, relative to the essentially fixed or constant engine torque. As the engine accelerates or decelerates, its power increases or decreases in proportion.

Analytical design of a parasitic-loading digital speed controller for a 400-hertz turbine driven alternator

NASA Technical Reports Server (NTRS)

Ingle, B. D.; Ryan, J. P.

1972-01-01

A design for a solid-state parasitic speed controller using digital logic was analyzed. Parasitic speed controllers are used in space power electrical generating systems to control the speed of turbine-driven alternators within specified limits. The analysis included the performance characteristics of the speed controller and the generation of timing functions. The speed controller using digital logic applies step loads to the alternator. The step loads conduct for a full half wave starting at either zero or 180 electrical degrees.

Measurements of Sound Speed and Grüneisen Parameter in Polystyrene Shocked to 8.5 Mbar

NASA Astrophysics Data System (ADS)

Boehly, T. R.; Rygg, J. R.; Zaghoo, M.; Hu, S. X.; Collins, G. W.; Fratanduono, D. E.; Celliers, P. M.; McCoy, C. A.

2017-10-01

The high-pressure behavior of polymers is important to fundamental high-energy-density studies and inertial confinement fusion experiments. The sound speed affects shock timing and determines the amplitude of modulations in unstable shocks. The Grüneisen parameter provides a means to model off-Hugoniot behavior, especially release physics. We use laser-driven shocks and a nonsteady wave analysis to infer sound speed in shocked material from the arrival times of drive-pressure perturbations at the shock front. Data are presented for CH shocked to 8.5 Mbar and compared to models. The Grüneisen parameter is observed to drop significantly near the insulator-conductor transition-a behavior not predicted by tabular models but is observed in quantum molecular dynamic simulations. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

Differences of muscle co-contraction of the ankle joint between young and elderly adults during dynamic postural control at different speeds.

PubMed

Iwamoto, Yoshitaka; Takahashi, Makoto; Shinkoda, Koichi

2017-08-02

Agonist and antagonist muscle co-contractions during motor tasks are greater in the elderly than in young adults. During normal walking, muscle co-contraction increases with gait speed in young adults, but not in elderly adults. However, no study has compared the effects of speed on muscle co-contraction of the ankle joint during dynamic postural control in young and elderly adults. We compared muscle co-contractions of the ankle joint between young and elderly subjects during a functional stability boundary test at different speeds. Fifteen young adults and 16 community-dwelling elderly adults participated in this study. The task was functional stability boundary tests at different speeds (preferred and fast). Electromyographic evaluations of the tibialis anterior and soleus were recorded. The muscle co-contraction was evaluated using the co-contraction index (CI). There were no statistically significant differences in the postural sway parameters between the two age groups. Elderly subjects showed larger CI in both speed conditions than did the young subjects. CI was higher in the fast speed condition than in the preferred speed condition in the young subjects, but there was no difference in the elderly subjects. Moreover, after dividing the analytical range into phases (acceleration and deceleration phases), the CI was larger in the deceleration phase than in the acceleration phase in both groups, except for the young subjects in the fast speed conditions. Our results showed a greater muscle co-contraction of the ankle joint during dynamic postural control in elderly subjects than in young subjects not only in the preferred speed condition but also in the fast speed condition. In addition, the young subjects showed increased muscle co-contraction in the fast speed condition compared with that in the preferred speed condition; however, the elderly subjects showed no significant difference in muscle co-contraction between the two speed conditions. This indicates

Rotor Position Sensorless Control and Its Parameter Sensitivity of Permanent Magnet Motor Based on Model Reference Adaptive System

NASA Astrophysics Data System (ADS)

Ohara, Masaki; Noguchi, Toshihiko

This paper describes a new method for a rotor position sensorless control of a surface permanent magnet synchronous motor based on a model reference adaptive system (MRAS). This method features the MRAS in a current control loop to estimate a rotor speed and position by using only current sensors. This method as well as almost all the conventional methods incorporates a mathematical model of the motor, which consists of parameters such as winding resistances, inductances, and an induced voltage constant. Hence, the important thing is to investigate how the deviation of these parameters affects the estimated rotor position. First, this paper proposes a structure of the sensorless control applied in the current control loop. Next, it proves the stability of the proposed method when motor parameters deviate from the nominal values, and derives the relationship between the estimated position and the deviation of the parameters in a steady state. Finally, some experimental results are presented to show performance and effectiveness of the proposed method.

Regardless-of-Speed Superconducting LSM Controlled-Repulsive MAGLEV Vehicle

NASA Technical Reports Server (NTRS)

Yoshida, Kinjiro; Egashira, Tatsuya; Hirai, Ryuichi

1996-01-01

This paper proposes a new repulsive Maglev vehicle which a superconducting linear synchronous motor (LSM) can levitate and propel simultaneously, independently of the vehicle speeds. The combined levitation and propulsion control is carried out by controlling mechanical-load angle and armature-current. Dynamic simulations show successful operations with good ride-quality by using a compact control method proposed here.

The effect of speed-accuracy strategy on response interference control in Parkinson's disease.

PubMed

Wylie, S A; van den Wildenberg, W P M; Ridderinkhof, K R; Bashore, T R; Powell, V D; Manning, C A; Wooten, G F

2009-07-01

Studies that used conflict paradigms such as the Eriksen Flanker task show that many individuals with Parkinson's disease (PD) have pronounced difficulty resolving the conflict that arises from the simultaneous activation of mutually exclusive responses. This finding fits well with contemporary views that postulate a key role for the basal ganglia in action selection. The present experiment aims to specify the cognitive processes that underlie action selection deficits among PD patients in the context of variations in speed-accuracy strategy. PD patients (n=28) and healthy controls (n=17) performed an arrow version of the flanker task under task instructions that either emphasized speed or accuracy of responses. Reaction time (RT) and accuracy rates decreased with speed compared to accuracy instructions, although to a lesser extent for the PD group. Differences in flanker interference effects among PD and healthy controls depended on speed-accuracy strategy. Compared to the healthy controls, PD patients showed larger flanker interference effects under speed stress. RT distribution analyses suggested that PD patients have greater difficulty suppressing incorrect response activation when pressing for speed. These initial findings point to an important interaction between strategic and computational aspects of interference control in accounting for cognitive impairments of PD. The results are also compatible with recent brain imaging studies that demonstrate basal ganglia activity to co-vary with speed-accuracy adjustments.

Predicting Minimum Control Speed on the Ground (VMCG) and Minimum Control Airspeed (VMCA) of Engine Inoperative Flight Using Aerodynamic Database and Propulsion Database Generators

NASA Astrophysics Data System (ADS)

Hadder, Eric Michael

There are many computer aided engineering tools and software used by aerospace engineers to design and predict specific parameters of an airplane. These tools help a design engineer predict and calculate such parameters such as lift, drag, pitching moment, takeoff range, maximum takeoff weight, maximum flight range and much more. However, there are very limited ways to predict and calculate the minimum control speeds of an airplane in engine inoperative flight. There are simple solutions, as well as complicated solutions, yet there is neither standard technique nor consistency throughout the aerospace industry. To further complicate this subject, airplane designers have the option of using an Automatic Thrust Control System (ATCS), which directly alters the minimum control speeds of an airplane. This work addresses this issue with a tool used to predict and calculate the Minimum Control Speed on the Ground (VMCG) as well as the Minimum Control Airspeed (VMCA) of any existing or design-stage airplane. With simple line art of an airplane, a program called VORLAX is used to generate an aerodynamic database used to calculate the stability derivatives of an airplane. Using another program called Numerical Propulsion System Simulation (NPSS), a propulsion database is generated to use with the aerodynamic database to calculate both VMCG and VMCA. This tool was tested using two airplanes, the Airbus A320 and the Lockheed Martin C130J-30 Super Hercules. The A320 does not use an Automatic Thrust Control System (ATCS), whereas the C130J-30 does use an ATCS. The tool was able to properly calculate and match known values of VMCG and VMCA for both of the airplanes. The fact that this tool was able to calculate the known values of VMCG and VMCA for both airplanes means that this tool would be able to predict the VMCG and VMCA of an airplane in the preliminary stages of design. This would allow design engineers the ability to use an Automatic Thrust Control System (ATCS) as part

Slip speed feedback for grip force control.

PubMed

Damian, D D; Arita, A H; Martinez, H; Pfeifer, R

2012-08-01

Grasp stability in the human hand has been resolved by means of an intricate network of mechanoreceptors integrating numerous cues about mechanical events, through an ontogenetic grasp practice. An engineered prosthetic interface introduces considerable perturbation risks in grasping, calling for feedback modalities that address the underlying slip phenomenon. In this study, we propose an enhanced slip feedback modality, with potential for myoelectric-based prosthetic applications, that relays information regarding slip events, particularly slip occurrence and slip speed. The proposed feedback modality, implemented using electrotactile stimulation, was evaluated in psychophysical studies of slip control in a simplified setup. The obtained results were compared with vision and a binary slip feedback that transmits on-off information about slip detection. The slip control efficiency of the slip speed display is comparable to that obtained with vision feedback, and it clearly outperforms the efficiency of the on-off slip modality in such tasks. These results suggest that the proposed tactile feedback is a promising sensory method for the restoration of stable grasp in prosthetic applications.

Speed Control Law for Precision Terminal Area In-Trail Self Spacing

NASA Technical Reports Server (NTRS)

Abbott, Terence S.

2002-01-01

This document describes a speed control law for precision in-trail airborne self-spacing during final approach. This control law was designed to provide an operationally viable means to obtain a desired runway threshold crossing time or minimum distance, one aircraft relative to another. The control law compensates for dissimilar final approach speeds between aircraft pairs and provides guidance for a stable final approach. This algorithm has been extensively tested in Monte Carlo simulation and has been evaluated in piloted simulation, with preliminary results indicating acceptability from operational and workload standpoints.

Association between reading speed, cycloplegic refractive error, and oculomotor function in reading disabled children versus controls.

PubMed

Quaid, Patrick; Simpson, Trefford

2013-01-01

Approximately one in ten students aged 6 to 16 in Ontario (Canada) school boards have an individual education plan (IEP) in place due to various learning disabilities, many of which are specific to reading difficulties. The relationship between reading (specifically objectively determined reading speed and eye movement data), refractive error, and binocular vision related clinical measurements remain elusive. One hundred patients were examined in this study (50 IEP and 50 controls, age range 6 to 16 years). IEP patients were referred by three local school boards, with controls being recruited from the routine clinic population (non-IEP patients in the same age group). A comprehensive eye examination was performed on all subjects, in addition to a full binocular vision work-up and cycloplegic refraction. In addition to the cycloplegic refractive error, the following binocular vision related data was also acquired: vergence facility, vergence amplitudes, accommodative facility, accommodative amplitudes, near point of convergence, stereopsis, and a standardized symptom scoring scale. Both the IEP and control groups were also examined using the Visagraph III system, which permits recording of the following reading parameters objectively: (i) reading speed, both raw values and values compared to grade normative data, and (ii) the number of eye movements made per 100 words read. Comprehension was assessed via a questionnaire administered at the end of the reading task, with each subject requiring 80% or greater comprehension. The IEP group had significantly greater hyperopia compared to the control group on cycloplegic examination. Vergence facility was significantly correlated to (i) reading speed, (ii) number of eye movements made when reading, and (iii) a standardized symptom scoring system. Vergence facility was also significantly reduced in the IEP group versus controls. Significant differences in several other binocular vision related scores were also found. This

Effects of walking speed on the step-by-step control of step width.

PubMed

Stimpson, Katy H; Heitkamp, Lauren N; Horne, Joscelyn S; Dean, Jesse C

2018-02-08

Young, healthy adults walking at typical preferred speeds use step-by-step adjustments of step width to appropriately redirect their center of mass motion and ensure mediolateral stability. However, it is presently unclear whether this control strategy is retained when walking at the slower speeds preferred by many clinical populations. We investigated whether the typical stabilization strategy is influenced by walking speed. Twelve young, neurologically intact participants walked on a treadmill at a range of prescribed speeds (0.2-1.2 m/s). The mediolateral stabilization strategy was quantified as the proportion of step width variance predicted by the mechanical state of the pelvis throughout a step (calculated as R 2 magnitude from a multiple linear regression). Our ability to accurately predict the upcoming step width increased over the course of a step. The strength of the relationship between step width and pelvis mechanics at the start of a step was reduced at slower speeds. However, these speed-dependent differences largely disappeared by the end of a step, other than at the slowest walking speed (0.2 m/s). These results suggest that mechanics-dependent adjustments in step width are a consistent component of healthy gait across speeds and contexts. However, slower walking speeds may ease this control by allowing mediolateral repositioning of the swing leg to occur later in a step, thus encouraging slower walking among clinical populations with limited sensorimotor control. Published by Elsevier Ltd.

Speed Pressure in Conflict Situations Impedes Inhibitory Action Control in Parkinson’s Disease

PubMed Central

Van Wouwe, N.C.; van den Wildenberg, W.P.M.; Claassen, D.O.; Kanoff, K.; Bashore, T.R.; Wylie, S.A.

2014-01-01

Parkinson’s disease (PD) is a neurodegenerative basal ganglia disease that disrupts cognitive control processes involved in response selection. The current study investigated the effects of PD on the ability to resolve conflicts during response selection when performance emphasized response speed versus response accuracy. Twenty-one (21) PD patients and 21 healthy controls (HC) completed a Simon conflict task, and a subset of 10 participants from each group provided simultaneous movement-related potential (MRP) data to track patterns of motor cortex activation and inhibition associated with the successful resolution of conflicting response tendencies. Both groups adjusted performance strategically to emphasize response speed or accuracy (i.e., speed-accuracy effect). For HC, interference from a conflicting response was reduced when response accuracy rather than speed was prioritized. For PD patients, however, there was a reduction in interference, but it was not statistically significant. The conceptual framework of the Dual-Process Activation-Suppression (DPAS) model revealed that the groups experienced similar susceptibility to making fast impulsive errors in conflict trials irrespective of speed-accuracy instructions, but PD patients were less proficient and delayed compared to HC at suppressing the interference from these incorrect response tendencies, especially under speed pressure. Analysis of MRPs on response conflict trials showed attenuated inhibition of the motor cortex controlling the conflicting impulsive response tendency in PD patients compared to HC. These results further confirm the detrimental effects of PD inhibitory control mechanisms and their exacerbation when patients perform under speed pressure. The results also suggest that a downstream effect of inhibitory dysfunction in PD is diminished inhibition of motor cortex controlling conflicting response tendencies. PMID:25017503

Low Speed Control for Automatic Welding

NASA Technical Reports Server (NTRS)

Iceland, W. E.

1982-01-01

Amplifier module allows rotating positioner of automatic welding machine to operate at speeds below normal range. Low speeds are precisely regulated by a servomechanism as are normal-range speeds. Addition of module to standard welding machine makes it unnecessary to purchase new equipment for low-speed welding.

Design of permanent magnet synchronous motor speed control system based on SVPWM

NASA Astrophysics Data System (ADS)

Wu, Haibo

2017-04-01

The control system is designed to realize TMS320F28335 based on the permanent magnet synchronous motor speed control system, and put it to quoting all electric of injection molding machine. The system of the control method used SVPWM, through the sampling motor current and rotating transformer position information, realize speed, current double closed loop control. Through the TMS320F28335 hardware floating-point processing core, realize the application for permanent magnet synchronous motor in the floating point arithmetic, to replace the past fixed-point algorithm, and improve the efficiency of the code.

Preload-Based Starling-Like Control for Rotary Blood Pumps: Numerical Comparison with Pulsatility Control and Constant Speed Operation

PubMed Central

Mansouri, Mahdi; Salamonsen, Robert F.; Lim, Einly; Akmeliawati, Rini; Lovell, Nigel H.

2015-01-01

In this study, we evaluate a preload-based Starling-like controller for implantable rotary blood pumps (IRBPs) using left ventricular end-diastolic pressure (PLVED) as the feedback variable. Simulations are conducted using a validated mathematical model. The controller emulates the response of the natural left ventricle (LV) to changes in PLVED. We report the performance of the preload-based Starling-like controller in comparison with our recently designed pulsatility controller and constant speed operation. In handling the transition from a baseline state to test states, which include vigorous exercise, blood loss and a major reduction in the LV contractility (LVC), the preload controller outperformed pulsatility control and constant speed operation in all three test scenarios. In exercise, preload-control achieved an increase of 54% in mean pump flow (QP-) with minimum loading on the LV, while pulsatility control achieved only a 5% increase in flow and a decrease in mean pump speed. In a hemorrhage scenario, the preload control maintained the greatest safety margin against LV suction. PLVED for the preload controller was 4.9 mmHg, compared with 0.4 mmHg for the pulsatility controller and 0.2 mmHg for the constant speed mode. This was associated with an adequate mean arterial pressure (MAP) of 84 mmHg. In transition to low LVC, QP- for preload control remained constant at 5.22 L/min with a PLVED of 8.0 mmHg. With regards to pulsatility control, QP- fell to the nonviable level of 2.4 L/min with an associated PLVED of 16 mmHg and a MAP of 55 mmHg. Consequently, pulsatility control was deemed inferior to constant speed mode with a PLVED of 11 mmHg and a QP- of 5.13 L/min in low LVC scenario. We conclude that pulsatility control imposes a danger to the patient in the severely reduced LVC scenario, which can be overcome by using a preload-based Starling-like control approach. PMID:25849979

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.

Low-Speed Stability and Control Test of a "Double-Bubble" Transport Configuration

NASA Technical Reports Server (NTRS)

Vicroy, Dan D.

2017-01-01

A test in the Langley 12-Foot Low-Speed Tunnel was conducted as a risk mitigation effort to quickly obtain some low-speed stability and control data on a "double-bubble" or D8 transport configuration. The test also tested some configuration design trades. A 5-percent scale model was tested with stabilizer, elevator, rudder and aileron control deflections. This report summarizes the test results.

An exploration of the influence of diagonal dissociation and moderate changes in speed on locomotor parameters in trotting horses.

PubMed

Hobbs, Sarah Jane; Bertram, John E A; Clayton, Hilary M

2016-01-01

Background. Although the trot is described as a diagonal gait, contacts of the diagonal pairs of hooves are not usually perfectly synchronized. Although subtle, the timing dissociation between contacts of each diagonal pair could have consequences on gait dynamics and provide insight into the functional strategies employed. This study explores the mechanical effects of different diagonal dissociation patterns when speed was matched between individuals and how these effects link to moderate, natural changes in trotting speed. We anticipate that hind-first diagonal dissociation at contact increases with speed, diagonal dissociation at contact can reduce collision-based energy losses and predominant dissociation patterns will be evident within individuals. Methods. The study was performed in two parts: in the first 17 horses performed speed-matched trotting trials and in the second, five horses each performed 10 trotting trials that represented a range of individually preferred speeds. Standard motion capture provided kinematic data that were synchronized with ground reaction force (GRF) data from a series of force plates. The data were analyzed further to determine temporal, speed, GRF, postural, mass distribution, moment, and collision dynamics parameters. Results. Fore-first, synchronous, and hind-first dissociations were found in horses trotting at (3.3 m/s ± 10%). In these speed-matched trials, mean centre of pressure (COP) cranio-caudal location differed significantly between the three dissociation categories. The COP moved systematically and significantly (P = .001) from being more caudally located in hind-first dissociation (mean location = 0.41 ± 0.04) through synchronous (0.36 ± 0.02) to a more cranial location in fore-first dissociation (0.32 ± 0.02). Dissociation patterns were found to influence function, posture, and balance parameters. Over a moderate speed range, peak vertical forelimb GRF had a strong relationship with dissociation time (R = .594

Planning Robot-Control Parameters With Qualitative Reasoning

NASA Technical Reports Server (NTRS)

Peters, Stephen F.

1993-01-01

Qualitative-reasoning planning algorithm helps to determine quantitative parameters controlling motion of robot. Algorithm regarded as performing search in multidimensional space of control parameters from starting point to goal region in which desired result of robotic manipulation achieved. Makes use of directed graph representing qualitative physical equations describing task, and interacts, at each sampling period, with history of quantitative control parameters and sensory data, to narrow search for reliable values of quantitative control parameters.

Transitions induced by speed in self-propelled particles system with attractive interactions

NASA Astrophysics Data System (ADS)

Cambui, Dorilson. S.; Rosas, Alexandre

2018-05-01

In this work, we consider a system of self-propelled particles with attractive interactions in two dimensions. The model presents an order-disorder transition with the speed playing the role of the control parameter. In order to characterize the transition, we investigate the behavior of the order parameter and the Binder cumulant as a function of the speed. Our main finding is that the transition can be either continuous or discontinuous depending on two parameter of the model: the strength of the noise and the radius of attraction.

Passive control of rotorcraft high-speed impulsive noise

NASA Astrophysics Data System (ADS)

Szulc, O.; Doerffer, P.; Tejero, F.

2016-10-01

A strong, normal shock wave, terminating a local supersonic area located at the tip of a helicopter blade, not only limits the aerodynamic performance, but also constitutes an origin of the High-Speed Impulsive (HSI) noise. The application of a passive control device (a shallow cavity covered by a perforated plate) just beneath the interaction region weakens the compression level, thus reducing the main source of the HSI noise. The numerical investigation based on the URANS approach and Bohning/Doerffer (BD) transpiration law (SPARC code) confirms a large potential of the new method. Two exemplary implementations, adapted to model helicopter rotors tested at NASA Ames facility in transonic conditions: Caradonna-Tung (lifting, transonic hover) and Caradonna-Laub-Tung (non-lifting, high-speed forward flight), demonstrate the possible gains in terms of the reduction of acoustic pressure fluctuations in the near-field of the blade tip. The CFD results are validated against the experimental data obtained for the reference configurations (no control), while the analysis of the passive control arrangement is based on a purely numerical research. The normal shock wave is effectively eliminated by the wall ventilation exerting a positive impact on the generated level of the HSI noise.

Speed control of an induction motor by 6-switched 3-level inverter

NASA Astrophysics Data System (ADS)

Saygin, Ali; Kerem, Alper

2017-12-01

This paper presents speed control analysis of an induction motor by a 6-switched 3-level inverter. In the analysis of topology, the study used the field oriented control technique which is widely used in the literature, easy and stable for operating systems. The field weaking technique was used for speeds exceeding nominal speed to reduce magnetic saturation and thermal losses. At the end of the process, it was observed to increase motor torque and inverter efficiency. Instead of using 12 switches in conventional 3-level inverters, 6 switches are used in this topology. Reduced number of switches is the greatest contribution of this study.

Hardware Evolution of Analog Speed Controllers for a DC Motor

NASA Technical Reports Server (NTRS)

Gwaltney, David A.; Ferguson, Michael I.

2003-01-01

Evolvable hardware provides the capability to evolve analog circuits to produce amplifier and filter functions. Conventional analog controller designs employ these same functions. Analog controllers for the control of the shaft speed of a DC motor are evolved on an evolvable hardware platform utilizing a Field Programmable Transistor Array (FPTA). The performance of these evolved controllers is compared to that of a conventional proportional-integral (PI) controller.

High-speed reference-beam-angle control technique for holographic memory drive

NASA Astrophysics Data System (ADS)

Yamada, Ken-ichiro; Ogata, Takeshi; Hosaka, Makoto; Fujita, Koji; Okuyama, Atsushi

2016-09-01

We developed a holographic memory drive for next-generation optical memory. In this study, we present the key technology for achieving a high-speed transfer rate for reproduction, that is, a high-speed control technique for the reference beam angle. In reproduction in a holographic memory drive, there is the issue that the optimum reference beam angle during reproduction varies owing to distortion of the medium. The distortion is caused by, for example, temperature variation, beam irradiation, and moisture absorption. Therefore, a reference-beam-angle control technique to position the reference beam at the optimum angle is crucial. We developed a new optical system that generates an angle-error-signal to detect the optimum reference beam angle. To achieve the high-speed control technique using the new optical system, we developed a new control technique called adaptive final-state control (AFSC) that adds a second control input to the first one derived from conventional final-state control (FSC) at the time of angle-error-signal detection. We established an actual experimental system employing AFSC to achieve moving control between each page (Page Seek) within 300 µs. In sequential multiple Page Seeks, we were able to realize positioning to the optimum angles of the reference beam that maximize the diffracted beam intensity. We expect that applying the new control technique to the holographic memory drive will enable a giga-bit/s-class transfer rate.

Steering Law Controlling the Constant Speeds of Control Moment Gyros

NASA Astrophysics Data System (ADS)

KOYASAKO, Y.; TAKAHASHI, M.

2016-09-01

To enable the agile control of satellites, using control moment gyros (CMGs) has become increasingly necessary because of their ability to generate large amounts of torque. However, CMGs have a singularity problem whereby the torque by the CMGs degenerates from three dimensions to two dimensions, affecting spacecraft attitude control performance. This study proposes a new steering control law for CMGs by controlling the constant speed of a CMG. The proposed method enables agile attitude changes, according to the required task, by managing the total angular momentum of the CMGs by considering the distance to external singularities. In the proposed method, the total angular momentum is biased in a specific direction and the angular momentum envelope is extended. The design method can increase the net angular momentum of CMGs which can be exchanged with the satellite. The effectiveness of the proposed method is demonstrated by numerical simulations.

75 FR 37453 - Notice of Issuance of Final Determination Concerning Dimmer and Fan Speed Switch Controls

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-29

... Determination Concerning Dimmer and Fan Speed Switch Controls AGENCY: U.S. Customs and Border Protection... country of origin of certain dimmer and fan speed switch controls which may be offered to the United... determination CBP concluded that Mexico is the country of origin of the dimmer and fan speed switch controls for...

Improved Speed Control System for the 87,000 HP Wind Tunnel Drive

NASA Technical Reports Server (NTRS)

Becks, Edward A.; Bencic, Timothy J.; Blumenthal, Philip Z.

1995-01-01

This paper describes the design, installation, and integrated systems tests for a new drive motor speed control system which was part of a recent rehab project for the NASA Lewis 8x6 Supersonic Wind Tunnel. The tunnel drive consists of three mechanically-coupled 29,000 HP wound rotor induction motors driving an axial flow compressor. Liquid rheostats are used to vary the impedance of the rotor circuits, thus varying the speed of the drive system. The new design utilizes a distributed digital control system with a dual touch screen CRT operator console to provide alarm monitoring, logging, and trending. The liquid rheostats are driven by brushtype servomotor systems with magnetostrictive linear displacement transducers used for position feedback. The new system achieved all goals for speed variations with load, motor load balance, and control of total power.

Improved speed control system for the 87,000 HP wind tunnel drive

NASA Astrophysics Data System (ADS)

Becks, Edward A.; Bencic, Timothy J.; Blumenthal, Philip Z.

1995-01-01

This paper describes the design, installation, and integrated systems tests for a new drive motor speed control system which was part of a recent rehab project for the NASA Lewis 8x6 Supersonic Wind Tunnel. The tunnel drive consists of three mechanically-coupled 29,000 HP wound rotor induction motors driving an axial flow compressor. Liquid rheostats are used to vary the impedance of the rotor circuits, thus varying the speed of the drive system. The new design utilizes a distributed digital control system with a dual touch screen CRT operator console to provide alarm monitoring, logging, and trending. The liquid rheostats are driven by brushtype servomotor systems with magnetostrictive linear displacement transducers used for position feedback. The new system achieved all goals for speed variations with load, motor load balance, and control of total power.

Helicopter main-rotor speed effects on far-field acoustic levels

NASA Technical Reports Server (NTRS)

Mueller, Arnold W.; Childress, Otis S.; Hardesty, Mark

1987-01-01

The design of a helicopter is based on an understanding of many parameters and their interactions. For example, in the design stage of a helicopter, the weight, engine, and rotor speed must be considered along with the rotor geometry when considering helicopter operations. However, the relationship between the noise radiated from the helicopter and these parameters is not well understood, with only limited model and full-scale test data to study. In general, these data have shown that reduced rotor speeds result in reduced far-field noise levels. This paper reviews the status of a recent helicopter noise research project designed to provide experimental flight data to be used to better understand helicopter rotor-speed effects on far-field acoustic levels. Preliminary results are presented relative to tests conducted with a McDonnell Douglas model 500E helicopter operating with the rotor speed as the control variable over the range of 103% of the main-rotor speed (NR) to 75% NR, and with the forward speed maintained at a constant value of 80 knots.

Linear Parameter Varying Control Synthesis for Actuator Failure, Based on Estimated Parameter

NASA Technical Reports Server (NTRS)

Shin, Jong-Yeob; Wu, N. Eva; Belcastro, Christine

2002-01-01

The design of a linear parameter varying (LPV) controller for an aircraft at actuator failure cases is presented. The controller synthesis for actuator failure cases is formulated into linear matrix inequality (LMI) optimizations based on an estimated failure parameter with pre-defined estimation error bounds. The inherent conservatism of an LPV control synthesis methodology is reduced using a scaling factor on the uncertainty block which represents estimated parameter uncertainties. The fault parameter is estimated using the two-stage Kalman filter. The simulation results of the designed LPV controller for a HiMXT (Highly Maneuverable Aircraft Technology) vehicle with the on-line estimator show that the desired performance and robustness objectives are achieved for actuator failure cases.

Load speed regulation in compliant mechanical transmission systems using feedback and feedforward control actions.

PubMed

Raul, P R; Dwivedula, R V; Pagilla, P R

2016-07-01

The problem of controlling the load speed of a mechanical transmission system consisting of a belt-pulley and gear-pair is considered. The system is modeled as two inertia (motor and load) connected by a compliant transmission. If the transmission is assumed to be rigid, then using either the motor or load speed feedback provides the same result. However, with transmission compliance, due to belts or long shafts, the stability characteristics and performance of the closed-loop system are quite different when either motor or load speed feedback is employed. We investigate motor and load speed feedback schemes by utilizing the singular perturbation method. We propose and discuss a control scheme that utilizes both motor and load speed feedback, and design an adaptive feedforward action to reject load torque disturbances. The control algorithms are implemented on an experimental platform that is typically used in roll-to-roll manufacturing and results are shown and discussed. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Speed-dependent Voigt lineshape parameter database from dual frequency comb measurements up to 1305 K. Part I: Pure H2O absorption, 6801-7188 cm-1

NASA Astrophysics Data System (ADS)

Schroeder, Paul J.; Cich, Matthew J.; Yang, Jinyu; Giorgetta, Fabrizio R.; Swann, William C.; Coddington, Ian; Newbury, Nathan R.; Drouin, Brian J.; Rieker, Gregory B.

2018-05-01

We measure speed-dependent Voigt lineshape parameters with temperature-dependence exponents for several hundred spectroscopic features of pure water spanning 6801-7188 cm-1. The parameters are extracted from broad bandwidth, high-resolution dual frequency comb absorption spectra with multispectrum fitting techniques. The data encompass 25 spectra ranging from 296 K to 1305 K and 1 to 17 Torr of pure water vapor. We present the extracted parameters, compare them to published data, and present speed-dependence, self-shift, and self-broadening temperature-dependent parameters for the first time. Lineshape data is extracted using a quadratic speed-dependent Voigt profile and a single self-broadening power law temperature-dependence exponent over the entire temperature range. The results represent an important step toward a new high-temperature database using advanced lineshape profiles.

Distinct neural markers of TVA-based visual processing speed and short-term storage capacity parameters.

PubMed

Wiegand, Iris; Töllner, Thomas; Habekost, Thomas; Dyrholm, Mads; Müller, Hermann J; Finke, Kathrin

2014-08-01

An individual's visual attentional capacity is characterized by 2 central processing resources, visual perceptual processing speed and visual short-term memory (vSTM) storage capacity. Based on Bundesen's theory of visual attention (TVA), independent estimates of these parameters can be obtained from mathematical modeling of performance in a whole report task. The framework's neural interpretation (NTVA) further suggests distinct brain mechanisms underlying these 2 functions. Using an interindividual difference approach, the present study was designed to establish the respective ERP correlates of both parameters. Participants with higher compared to participants with lower processing speed were found to show significantly reduced visual N1 responses, indicative of higher efficiency in early visual processing. By contrast, for participants with higher relative to lower vSTM storage capacity, contralateral delay activity over visual areas was enhanced while overall nonlateralized delay activity was reduced, indicating that holding (the maximum number of) items in vSTM relies on topographically specific sustained activation within the visual system. Taken together, our findings show that the 2 main aspects of visual attentional capacity are reflected in separable neurophysiological markers, validating a central assumption of NTVA. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Heat engine generator control system

DOEpatents

Rajashekara, K.; Gorti, B.V.; McMullen, S.R.; Raibert, R.J.

1998-05-12

An electrical power generation system includes a heat engine having an output member operatively coupled to the rotor of a dynamoelectric machine. System output power is controlled by varying an electrical parameter of the dynamoelectric machine. A power request signal is related to an engine speed and the electrical parameter is varied in accordance with a speed control loop. Initially, the sense of change in the electrical parameter in response to a change in the power request signal is opposite that required to effectuate a steady state output power consistent with the power request signal. Thereafter, the electrical parameter is varied to converge the output member speed to the speed known to be associated with the desired electrical output power. 8 figs.

Heat engine generator control system

DOEpatents

Rajashekara, Kaushik; Gorti, Bhanuprasad Venkata; McMullen, Steven Robert; Raibert, Robert Joseph

1998-01-01

An electrical power generation system includes a heat engine having an output member operatively coupled to the rotor of a dynamoelectric machine. System output power is controlled by varying an electrical parameter of the dynamoelectric machine. A power request signal is related to an engine speed and the electrical parameter is varied in accordance with a speed control loop. Initially, the sense of change in the electrical parameter in response to a change in the power request signal is opposite that required to effectuate a steady state output power consistent with the power request signal. Thereafter, the electrical parameter is varied to converge the output member speed to the speed known to be associated with the desired electrical output power.

Direct Evidence for Vision-based Control of Flight Speed in Budgerigars.

PubMed

Schiffner, Ingo; Srinivasan, Mandyam V

2015-06-05

We have investigated whether, and, if so, how birds use vision to regulate the speed of their flight. Budgerigars, Melopsittacus undulatus, were filmed in 3-D using high-speed video cameras as they flew along a 25 m tunnel in which stationary or moving vertically oriented black and white stripes were projected on the side walls. We found that the birds increased their flight speed when the stripes were moved in the birds' flight direction, but decreased it only marginally when the stripes were moved in the opposite direction. The results provide the first direct evidence that Budgerigars use cues based on optic flow, to regulate their flight speed. However, unlike the situation in flying insects, it appears that the control of flight speed in Budgerigars is direction-specific. It does not rely solely on cues derived from optic flow, but may also be determined by energy constraints.

Direct Evidence for Vision-based Control of Flight Speed in Budgerigars

PubMed Central

Schiffner, Ingo; Srinivasan, Mandyam V.

2015-01-01

We have investigated whether, and, if so, how birds use vision to regulate the speed of their flight. Budgerigars, Melopsittacus undulatus, were filmed in 3-D using high-speed video cameras as they flew along a 25 m tunnel in which stationary or moving vertically oriented black and white stripes were projected on the side walls. We found that the birds increased their flight speed when the stripes were moved in the birds’ flight direction, but decreased it only marginally when the stripes were moved in the opposite direction. The results provide the first direct evidence that Budgerigars use cues based on optic flow, to regulate their flight speed. However, unlike the situation in flying insects, it appears that the control of flight speed in Budgerigars is direction-specific. It does not rely solely on cues derived from optic flow, but may also be determined by energy constraints. PMID:26046799

Method and system for controlling a rotational speed of a rotor of a turbogenerator

DOEpatents

Stahlhut, Ronnie Dean; Vuk, Carl Thomas

2008-12-30

A system and method controls a rotational speed of a rotor or shaft of a turbogenerator in accordance with a present voltage level on a direct current bus. A lower threshold and a higher threshold are established for a speed of a rotor or shaft of a turbogenerator. A speed sensor determines speed data or a speed signal for the rotor or shaft associated with a turbogenerator. A voltage regulator adjusts a voltage level associated with a direct current bus within a target voltage range if the speed data or speed signal indicates that the speed is above the higher threshold or below the lower threshold.

Speed synchronization control for integrated automotive motor-transmission powertrain system with random delays

NASA Astrophysics Data System (ADS)

Zhu, Xiaoyuan; Zhang, Hui; Fang, Zongde

2015-12-01

This paper presents a robust speed synchronization controller design for an integrated motor-transmission powertrain system in which the driving motor and multi-gearbox are directly coupled. As the controller area network (CAN) is commonly used in the vehicle powertrain system, the possible network-induced random delays in both feedback and forward channel are considered and modeled by using two Markov chains in the controller design process. For the application perspective, the control law adopted here is a generalized proportional-integral (PI) control. By employing the system-augmentation technique, a delay-free stochastic closed-loop system is obtained and the generalized PI controller design problem is converted to a static output feedback (SOF) controller design problem. Since there are external disturbances involved in the closed-loop system, the energy-to-peak performance is considered to guarantee the robustness of the controller. And the controlled output is chosen as the speed synchronization error. To further improve the transient response of the closed-loop system, the pole placement is also employed in the energy-to-peak performance based speed synchronization control. The mode-dependent control gains are obtained by using an iterative linear matrix inequality (LMI) algorithm. Simulation results show the effectiveness of the proposed control approach.

Solid state circuit controls direction, speed, and braking of dc motor

NASA Technical Reports Server (NTRS)

Hanna, M. F.

1966-01-01

Full-wave bridge rectifier circuit controls the direction, speed, and braking of a dc motor. Gating in the circuit of Silicon Controlled Rectifiers /SCRS/ controls output polarity and braking is provided by an SCR that is gated to short circuit the reverse voltage generated by reversal of motor rotation.

Parameter Design and Optimal Control of an Open Core Flywheel Energy Storage System

NASA Technical Reports Server (NTRS)

Pang, D.; Anand, D. K.; Kirk, J. A.

1996-01-01

In low earth orbit (LEO) satellite applications spacecraft power is provided by photovoltaic cells and batteries. To overcome battery shortcomings the University of Maryland, working in cooperation with NASA/GSFC and NASA/LeRC, has developed a magnetically suspended flywheel for energy storage applications. The system is referred to as an Open Core Composite Flywheel (OCCF) energy storage system. Successful application of flywheel energy storage requires integration of several technologies, viz. bearings, rotor design, motor/generator, power conditioning, and system control. In this paper we present a parameter design method which has been developed for analyzing the linear SISO model of the magnetic bearing controller for the OCCF. The objective of this continued research is to principally analyze the magnetic bearing system for nonlinear effects in order to increase the region of stability, as determined by high speed and large air gap control. This is achieved by four tasks: (1) physical modeling, design, prototyping, and testing of an improved magnetically suspended flywheel energy storage system, (2) identification of problems that limit performance and their corresponding solutions, (3) development of a design methodology for magnetic bearings, and (4) design of an optimal controller for future high speed applications. Both nonlinear SISO and MIMO models of the magnetic system were built to study limit cycle oscillations and power amplifier saturation phenomenon observed in experiments. The nonlinear models include the inductance of EM coils, the power amplifier saturation, and the physical limitation of the flywheel movement as discussed earlier. The control program EASY5 is used to study the nonlinear SISO and MIMO models. Our results have shown that the characteristics and frequency responses of the magnetic bearing system obtained from modeling are comparable to those obtained experimentally. Although magnetic saturation is shown in the bearings, there

High-Speed Current dq PI Controller for Vector Controlled PMSM Drive

PubMed Central

Reaz, Mamun Bin Ibne; Rahman, Labonnah Farzana; Chang, Tae Gyu

2014-01-01

High-speed current controller for vector controlled permanent magnet synchronous motor (PMSM) is presented. The controller is developed based on modular design for faster calculation and uses fixed-point proportional-integral (PI) method for improved accuracy. Current dq controller is usually implemented in digital signal processor (DSP) based computer. However, DSP based solutions are reaching their physical limits, which are few microseconds. Besides, digital solutions suffer from high implementation cost. In this research, the overall controller is realizing in field programmable gate array (FPGA). FPGA implementation of the overall controlling algorithm will certainly trim down the execution time significantly to guarantee the steadiness of the motor. Agilent 16821A Logic Analyzer is employed to validate the result of the implemented design in FPGA. Experimental results indicate that the proposed current dq PI controller needs only 50 ns of execution time in 40 MHz clock, which is the lowest computational cycle for the era. PMID:24574913

The hippocampus participates in the control of locomotion speed.

PubMed

López Ruiz, J R; Osuna Carrasco, L P; López Valenzuela, C L; Franco Rodríguez, N E; de la Torre Valdovinos, B; Jiménez Estrada, I; Dueñas Jiménez, J M; Dueñas Jiménez, S H

2015-12-17

The hippocampus role in sensory-motor integration remains unclear. In these experiments we study its function in the locomotor control. To establish the connection between the hippocampus and the locomotor system, electrical stimulation in the CA1 region was applied and EMG recordings were obtained. We also evaluated the hindlimbs and forelimbs kinematic patterns in rats with a penetrating injury (PI) in the hippocampus as well as in a cortex-injured group (CI), which served as control. After the PI, tamoxifen a selective estrogen receptor modulator (SERM) that has been described as a neuroprotector and antiinflammatory drug, or vehicle was administered. Electrical stimulation in the hippocampus produces muscle contractions in the contralateral triceps, when 6 Hz or 8 Hz pulse trains were applied. The penetrating injury in the hippocampus reduced the EMG amplitude after the electrical stimulation. At 7 DPI (days post-injury) we observed an increase in the strides speed in all four limbs of the non-treated group, decreasing the correlation percentage of the studied joints. After 15 DPI the strides speed in the non-treated returned to normal. These changes did not occur in the tamoxifen group nor in cortex-injured group. After 30 days, the nontreated group presented a reduction in the number of pyramidal cell layer neurons at the injury site, in comparison to the tam-treated group. The loss of neurons, may cause the interruption of the trisynaptic circuit and changes in the locomotion speed. Tamoxifen preserves the pyramidal neurons after the injury, probably resulting in the strides speed recovery. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Power Maximization Control of Variable Speed Wind Generation System Using Permanent Magnet Synchronous Generator

NASA Astrophysics Data System (ADS)

Morimoto, Shigeo; Nakamura, Tomohiko; Takeda, Yoji

This paper proposes the sensorless output power maximization control of the wind generation system. A permanent magnet synchronous generator (PMSG) is used as a variable speed generator in the proposed system. The generator torque is suitably controlled according to the generator speed and thus the power from a wind turbine settles down on the maximum power point by the proposed MPPT control method, where the information of wind velocity is not required. Moreover, the maximum available generated power is obtained by the optimum current vector control. The current vector of PMSG is optimally controlled according to the generator speed and the required torque in order to minimize the losses of PMSG considering the voltage and current constraints. The proposed wind power generation system can be achieved without mechanical sensors such as a wind velocity detector and a position sensor. Several experimental results show the effectiveness of the proposed control method.

Excitations for Rapidly Estimating Flight-Control Parameters

NASA Technical Reports Server (NTRS)

Moes, Tim; Smith, Mark; Morelli, Gene

2006-01-01

A flight test on an F-15 airplane was performed to evaluate the utility of prescribed simultaneous independent surface excitations (PreSISE) for real-time estimation of flight-control parameters, including stability and control derivatives. The ability to extract these derivatives in nearly real time is needed to support flight demonstration of intelligent flight-control system (IFCS) concepts under development at NASA, in academia, and in industry. Traditionally, flight maneuvers have been designed and executed to obtain estimates of stability and control derivatives by use of a post-flight analysis technique. For an IFCS, it is required to be able to modify control laws in real time for an aircraft that has been damaged in flight (because of combat, weather, or a system failure). The flight test included PreSISE maneuvers, during which all desired control surfaces are excited simultaneously, but at different frequencies, resulting in aircraft motions about all coordinate axes. The objectives of the test were to obtain data for post-flight analysis and to perform the analysis to determine: 1) The accuracy of derivatives estimated by use of PreSISE, 2) The required durations of PreSISE inputs, and 3) The minimum required magnitudes of PreSISE inputs. The PreSISE inputs in the flight test consisted of stacked sine-wave excitations at various frequencies, including symmetric and differential excitations of canard and stabilator control surfaces and excitations of aileron and rudder control surfaces of a highly modified F-15 airplane. Small, medium, and large excitations were tested in 15-second maneuvers at subsonic, transonic, and supersonic speeds. Typical excitations are shown in Figure 1. Flight-test data were analyzed by use of pEst, which is an industry-standard output-error technique developed by Dryden Flight Research Center. Data were also analyzed by use of Fourier-transform regression (FTR), which was developed for onboard, real-time estimation of the

Intelligent control for PMSM based on online PSO considering parameters change

NASA Astrophysics Data System (ADS)

Song, Zhengqiang; Yang, Huiling

2018-03-01

A novel online particle swarm optimization method is proposed to design speed and current controllers of vector controlled interior permanent magnet synchronous motor drives considering stator resistance variation. In the proposed drive system, the space vector modulation technique is employed to generate the switching signals for a two-level voltage-source inverter. The nonlinearity of the inverter is also taken into account due to the dead-time, threshold and voltage drop of the switching devices in order to simulate the system in the practical condition. Speed and PI current controller gains are optimized with PSO online, and the fitness function is changed according to the system dynamic and steady states. The proposed optimization algorithm is compared with conventional PI control method in the condition of step speed change and stator resistance variation, showing that the proposed online optimization method has better robustness and dynamic characteristics compared with conventional PI controller design.

Speed dependence of CH335Cl-O2 line-broadening parameters probed on rotational transitions: Measurements and semi-classical calculations

NASA Astrophysics Data System (ADS)

Buldyreva, J.; Margulès, L.; Motiyenko, R. A.; Rohart, F.

2013-11-01

Relaxation parameters for K-components (K≤6) of six J→J+1 rotational transitions (J=6, 10, 17, 22, 31 and 33) of CH335Cl perturbed by O2 are measured at room temperature with Voigt, speed-dependent Voigt and Galatry profiles in order to probe the speed-dependence effects. With respect to the previous study of CH335Cl-N2 system [Guinet et al., J Quant Spectrosc Radiat Transfer 2012;113:1113], higher active-gas pressures are reached, providing better signal-to-noise ratios, and the exact expression of the Beer-Lambert law is introduced in the fitting procedure, leading, among other advantages, to much more realistic low-pressure results. The broadening parameters of the considered lines are also computed by a semi-classical method for various relative velocities of colliders and the powers characterizing the dependence of the collisional cross-sections on relative speeds are deduced as functions of the rotational numbers J and K. Additional calculations performed with the Maxwell-Boltzmann distribution of velocities show no significant difference with the earlier results [Buldyreva et al., Phys Chem Chem Phys 2011;13:20326] obtained within the mean thermal velocity approximation. Weighted sums of the presently measured Voigt-profile O2-broadening parameters and of the previously published N2-broadening ones are calculated to yield experimental air-broadening coefficients for spectroscopic databases.

A New Turbo-shaft Engine Control Law during Variable Rotor Speed Transient Process

NASA Astrophysics Data System (ADS)

Hua, Wei; Miao, Lizhen; Zhang, Haibo; Huang, Jinquan

2015-12-01

A closed-loop control law employing compressor guided vanes is firstly investigated to solve unacceptable fuel flow dynamic change in single fuel control for turbo-shaft engine here, especially for rotorcraft in variable rotor speed process. Based on an Augmented Linear Quadratic Regulator (ALQR) algorithm, a dual-input, single-output robust control scheme is proposed for a turbo-shaft engine, involving not only the closed loop adjustment of fuel flow but also that of compressor guided vanes. Furthermore, compared to single fuel control, some digital simulation cases using this new scheme about variable rotor speed have been implemented on the basis of an integrated system of helicopter and engine model. The results depict that the command tracking performance to the free turbine rotor speed can be asymptotically realized. Moreover, the fuel flow transient process has been significantly improved, and the fuel consumption has been dramatically cut down by more than 2% while keeping the helicopter level fight unchanged.

The spinal control of locomotion and step-to-step variability in left-right symmetry from slow to moderate speeds

PubMed Central

Dambreville, Charline; Labarre, Audrey; Thibaudier, Yann; Hurteau, Marie-France

2015-01-01

When speed changes during locomotion, both temporal and spatial parameters of the pattern must adjust. Moreover, at slow speeds the step-to-step pattern becomes increasingly variable. The objectives of the present study were to assess if the spinal locomotor network adjusts both temporal and spatial parameters from slow to moderate stepping speeds and to determine if it contributes to step-to-step variability in left-right symmetry observed at slow speeds. To determine the role of the spinal locomotor network, the spinal cord of 6 adult cats was transected (spinalized) at low thoracic levels and the cats were trained to recover hindlimb locomotion. Cats were implanted with electrodes to chronically record electromyography (EMG) in several hindlimb muscles. Experiments began once a stable hindlimb locomotor pattern emerged. During experiments, EMG and bilateral video recordings were made during treadmill locomotion from 0.1 to 0.4 m/s in 0.05 m/s increments. Cycle and stance durations significantly decreased with increasing speed, whereas swing duration remained unaffected. Extensor burst duration significantly decreased with increasing speed, whereas sartorius burst duration remained unchanged. Stride length, step length, and the relative distance of the paw at stance offset significantly increased with increasing speed, whereas the relative distance at stance onset and both the temporal and spatial phasing between hindlimbs were unaffected. Both temporal and spatial step-to-step left-right asymmetry decreased with increasing speed. Therefore, the spinal cord is capable of adjusting both temporal and spatial parameters during treadmill locomotion, and it is responsible, at least in part, for the step-to-step variability in left-right symmetry observed at slow speeds. PMID:26084910

Simple and Reproducible Two-Stage Agitation Speed Control Strategy for Enhanced Triterpene Production by Lingzhi or Reishi Medicinal Mushrooms, Ganoderma lucidum ACCC G0119 (Higher Basidiomycetes) Based on Submerged Liquid Fermentation.

PubMed

Feng, Jie; Feng, Na; Yang, Yan; Liu, Fang; Zhang, Jingsong; Jia, Wei; Lin, Chi-Chung

2015-01-01

Triterpenes are important anticancer agents produced by batch submerged liquid fermentation, with the medicinal mushroom Ganoderma lucidum ACCC G0119, which was investigated under various dissolved oxygen levels by varying agitation speeds. Three kinetic parameters were analyzed: specific mycelial growth rate (μsmg), specific glucose consumption rate (qsgc), and specific triterpene production rate (qstp). High concentration, yield, and productivity of triterpenes were achieved by developing a simple and reproducible two-stage agitation speed control strategy. At the first 40 h, agitation speed was controlled at 150 rpm to obtain the quickest peak qstp for triterpene production, subsequently agitation speed was controlled at 100 rpm to maintain high qstp for high triterpene accumulation. The maximum concentration of triterpenes reached 0.086 g/l with the yield of 6.072 g/kg and the productivity of 6.532 × 10-4 g/(l·h), which were 39.61%, 36.48%, and 49.22%, respectively, better than the best results controlled by fixed agitation speeds. Conceivably, such a triterpene fermentation production strategy would be useful for industrial large-scale production of triterpenes with G. lucidum.

Performance verification and system parameter identification of spacecraft tape recorder control servo

NASA Technical Reports Server (NTRS)

Mukhopadhyay, A. K.

1979-01-01

Design adequacy of the lead-lag compensator of the frequency loop, accuracy checking of the analytical expression for the electrical motor transfer function, and performance evaluation of the speed control servo of the digital tape recorder used on-board the 1976 Viking Mars Orbiters and Voyager 1977 Jupiter-Saturn flyby spacecraft are analyzed. The transfer functions of the most important parts of a simplified frequency loop used for test simulation are described and ten simulation cases are reported. The first four of these cases illustrate the method of selecting the most suitable transfer function for the hysteresis synchronous motor, while the rest verify and determine the servo performance parameters and alternative servo compensation schemes. It is concluded that the linear methods provide a starting point for the final verification/refinement of servo design by nonlinear time response simulation and that the variation of the parameters of the static/dynamic Coulomb friction is as expected in a long-life space mission environment.

Constant speed control of four-stroke micro internal combustion swing engine

NASA Astrophysics Data System (ADS)

Gao, Dedong; Lei, Yong; Zhu, Honghai; Ni, Jun

2015-09-01

The increasing demands on safety, emission and fuel consumption require more accurate control models of micro internal combustion swing engine (MICSE). The objective of this paper is to investigate the constant speed control models of four-stroke MICSE. The operation principle of the four-stroke MICSE is presented based on the description of MICSE prototype. A two-level Petri net based hybrid model is proposed to model the four-stroke MICSE engine cycle. The Petri net subsystem at the upper level controls and synchronizes the four Petri net subsystems at the lower level. The continuous sub-models, including breathing dynamics of intake manifold, thermodynamics of the chamber and dynamics of the torque generation, are investigated and integrated with the discrete model in MATLAB Simulink. Through the comparison of experimental data and simulated DC voltage output, it is demonstrated that the hybrid model is valid for the four-stroke MICSE system. A nonlinear model is obtained from the cycle average data via the regression method, and it is linearized around a given nominal equilibrium point for the controller design. The feedback controller of the spark timing and valve duration timing is designed with a sequential loop closing design approach. The simulation of the sequential loop closure control design applied to the hybrid model is implemented in MATLAB. The simulation results show that the system is able to reach its desired operating point within 0.2 s, and the designed controller shows good MICSE engine performance with a constant speed. This paper presents the constant speed control models of four-stroke MICSE and carries out the simulation tests, the models and the simulation results can be used for further study on the precision control of four-stroke MICSE.

High-speed atomic force microscopy and peak force tapping control

NASA Astrophysics Data System (ADS)

Hu, Shuiqing; Mininni, Lars; Hu, Yan; Erina, Natalia; Kindt, Johannes; Su, Chanmin

2012-03-01

ITRS Roadmap requires defect size measurement below 10 nanometers and challenging classifications for both blank and patterned wafers and masks. Atomic force microscope (AFM) is capable of providing metrology measurement in 3D at sub-nanometer accuracy but has long suffered from drawbacks in throughput and limitation of slow topography imaging without chemical information. This presentation focus on two disruptive technology developments, namely high speed AFM and quantitative nanomechanical mapping, which enables high throughput measurement with capability of identifying components through concurrent physical property imaging. The high speed AFM technology has allowed the imaging speed increase by 10-100 times without loss of the data quality. Such improvement enables the speed of defect review on a wafer to increase from a few defects per hour to nearly 100 defects an hour, approaching the requirements of ITRS Roadmap. Another technology development, Peak Force Tapping, substantially simplified the close loop system response, leading to self-optimization of most challenging samples groups to generate expert quality data. More importantly, AFM also simultaneously provides a series of mechanical property maps with a nanometer spatial resolution during defect review. These nanomechanical maps (including elastic modulus, hardness, and surface adhesion) provide complementary information for elemental analysis, differentiate defect materials by their physical properties, and assist defect classification beyond topographic measurements. This paper will explain the key enabling technologies, namely high speed tip-scanning AFM using innovative flexure design and control algorithm. Another critical element is AFM control using Peak Force Tapping, in which the instantaneous tip-sample interaction force is measured and used to derive a full suite of physical properties at each imaging pixel. We will provide examples of defect review data on different wafers and media disks

An interdisciplinary school project using a Nintendo Wii controller for measuring car speed

NASA Astrophysics Data System (ADS)

Hansen, Nils Kristian; Mitchell, James Robert

2013-03-01

This work examines the feasibility of employing a Nintendo Wii game controller for measuring car speed in an interdisciplinary school project. It discusses the physical characteristics of the controller and of vehicle headlights. It suggests how an experiment may be linked to topics in mathematics, statistics, physics and computer science. An algorithm for calculating speed from repeated recordings of car headlights is provided. Finally the results of repeated experiments with an approaching car are provided.

Numerical optimization methods for controlled systems with parameters

NASA Astrophysics Data System (ADS)

Tyatyushkin, A. I.

2017-10-01

First- and second-order numerical methods for optimizing controlled dynamical systems with parameters are discussed. In unconstrained-parameter problems, the control parameters are optimized by applying the conjugate gradient method. A more accurate numerical solution in these problems is produced by Newton's method based on a second-order functional increment formula. Next, a general optimal control problem with state constraints and parameters involved on the righthand sides of the controlled system and in the initial conditions is considered. This complicated problem is reduced to a mathematical programming one, followed by the search for optimal parameter values and control functions by applying a multimethod algorithm. The performance of the proposed technique is demonstrated by solving application problems.

High speed multiphoton imaging

NASA Astrophysics Data System (ADS)

Li, Yongxiao; Brustle, Anne; Gautam, Vini; Cockburn, Ian; Gillespie, Cathy; Gaus, Katharina; Lee, Woei Ming

2016-12-01

Intravital multiphoton microscopy has emerged as a powerful technique to visualize cellular processes in-vivo. Real time processes revealed through live imaging provided many opportunities to capture cellular activities in living animals. The typical parameters that determine the performance of multiphoton microscopy are speed, field of view, 3D imaging and imaging depth; many of these are important to achieving data from in-vivo. Here, we provide a full exposition of the flexible polygon mirror based high speed laser scanning multiphoton imaging system, PCI-6110 card (National Instruments) and high speed analog frame grabber card (Matrox Solios eA/XA), which allows for rapid adjustments between frame rates i.e. 5 Hz to 50 Hz with 512 × 512 pixels. Furthermore, a motion correction algorithm is also used to mitigate motion artifacts. A customized control software called Pscan 1.0 is developed for the system. This is then followed by calibration of the imaging performance of the system and a series of quantitative in-vitro and in-vivo imaging in neuronal tissues and mice.

Investigation of Inner Loop Flight Control Strategies for High-Speed Research

NASA Technical Reports Server (NTRS)

Newman, Brett; Kassem, Ayman

1999-01-01

This report describes the activities and findings conducted under contract NAS1-19858 with NASA Langley Research Center. Subject matter is the investigation of suitable flight control design methodologies and solutions for large, flexible high-speed vehicles. Specifically, methodologies are to address the inner control loops used for stabilization and augmentation of a highly coupled airframe system possibly involving rigid-body motion, structural vibrations, unsteady aerodynamics, and actuator dynamics. Techniques considered in this body of work are primarily conventional-based, and the vehicle of interest is the High-Speed Civil Transport (HSCT). Major findings include 1) current aeroelastic vehicle modeling procedures require further emphasis and refinement, 2) traditional and nontraditional inner loop flight control strategies employing a single feedback loop do not appear sufficient for highly flexible HSCT class vehicles, 3) inner loop flight control systems will, in all likelihood, require multiple interacting feedback loops, and 4) Ref. H HSCT configuration presents major challenges to designing acceptable closed-loop flight dynamics.

Vision-Based Steering Control, Speed Assistance and Localization for Inner-City Vehicles

PubMed Central

Olivares-Mendez, Miguel Angel; Sanchez-Lopez, Jose Luis; Jimenez, Felipe; Campoy, Pascual; Sajadi-Alamdari, Seyed Amin; Voos, Holger

2016-01-01

Autonomous route following with road vehicles has gained popularity in the last few decades. In order to provide highly automated driver assistance systems, different types and combinations of sensors have been presented in the literature. However, most of these approaches apply quite sophisticated and expensive sensors, and hence, the development of a cost-efficient solution still remains a challenging problem. This work proposes the use of a single monocular camera sensor for an automatic steering control, speed assistance for the driver and localization of the vehicle on a road. Herein, we assume that the vehicle is mainly traveling along a predefined path, such as in public transport. A computer vision approach is presented to detect a line painted on the road, which defines the path to follow. Visual markers with a special design painted on the road provide information to localize the vehicle and to assist in its speed control. Furthermore, a vision-based control system, which keeps the vehicle on the predefined path under inner-city speed constraints, is also presented. Real driving tests with a commercial car on a closed circuit finally prove the applicability of the derived approach. In these tests, the car reached a maximum speed of 48 km/h and successfully traveled a distance of 7 km without the intervention of a human driver and any interruption. PMID:26978365

Vision-Based Steering Control, Speed Assistance and Localization for Inner-City Vehicles.

PubMed

Olivares-Mendez, Miguel Angel; Sanchez-Lopez, Jose Luis; Jimenez, Felipe; Campoy, Pascual; Sajadi-Alamdari, Seyed Amin; Voos, Holger

2016-03-11

Autonomous route following with road vehicles has gained popularity in the last few decades. In order to provide highly automated driver assistance systems, different types and combinations of sensors have been presented in the literature. However, most of these approaches apply quite sophisticated and expensive sensors, and hence, the development of a cost-efficient solution still remains a challenging problem. This work proposes the use of a single monocular camera sensor for an automatic steering control, speed assistance for the driver and localization of the vehicle on a road. Herein, we assume that the vehicle is mainly traveling along a predefined path, such as in public transport. A computer vision approach is presented to detect a line painted on the road, which defines the path to follow. Visual markers with a special design painted on the road provide information to localize the vehicle and to assist in its speed control. Furthermore, a vision-based control system, which keeps the vehicle on the predefined path under inner-city speed constraints, is also presented. Real driving tests with a commercial car on a closed circuit finally prove the applicability of the derived approach. In these tests, the car reached a maximum speed of 48 km/h and successfully traveled a distance of 7 km without the intervention of a human driver and any interruption.

Variable speed wind turbine control by discrete-time sliding mode approach.

PubMed

Torchani, Borhen; Sellami, Anis; Garcia, Germain

2016-05-01

The aim of this paper is to propose a new design variable speed wind turbine control by discrete-time sliding mode approach. This methodology is designed for linear saturated system. The saturation constraint is reported on inputs vector. To this end, the back stepping design procedure is followed to construct a suitable sliding manifold that guarantees the attainment of a stabilization control objective. It is well known that the mechanisms are investigated in term of the most proposed assumptions to deal with the damping, shaft stiffness and inertia effect of the gear. The objectives are to synthesize robust controllers that maximize the energy extracted from wind, while reducing mechanical loads and rotor speed tracking combined with an electromagnetic torque. Simulation results of the proposed scheme are presented. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Variable-Speed Induction Motor Drives for Aircraft Environmental Control Compressors

NASA Technical Reports Server (NTRS)

Mildice, J. W.; Hansen, I. G.; Schreiner, K. E.; Roth, M. E.

1996-01-01

New, more-efficient designs for aircraft jet engines are not capable of supplying the large quantities of bleed air necessary to provide pressurization and air conditioning for the environmental control systems (ECS) of the next generation of large passenger aircraft. System analysis and engineering have determined that electrically-driven ECS can help to maintain the improved fuel efficiencies; and electronic controllers and induction motors are now being developed in a NASA/NPD SBIR Program to drive both types of ECS compressors. Previous variable-speed induction motor/controller system developments and publications have primarily focused on field-oriented control, with large transient reserve power, for maximum acceleration and optimum response in actuator and robotics systems. The application area addressed herein is characterized by slowly-changing inputs and outputs, small reserve power capability for acceleration, and optimization for maximum efficiency. This paper therefore focuses on the differences between this case and the optimum response case, and shows the development of this new motor/controller approach. It starts with the creation of a new set of controller requirements. In response to those requirements, new control algorithms are being developed and implemented in an embedded computer, which is integrated into the motor controller closed loop. Buffered logic outputs are used to drive the power switches in a resonant-technology, power processor/motor-controller, at switching/resonant frequencies high enough to support efficient high-frequency induction motor operation at speeds up to 50,000-RPA

Gait Parameter Adjustments for Walking on a Treadmill at Preferred, Slower, and Faster Speeds in Older Adults with Down Syndrome

PubMed Central

Smith, Beth A.; Kubo, Masayoshi; Ulrich, Beverly D.

2012-01-01

The combined effects of ligamentous laxity, hypotonia, and decrements associated with aging lead to stability-enhancing foot placement adaptations during routine overground walking at a younger age in adults with Down syndrome (DS) compared to their peers with typical development (TD). Our purpose here was to examine real-time adaptations in older adults with DS by testing their responses to walking on a treadmill at their preferred speed and at speeds slower and faster than preferred. We found that older adults with DS were able to adapt their gait to slower and faster than preferred treadmill speeds; however, they maintained their stability-enhancing foot placements at all speeds compared to their peers with TD. All adults adapted their gait patterns similarly in response to faster and slower than preferred treadmill-walking speeds. They increased stride frequency and stride length, maintained step width, and decreased percent stance as treadmill speed increased. Older adults with DS, however, adjusted their stride frequencies significantly less than their peers with TD. Our results show that older adults with DS have the capacity to adapt their gait parameters in response to different walking speeds while also supporting the need for intervention to increase gait stability. PMID:22693497

Distributed flow sensing for closed-loop speed control of a flexible fish robot.

PubMed

Zhang, Feitian; Lagor, Francis D; Yeo, Derrick; Washington, Patrick; Paley, Derek A

2015-10-23

Flexibility plays an important role in fish behavior by enabling high maneuverability for predator avoidance and swimming in turbulent flow. This paper presents a novel flexible fish robot equipped with distributed pressure sensors for flow sensing. The body of the robot is molded from soft, hyperelastic material, which provides flexibility. Its Joukowski-foil shape is conducive to modeling the fluid analytically. A quasi-steady potential-flow model is adopted for real-time flow estimation, whereas a discrete-time vortex-shedding flow model is used for higher-fidelity simulation. The dynamics for the flexible fish robot yield a reduced model for one-dimensional swimming. A recursive Bayesian filter assimilates pressure measurements to estimate flow speed, angle of attack, and foil camber. The closed-loop speed-control strategy combines an inverse-mapping feedforward controller based on an average model derived for periodic actuation of angle-of-attack and a proportional-integral feedback controller utilizing the estimated flow information. Simulation and experimental results are presented to show the effectiveness of the estimation and control strategy. The paper provides a systematic approach to distributed flow sensing for closed-loop speed control of a flexible fish robot by regulating the flapping amplitude.

Influence of pre-injection control parameters on main-injection fuel quantity for an electronically controlled double-valve fuel injection system of diesel engine

NASA Astrophysics Data System (ADS)

Song, Enzhe; Fan, Liyun; Chen, Chao; Dong, Quan; Ma, Xiuzhen; Bai, Yun

2013-09-01

A simulation model of an electronically controlled two solenoid valve fuel injection system for a diesel engine is established in the AMESim environment. The accuracy of the model is validated through comparison with experimental data. The influence of pre-injection control parameters on main-injection quantity under different control modes is analyzed. In the spill control valve mode, main-injection fuel quantity decreases gradually and then reaches a stable level because of the increase in multi-injection dwell time. In the needle control valve mode, main-injection fuel quantity increases with rising multi-injection dwell time; this effect becomes more obvious at high-speed revolutions and large main-injection pulse widths. Pre-injection pulse width has no obvious influence on main-injection quantity under the two control modes; the variation in main-injection quantity is in the range of 1 mm3.

Quantitative Measurement of Vocal Fold Vibration in Male Radio Performers and Healthy Controls Using High-Speed Videoendoscopy

PubMed Central

Warhurst, Samantha; McCabe, Patricia; Heard, Rob; Yiu, Edwin; Wang, Gaowu; Madill, Catherine

2014-01-01

Purpose Acoustic and perceptual studies show a number of differences between the voices of radio performers and controls. Despite this, the vocal fold kinematics underlying these differences are largely unknown. Using high-speed videoendoscopy, this study sought to determine whether the vocal vibration features of radio performers differed from those of non-performing controls. Method Using high-speed videoendoscopy, recordings of a mid-phonatory/i/ in 16 male radio performers (aged 25–52 years) and 16 age-matched controls (aged 25–52 years) were collected. Videos were extracted and analysed semi-automatically using High-Speed Video Program, obtaining measures of fundamental frequency (f0), open quotient and speed quotient. Post-hoc analyses of sound pressure level (SPL) were also performed (n = 19). Pearson's correlations were calculated between SPL and both speed and open quotients. Results Male radio performers had a significantly higher speed quotient than their matched controls (t = 3.308, p = 0.005). No significant differences were found for f0 or open quotient. No significant correlation was found between either open or speed quotient with SPL. Discussion A higher speed quotient in male radio performers suggests that their vocal fold vibration was characterised by a higher ratio of glottal opening to closing times than controls. This result may explain findings of better voice quality, higher equivalent sound level and greater spectral tilt seen in previous research. Open quotient was not significantly different between groups, indicating that the durations of complete vocal fold closure were not different between the radio performers and controls. Further validation of these results is required to determine the aetiology of the higher speed quotient result and its implications for voice training and clinical management in performers. PMID:24971625

Design and analysis issues of integrated control systems for high-speed civil transports

NASA Technical Reports Server (NTRS)

Mccarty, Craig A.; Feather, John B.; Dykman, John R.; Page, Mark A.; Hodgkinson, John

1992-01-01

A study was conducted to identify, rank, and define development plans for the critical guidance and control design and analysis issues as related to economically viable and environmentally acceptable high-speed civil transport. The issues were identified in a multistep process. First, pertinent literature on supersonic cruise aircraft was reviewed, and experts were consulted to establish the fundamental characteristics and problems inherent to supersonic cruise aircraft. Next, the advanced technologies and strategies being pursued for the high-speed civil transport were considered to determine any additional unique control problems the transport may have. Finally, existing technologies and methods were examined to determine their capabilities for the design and analysis of high-speed civil transport control systems and to identify the shortcomings and issues. Three priority levels - mandatory, highly beneficial, and desirable - were established. Within each of these levels, the issues were further ranked. Technology development plans for each issue were defined. Each plan contains a task breakdown and schedule.

Decomposing ADHD-Related Effects in Response Speed and Variability

PubMed Central

Karalunas, Sarah L.; Huang-Pollock, Cynthia L.; Nigg, Joel T.

2012-01-01

Objective Slow and variable reaction times (RTs) on fast tasks are such a prominent feature of Attention Deficit Hyperactivity Disorder (ADHD) that any theory must account for them. However, this has proven difficult because the cognitive mechanisms responsible for this effect remain unexplained. Although speed and variability are typically correlated, it is unclear whether single or multiple mechanisms are responsible for group differences in each. RTs are a result of several semi-independent processes, including stimulus encoding, rate of information processing, speed-accuracy trade-offs, and motor response, which have not been previously well characterized. Method A diffusion model was applied to RTs from a forced-choice RT paradigm in two large, independent case-control samples (NCohort 1= 214 and N Cohort 2=172). The decomposition measured three validated parameters that account for the full RT distribution, and assessed reproducibility of ADHD effects. Results In both samples, group differences in traditional RT variables were explained by slow information processing speed, and unrelated to speed-accuracy trade-offs or non-decisional processes (e.g. encoding, motor response). Conclusions RT speed and variability in ADHD may be explained by a single information processing parameter, potentially simplifying explanations that assume different mechanisms are required to account for group differences in the mean and variability of RTs. PMID:23106115

Workload of horses on a water treadmill: effect of speed and water height on oxygen consumption and cardiorespiratory parameters.

PubMed

Greco-Otto, Persephone; Bond, Stephanie; Sides, Raymond; Kwong, Grace P S; Bayly, Warwick; Léguillette, Renaud

2017-11-28

Despite the use of water treadmills (WT) in conditioning horses, the intensity of WT exercise has not been well documented. The workload on a WT is a function of water height and treadmill speed. Therefore, the purpose of this study was to determine the effects of these factors on workload during WT exercise. Fifteen client-owned Quarter Horses were used in a randomized, controlled study. Three belt speeds and three water heights (mid cannon, carpus and stifle), along with the control condition (dry treadmill, all three speeds), were tested. Measured outcomes were oxygen consumption (V̇O 2 ), ventilation (respiratory frequency, tidal volume (V T )), heart rate (HR), and blood lactate. An ergospirometry system was used to measure V̇O 2 and ventilation. Linear mixed effects models were used to examine the effects of presence or absence of water, water height and speed (as fixed effects) on measured outcomes. Water height and its interaction with speed had a significant effect on V̇O 2 , V T and HR, all peaking at the highest water level and speed (stifle at 1.39 m/s, median V̇O 2  = 16.70 ml/(kg.min), V T  = 6 L, HR = 69 bpm). Respiratory frequency peaked with water at the carpus at 1.39 m/s (median 49 breaths/min). For a given water height, the small increments in speed did not affect the measured outcomes. Post-exercise blood lactate concentration did not change. Varying water height and speed affects the workload associated with WT exercise. The conditions utilized in this study were associated with low intensity exercise. Water height had a greater impact on exercise intensity than speed.

An Improved Method to Control the Critical Parameters of a Multivariable Control System

NASA Astrophysics Data System (ADS)

Subha Hency Jims, P.; Dharmalingam, S.; Wessley, G. Jims John

2017-10-01

The role of control systems is to cope with the process deficiencies and the undesirable effect of the external disturbances. Most of the multivariable processes are highly iterative and complex in nature. Aircraft systems, Modern Power Plants, Refineries, Robotic systems are few such complex systems that involve numerous critical parameters that need to be monitored and controlled. Control of these important parameters is not only tedious and cumbersome but also is crucial from environmental, safety and quality perspective. In this paper, one such multivariable system, namely, a utility boiler has been considered. A modern power plant is a complex arrangement of pipework and machineries with numerous interacting control loops and support systems. In this paper, the calculation of controller parameters based on classical tuning concepts has been presented. The controller parameters thus obtained and employed has controlled the critical parameters of a boiler during fuel switching disturbances. The proposed method can be applied to control the critical parameters like elevator, aileron, rudder, elevator trim rudder and aileron trim, flap control systems of aircraft systems.

Wind speed vector restoration algorithm

NASA Astrophysics Data System (ADS)

Baranov, Nikolay; Petrov, Gleb; Shiriaev, Ilia

2018-04-01

Impulse wind lidar (IWL) signal processing software developed by JSC «BANS» recovers full wind speed vector by radial projections and provides wind parameters information up to 2 km distance. Increasing accuracy and speed of wind parameters calculation signal processing technics have been studied in this research. Measurements results of IWL and continuous scanning lidar were compared. Also, IWL data processing modeling results have been analyzed.

Robust control of speed and temperature in a power plant gas turbine.

PubMed

Najimi, Ebrahim; Ramezani, Mohammad Hossein

2012-03-01

In this paper, an H(∞) robust controller has been designed for an identified model of MONTAZER GHAEM power plant gas turbine (GE9001E). In design phase, a linear model (ARX model) which is obtained using real data has been applied. Since the turbine has been used in a combined cycle power plant, its speed and also the exhaust gas temperature should be adjusted simultaneously by controlling fuel signals and compressor inlet guide vane (IGV) position. Considering the limitations on the system inputs, the aim of the control is to maintain the turbine speed and the exhaust gas temperature within desired interval under uncertainties and load demand disturbances. Simulation results of applying the proposed robust controller on the nonlinear model of the system (NARX model), fairly fulfilled the predefined aims. Simulations also show the improvement in the performance compared to MPC and PID controllers for the same conditions. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

MM-122: High speed civil transport

NASA Technical Reports Server (NTRS)

Demarest, Bill; Anders, Kurt; Manchec, John; Yang, Eric; Overgaard, Dan; Kalkwarf, Mike

1992-01-01

The rapidly expanding Pacific Rim market along with other growing markets indicates that the future market potential for a high speed civil transport is great indeed. The MM-122 is the answer to the international market desire for a state of the art, long range, high speed civil transport. It will carry 250 passengers a distance of 5200 nm at over twice the speed of sound. The MM-122 is designed to incorporate the latest technologies in the areas of control systems, propulsions, aerodynamics, and materials. The MM-122 will accomplish these goals using the following design parameters. First, a double delta wing planform with highly swept canards and an appropriately area ruled fuselage will be incorporated to accomplish desired aerodynamic characteristics. Propulsion will be provided by four low bypass variable cycle turbofan engines. A quad-redundant fly-by-wire flight control system will be incorporated to provide appropriate static stability and level 1 handling qualities. Finally, the latest in conventional metallic and modern composite materials will be used to provide desired weight and performance characteristics. The MM-122 incorporates the latest in technology and cost minimization techniques to provide a viable solution to this future market potential.

Controller and interface module for the High-Speed Data Acquisition System correlator/accumulator

NASA Technical Reports Server (NTRS)

Brokl, S. S.

1985-01-01

One complex channel of the High-Speed Data Acquisition System (a subsystem used in the Goldstone solar system radar), consisting of two correlator modules and one accumulator module, is operated by the controller and interface module interfaces are provided to the VAX UNIBUS for computer control, monitor, and test of the controller and correlator/accumulator. The correlator and accumulator modules controlled by this module are the key digital signal processing elements of the Goldstone High-Speed Data Acquisition System. This fully programmable unit provides for a wide variety of correlation and filtering functions operating on a three megaword/second data flow. Data flow is to the VAX by way of the I/O port of a FPS 5210 array processor.

Residual vibration control based on a global search method in a high-speed white light scanning interferometer.

PubMed

Song, Zhenyuan; Guo, Tong; Fu, Xing; Hu, Xiaotang

2018-05-01

To achieve high-speed measurements using white light scanning interferometers, the scanning devices used need to have high feedback gain in closed-loop operations. However, flexure hinges induce a residual vibration that can cause a misidentification of the fringe order. The reduction of this residual vibration is crucial because the highly nonlinear distortions in interferograms lead to clearly incorrect measured profiles. Input shaping can be used to control the amplitude of the residual vibration. The conventional method uses continuous wavelet transform (CWT) to estimate parameters of the scanning device. Our proposed method extracts equivalent modal parameters using a global search algorithm. Due to its simplicity, ease of implementation, and response speed, this global search method outperforms CWT. The delay time is shortened by searching, because fewer modes are needed for the shaper. The effectiveness of the method has been confirmed by the agreement between simulated shaped responses and experimental displacement information from the capacitive sensor inside the scanning device, and the intensity profiles of the interferometer have been greatly improved. An experiment measuring the surface of a silicon wafer is also presented. The method is shown to be effective at improving the intensity profiles and recovering accurate surface topography. Finally, frequency localizations are found to be almost stable with different proportional gains, but their energy distributions change.

Effect of travel speed on the visual control of steering toward a goal.

PubMed

Chen, Rongrong; Niehorster, Diederick C; Li, Li

2018-03-01

Previous studies have proposed that people can use visual cues such as the instantaneous direction (i.e., heading) or future path trajectory of travel specified by optic flow or target visual direction in egocentric space to steer or walk toward a goal. In the current study, we examined what visual cues people use to guide their goal-oriented locomotion and whether their reliance on such visual cues changes as travel speed increases. We presented participants with optic flow displays that simulated their self-motion toward a target at various travel speeds under two viewing conditions in which we made target egocentric direction available or unavailable for steering. We found that for both viewing conditions, participants did not steer along a curved path toward the target such that the actual and the required path curvature to reach the target would converge when approaching the target. At higher travel speeds, participants showed a faster and larger reduction in target-heading angle and more accurate and precise steady-state control of aligning their heading specified by optic flow with the target. These findings support the claim that people use heading and target egocentric direction but not path for goal-oriented locomotion control, and their reliance on heading increases at higher travel speeds. The increased reliance on heading for goal-oriented locomotion control could be due to an increased reliability in perceiving heading from optic flow as the magnitude of flow increases with travel speed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

6. GOVERNOR AND SPEED CONTROL MECHANISMS TANK, AT LEFT AN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. GOVERNOR AND SPEED CONTROL MECHANISMS TANK, AT LEFT AN ACCUMULATOR TANK WHICH STORE AIR PRESSURE TO OPEN GATES AND GET GENERATOR STARTED. LARGE TANK AT RIGHT IS THE MAIN GUARD VALVE FOR THE GENERATOR - Los Angeles Aqueduct, Haiwee Power Plant, Los Angeles, Los Angeles County, CA

Robust Control Analysis of Hydraulic Turbine Speed

NASA Astrophysics Data System (ADS)

Jekan, P.; Subramani, C.

2018-04-01

An effective control strategy for the hydro-turbine governor in time scenario is adjective for this paper. Considering the complex dynamic characteristic and the uncertainty of the hydro-turbine governor model and taking the static and dynamic performance of the governing system as the ultimate goal, the designed logic combined the classical PID control theory with artificial intelligence used to obtain the desired output. The used controller will be a variable control techniques, therefore, its parameters can be adaptively adjusted according to the information about the control error signal.

Reliability and validity of a smartphone-based assessment of gait parameters across walking speed and smartphone locations: Body, bag, belt, hand, and pocket.

PubMed

Silsupadol, Patima; Teja, Kunlanan; Lugade, Vipul

2017-10-01

The assessment of spatiotemporal gait parameters is a useful clinical indicator of health status. Unfortunately, most assessment tools require controlled laboratory environments which can be expensive and time consuming. As smartphones with embedded sensors are becoming ubiquitous, this technology can provide a cost-effective, easily deployable method for assessing gait. Therefore, the purpose of this study was to assess the reliability and validity of a smartphone-based accelerometer in quantifying spatiotemporal gait parameters when attached to the body or in a bag, belt, hand, and pocket. Thirty-four healthy adults were asked to walk at self-selected comfortable, slow, and fast speeds over a 10-m walkway while carrying a smartphone. Step length, step time, gait velocity, and cadence were computed from smartphone-based accelerometers and validated with GAITRite. Across all walking speeds, smartphone data had excellent reliability (ICC 2,1 ≥0.90) for the body and belt locations, with bag, hand, and pocket locations having good to excellent reliability (ICC 2,1 ≥0.69). Correlations between the smartphone-based and GAITRite-based systems were very high for the body (r=0.89, 0.98, 0.96, and 0.87 for step length, step time, gait velocity, and cadence, respectively). Similarly, Bland-Altman analysis demonstrated that the bias approached zero, particularly in the body, bag, and belt conditions under comfortable and fast speeds. Thus, smartphone-based assessments of gait are most valid when placed on the body, in a bag, or on a belt. The use of a smartphone to assess gait can provide relevant data to clinicians without encumbering the user and allow for data collection in the free-living environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Minimum viewing angle for visually guided ground speed control in bumblebees.

PubMed

Baird, Emily; Kornfeldt, Torill; Dacke, Marie

2010-05-01

To control flight, flying insects extract information from the pattern of visual motion generated during flight, known as optic flow. To regulate their ground speed, insects such as honeybees and Drosophila hold the rate of optic flow in the axial direction (front-to-back) constant. A consequence of this strategy is that its performance varies with the minimum viewing angle (the deviation from the frontal direction of the longitudinal axis of the insect) at which changes in axial optic flow are detected. The greater this angle, the later changes in the rate of optic flow, caused by changes in the density of the environment, will be detected. The aim of the present study is to examine the mechanisms of ground speed control in bumblebees and to identify the extent of the visual range over which optic flow for ground speed control is measured. Bumblebees were trained to fly through an experimental tunnel consisting of parallel vertical walls. Flights were recorded when (1) the distance between the tunnel walls was either 15 or 30 cm, (2) the visual texture on the tunnel walls provided either strong or weak optic flow cues and (3) the distance between the walls changed abruptly halfway along the tunnel's length. The results reveal that bumblebees regulate ground speed using optic flow cues and that changes in the rate of optic flow are detected at a minimum viewing angle of 23-30 deg., with a visual field that extends to approximately 155 deg. By measuring optic flow over a visual field that has a low minimum viewing angle, bumblebees are able to detect and respond to changes in the proximity of the environment well before they are encountered.

Study on the stability of waterpower-speed control system for hydropower station with air cushion surge chamber

NASA Astrophysics Data System (ADS)

Guo, W. C.; Yang, J. D.; Chen, J. P.; Teng, Y.

2014-03-01

According to the fact that the effects of penstock, unit and governor on stability of water level fluctuation for hydropower station with air cushion surge chamber are neglected in previous researches, in this paper, Thoma assumption is broken through, the complete mathematical model of waterpower-speed control system for hydropower station with air cushion surge chamber is established, and the comprehensive transfer function and linear homogeneous differential equation that characterize the dynamic characteristics of system are derived. The stability domain that characterizes the good or bad of stability quantitatively is drawn by using the stability conditions. The effects of the fluid inertia in water diversion system, the air cushion surge chamber parameters, hydraulic turbine characteristics, generator characteristics, and regulation modes of governor on the stability of waterpower-speed control system are analyzed through stability domain. The main conclusions are as follows: The fluid inertia in water diversion system and hydraulic turbine characteristics have unfavorable effects on the system while generator characteristics have favorable effect. The stability keeps getting better with the increase of chamber height and basal area and the decrease of air pressure and air polytropic exponent. The stability of power regulation mode is obviously better than that of frequency regulation mode.

Applications of variable speed control for contending with recurrent highway congestion.

DOT National Transportation Integrated Search

2014-07-01

This research project developed vital operational guidelines for design of a variable speed limit (VSL) system and its integrated operations with ramp metering control in contending with recurrent highway congestion. The developed guidelines can serv...

Target of physiological gait: Realization of speed adaptive control for a prosthetic knee during swing flexion.

PubMed

Cao, Wujing; Yu, Hongliu; Zhao, Weiliang; Li, Jin; Wei, Xiaodong

2018-01-01

Prosthetic knee is the most important component of lower limb prosthesis. Speed adaptive for prosthetic knee during swing flexion is the key method to realize physiological gait. This study aims to discuss the target of physiological gait, propose a speed adaptive control method during swing flexion and research the damping adjustment law of intelligent hydraulic prosthetic knee. According to the physiological gait trials of healthy people, the control target during swing flexion is defined. A new prosthetic knee with fuzzy logical control during swing flexion is designed to realize the damping adjustment automatically. The function simulation and evaluation system of intelligent knee prosthesis is provided. Speed adaptive control test of the intelligent prosthetic knee in different velocities are researched. The maximum swing flexion of the knee angle is set between sixty degree and seventy degree as the target of physiological gait. Preliminary experimental results demonstrate that the prosthetic knee with fuzzy logical control is able to realize physiological gait under different speeds. The faster the walking, the bigger the valve closure percentage of the hydraulic prosthetic knee. The proposed fuzzy logical control strategy and intelligent hydraulic prosthetic knee are effective for the amputee to achieve physiological gait.

Optimized design on condensing tubes high-speed TIG welding technology magnetic control based on genetic algorithm

NASA Astrophysics Data System (ADS)

Lu, Lin; Chang, Yunlong; Li, Yingmin; Lu, Ming

2013-05-01

An orthogonal experiment was conducted by the means of multivariate nonlinear regression equation to adjust the influence of external transverse magnetic field and Ar flow rate on welding quality in the process of welding condenser pipe by high-speed argon tungsten-arc welding (TIG for short). The magnetic induction and flow rate of Ar gas were used as optimum variables, and tensile strength of weld was set to objective function on the base of genetic algorithm theory, and then an optimal design was conducted. According to the request of physical production, the optimum variables were restrained. The genetic algorithm in the MATLAB was used for computing. A comparison between optimum results and experiment parameters was made. The results showed that the optimum technologic parameters could be chosen by the means of genetic algorithm with the conditions of excessive optimum variables in the process of high-speed welding. And optimum technologic parameters of welding coincided with experiment results.

Daily modulation of the speed-accuracy trade-off.

PubMed

Gueugneau, Nicolas; Pozzo, Thierry; Darlot, Christian; Papaxanthis, Charalambos

2017-07-25

Goal-oriented arm movements are characterized by a balance between speed and accuracy. The relation between speed and accuracy has been formalized by Fitts' law and predicts a linear increase in movement duration with task constraints. Up to now this relation has been investigated on a short-time scale only, that is during a single experimental session, although chronobiological studies report that the motor system is shaped by circadian rhythms. Here, we examine whether the speed-accuracy trade-off could vary during the day. Healthy adults carried out arm-pointing movements as accurately and fast as possible toward targets of different sizes at various hours of the day, and variations in Fitts' law parameters were scrutinized. To investigate whether the potential modulation of the speed-accuracy trade-off has peripheral and/or central origins, a motor imagery paradigm was used as well. Results indicated a daily (circadian-like) variation for the durations of both executed and mentally simulated movements, in strictly controlled accuracy conditions. While Fitts' law was held for the whole sessions of the day, the slope of the relation between movement duration and task difficulty expressed a clear modulation, with the lowest values in the afternoon. This variation of the speed-accuracy trade-off in executed and mental movements suggests that, beyond execution parameters, motor planning mechanisms are modulated during the day. Daily update of forward models is discussed as a potential mechanism. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

High-Speed Magnetohydrodynamic Flow Control Analyses With 3-D Simulations

DTIC Science & Technology

2008-01-01

color. 14. ABSTRACT Magnetohydrodynamic studies of high-speed flow control are described with emphasis on understanding fluid response to specific...interactions play a crucial role by distorting the velocity field. The interaction with an external circuit through electrodes is relatively efficient when... Entropy layer . . . . . . . . . . . . . 20 6 Energy management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 7 Conclusion

Dual motor drive vehicle speed synchronization and coordination control strategy

NASA Astrophysics Data System (ADS)

Huang, Hao; Tu, Qunzhang; Jiang, Chenming; Ma, Limin; Li, Pei; Zhang, Hongxing

2018-04-01

Multi-motor driven systems are more and more widely used in the field of electric engineering vehicles, as a result of the road conditions and the variable load of engineering vehicles, makes multi-motors synchronization coordinated control system as a key point of the development of the electric vehicle drive system. This paper based on electrical machinery transmission speed in the process of engineering vehicles headed for coordinated control problem, summarized control strategies at home and abroad in recent years, made analysis and comparison of the characteristics, finally discussed the trend of development of the multi-motor coordination control, provided a reference for synchronized control system research of electric drive engineering vehicles.

Mixture distributions of wind speed in the UAE

NASA Astrophysics Data System (ADS)

Shin, J.; Ouarda, T.; Lee, T. S.

2013-12-01

Wind speed probability distribution is commonly used to estimate potential wind energy. The 2-parameter Weibull distribution has been most widely used to characterize the distribution of wind speed. However, it is unable to properly model wind speed regimes when wind speed distribution presents bimodal and kurtotic shapes. Several studies have concluded that the Weibull distribution should not be used for frequency analysis of wind speed without investigation of wind speed distribution. Due to these mixture distributional characteristics of wind speed data, the application of mixture distributions should be further investigated in the frequency analysis of wind speed. A number of studies have investigated the potential wind energy in different parts of the Arabian Peninsula. Mixture distributional characteristics of wind speed were detected from some of these studies. Nevertheless, mixture distributions have not been employed for wind speed modeling in the Arabian Peninsula. In order to improve our understanding of wind energy potential in Arabian Peninsula, mixture distributions should be tested for the frequency analysis of wind speed. The aim of the current study is to assess the suitability of mixture distributions for the frequency analysis of wind speed in the UAE. Hourly mean wind speed data at 10-m height from 7 stations were used in the current study. The Weibull and Kappa distributions were employed as representatives of the conventional non-mixture distributions. 10 mixture distributions are used and constructed by mixing four probability distributions such as Normal, Gamma, Weibull and Extreme value type-one (EV-1) distributions. Three parameter estimation methods such as Expectation Maximization algorithm, Least Squares method and Meta-Heuristic Maximum Likelihood (MHML) method were employed to estimate the parameters of the mixture distributions. In order to compare the goodness-of-fit of tested distributions and parameter estimation methods for

Bumblebees measure optic flow for position and speed control flexibly within the frontal visual field.

PubMed

Linander, Nellie; Dacke, Marie; Baird, Emily

2015-04-01

When flying through narrow spaces, insects control their position by balancing the magnitude of apparent image motion (optic flow) experienced in each eye and their speed by holding this value about a desired set point. Previously, it has been shown that when bumblebees encounter sudden changes in the proximity to nearby surfaces - as indicated by a change in the magnitude of optic flow on each side of the visual field - they adjust their flight speed well before the change, suggesting that they measure optic flow for speed control at low visual angles in the frontal visual field. Here, we investigated the effect that sudden changes in the magnitude of translational optic flow have on both position and speed control in bumblebees if these changes are asymmetrical; that is, if they occur only on one side of the visual field. Our results reveal that the visual region over which bumblebees respond to optic flow cues for flight control is not dictated by a set viewing angle. Instead, bumblebees appear to use the maximum magnitude of translational optic flow experienced in the frontal visual field. This strategy ensures that bumblebees use the translational optic flow generated by the nearest obstacles - that is, those with which they have the highest risk of colliding - to control flight. © 2015. Published by The Company of Biologists Ltd.

Driver speed selection on high-speed two-lane highways: Comparing speed profiles between uniform and differential speed limits.

PubMed

Russo, Brendan J; Savolainen, Peter T; Gates, Timothy J; Kay, Jonathan J; Frazier, Sterling

2017-07-04

Although a considerable amount of prior research has investigated the impacts of speed limits on traffic safety and operations, much of this research, and nearly all of the research related to differential speed limits, has been specific to limited access freeways. The unique safety and operational issues on highways without access control create difficulty relating the conclusions from prior freeway-related speed limit research to 2-lane highways, particularly research on differential limits due to passing limitations and subsequent queuing. Therefore, the objective of this study was to assess differences in driver speed selection with respect to the posted speed limit on rural 2-lane highways, with a particular emphasis on the differences between uniform and differential speed limits. Data were collected from nearly 59,000 vehicles across 320 sites in Montana and 4 neighboring states. Differences in mean speeds, 85th percentile speeds, and the standard deviation in speeds for free-flowing vehicles were examined across these sites using ordinary least squares regression models. Ultimately, the results of the analysis show that the mean speed, 85th percentile speed, and variability in travel speeds for free-flowing vehicles on 2-lane highways are generally lower at locations with uniform 65 mph speed limits, compared to locations with differential limits of 70 mph for cars and 60 mph for trucks. In addition to posted speed limits, several site characteristics were shown to influence speed selection including shoulder widths, frequency of horizontal curves, percentage of the segment that included no passing zones, and hourly volumes. Differences in vehicle speed characteristics were also observed between states, indicating that speed selection may also be influenced by local factors, such as driver population or enforcement.

Linear Parameter Varying Control for Actuator Failure

NASA Technical Reports Server (NTRS)

Shin, Jong-Yeob; Wu, N. Eva; Belcastro, Christine; Bushnell, Dennis M. (Technical Monitor)

2002-01-01

A robust linear parameter varying (LPV) control synthesis is carried out for an HiMAT vehicle subject to loss of control effectiveness. The scheduling parameter is selected to be a function of the estimates of the control effectiveness factors. The estimates are provided on-line by a two-stage Kalman estimator. The inherent conservatism of the LPV design is reducing through the use of a scaling factor on the uncertainty block that represents the estimation errors of the effectiveness factors. Simulations of the controlled system with the on-line estimator show that a superior fault-tolerance can be achieved.

White matter integrity and processing speed in sickle cell anemia.

PubMed

Stotesbury, Hanne; Kirkham, Fenella J; Kölbel, Melanie; Balfour, Philippa; Clayden, Jonathan D; Sahota, Sati; Sakaria, Simrat; Saunders, Dawn E; Howard, Jo; Kesse-Adu, Rachel; Inusa, Baba; Pelidis, Maria; Chakravorty, Subarna; Rees, David C; Awogbade, Moji; Wilkey, Olu; Layton, Mark; Clark, Christopher A; Kawadler, Jamie M

2018-05-11

The purpose of this retrospective cross-sectional study was to investigate whether changes in white matter integrity are related to slower processing speed in sickle cell anemia. Thirty-seven patients with silent cerebral infarction, 46 patients with normal MRI, and 32 sibling controls (age range 8-37 years) underwent cognitive assessment using the Wechsler scales and 3-tesla MRI. Tract-based spatial statistics analyses of diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) parameters were performed. Processing speed index (PSI) was lower in patients than controls by 9.34 points (95% confidence interval: 4.635-14.855, p = 0.0003). Full Scale IQ was lower by 4.14 scaled points (95% confidence interval: -1.066 to 9.551, p = 0.1), but this difference was abolished when PSI was included as a covariate ( p = 0.18). There were no differences in cognition between patients with and without silent cerebral infarction, and both groups had lower PSI than controls (both p < 0.001). In patients, arterial oxygen content, socioeconomic status, age, and male sex were identified as predictors of PSI, and correlations were found between PSI and DTI scalars (fractional anisotropy r = 0.614, p < 0.00001; r = -0.457, p < 0.00001; mean diffusivity r = -0.341, p = 0.0016; radial diffusivity r = -0.457, p < 0.00001) and NODDI parameters (intracellular volume fraction r = 0.364, p = 0.0007) in widespread regions. Our results extend previous reports of impairment that is independent of presence of infarction and may worsen with age. We identify processing speed as a vulnerable domain, with deficits potentially mediating difficulties across other domains, and provide evidence that reduced processing speed is related to the integrity of normal-appearing white matter using microstructure parameters from DTI and NODDI. Copyright © 2018 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

Genetic Algorithm Optimizes Q-LAW Control Parameters

NASA Technical Reports Server (NTRS)

Lee, Seungwon; von Allmen, Paul; Petropoulos, Anastassios; Terrile, Richard

2008-01-01

A document discusses a multi-objective, genetic algorithm designed to optimize Lyapunov feedback control law (Q-law) parameters in order to efficiently find Pareto-optimal solutions for low-thrust trajectories for electronic propulsion systems. These would be propellant-optimal solutions for a given flight time, or flight time optimal solutions for a given propellant requirement. The approximate solutions are used as good initial solutions for high-fidelity optimization tools. When the good initial solutions are used, the high-fidelity optimization tools quickly converge to a locally optimal solution near the initial solution. Q-law control parameters are represented as real-valued genes in the genetic algorithm. The performances of the Q-law control parameters are evaluated in the multi-objective space (flight time vs. propellant mass) and sorted by the non-dominated sorting method that assigns a better fitness value to the solutions that are dominated by a fewer number of other solutions. With the ranking result, the genetic algorithm encourages the solutions with higher fitness values to participate in the reproduction process, improving the solutions in the evolution process. The population of solutions converges to the Pareto front that is permitted within the Q-law control parameter space.

A new procedure of modal parameter estimation for high-speed digital image correlation

NASA Astrophysics Data System (ADS)

Huňady, Róbert; Hagara, Martin

2017-09-01

The paper deals with the use of 3D digital image correlation in determining modal parameters of mechanical systems. It is a non-contact optical method, which for the measurement of full-field spatial displacements and strains of bodies uses precise digital cameras with high image resolution. Most often this method is utilized for testing of components or determination of material properties of various specimens. In the case of using high-speed cameras for measurement, the correlation system is capable of capturing various dynamic behaviors, including vibration. This enables the potential use of the mentioned method in experimental modal analysis. For that purpose, the authors proposed a measuring chain for the correlation system Q-450 and developed a software application called DICMAN 3D, which allows the direct use of this system in the area of modal testing. The created application provides the post-processing of measured data and the estimation of modal parameters. It has its own graphical user interface, in which several algorithms for the determination of natural frequencies, mode shapes and damping of particular modes of vibration are implemented. The paper describes the basic principle of the new estimation procedure which is crucial in the light of post-processing. Since the FRF matrix resulting from the measurement is usually relatively large, the estimation of modal parameters directly from the FRF matrix may be time-consuming and may occupy a large part of computer memory. The procedure implemented in DICMAN 3D provides a significant reduction in memory requirements and computational time while achieving a high accuracy of modal parameters. Its computational efficiency is particularly evident when the FRF matrix consists of thousands of measurement DOFs. The functionality of the created software application is presented on a practical example in which the modal parameters of a composite plate excited by an impact hammer were determined. For the

VMAT linear accelerator commissioning and quality assurance: dose control and gantry speed tests

PubMed Central

Rowshanfarzad, Pejman; Greer, Peter B.

2016-01-01

In VMAT treatment delivery the ability of the linear accelerator (linac) to accurately control dose versus gantry angle is critical to delivering the plan correctly. A new VMAT test delivery was developed to specifically test the dose versus gantry angle with the full range of allowed gantry speeds and dose rates. The gantry‐mounted IBA MatriXX with attached inclinometer was used in movie mode to measure the instantaneous relative dose versus gantry angle during the plan every 0.54 s. The results were compared to the expected relative dose at each gantry angle calculated from the plan. The same dataset was also used to compare the instantaneous gantry speeds throughout the delivery compared to the expected gantry speeds from the plan. Measurements performed across four linacs generally show agreement between measurement and plan to within 1.5% in the constant dose rate regions and dose rate modulation within 0.1 s of the plan. Instantaneous gantry speed was measured to be within 0.11∘/s of the plan (1 SD). An error in one linac was detected in that the nominal gantry speed was incorrectly calibrated. This test provides a practical method to quality‐assure critical aspects of VMAT delivery including dose versus gantry angle and gantry speed control. The method can be performed with any detector that can acquire time‐resolved dosimetric information that can be synchronized with a measurement of gantry angle. The test fulfils several of the aims of the recent Netherlands Commission on Radiation Dosimetry (NCS) Report 24, which provides recommendations for comprehensive VMAT quality assurance. PACS number(s): 87.55.Qr PMID:27167282

Effect of rotation speed and welding speed on Friction Stir Welding of AA1100 Aluminium alloy

NASA Astrophysics Data System (ADS)

Raja, P.; Bojanampati, S.; Karthikeyan, R.; Ganithi, R.

2018-04-01

Aluminum AA1100 is the most widely used grade of Aluminium due to its excellent corrosion resistance, high ductility and reflective finish, the selected material was welded with Friction Stir Welding (FSW) process on a CNC machine, using a combination of different tool rotation speed (1500 rpm, 2500 rpm, 3500 rpm) and welding speed (10 mm/min, 30 mm/min, 50 mm/min) as welding parameters. The effect of FSW using this welding parameter was studied by measuring the ultimate tensile strength of the welded joints. A high-speed steel tool was prepared for welding the Aluminium AA1100 alloy having an 8mm shoulder diameter and pin dimension of 4mm diameter and 2.8 mm length. The welded joints were tested using the universal testing machine. It was found that Ultimate Tensile Strength of FSW specimen was highest with a value of 98.08 MPa when the weld was performed at rotation speed of 1500 RPM and welding speed of 50 mm/min.

Parameter study and optimization for piezoelectric energy harvester for TPMS considering speed variation

NASA Astrophysics Data System (ADS)

Toghi Eshghi, Amin; Lee, Soobum; Lee, Hanmin; Kim, Young-Cheol

2016-04-01

In this paper, we perform design parameter study and design optimization for a piezoelectric energy harvester considering vehicle speed variation. Initially, a FEM model using ANSYS is developed to appraise the performance of a piezoelectric harvester in a rotating tire. The energy harvester proposed here uses the vertical deformation at contact patch area from the car weight and centrifugal acceleration. This harvester is composed of a beam which is clamped at both ends and a piezoelectric material is attached on the top of that. The piezoelectric material possesses the 31 mode of transduction in which the direction of applied field is perpendicular to that of the electric field. To optimize the harvester performance, we would change the geometrical parameters of the harvester to obtain the maximum power. One of the main challenges in the design process is obtaining the required power while considering the constraints for harvester weight and volume. These two concerns are addressed in this paper. Since the final goal of this study is the development of an energy harvester with a wireless sensor system installed in a real car, the real time data for varied velocity of a vehicle are taken into account for power measurements. This study concludes that the proposed design is applicable to wireless tire sensor systems.

Comparison of standing postural control and gait parameters in people with and without chronic low back pain: a cross-sectional case-control study.

PubMed

MacRae, Catharine Siân; Critchley, Duncan; Lewis, Jeremy S; Shortland, Adam

2018-01-01

Differences in postural control and gait have been identified between people with and without chronic low back pain (CLBP); however, many previous studies present data from small samples, or have used methodologies with questionable reliability. This study, employing robust methodology, hypothesised that there would be a difference in postural control, and spatiotemporal parameters of gait in people with CLBP compared with asymptomatic individuals. This cross-sectional case-control study age-matched and gender-matched 16 CLBP and 16 asymptomatic participants. Participants were assessed barefoot (1) standing, over three 40 s trials, under four posture challenging conditions (2) during gait. Primary outcome was postural stability (assessed by root mean squared error of centre of pressure (CoP) displacement (CoP RMSEAP ) and mean CoP velocity (CoP VELAP ), both in the anteroposterior direction); gait outcomes were hip range of movement and peak moments, walking speed, cadence and stride length, assessed using force plates and a motion analysis system. There were no differences between groups in CoP RMSEAP (P=0.26), or CoP VELAP (P=0.60) for any standing condition. During gait, no differences were observed between groups for spatiotemporal parameters, maximum, minimum and total ranges of hip movement, or peak hip flexor or extensor moments in the sagittal plane. In contrast to previous research, this study suggests that people with mild to moderate CLBP present with similar standing postural control, and parameters of gait to asymptomatic individuals. Treatments directed at influencing postural stability (eg, standing on a wobble board) or specific parameters of gait may be an unnecessary addition to a treatment programme.

Distinct mechanisms explain the control of reach speed planning: evidence from a race model framework.

PubMed

Venkataratamani, Prasanna Venkhatesh; Murthy, Aditya

2018-05-16

Previous studies have investigated the computational architecture underlying the voluntary control of reach movements that demands a change in position or direction of movement planning. Here we used a novel task, where subjects either had to increase or decrease the movement speed according to a change in target color that occurred randomly during a trial. The applicability of different race models to such a speed redirect task was assessed. We found that the predictions of an independent race model that instantiated an abort and re-plan strategy was consistent with all aspects of performance in the fast to slow speed condition. The results from modeling indicated a peculiar asymmetry, in that while the fast to slow speed change required inhibition, none of the standard race models were able to explain how movements changed from slow to fast speeds. Interestingly, a weighted averaging model that simulated the gradual merge of two kinematic plans explained behavior in the slow to fast speed task. In summary, our work shows how a race model framework can provide an understanding of how the brain controls of different aspects of reach movement planning and help distinguish between an abort and re-plan strategy from merging of plans.

Mildly disabled persons with multiple sclerosis use similar net joint power strategies as healthy controls when walking speed increases.

PubMed

Brincks, John; Christensen, Lars Ejsing; Rehnquist, Mette Voigt; Petersen, Jesper; Sørensen, Henrik; Dalgas, Ulrik

2018-01-01

To improve walking in persons with multiple sclerosis (MS), it is essential to understand the underlying mechanisms of walking. This study examined strategies in net joint power generated or absorbed by hip flexors, hip extensors, hip abductors, knee extensors, and plantar flexors in mildly disabled persons with MS and healthy controls at different walking speeds. Thirteen persons with MS and thirteen healthy controls participated and peak net joint power was calculated using 3D motion analysis. In general, no differences were found between speed-matched healthy controls and persons with MS, but the fastest walking speed was significantly higher in healthy controls (2.42 m/s vs. 1.70 m/s). The net joint power increased in hip flexors, hip extensors, hip abductors, knee extensors and plantar flexors in both groups, when walking speed increased. Significant correlations between changes in walking speed and changes in net joint power of plantar flexors, hip extensors and hip flexors existed in healthy controls and persons with MS, and in net knee extensor absorption power of persons with MS only. In contrast to previous studies, these findings suggest that mildly disabled persons with MS used similar kinetic strategies as healthy controls to increase walking speed.

Method and apparatus for selectively controlling the speed of an engine

DOEpatents

Davis, Roy Inge

2001-02-27

A control assembly 12 for use within a vehicle 10 having an engine 14 and which selectively controls the speed of the engine 14 in order to increase fuel efficiency and to effect relatively smooth starting and stopping of the engine. Particularly, in one embodiment, control assembly 12 cooperatively operates with a starter/alternator assembly 20 and is adapted for use with hybrid vehicles employing a start/stop powertrain assembly, wherein fuel efficiency is increased by selectively stopping engine operation when the vehicle has stopped.

Concurrently adjusting interrelated control parameters to achieve optimal engine performance

DOEpatents

Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

2015-12-01

Methods and systems for real-time engine control optimization are provided. A value of an engine performance variable is determined, a value of a first operating condition and a value of a second operating condition of a vehicle engine are detected, and initial values for a first engine control parameter and a second engine control parameter are determined based on the detected first operating condition and the detected second operating condition. The initial values for the first engine control parameter and the second engine control parameter are adjusted based on the determined value of the engine performance variable to cause the engine performance variable to approach a target engine performance variable. In order to cause the engine performance variable to approach the target engine performance variable, adjusting the initial value for the first engine control parameter necessitates a corresponding adjustment of the initial value for the second engine control parameter.

On The Export Control Of High Speed Imaging For Nuclear Weapons Applications

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

Watson, Scott Avery; Altherr, Michael Robert

Since the Manhattan Project, the use of high-speed photography, and its cousins flash radiography1 and schieleren photography have been a technological proliferation concern. Indeed, like the supercomputer, the development of high-speed photography as we now know it essentially grew out of the nuclear weapons program at Los Alamos2,3,4. Naturally, during the course of the last 75 years the technology associated with computers and cameras has been export controlled by the United States and others to prevent both proliferation among non-P5-nations and technological parity among potential adversaries among P5 nations. Here we revisit these issues as they relate to high-speed photographicmore » technologies and make recommendations about how future restrictions, if any, should be guided.« less

Extended Constant Power Speed Range of the Brushless DC Motor Through Dual Mode Inverter Control

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

Lawler, J.S.

2000-06-23

The trapezoidal back electromotive force (emf) brushless direct current (dc) motor (BDCM) with surface-mounted magnets has high-power density and efficiency especially when rare-earth magnet materials are used. Traction applications, such as electric vehicles, could benefit significantly from the use of such motors. Unfortunately, a practical means for driving the motor over a constant power speed ratio (CPSR) of 5:1 or more has not yet been developed. A key feature of these motors is that they have low internal inductance. The phase advance method is effective in controlling the motor power over such a speed range, but the current at highmore » speed may be several times greater than that required at the base speed. The increase in current during high-speed operation is due to the low motor inductance and the action of the bypass diodes of the inverter. The use of such a control would require increased current rating of the inverter semiconductors and additional cooling for the inverter, where the conduction losses increase proportionally with current, and especially for the motor, where the losses increase with the square of the current. The high current problems of phase advance can be mitigated by adding series inductance; however, this reduces power density, requires significant increase in supply voltage, and leaves the CPSR performance of the system highly sensitive to variations in the available voltage. A new inverter topology and control scheme has been developed that can drive low-inductance BDCMs over the CPSR that would be required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC). It is shown that the BDCM has an infinite CPSR when it is driven by the DMIC.« less

DSP-based adaptive backstepping using the tracking errors for high-performance sensorless speed control of induction motor drive.

PubMed

Zaafouri, Abderrahmen; Regaya, Chiheb Ben; Azza, Hechmi Ben; Châari, Abdelkader

2016-01-01

This paper presents a modified structure of the backstepping nonlinear control of the induction motor (IM) fitted with an adaptive backstepping speed observer. The control design is based on the backstepping technique complemented by the introduction of integral tracking errors action to improve its robustness. Unlike other research performed on backstepping control with integral action, the control law developed in this paper does not propose the increase of the number of system state so as not increase the complexity of differential equations resolution. The digital simulation and experimental results show the effectiveness of the proposed control compared to the conventional PI control. The results analysis shows the characteristic robustness of the adaptive control to disturbances of the load, the speed variation and low speed. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

High-speed holocinematographic velocimeter for studying turbulent flow control physics

NASA Technical Reports Server (NTRS)

Weinstein, L. M.; Beeler, G. B.; Lindemann, A. M.

1985-01-01

Use of a dual view, high speed, holographic movie technique is examined for studying turbulent flow control physics. This approach, which eliminates some of the limitations of previous holographic techniques, is termed a holocinematographic velocimeter (HCV). The data from this system can be used to check theoretical turbulence modeling and numerical simulations, visualize and measure coherent structures in 'non-simple' turbulent flows, and examine the mechanisms operative in various turbulent control/drag reduction concepts. This system shows promise for giving the most complete experimental characterization of turbulent flows yet available.

Induction motor speed drive improvement using fuzzy IP-self-tuning controller. A real time implementation.

PubMed

Lokriti, Abdesslam; Salhi, Issam; Doubabi, Said; Zidani, Youssef

2013-05-01

An IP-self-tuning controller tuned by a fuzzy adjustor, is proposed to improve induction machine speed control. The interest of such controller is the possibility to adjust only one gain, instead of two gains for the case of the PI-self-tuning controllers commonly used in the literature. This paper presents simulation and experimental results. These latter were obtained by practical implementation on a DSPace 1104 board of three different speed controllers (the classical IP, the fuzzy-like-PI and the IP-self-tuning), for a 1.5KW induction machine. The paper presents different tests used to compare the performances of the proposed controller to the two others in terms of computation time, tracking performances and disturbances rejection. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Application of drive circuit based on L298N in direct current motor speed control system

NASA Astrophysics Data System (ADS)

Yin, Liuliu; Wang, Fang; Han, Sen; Li, Yuchen; Sun, Hao; Lu, Qingjie; Yang, Cheng; Wang, Quanzhao

2016-10-01

In the experiment of researching the nanometer laser interferometer, our design of laser interferometer circuit system is up to the wireless communication technique of the 802.15.4 IEEE standard, and we use the RF TI provided by Basic to receive the data on speed control system software. The system's hardware is connected with control module and the DC motor. However, in the experiment, we found that single chip microcomputer control module is very difficult to drive the DC motor directly. The reason is that the DC motor's starting and braking current is larger than the causing current of the single chip microcomputer control module. In order to solve this problem, we add a driving module that control board can transmit PWM wave signal through I/O port to drive the DC motor, the driving circuit board can come true the function of the DC motor's positive and reversal rotation and speed adjustment. In many various driving module, the L298N module's integrated level is higher compared with other driver module. The L298N model is easy to control, it not only can control the DC motor, but also achieve motor speed control by modulating PWM wave that the control panel output. It also has the over-current protection function, when the motor lock, the L298N model can protect circuit and motor. So we use the driver module based on L298N to drive the DC motor. It is concluded that the L298N driver circuit module plays a very important role in the process of driving the DC motor in the DC motor speed control system.

Age-related decline in cognitive control: the role of fluid intelligence and processing speed

PubMed Central

2014-01-01

Background Research on cognitive control suggests an age-related decline in proactive control abilities whereas reactive control seems to remain intact. However, the reason of the differential age effect on cognitive control efficiency is still unclear. This study investigated the potential influence of fluid intelligence and processing speed on the selective age-related decline in proactive control. Eighty young and 80 healthy older adults were included in this study. The participants were submitted to a working memory recognition paradigm, assessing proactive and reactive cognitive control by manipulating the interference level across items. Results Repeated measures ANOVAs and hierarchical linear regressions indicated that the ability to appropriately use cognitive control processes during aging seems to be at least partially affected by the amount of available cognitive resources (assessed by fluid intelligence and processing speed abilities). Conclusions This study highlights the potential role of cognitive resources on the selective age-related decline in proactive control, suggesting the importance of a more exhaustive approach considering the confounding variables during cognitive control assessment. PMID:24401034

The Radial Speed - Expansion Speed Relation for Earth-Directed CMEs

NASA Astrophysics Data System (ADS)

Makela, P. A.; Gopalswamy, N.; Yashiro, S.

2013-12-01

The propagation speed of Earth-directed coronal mass ejections (CMEs) is an essential parameter needed in space weather forecasting. However, the true propagation speed of Earth-directed CMEs cannot be measured accurately from coronagraph images taken from Earth's view. In order to circumvent the inaccuracies of speed measurements due to the projection effects, empirical relations expressing the radial speed (Vrad) of the CME as a function of the CME expansion speed (Vexp) have been suggested. Vexp is defined as the apparent speed the CME is spreading in the coronagraph's field of view. During 2010-2012 STEREO spacecraft provided a side view of Earth-directed CMEs, allowing measurements of true CME speeds and widths. In a case study of the 2011 February 15 CME Gopalswamy et al. (2012) compared three Vrad-Vexp relations (flat cone, full or shallow ice cream cone - Gopalswamy et al., 2009) and found the closest match with the observations for the (full ice cream cone) relation Vrad = 1/2(1 + cot w)Vexp, where w is the half width of the CME. Using the STEREO/SECCHI and SOHO/LASCO observations during this opportune period, we expand this analysis to a larger set of Earth-directed CMEs. We compare the computed CME speed estimates with the measured true speeds and estimate the accuracy of the Vrad-Vexp relations. References: Gopalswamy, N. et al. (2009), The expansion and radial speeds of coronal mass ejections, Cent. Eur. Astrophys. Bull., 33, 115. Gopalswamy, N. et al. (2012), The relationship between the expansion speed and radial speed of CMEs confirmed using quadrature observations of the 2011 February 15 CME, Sun and Geosphere, 7(1), 7.

Development of a controlled release formulation by continuous twin screw granulation: Influence of process and formulation parameters.

PubMed

Vanhoorne, V; Vanbillemont, B; Vercruysse, J; De Leersnyder, F; Gomes, P; Beer, T De; Remon, J P; Vervaet, C

2016-05-30

The aim of this study was to evaluate the potential of twin screw granulation for the continuous production of controlled release formulations with hydroxypropylmethylcellulose as hydrophilic matrix former. Metoprolol tartrate was included in the formulation as very water soluble model drug. A premix of metoprolol tartrate, hydroxypropylmethylcellulose and filler (ratio 20/20/60, w/w) was granulated with demineralized water via twin screw granulation. After oven drying and milling, tablets were produced on a rotary Modul™ P tablet press. A D-optimal design (29 experiments) was used to assess the influence of process (screw speed, throughput, barrel temperature and screw design) and formulation parameters (starch content of the filler) on the process (torque), granule (size distribution, shape, friability, density) and tablet (hardness, friability and dissolution) critical quality attributes. The torque was dominated by the number of kneading elements and throughput, whereas screw speed and filling degree only showed a minor influence on torque. Addition of screw mixing elements after a block of kneading elements improved the yield of the process before milling as it resulted in less oversized granules and also after milling as less fines were present. Temperature was also an important parameter to optimize as a higher temperature yielded less fines and positively influenced the aspect ratio. The shape of hydroxypropylmethylcellulose granules was comparable to that of immediate release formulations. Tensile strength and friability of tablets were not dependent on the process parameters. The use of starch as filler was not beneficial with regard to granule and tablet properties. Complete drug release was obtained after 16-20h and was independent of the design's parameters. Copyright © 2016 Elsevier B.V. All rights reserved.

Self selected speed and maximal lactate steady state speed in swimming.

PubMed

Baron, B; Dekerle, J; Depretz, S; Lefevre, T; Pelayo, P

2005-03-01

The purposes of this study were to ascertain whether physiological and stroking parameters remain stable during a 2-hour exercise performed at self-selected swimming speed (S4) and whether this speed corresponds to those associated with the maximal lactate steady state (SMLSS). Ten well-trained competitive swimmers performed a maximal 400-m front crawl test, 4 30-min swimming tests in order to determine S(MLSS) and a 2-hour test swum at their preferred paces to determine self-selected swimming speed (S4), stroke rate (SR4), and stroke length (SL4) defined as the mean values observed between the 5th and the 15th min of this test. The stroking, metabolic and respiratory parameters, and ratings of perceived exertion (CR10) were reported throughout the 2-hour test. S4 and SMLSS were not significantly different and were highly correlated (r=0.891). S4 and SL4 decreased significantly after a steady state of 68 min and 100 min, respectively, whereas SR4 remained constant. Mean VO2, dioxide output, and heart rate values did not evolve significantly between the 10th and 120th minute of the test whereas capillary blood lactate concentration (La) decreased significantly (p<0.05). Moreover, respiratory CR10 did not evolve significantly between the 10th and the 120th minute of the test whereas general CR10 and muscular CR10 increased significantly. Considering the (La), SL4 and CR10 values variations, muscular parameters and a probably glycogenic depletion seem to be the main limiting factors that prevent maintaining the self selected swimming speed.

Modelling and control algorithms of the cross conveyors line with multiengine variable speed drives

NASA Astrophysics Data System (ADS)

Cheremushkina, M. S.; Baburin, S. V.

2017-02-01

The paper deals with the actual problem of developing the control algorithm that meets the technical requirements of the mine belt conveyors, and enables energy and resource savings taking into account a random sort of traffic. The most effective method of solution of these tasks is the construction of control systems with the use of variable speed drives for asynchronous motors. The authors designed the mathematical model of the system ‘variable speed multiengine drive - conveyor - control system of conveyors’ that takes into account the dynamic processes occurring in the elements of the transport system, provides an assessment of the energy efficiency of application the developed algorithms, which allows one to reduce the dynamic overload in the belt to 15-20%.

Effectiveness of double fines as a speed control measure in safety corridors.

DOT National Transportation Integrated Search

2002-12-01

The use of elevated traffic fines, and specifically doubling of applicable traffic fines under certain conditions, is widely used in Oregon as a speed control measure. Double fines have applied to safety corridors in Oregon since 1999. Double f...

Evaluation Of Traffic Control Devices For Rural High-Speed Maintenance Work Zones

DOT National Transportation Integrated Search

2000-10-01

This report documents the first year activities of a two-year project in which various work zone traffic control devices, treatments, and practices were implemented and evaluated. The focus was on rural high-speed work zones. Nine work zones were stu...

Adaptive AFM scan speed control for high aspect ratio fast structure tracking

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

Ahmad, Ahmad; Schuh, Andreas; Rangelow, Ivo W.

2014-10-15

Improved imaging rates in Atomic Force Microscopes (AFM) are of high interest for disciplines such as life sciences and failure analysis of semiconductor wafers, where the sample topology shows high aspect ratios. Also, fast imaging is necessary to cover a large surface under investigation in reasonable times. Since AFMs are composed of mechanical components, they are associated with comparably low resonance frequencies that undermine the effort to increase the acquisition rates. In particular, high and steep structures are difficult to follow, which causes the cantilever to temporarily loose contact to or crash into the sample. Here, we report on amore » novel approach that does not affect the scanner dynamics, but adapts the lateral scanning speed of the scanner. The controller monitors the control error signal and, only when necessary, decreases the scan speed to allow the z-piezo more time to react to changes in the sample's topography. In this case, the overall imaging rate can be significantly increased, because a general scan speed trade-off decision is not needed and smooth areas are scanned fast. In contrast to methods trying to increase the z-piezo bandwidth, our method is a comparably simple approach that can be easily adapted to standard systems.« less

Sensitivity of Turbine-Height Wind Speeds to Parameters in Planetary Boundary-Layer and Surface-Layer Schemes in the Weather Research and Forecasting Model

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

Yang, Ben; Qian, Yun; Berg, Larry K.

We evaluate the sensitivity of simulated turbine-height winds to 26 parameters applied in a planetary boundary layer (PBL) scheme and a surface layer scheme of the Weather Research and Forecasting (WRF) model over an area of complex terrain during the Columbia Basin Wind Energy Study. An efficient sampling algorithm and a generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of modeled turbine-height winds. The results indicate that most of the variability in the ensemble simulations is contributed by parameters related to the dissipation of the turbulence kinetic energy (TKE), Prandtl number, turbulencemore » length scales, surface roughness, and the von Kármán constant. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability. The parameter associated with the TKE dissipation rate is found to be the most important one, and a larger dissipation rate can produce larger hub-height winds. A larger Prandtl number results in weaker nighttime winds. Increasing surface roughness reduces the frequencies of both extremely weak and strong winds, implying a reduction in the variability of the wind speed. All of the above parameters can significantly affect the vertical profiles of wind speed, the altitude of the low-level jet and the magnitude of the wind shear strength. The wind direction is found to be modulated by the same subset of influential parameters. Remainder of abstract is in attachment.« less

Integration of Variable Speed Pumped Hydro Storage in Automatic Generation Control Systems

NASA Astrophysics Data System (ADS)

Fulgêncio, N.; Moreira, C.; Silva, B.

2017-04-01

Pumped storage power (PSP) plants are expected to be an important player in modern electrical power systems when dealing with increasing shares of new renewable energies (NRE) such as solar or wind power. The massive penetration of NRE and consequent replacement of conventional synchronous units will significantly affect the controllability of the system. In order to evaluate the capability of variable speed PSP plants participation in the frequency restoration reserve (FRR) provision, taking into account the expected performance in terms of improved ramp response capability, a comparison with conventional hydro units is presented. In order to address this issue, a three area test network was considered, as well as the corresponding automatic generation control (AGC) systems, being responsible for re-dispatching the generation units to re-establish power interchange between areas as well as the system nominal frequency. The main issue under analysis in this paper is related to the benefits of the fast response of variable speed PSP with respect to its capability of providing fast power balancing in a control area.

A multiple-fan active control wind tunnel for outdoor wind speed and direction simulation

NASA Astrophysics Data System (ADS)

Wang, Jia-Ying; Meng, Qing-Hao; Luo, Bing; Zeng, Ming

2018-03-01

This article presents a new type of active controlled multiple-fan wind tunnel. The wind tunnel consists of swivel plates and arrays of direct current fans, and the rotation speed of each fan and the shaft angle of each swivel plate can be controlled independently for simulating different kinds of outdoor wind fields. To measure the similarity between the simulated wind field and the outdoor wind field, wind speed and direction time series of two kinds of wind fields are recorded by nine two-dimensional ultrasonic anemometers, and then statistical properties of the wind signals in different time scales are analyzed based on the empirical mode decomposition. In addition, the complexity of wind speed and direction time series is also investigated using multiscale entropy and multivariate multiscale entropy. Results suggest that the simulated wind field in the multiple-fan wind tunnel has a high degree of similarity with the outdoor wind field.

A Control Simulation Method of High-Speed Trains on Railway Network with Irregular Influence

NASA Astrophysics Data System (ADS)

Yang, Li-Xing; Li, Xiang; Li, Ke-Ping

2011-09-01

Based on the discrete time method, an effective movement control model is designed for a group of highspeed trains on a rail network. The purpose of the model is to investigate the specific traffic characteristics of high-speed trains under the interruption of stochastic irregular events. In the model, the high-speed rail traffic system is supposed to be equipped with the moving-block signalling system to guarantee maximum traversing capacity of the railway. To keep the safety of trains' movements, some operational strategies are proposed to control the movements of trains in the model, including traction operation, braking operation, and entering-station operation. The numerical simulations show that the designed model can well describe the movements of high-speed trains on the rail network. The research results can provide the useful information not only for investigating the propagation features of relevant delays under the irregular disturbance but also for rerouting and rescheduling trains on the rail network.

Switching State-Feedback LPV Control with Uncertain Scheduling Parameters

NASA Technical Reports Server (NTRS)

He, Tianyi; Al-Jiboory, Ali Khudhair; Swei, Sean Shan-Min; Zhu, Guoming G.

2017-01-01

This paper presents a new method to design Robust Switching State-Feedback Gain-Scheduling (RSSFGS) controllers for Linear Parameter Varying (LPV) systems with uncertain scheduling parameters. The domain of scheduling parameters are divided into several overlapped subregions to undergo hysteresis switching among a family of simultaneously designed LPV controllers over the corresponding subregion with the guaranteed H-infinity performance. The synthesis conditions are given in terms of Parameterized Linear Matrix Inequalities that guarantee both stability and performance at each subregion and associated switching surfaces. The switching stability is ensured by descent parameter-dependent Lyapunov function on switching surfaces. By solving the optimization problem, RSSFGS controller can be obtained for each subregion. A numerical example is given to illustrate the effectiveness of the proposed approach over the non-switching controllers.

Systems and methods for vehicle speed management

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

Sujan, Vivek Anand; Vajapeyazula, Phani; Follen, Kenneth

Controlling a speed of a vehicle based on at least a portion of a route grade and a route distance divided into a plurality of route sections, each including at least one of a section grade and section length. Controlling the speed of the vehicle is further based on determining a cruise control speed mode for the vehicle for each of the plurality of route sections and determining a speed reference command of the vehicle based on at least one of the cruise control speed mode, the section length, the section grade, and a current speed.

Relationship between speed and EEG activity during imagined and executed hand movements

NASA Astrophysics Data System (ADS)

Yuan, Han; Perdoni, Christopher; He, Bin

2010-04-01

The relationship between primary motor cortex and movement kinematics has been shown in nonhuman primate studies of hand reaching or drawing tasks. Studies have demonstrated that the neural activities accompanying or immediately preceding the movement encode the direction, speed and other information. Here we investigated the relationship between the kinematics of imagined and actual hand movement, i.e. the clenching speed, and the EEG activity in ten human subjects. Study participants were asked to perform and imagine clenching of the left hand and right hand at various speeds. The EEG activity in the alpha (8-12 Hz) and beta (18-28 Hz) frequency bands were found to be linearly correlated with the speed of imagery clenching. Similar parametric modulation was also found during the execution of hand movements. A single equation relating the EEG activity to the speed and the hand (left versus right) was developed. This equation, which contained a linear independent combination of the two parameters, described the time-varying neural activity during the tasks. Based on the model, a regression approach was developed to decode the two parameters from the multiple-channel EEG signals. We demonstrated the continuous decoding of dynamic hand and speed information of the imagined clenching. In particular, the time-varying clenching speed was reconstructed in a bell-shaped profile. Our findings suggest an application to providing continuous and complex control of noninvasive brain-computer interface for movement-impaired paralytics.

Driver's behavioral adaptation to adaptive cruise control (ACC): the case of speed and time headway.

PubMed

Bianchi Piccinini, Giulio Francesco; Rodrigues, Carlos Manuel; Leitão, Miguel; Simões, Anabela

2014-06-01

The Adaptive Cruise Control is an Advanced Driver Assistance System (ADAS) that allows maintaining given headway and speed, according to settings pre-defined by the users. Despite the potential benefits associated to the utilization of ACC, previous studies warned against negative behavioral adaptations that might occur while driving with the system activated. Unfortunately, up to now, there are no unanimous results about the effects induced by the usage of ACC on speed and time headway to the vehicle in front. Also, few studies were performed including actual users of ACC among the subjects. This research aimed to investigate the effect of the experience gained with ACC on speed and time headway for a group of users of the system. In addition, it explored the impact of ACC usage on speed and time headway for ACC users and regular drivers. A matched sample driving simulator study was planned as a two-way (2×2) repeated measures mixed design, with the experience with ACC as between-subjects factor and the driving condition (with ACC and manually) as within-subjects factor. The results show that the usage of ACC brought a small but not significant reduction of speed and, especially, the maintenance of safer time headways, being the latter result greater for ACC users, probably as a consequence of their experience in using the system. The usage of ACC did not cause any negative behavioral adaptations to the system regarding speed and time headway. Based on this research work, the Adaptive Cruise Control showed the potential to improve road safety for what concerns the speed and the time headway maintained by the drivers. The speed of the surrounding traffic and the minimum time headway settable through the ACC seem to have an important effect on the road safety improvement achievable with the system. Copyright © 2014 Elsevier Ltd. All rights reserved.

Speeds in school zones.

DOT National Transportation Integrated Search

2009-02-01

School speed zones are frequently requested traffic controls for school areas, based on the common belief : that if the transportation agency would only install a reduced speed limit, then drivers would no longer : speed through the area. This resear...

A simulation investigation of scout/attack helicopter directional control requirements for hover and low-speed tasks

NASA Technical Reports Server (NTRS)

Bivens, Courtland C.; Guercio, Joseph G.

1987-01-01

A piloted simulator experiment was conducted to investigate directional axis handling qualities requirements for low speed and hover tasks performed by a Scout/Attack helicopter. Included were the directional characteristics of various candidate light helicopter family configurations. Also, the experiment focused on conventional single main/tail rotor configurations of the OH-58 series aircraft, where the first-order yaw-axis dynamic effects that contributed to the loss of tail rotor control were modeled. Five pilots flew 22 configurations under various wind conditions. Cooper-Harper handling quality ratings were used as the primary measure of merit of each configuration. The results of the experiment indicate that rotorcraft configurations with high directional gust sensitivity require greater minimum yaw damping to maintain satisfactory handling qualities during nap-of-the-Earth flying tasks. It was also determined that both yaw damping and control response are critical handling qualities parameters in performing the air-to-air target acquisition and tracking task. Finally, the lack of substantial yaw damping and larger values of gust sensitivity increased the possibility of loss of directional control at low airspeeds for the single main/tail rotor configurations.

Speed and path control for conflict-free flight in high air traffic demand in terminal airspace

NASA Astrophysics Data System (ADS)

Rezaei, Ali

To accommodate the growing air traffic demand, flights will need to be planned and navigated with a much higher level of precision than today's aircraft flight path. The Next Generation Air Transportation System (NextGen) stands to benefit significantly in safety and efficiency from such movement of aircraft along precisely defined paths. Air Traffic Operations (ATO) relying on such precision--the Precision Air Traffic Operations or PATO--are the foundation of high throughput capacity envisioned for the future airports. In PATO, the preferred method is to manage the air traffic by assigning a speed profile to each aircraft in a given fleet in a given airspace (in practice known as (speed control). In this research, an algorithm has been developed, set in the context of a Hybrid Control System (HCS) model, that determines whether a speed control solution exists for a given fleet of aircraft in a given airspace and if so, computes this solution as a collective speed profile that assures separation if executed without deviation. Uncertainties such as weather are not considered but the algorithm can be modified to include uncertainties. The algorithm first computes all feasible sequences (i.e., all sequences that allow the given fleet of aircraft to reach destinations without violating the FAA's separation requirement) by looking at all pairs of aircraft. Then, the most likely sequence is determined and the speed control solution is constructed by a backward trajectory generation, starting with the aircraft last out and proceeds to the first out. This computation can be done for different sequences in parallel which helps to reduce the computation time. If such a solution does not exist, then the algorithm calculates a minimal path modification (known as path control) that will allow separation-compliance speed control. We will also prove that the algorithm will modify the path without creating a new separation violation. The new path will be generated by adding new

A parameter optimization approach to controller partitioning for integrated flight/propulsion control application

NASA Technical Reports Server (NTRS)

Schmidt, Phillip; Garg, Sanjay; Holowecky, Brian

1992-01-01

A parameter optimization framework is presented to solve the problem of partitioning a centralized controller into a decentralized hierarchical structure suitable for integrated flight/propulsion control implementation. The controller partitioning problem is briefly discussed and a cost function to be minimized is formulated, such that the resulting 'optimal' partitioned subsystem controllers will closely match the performance (including robustness) properties of the closed-loop system with the centralized controller while maintaining the desired controller partitioning structure. The cost function is written in terms of parameters in a state-space representation of the partitioned sub-controllers. Analytical expressions are obtained for the gradient of this cost function with respect to parameters, and an optimization algorithm is developed using modern computer-aided control design and analysis software. The capabilities of the algorithm are demonstrated by application to partitioned integrated flight/propulsion control design for a modern fighter aircraft in the short approach to landing task. The partitioning optimization is shown to lead to reduced-order subcontrollers that match the closed-loop command tracking and decoupling performance achieved by a high-order centralized controller.

A parameter optimization approach to controller partitioning for integrated flight/propulsion control application

NASA Technical Reports Server (NTRS)

Schmidt, Phillip H.; Garg, Sanjay; Holowecky, Brian R.

1993-01-01

A parameter optimization framework is presented to solve the problem of partitioning a centralized controller into a decentralized hierarchical structure suitable for integrated flight/propulsion control implementation. The controller partitioning problem is briefly discussed and a cost function to be minimized is formulated, such that the resulting 'optimal' partitioned subsystem controllers will closely match the performance (including robustness) properties of the closed-loop system with the centralized controller while maintaining the desired controller partitioning structure. The cost function is written in terms of parameters in a state-space representation of the partitioned sub-controllers. Analytical expressions are obtained for the gradient of this cost function with respect to parameters, and an optimization algorithm is developed using modern computer-aided control design and analysis software. The capabilities of the algorithm are demonstrated by application to partitioned integrated flight/propulsion control design for a modern fighter aircraft in the short approach to landing task. The partitioning optimization is shown to lead to reduced-order subcontrollers that match the closed-loop command tracking and decoupling performance achieved by a high-order centralized controller.

Prefrontal, posterior parietal and sensorimotor network activity underlying speed control during walking

PubMed Central

Bulea, Thomas C.; Kim, Jonghyun; Damiano, Diane L.; Stanley, Christopher J.; Park, Hyung-Soon

2015-01-01

Accumulating evidence suggests cortical circuits may contribute to control of human locomotion. Here, noninvasive electroencephalography (EEG) recorded from able-bodied volunteers during a novel treadmill walking paradigm was used to assess neural correlates of walking. A systematic processing method, including a recently developed subspace reconstruction algorithm, reduced movement-related EEG artifact prior to independent component analysis and dipole source localization. We quantified cortical activity while participants tracked slow and fast target speeds across two treadmill conditions: an active mode that adjusted belt speed based on user movements and a passive mode reflecting a typical treadmill. Our results reveal frequency specific, multi-focal task related changes in cortical oscillations elicited by active walking. Low γ band power, localized to the prefrontal and posterior parietal cortices, was significantly increased during double support and early swing phases, critical points in the gait cycle since the active controller adjusted speed based on pelvis position and swing foot velocity. These phasic γ band synchronizations provide evidence that prefrontal and posterior parietal networks, previously implicated in visuo-spatial and somotosensory integration, are engaged to enhance lower limb control during gait. Sustained μ and β band desynchronization within sensorimotor cortex, a neural correlate for movement, was observed during walking thereby validating our methods for isolating cortical activity. Our results also demonstrate the utility of EEG recorded during locomotion for probing the multi-regional cortical networks which underpin its execution. For example, the cortical network engagement elicited by the active treadmill suggests that it may enhance neuroplasticity for more effective motor training. PMID:26029077

Separation control in adverse pressure gradients using high-speed microjets

NASA Astrophysics Data System (ADS)

Kumar, Vikas

Inlets to aircraft propulsion systems must supply flow to the compressor with minimal pressure loss, flow distortion or unsteadiness. Flow separation in internal flows such as inlets and ducts in aircraft propulsion systems and external flows such as over aircraft wings, is undesirable as it reduces the overall system performance. The objective of present study is to understand the nature of separation and more importantly, to explore the applicability of high-speed microjets to actively control this flow separation. The geometry used for this experimental study was a generic backward facing "Stratford Ramp" equipped with arrays of high-speed microjets. The incoming flow was examined over a freestream velocity range of 10-65m/s and at ramp angle in range of 0-10°. It was observed that the flow separates at 30m/s and beyond for all angle of attack. The magnitude and extent of separation bubble increases with increasing adverse pressure gradients and/or increase in free-stream velocity. The separated flow for all the examined conditions was completely attached using suitable array of high-speed microjets. The most notable fact was that elimination of reverse velocity regions was accompanied by a reduction in flow unsteadiness and increased two-dimensionality in the flow. In particular, these gains were achieved with a minimal mass flux, less than 0.2% of the primary flow based on 30% Boundary Layer Ingesting duct. Detailed measurements were obtained to understand the flow control dynamics. The control effectiveness was found to be dependent on the actuation location with respect to separation, jet to cross-flow momentum ratio and the angle at which microjets supply the momentum. It was also determined that the control effect of the microjets, in part, is due to creation of strong stream-wise vortices which enhance the mixing between low-momentum fluid closer to the surface and high-momentum fluid further away from the surface. The penetration depth of microjets was

Insulin/Insulin-like growth factor signaling controls non-Dauer developmental speed in the nematode Caenorhabditis elegans.

PubMed

Ruaud, Anne-Françoise; Katic, Iskra; Bessereau, Jean-Louis

2011-01-01

Identified as a major pathway controlling entry in the facultative dauer diapause stage, the DAF-2/Insulin receptor (InsR) signaling acts in multiple developmental and physiological regulation events in Caenorhabditis elegans. Here we identified a role of the insulin-like pathway in controlling developmental speed during the C. elegans second larval stage. This role relies on the canonical DAF-16/FOXO-dependent branch of the insulin-like signaling and is largely independent of dauer formation. Our studies provide further evidence for broad conservation of insulin/insulin-like growth factor (IGF) functions in developmental speed control.

The study of optimization on process parameters of high-accuracy computerized numerical control polishing

NASA Astrophysics Data System (ADS)

Huang, Wei-Ren; Huang, Shih-Pu; Tsai, Tsung-Yueh; Lin, Yi-Jyun; Yu, Zong-Ru; Kuo, Ching-Hsiang; Hsu, Wei-Yao; Young, Hong-Tsu

2017-09-01

Spherical lenses lead to forming spherical aberration and reduced optical performance. Consequently, in practice optical system shall apply a combination of spherical lenses for aberration correction. Thus, the volume of the optical system increased. In modern optical systems, aspherical lenses have been widely used because of their high optical performance with less optical components. However, aspherical surfaces cannot be fabricated by traditional full aperture polishing process due to their varying curvature. Sub-aperture computer numerical control (CNC) polishing is adopted for aspherical surface fabrication in recent years. By using CNC polishing process, mid-spatial frequency (MSF) error is normally accompanied during this process. And the MSF surface texture of optics decreases the optical performance for high precision optical system, especially for short-wavelength applications. Based on a bonnet polishing CNC machine, this study focuses on the relationship between MSF surface texture and CNC polishing parameters, which include feed rate, head speed, track spacing and path direction. The power spectral density (PSD) analysis is used to judge the MSF level caused by those polishing parameters. The test results show that controlling the removal depth of single polishing path, through the feed rate, and without same direction polishing path for higher total removal depth can efficiently reduce the MSF error. To verify the optical polishing parameters, we divided a correction polishing process to several polishing runs with different direction polishing paths. Compare to one shot polishing run, multi-direction path polishing plan could produce better surface quality on the optics.

The comparison of transfemoral amputees using mechanical and microprocessor- controlled prosthetic knee under different walking speeds: A randomized cross-over trial.

PubMed

Cao, Wujing; Yu, Hongliu; Zhao, Weiliang; Meng, Qiaoling; Chen, Wenming

2018-04-20

The microprocessor-controlled prosthetic knees have been introduced to transfemoral amputees due to advances in biomedical engineering. A body of scientific literature has shown that the microprocessor-controlled prosthetic knees improve the gait and functional abilities of persons with transfemoral amputation. The aim of this study was to propose a new microprocessor-controlled prosthetic knee (MPK) and compare it with non-microprocessor-controlled prosthetic knees (NMPKs) under different walking speeds. The microprocessor-controlled prosthetic knee (i-KNEE) with hydraulic damper was developed. The comfortable self-selected walking speeds of 12 subjects with i-KNEE and NMPK were obtained. The maximum swing flexion knee angle and gait symmetry were compared in i-KNEE and NMPK condition. The comfortable self-selected walking speeds of some subjects were higher with i-KNEE while some were not. There was no significant difference in comfortable self-selected walking speed between the i-KNEE and the NMPK condition (P= 0.138). The peak prosthetic knee flexion during swing in the i-KNEE condition was between sixty and seventy degree under any walking speed. In the NMPK condition, the maximum swing flexion knee angle changed significantly. And it increased with walking speed. There is no significant difference in knee kinematic symmetry when the subjects wear the i-KNEE or NMPK. The results of this study indicated that the new microprocessor-controlled prosthetic knee was suitable for transfemoral amputees. The maximum swing flexion knee angle under different walking speeds showed different properties in the NMPK and i-KNEE condition. The i-KNEE was more adaptive to speed changes. There was little difference of comfortable self-selected walking speed between i-KNEE and NMPK condition.

Aircraft dual-shaft jet engine with indirect action fuel flow controller

NASA Astrophysics Data System (ADS)

Tudosie, Alexandru-Nicolae

2017-06-01

The paper deals with an aircraft single-jet engine's control system, based on a fuel flow controller. Considering the engine as controlled object and its thrust the most important operation effect, from the multitude of engine's parameters only its rotational speed n is measurable and proportional to its thrust, so engine's speed has become the most important controlled parameter. Engine's control system is based on fuel injection Qi dosage, while the output is engine's speed n. Based on embedded system's main parts' mathematical models, the author has described the system by its block diagram with transfer functions; furthermore, some Simulink-Matlab simulations are performed, concerning embedded system quality (its output parameters time behavior) and, meanwhile, some conclusions concerning engine's parameters mutual influences are revealed. Quantitative determinations are based on author's previous research results and contributions, as well as on existing models (taken from technical literature). The method can be extended for any multi-spool engine, single- or twin-jet.

Linear-parameter-varying gain-scheduled control of aerospace systems

NASA Astrophysics Data System (ADS)

Barker, Jeffrey Michael

The dynamics of many aerospace systems vary significantly as a function of flight condition. Robust control provides methods of guaranteeing performance and stability goals across flight conditions. In mu-syntthesis, changes to the dynamical system are primarily treated as uncertainty. This method has been successfully applied to many control problems, and here is applied to flutter control. More recently, two techniques for generating robust gain-scheduled controller have been developed. Linear fractional transformation (LFT) gain-scheduled control is an extension of mu-synthesis in which the plant and controller are explicit functions of parameters measurable in real-time. This LFT gain-scheduled control technique is applied to the Benchmark Active Control Technology (BACT) wing, and compared with mu-synthesis control. Linear parameter-varying (LPV) gain-scheduled control is an extension of Hinfinity control to parameter varying systems. LPV gain-scheduled control directly incorporates bounds on the rate of change of the scheduling parameters, and often reduces conservatism inherent in LFT gain-scheduled control. Gain-scheduled LPV control of the BACT wing compares very favorably with the LFT controller. Gain-scheduled LPV controllers are generated for the lateral-directional and longitudinal axes of the Innovative Control Effectors (ICE) aircraft and implemented in nonlinear simulations and real-time piloted nonlinear simulations. Cooper-Harper and pilot-induced oscillation ratings were obtained for an initial design, a reference aircraft and a redesign. Piloted simulation results for the initial LPV gain-scheduled control of the ICE aircraft are compared with results for a conventional fighter aircraft in discrete pitch and roll angle tracking tasks. The results for the redesigned controller are significantly better than both the previous LPV controller and the conventional aircraft.

Adaptive PIF Control for Permanent Magnet Synchronous Motors Based on GPC

PubMed Central

Lu, Shaowu; Tang, Xiaoqi; Song, Bao

2013-01-01

To enhance the control performance of permanent magnet synchronous motors (PMSMs), a generalized predictive control (GPC)-based proportional integral feedforward (PIF) controller is proposed for the speed control system. In this new approach, firstly, based on the online identification of controlled model parameters, a simplified GPC law supplies the PIF controller with suitable control parameters according to the uncertainties in the operating conditions. Secondly, the speed reference curve for PMSMs is usually required to be continuous and continuously differentiable according to the general servo system design requirements, so the adaptation of the speed reference is discussed in details in this paper. Hence, the performance of the speed control system using a GPC-based PIF controller is improved for tracking some specified signals. The main motivation of this paper is the extension of GPC law to replace the traditional PI or PIF controllers in industrial applications. The efficacy and usefulness of the proposed controller are verified through experimental results. PMID:23262481

Adaptive PIF control for permanent magnet synchronous motors based on GPC.

PubMed

Lu, Shaowu; Tang, Xiaoqi; Song, Bao

2012-12-24

To enhance the control performance of permanent magnet synchronous motors (PMSMs), a generalized predictive control (GPC)-based proportional integral feedforward (PIF) controller is proposed for the speed control system. In this new approach, firstly, based on the online identification of controlled model parameters, a simplified GPC law supplies the PIF controller with suitable control parameters according to the uncertainties in the operating conditions. Secondly, the speed reference curve for PMSMs is usually required to be continuous and continuously differentiable according to the general servo system design requirements, so the adaptation of the speed reference is discussed in details in this paper. Hence, the performance of the speed control system using a GPC-based PIF controller is improved for tracking some specified signals. The main motivation of this paper is the extension of GPC law to replace the traditional PI or PIF controllers in industrial applications. The efficacy and usefulness of the proposed controller are verified through experimental results.

A sequential sampling account of response bias and speed-accuracy tradeoffs in a conflict detection task.

PubMed

Vuckovic, Anita; Kwantes, Peter J; Humphreys, Michael; Neal, Andrew

2014-03-01

Signal Detection Theory (SDT; Green & Swets, 1966) is a popular tool for understanding decision making. However, it does not account for the time taken to make a decision, nor why response bias might change over time. Sequential sampling models provide a way of accounting for speed-accuracy trade-offs and response bias shifts. In this study, we test the validity of a sequential sampling model of conflict detection in a simulated air traffic control task by assessing whether two of its key parameters respond to experimental manipulations in a theoretically consistent way. Through experimental instructions, we manipulated participants' response bias and the relative speed or accuracy of their responses. The sequential sampling model was able to replicate the trends in the conflict responses as well as response time across all conditions. Consistent with our predictions, manipulating response bias was associated primarily with changes in the model's Criterion parameter, whereas manipulating speed-accuracy instructions was associated with changes in the Threshold parameter. The success of the model in replicating the human data suggests we can use the parameters of the model to gain an insight into the underlying response bias and speed-accuracy preferences common to dynamic decision-making tasks. © 2013 American Psychological Association

Polarization speed meter for gravitational-wave detection

NASA Astrophysics Data System (ADS)

Wade, Andrew R.; McKenzie, Kirk; Chen, Yanbei; Shaddock, Daniel A.; Chow, Jong H.; McClelland, David E.

2012-09-01

We propose a modified configuration of an advanced gravitational-wave detector that is a speed-meter-type interferometer with improved sensitivity with respect to quantum noise. With the addition of polarization-controlling components to the output of an arm cavity Michelson interferometer, an orthogonal polarization state of the interferometer can be used to store signal, returning it later with opposite phase to cancel position information below the storage bandwidth of the opposite mode. This modification provides an alternative to an external kilometer-scale Fabry-Pérot cavity, as presented in earlier work of Purdue and Chen [Phys. Rev. D 66, 122004 (2002)]. The new configuration requires significantly less physical infrastructure to achieve speed meter operation. The quantity of length and alignment degrees of freedom is also reduced. We present theoretical calculations to show that such a speed meter detector is capable of beating the strain sensitivity imposed by the standard quantum limit over a broad range of frequencies for Advanced Laser Interferometer Gravitational-wave Observatory-like parameters. The benefits and possible difficulties of implementing such a scheme are outlined. We also present results for tuning of the speed meter by adjusting the degree of polarization coupling, a novel possibility that does not exist in previously proposed designs, showing that there is a smooth transition from speed meter operation to that of a signal-recycling Michelson behavior.

Quantum Speed Limit of a Photon under Non-Markovian Dynamics

NASA Astrophysics Data System (ADS)

Xu, Zhen-Yu; Zhu, Shi-Qun

2014-02-01

Quantum speed limit (QSL) time under noise has drawn considerable attention in real quantum computational processes. Though non-Markovian noise is found to be able to accelerate quantum evolution for a damped Jaynes—Cummings model, in this work we show that non-Markovianity will slow down the quantum evolution of an experimentally controllable photon system. As an application, QSL time of a photon can be controlled by regulating the relevant environment parameter properly, which nearly reaches the currently available photonic experimental technology.

Optimal Predictive Control for Path Following of a Full Drive-by-Wire Vehicle at Varying Speeds

NASA Astrophysics Data System (ADS)

SONG, Pan; GAO, Bolin; XIE, Shugang; FANG, Rui

2017-05-01

The current research of the global chassis control problem for the full drive-by-wire vehicle focuses on the control allocation (CA) of the four-wheel-distributed traction/braking/steering systems. However, the path following performance and the handling stability of the vehicle can be enhanced a step further by automatically adjusting the vehicle speed to the optimal value. The optimal solution for the combined longitudinal and lateral motion control (MC) problem is given. First, a new variable step-size spatial transformation method is proposed and utilized in the prediction model to derive the dynamics of the vehicle with respect to the road, such that the tracking errors can be explicitly obtained over the prediction horizon at varying speeds. Second, a nonlinear model predictive control (NMPC) algorithm is introduced to handle the nonlinear coupling between any two directions of the vehicular planar motion and computes the sequence of the optimal motion states for following the desired path. Third, a hierarchical control structure is proposed to separate the motion controller into a NMPC based path planner and a terminal sliding mode control (TSMC) based path follower. As revealed through off-line simulations, the hierarchical methodology brings nearly 1700% improvement in computational efficiency without loss of control performance. Finally, the control algorithm is verified through a hardware in-the-loop simulation system. Double-lane-change (DLC) test results show that by using the optimal predictive controller, the root-mean-square (RMS) values of the lateral deviations and the orientation errors can be reduced by 41% and 30%, respectively, comparing to those by the optimal preview acceleration (OPA) driver model with the non-preview speed-tracking method. Additionally, the average vehicle speed is increased by 0.26 km/h with the peak sideslip angle suppressed to 1.9°. This research proposes a novel motion controller, which provides the full drive

Microprocessor Control of Low Speed VSTOL Flight.

DTIC Science & Technology

1979-06-08

Analog IAS Indicated Air Speed I/O Input/Output KIAS Knots, Indicated Air Speed NATOPS Naval Air Training and Operating Procedures Standardization SAS...computer programming necessary in the research, and contain, in the form of computer- generated time histories, the results of the project. -17- I...of the aircraft causes airflow over the wings and therefore produces aerodynamic lift. As the transition progresses, wing- generated lift gradually

Maximum speed limits. Volume 2, The development of speed limits : a review of the literature

DOT National Transportation Integrated Search

1970-10-01

This report contains the literature review conducted as a part of the project "A Study for the Selection of Maximum Speed Limits." Five aspects of speed and speed control are discussed. These topics include: the history of speed limits; the relations...

Gaining control: changing relations between executive control and processing speed and their relevance for mathematics achievement over course of the preschool period

PubMed Central

Clark, Caron A. C.; Nelson, Jennifer Mize; Garza, John; Sheffield, Tiffany D.; Wiebe, Sandra A.; Espy, Kimberly Andrews

2014-01-01

Early executive control (EC) predicts a range of academic outcomes and shows particularly strong associations with children's mathematics achievement. Nonetheless, a major challenge for EC research lies in distinguishing EC from related cognitive constructs that also are linked to achievement outcomes. Developmental cascade models suggest that children's information processing speed is a driving mechanism in cognitive development that supports gains in working memory, inhibitory control and associated cognitive abilities. Accordingly, individual differences in early executive task performance and their relation to mathematics may reflect, at least in part, underlying variation in children's processing speed. The aims of this study were to: (1) examine the degree of overlap between EC and processing speed at different preschool age points; and (2) determine whether EC uniquely predicts children's mathematics achievement after accounting for individual differences in processing speed. As part of a longitudinal, cohort-sequential study, 388 children (50% boys; 44% from low income households) completed the same battery of EC tasks at ages 3, 3.75, 4.5, and 5.25 years. Several of the tasks incorporated baseline speeded naming conditions with minimal EC demands. Multidimensional latent models were used to isolate the variance in executive task performance that did not overlap with baseline processing speed, covarying for child language proficiency. Models for separate age points showed that, while EC did not form a coherent latent factor independent of processing speed at age 3 years, it did emerge as a distinct factor by age 5.25. Although EC at age 3 showed no distinct relation with mathematics achievement independent of processing speed, EC at ages 3.75, 4.5, and 5.25 showed independent, prospective links with mathematics achievement. Findings suggest that EC and processing speed are tightly intertwined in early childhood. As EC becomes progressively decoupled from

A Fuzzy-Based Control Method for Smoothing Power Fluctuations in Substations along High-Speed Railways

NASA Astrophysics Data System (ADS)

Sugio, Tetsuya; Yamamoto, Masayoshi; Funabiki, Shigeyuki

The use of an SMES (Superconducting Magnetic Energy Storage) for smoothing power fluctuations in a railway substation has been discussed. This paper proposes a smoothing control method based on fuzzy reasoning for reducing the SMES capacity at substations along high-speed railways. The proposed smoothing control method comprises three countermeasures for reduction of the SMES capacity. The first countermeasure involves modification of rule 1 for smoothing out the fluctuating electric power to its average value. The other countermeasures involve the modification of the central value of the stored energy control in the SMES and revision of the membership function in rule 2 for reduction of the SMES capacity. The SMES capacity in the proposed smoothing control method is reduced by 49.5% when compared to that in the nonrevised control method. It is confirmed by computer simulations that the proposed control method is suitable for smoothing out power fluctuations in substations along high-speed railways and for reducing the SMES capacity.

Sensorimotor Control of Tracking Movements at Various Speeds for Stroke Patients as Well as Age-Matched and Young Healthy Subjects

PubMed Central

Ao, Di; Song, Rong; Tong, Kai-yu

2015-01-01

There are aging- and stroke-induced changes on sensorimotor control in daily activities, but their mechanisms have not been well investigated. This study explored speed-, aging-, and stroke-induced changes on sensorimotor control. Eleven stroke patients (affected sides and unaffected sides) and 20 control subjects (10 young and 10 age-matched individuals) were enrolled to perform elbow tracking tasks using sinusoidal trajectories, which included 6 target speeds (15.7, 31.4, 47.1, 62.8, 78.5, and 94.2 deg/s). The actual elbow angle was recorded and displayed on a screen as visual feedback, and three indicators, the root mean square error (RMSE), normalized integrated jerk (NIJ) and integral of the power spectrum density of normalized speed (IPNS), were used to investigate the strategy of sensorimotor control. Both NIJ and IPNS had significant differences among the four groups (P<0.01), and the values were ranked in the following order: young controls < age-matched controls control. The RMSE increased with the increase in the target speed and the NIJ and IPNS initially declined and then remained steady for all four groups, which indicated a shift from feedback to feedforward control as the target speed increased. The feedback-feedforward trade-off induced by stroke, aging and speed might be explained by a change in the transmission delay and neuromotor noise. The findings in this study improve our understanding of the mechanism underlying the sensorimotor control and neurological changes caused by stroke and aging. PMID:26030289

Dynamic design and control of a high-speed pneumatic jet actuator

NASA Astrophysics Data System (ADS)

Misyurin, S. Yu; Ivlev, V. I.; Kreinin, G. V.

2017-12-01

Mathematical model of an actuator, consisting of a pneumatic (gas) high-speed jet engine, transfer mechanism, and a control device used for switching the ball valve is worked out. The specific attention was paid to the transition (normalization) of the dynamic model into the dimensionless form. Its dynamic simulation criteria are determined, and dynamics study of an actuator was carried out. The simple control algorithm of relay action with a velocity feedback enabling the valve plug to be turned with a smooth nonstop and continuous approach to the final position is demonstrated

Attitude Control for an Aero-Vehicle Using Vector Thrusting and Variable Speed Control Moment Gyros

NASA Technical Reports Server (NTRS)

Shin, Jong-Yeob; Lim, K. B.; Moerder, D. D.

2005-01-01

Stabilization of passively unstable thrust-levitated vehicles can require significant control inputs. Although thrust vectoring is a straightforward choice for realizing these inputs, this may lead to difficulties discussed in the paper. This paper examines supplementing thrust vectoring with Variable-Speed Control Moment Gyroscopes (VSCMGs). The paper describes how to allocate VSCMGs and the vectored thrust mechanism for attitude stabilization in frequency domain and also shows trade-off between vectored thrust and VSCMGs. Using an H2 control synthesis methodology in LMI optimization, a feedback control law is designed for a thrust-levitated research vehicle and is simulated with the full nonlinear model. It is demonstrated that VSCMGs can reduce the use of vectored thrust variation for stabilizing the hovering platform in the presence of strong wind gusts.

40 CFR Appendix I to Part 94 - Emission-Related Engine Parameters and Specifications

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Temperature control system calibration. 4. Maximum allowable inlet air restriction. III. Fuel System. 1. General. a. Engine idle speed. 2. Fuel injection—compression ignition engines. a. Control parameters and calibrations. b. Transient enrichment system calibration. c. Air-fuel flow calibration. d. Altitude...

40 CFR Appendix I to Part 94 - Emission-Related Engine Parameters and Specifications

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Temperature control system calibration. 4. Maximum allowable inlet air restriction. III. Fuel System. 1. General. a. Engine idle speed. 2. Fuel injection—compression ignition engines. a. Control parameters and calibrations. b. Transient enrichment system calibration. c. Air-fuel flow calibration. d. Altitude...

40 CFR Appendix I to Part 94 - Emission-Related Engine Parameters and Specifications

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Temperature control system calibration. 4. Maximum allowable inlet air restriction. III. Fuel System. 1. General. a. Engine idle speed. 2. Fuel injection—compression ignition engines. a. Control parameters and calibrations. b. Transient enrichment system calibration. c. Air-fuel flow calibration. d. Altitude...

40 CFR Appendix I to Part 94 - Emission-Related Engine Parameters and Specifications

Code of Federal Regulations, 2013 CFR

2013-07-01

.... Temperature control system calibration. 4. Maximum allowable inlet air restriction. III. Fuel System. 1. General. a. Engine idle speed. 2. Fuel injection—compression ignition engines. a. Control parameters and calibrations. b. Transient enrichment system calibration. c. Air-fuel flow calibration. d. Altitude...

The development of a control system for a small high speed steam microturbine generator system

NASA Astrophysics Data System (ADS)

Alford, A.; Nichol, P.; Saunders, M.; Frisby, B.

2015-08-01

Steam is a widely used energy source. In many situations steam is generated at high pressures and then reduced in pressure through control valves before reaching point of use. An opportunity was identified to convert some of the energy at the point of pressure reduction into electricity. To take advantage of a market identified for small scale systems, a microturbine generator was designed based on a small high speed turbo machine. This machine was packaged with the necessary control valves and systems to allow connection of the machine to the grid. Traditional machines vary the speed of the generator to match the grid frequency. This was not possible due to the high speed of this machine. The characteristics of the rotating unit had to be understood to allow a control that allowed export of energy at the right frequency to the grid under the widest possible range of steam conditions. A further goal of the control system was to maximise the efficiency of generation under all conditions. A further complication was to provide adequate protection for the rotating unit in the event of the loss of connection to the grid. The system to meet these challenges is outlined with the solutions employed and tested for this application.

Fractional Order PIλDμ Control for Maglev Guiding System

NASA Astrophysics Data System (ADS)

Hu, Qing; Hu, Yuwei

To effectively suppress the external disturbances and parameter perturbation problem of the maglev guiding system, and improve speed and robustness, the electromagnetic guiding system is exactly linearized using state feedback method, Fractional calculus theory is introduced, the order of integer order PID control was extended to the field of fractional, then fractional order PIλDμ Controller was presented, Due to the extra two adjustable parameters compared with traditional PID controller, fractional order PIλDμ controllers were expected to show better control performance. The results of the computer simulation show that the proposed controller suppresses the external disturbances and parameter perturbation of the system effectively; the system response speed was increased; at the same time, it had flexible structure and stronger robustness.

High-speed, automatic controller design considerations for integrating array processor, multi-microprocessor, and host computer system architectures

NASA Technical Reports Server (NTRS)

Jacklin, S. A.; Leyland, J. A.; Warmbrodt, W.

1985-01-01

Modern control systems must typically perform real-time identification and control, as well as coordinate a host of other activities related to user interaction, online graphics, and file management. This paper discusses five global design considerations which are useful to integrate array processor, multimicroprocessor, and host computer system architectures into versatile, high-speed controllers. Such controllers are capable of very high control throughput, and can maintain constant interaction with the nonreal-time or user environment. As an application example, the architecture of a high-speed, closed-loop controller used to actively control helicopter vibration is briefly discussed. Although this system has been designed for use as the controller for real-time rotorcraft dynamics and control studies in a wind tunnel environment, the controller architecture can generally be applied to a wide range of automatic control applications.

Choosing the appropriate forecasting model for predictive parameter control.

PubMed

Aleti, Aldeida; Moser, Irene; Meedeniya, Indika; Grunske, Lars

2014-01-01

All commonly used stochastic optimisation algorithms have to be parameterised to perform effectively. Adaptive parameter control (APC) is an effective method used for this purpose. APC repeatedly adjusts parameter values during the optimisation process for optimal algorithm performance. The assignment of parameter values for a given iteration is based on previously measured performance. In recent research, time series prediction has been proposed as a method of projecting the probabilities to use for parameter value selection. In this work, we examine the suitability of a variety of prediction methods for the projection of future parameter performance based on previous data. All considered prediction methods have assumptions the time series data has to conform to for the prediction method to provide accurate projections. Looking specifically at parameters of evolutionary algorithms (EAs), we find that all standard EA parameters with the exception of population size conform largely to the assumptions made by the considered prediction methods. Evaluating the performance of these prediction methods, we find that linear regression provides the best results by a very small and statistically insignificant margin. Regardless of the prediction method, predictive parameter control outperforms state of the art parameter control methods when the performance data adheres to the assumptions made by the prediction method. When a parameter's performance data does not adhere to the assumptions made by the forecasting method, the use of prediction does not have a notable adverse impact on the algorithm's performance.

Dimming-discrete-multi-tone (DMT) for simultaneous color control and high speed visible light communication.

PubMed

Sung, Jiun-Yu; Chow, Chi-Wai; Yeh, Chien-Hung

2014-04-07

Visible light communication (VLC) using LEDs has attracted significant attention recently for the future secure, license-free and electromagnetic-interference (EMI)-free optical wireless communication. Dimming technique in LED lamp is advantageous for energy efficiency. Color control can be performed in the red-green-blue (RGB) LEDs by using dimming technique. It is highly desirable to employ dimming technique to provide simultaneous color and dimming control and high speed VLC. Here, we proposed and demonstrated a LED dimming control using dimming-discrete-multi-tone (DMT) modulation. High speed DMT-based VLC with simultaneous color and dimming control is demonstrated for the first time to the best of our knowledge. Demonstration and analyses for several modulation conditions and transmission distances are performed, for instance, demonstrating the data rate of 103.5 Mb/s (using RGB LED) with fast Fourier transform (FFT) size of 512.

Speed, speed variation and crash relationships for urban arterials.

PubMed

Wang, Xuesong; Zhou, Qingya; Quddus, Mohammed; Fan, Tianxiang; Fang, Shou'en

2018-04-01

Speed and speed variation are closely associated with traffic safety. There is, however, a dearth of research on this subject for the case of urban arterials in general, and in the context of developing nations. In downtown Shanghai, the traffic conditions in each direction are very different by time of day, and speed characteristics during peak hours are also greatly different from those during off-peak hours. Considering that traffic demand changes with time and in different directions, arterials in this study were divided into one-way segments by the direction of flow, and time of day was differentiated and controlled for. In terms of data collection, traditional fixed-based methods have been widely used in previous studies, but they fail to capture the spatio-temporal distributions of speed along a road. A new approach is introduced to estimate speed variation by integrating spatio-temporal speed fluctuation of a single vehicle with speed differences between vehicles using taxi-based high frequency GPS data. With this approach, this paper aims to comprehensively establish a relationship between mean speed, speed variation and traffic crashes for the purpose of formulating effective speed management measures, specifically using an urban dataset. From a total of 234 one-way road segments from eight arterials in Shanghai, mean speed, speed variation, geometric design features, traffic volume, and crash data were collected. Because the safety effects of mean speed and speed variation may vary at different segment lengths, arterials with similar signal spacing density were grouped together. To account for potential correlations among these segments, a hierarchical Poisson log-normal model with random effects was developed. Results show that a 1% increase in mean speed on urban arterials was associated with a 0.7% increase in total crashes, and larger speed variation was also associated with increased crash frequency. Copyright © 2018 Elsevier Ltd. All rights

Estimation of effective wind speed

NASA Astrophysics Data System (ADS)

Østergaard, K. Z.; Brath, P.; Stoustrup, J.

2007-07-01

The wind speed has a huge impact on the dynamic response of wind turbine. Because of this, many control algorithms use a measure of the wind speed to increase performance, e.g. by gain scheduling and feed forward. Unfortunately, no accurate measurement of the effective wind speed is online available from direct measurements, which means that it must be estimated in order to make such control methods applicable in practice. In this paper a new method is presented for the estimation of the effective wind speed. First, the rotor speed and aerodynamic torque are estimated by a combined state and input observer. These two variables combined with the measured pitch angle is then used to calculate the effective wind speed by an inversion of a static aerodynamic model.

Invited review article: high-speed flexure-guided nanopositioning: mechanical design and control issues.

PubMed

Yong, Y K; Moheimani, S O R; Kenton, B J; Leang, K K

2012-12-01

Recent interest in high-speed scanning probe microscopy for high-throughput applications including video-rate atomic force microscopy and probe-based nanofabrication has sparked attention on the development of high-bandwidth flexure-guided nanopositioning systems (nanopositioners). Such nanopositioners are designed to move samples with sub-nanometer resolution with positioning bandwidth in the kilohertz range. State-of-the-art designs incorporate uniquely designed flexure mechanisms driven by compact and stiff piezoelectric actuators. This paper surveys key advances in mechanical design and control of dynamic effects and nonlinearities, in the context of high-speed nanopositioning. Future challenges and research topics are also discussed.

40 CFR 1066.235 - Speed verification procedure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... before testing, and after major maintenance. (c) Procedure. Use one of the following procedures to verify... dynamometer control circuits. Determine the speed error as follows: (i) Set the dynamometer to speed-control mode. Set the dynamometer speed to a value between 4.2 m/s and the maximum speed expected during...

High-speed civil transport flight- and propulsion-control technological issues

NASA Technical Reports Server (NTRS)

Ray, J. K.; Carlin, C. M.; Lambregts, A. A.

1992-01-01

Technology advances required in the flight and propulsion control system disciplines to develop a high speed civil transport (HSCT) are identified. The mission and requirements of the transport and major flight and propulsion control technology issues are discussed. Each issue is ranked and, for each issue, a plan for technology readiness is given. Certain features are unique and dominate control system design. These features include the high temperature environment, large flexible aircraft, control-configured empennage, minimizing control margins, and high availability and excellent maintainability. The failure to resolve most high-priority issues can prevent the transport from achieving its goals. The flow-time for hardware may require stimulus, since market forces may be insufficient to ensure timely production. Flight and propulsion control technology will contribute to takeoff gross weight reduction. Similar technology advances are necessary also to ensure flight safety for the transport. The certification basis of the HSCT must be negotiated between airplane manufacturers and government regulators. Efficient, quality design of the transport will require an integrated set of design tools that support the entire engineering design team.

High-Speed, High-Power Active Control Coils for HBT-EP

NASA Astrophysics Data System (ADS)

Debono, Bryan

2010-11-01

We report the performance of a newly installed high-speed, high-power active control system for the application of non-symmetric magnetic fields and the study of rotating MHD and resistive wall modes in the HBTEP tokamak. The new control system consists of an array of 120 modular control coils and 40 solid-state, high-power amplifiers that can apply non-symmetric control fields that are more than 10 times larger than previous studies in HBT-EP and exceed 5% of the equilibrium poloidal field strength. Measurements of the current and field response of the control system are presented as a function of frequency and control coil geometry, and these demonstrate the effectiveness of the system to interact with both growing RWM instabilities and long-wavelength modes rotating with the plasma. We describe a research plan to study the interaction of both kink and tearing mode fluctuations with applied static and rotating magnetic perturbations while systematically changing the plasma rotation with a biased molybdenum electrode inserted into the edge plasma.

Sensorless FOC Performance Improved with On-Line Speed and Rotor Resistance Estimator Based on an Artificial Neural Network for an Induction Motor Drive.

PubMed

Gutierrez-Villalobos, Jose M; Rodriguez-Resendiz, Juvenal; Rivas-Araiza, Edgar A; Martínez-Hernández, Moisés A

2015-06-29

Three-phase induction motor drive requires high accuracy in high performance processes in industrial applications. Field oriented control, which is one of the most employed control schemes for induction motors, bases its function on the electrical parameter estimation coming from the motor. These parameters make an electrical machine driver work improperly, since these electrical parameter values change at low speeds, temperature changes, and especially with load and duty changes. The focus of this paper is the real-time and on-line electrical parameters with a CMAC-ADALINE block added in the standard FOC scheme to improve the IM driver performance and endure the driver and the induction motor lifetime. Two kinds of neural network structures are used; one to estimate rotor speed and the other one to estimate rotor resistance of an induction motor.

Controlling chaos faster.

PubMed

Bick, Christian; Kolodziejski, Christoph; Timme, Marc

2014-09-01

Predictive feedback control is an easy-to-implement method to stabilize unknown unstable periodic orbits in chaotic dynamical systems. Predictive feedback control is severely limited because asymptotic convergence speed decreases with stronger instabilities which in turn are typical for larger target periods, rendering it harder to effectively stabilize periodic orbits of large period. Here, we study stalled chaos control, where the application of control is stalled to make use of the chaotic, uncontrolled dynamics, and introduce an adaptation paradigm to overcome this limitation and speed up convergence. This modified control scheme is not only capable of stabilizing more periodic orbits than the original predictive feedback control but also speeds up convergence for typical chaotic maps, as illustrated in both theory and application. The proposed adaptation scheme provides a way to tune parameters online, yielding a broadly applicable, fast chaos control that converges reliably, even for periodic orbits of large period.

Inner loop flight control for the High-Speed Civil Transport

NASA Technical Reports Server (NTRS)

Newman, Brett A.

1994-01-01

High-speed aerospace vehicles which employ high strength, light weight, yet deformable materials may exhibit significant interaction between the rigid-body and vibrational dynamics. Preliminary High-Speed Civil Transport (HSCT) configurations are a prime example. Traditionally, separate control systems have been used to augment the rigid-body and vibrational dynamics. In the HSCT arena, the highly coupled motions may not allow this design freedom. The research activity addresses two specific issues associated with the design and development of an integrated flight control system (FCS) for HSCT configurations, which are discussed next. The HSCT is expected to have a short period instability at subsonic speeds. Flight vehicles with this characteristic (i.e., F-16, F-22, X-29, Space Shuttle) are stabilized with what is called a superaugmented pitch rate loop. One concern is 'Will this stability augmentation logic work for a HSCT?' Studies show that an idealized pitch rate design would be acceptable, but is not realistic. Investigations using a contaminated pitch rate design reveal serious hurdles to overcome in the FCS design. Mounting location for the pitch rate sensor is critical. Results indicate a forward location leads to destabilizing pick-up of aeroelastic modes, while aft locations lead to undesirable coupling of the dominate pitch mode with the first aeroelastic mode. Intermediate locations for the sensor may not be acceptable. The source of the problem is the presence of low frequency aeroelastic modes in HSCT configurations, which are not present in vehicles currently using the superaugmented logic. To say the least, a conventional superaugmented pitch rate loop strategy may have undesirable characteristics. An unconventional strategy, which attempts to eliminate the above deficiencies by blending several pitch rate signals, indicates an improvement in the FCS architecture feasibility, but is still lacking in some respects. The HSCT configuration does not

Development of a Pulsed Combustion Actuator For High-Speed Flow Control

NASA Technical Reports Server (NTRS)

Cutler, Andrew D.; Beck, B. Terry; Wilkes, Jennifer A.; Drummond, J. Philip; Alderfer, David W.; Danehy, Paul M.

2005-01-01

This paper describes the flow within a prototype actuator, energized by pulsed combustion or detonations, that provides a pulsed jet suitable for flow control in high-speed applications. A high-speed valve, capable of delivering a pulsed stream of reactants a mixture of H2 and air at rates of up to 1500 pulses per second, has been constructed. The reactants burn in a resonant chamber, and the products exit the device as a pulsed jet. High frequency pressure transducers have been used to monitor the pressure fluctuations in the device at various reactant injection frequencies, including both resonant and off-resonant conditions. The combustion chamber has been constructed with windows, and the flow inside it has been visualized using Planar Laser-Induced Fluorescence (PLIF). The pulsed jet at the exit of the device has been observed using schlieren.

Enhancement of Speed Margins for 16× Digital Versatile Disc-Random Access Memory

NASA Astrophysics Data System (ADS)

Watanabe, Koichi; Minemura, Hiroyuki; Miyamoto, Makoto; Iimura, Makoto

2006-02-01

We have evaluated the speed margins of write/read 16× digital versatile disc-random access memory (DVD-RAM) test discs using write strategies for 6--16× constant angular velocity (CAV) control. Our approach is to determine the writing parameters for the middle zones by interpolating the zone numbers. Using this interpolation strategy, we successfully obtained overwrite jitter values of less than 8% and bit error rates of less than 10-5 in 6--16× DVD-RAM. Moreover, we confirmed that the speed margins were ± 20% for a 6--16× CAV.

High speed demodulation systems for fiber optic grating sensors

NASA Technical Reports Server (NTRS)

Udd, Eric (Inventor); Weisshaar, Andreas (Inventor)

2002-01-01

Fiber optic grating sensor demodulation systems are described that offer high speed and multiplexing options for both single and multiple parameter fiber optic grating sensors. To attain very high speeds for single parameter fiber grating sensors ratio techniques are used that allow a series of sensors to be placed in a single fiber while retaining high speed capability. These methods can be extended to multiparameter fiber grating sensors. Optimization of speeds can be obtained by minimizing the number of spectral peaks that must be processed and it is shown that two or three spectral peak measurements may in specific multiparameter applications offer comparable or better performance than processing four spectral peaks. Combining the ratio methods with minimization of peak measurements allows very high speed measurement of such important environmental effects as transverse strain and pressure.

Reduction of tablet weight variability by optimizing paddle speed in the forced feeder of a high-speed rotary tablet press.

PubMed

Peeters, Elisabeth; De Beer, Thomas; Vervaet, Chris; Remon, Jean-Paul

2015-04-01

Tableting is a complex process due to the large number of process parameters that can be varied. Knowledge and understanding of the influence of these parameters on the final product quality is of great importance for the industry, allowing economic efficiency and parametric release. The aim of this study was to investigate the influence of paddle speeds and fill depth at different tableting speeds on the weight and weight variability of tablets. Two excipients possessing different flow behavior, microcrystalline cellulose (MCC) and dibasic calcium phosphate dihydrate (DCP), were selected as model powders. Tablets were manufactured via a high-speed rotary tablet press using design of experiments (DoE). During each experiment also the volume of powder in the forced feeder was measured. Analysis of the DoE revealed that paddle speeds are of minor importance for tablet weight but significantly affect volume of powder inside the feeder in case of powders with excellent flowability (DCP). The opposite effect of paddle speed was observed for fairly flowing powders (MCC). Tableting speed played a role in weight and weight variability, whereas changing fill depth exclusively influenced tablet weight. The DoE approach allowed predicting the optimum combination of process parameters leading to minimum tablet weight variability. Monte Carlo simulations allowed assessing the probability to exceed the acceptable response limits if factor settings were varied around their optimum. This multi-dimensional combination and interaction of input variables leading to response criteria with acceptable probability reflected the design space.

Parameter identification using a creeping-random-search algorithm

NASA Technical Reports Server (NTRS)

Parrish, R. V.

1971-01-01

A creeping-random-search algorithm is applied to different types of problems in the field of parameter identification. The studies are intended to demonstrate that a random-search algorithm can be applied successfully to these various problems, which often cannot be handled by conventional deterministic methods, and, also, to introduce methods that speed convergence to an extremal of the problem under investigation. Six two-parameter identification problems with analytic solutions are solved, and two application problems are discussed in some detail. Results of the study show that a modified version of the basic creeping-random-search algorithm chosen does speed convergence in comparison with the unmodified version. The results also show that the algorithm can successfully solve problems that contain limits on state or control variables, inequality constraints (both independent and dependent, and linear and nonlinear), or stochastic models.

High Rotation Speed Friction Stir Welding for 2014 Aluminum Alloy Thin Sheets

NASA Astrophysics Data System (ADS)

Chen, Shujin; Zhou, Yang; Xue, Junrong; Ni, Ruiyang; Guo, Yue; Dong, Jianghui

2017-03-01

In this study, 2014 aluminum alloy sheets with 1 mm thickness are welded successfully by friction stir welding (FSW) robot under the condition of high rotation speed. When the high rotation speed of 10,000-16,500 rpm is applied, the lower axial pressure (less than 200 N) is obtained, which reduces stiffness requirements for equipment. Welding deformation is inevitable because high rotation speed can easily result in rapid heating rate and uneven heat input. The welding distortion caused by two cooling methods is measured, respectively, by laser range finder. The experimental results show that the welding distortion is smaller under the condition of water cooling. When the rotation speed is up to 15,000 rpm and welding speed 50-170 mm/min, the whole welding process is controllable. Under the higher rotation speed condition, the welding defects disappear gradually and more stable mechanical properties can be obtained up to 75% of base metal (ω = 16,000 rpm, ν = 110 mm/min). The results of different welding parameters demonstrate that the high rotation speed can increase material mixing and reduce the axial force (z force), and it can benefit lightweight sheet welding by using FSW robot.

Kinetic parameters of grinding media in ball mills with various liner design and mill speed based on DEM modeling

NASA Astrophysics Data System (ADS)

Khakhalev, P. A.; Bogdanov, VS; Kovshechenko, V. M.

2018-03-01

The article presents analysis of the experiments in the ball mill of 0.5x0.3 m with four different liner types based on DEM modeling. The numerical experiment always complements laboratory research and allow obtaining high accuracy output data. An important property of the numerical experiment is the possibility of visualization of the results. The EDEM software allows calculating trajectory of the grinding bodies and kinetic parameters of each ball for the relative mill speed and the different types of mill’s liners.

Active Flow Control for High-Speed Weapon Release from a Bay

DTIC Science & Technology

2004-06-01

and supersonic microjets . Each of these control devices offers unique attributes for high-speed weapon release and was the subject of considerable...final HIFEX actuator is the supersonic microjet , a device developed at Florida A&M/Florida State University and described by [3]. Small (0.016-inch...effectiveness of the microjets is that they destroy the spanwise coherence of the instabilities generated in an open weapons bay. Figure 4 illustrates the

Research on natural frequency based on modal test for high speed vehicles

NASA Astrophysics Data System (ADS)

Ma, Guangsong; He, Guanglin; Guo, Yachao

2018-04-01

High speed vehicle as a vibration system, resonance generated in flight may be harmful to high speed vehicles. It is possible to solve the resonance problem by acquiring the natural frequency of the high-speed aircraft and then taking some measures to avoid the natural frequency of the high speed vehicle. Therefore, In this paper, the modal test of the high speed vehicle was carried out by using the running hammer method and the PolyMAX modal parameter identification method. Firstly, the total frequency response function, coherence function of the high speed vehicle are obtained by the running hammer stimulation test, and through the modal assurance criterion (MAC) to determine the accuracy of the estimated parameters. Secondly, the first three order frequencies, the pole steady state diagram of the high speed vehicles is obtained by the PolyMAX modal parameter identification method. At last, the natural frequency of the vibration system was accurately obtained by the running hammer method.

Variable-frequency inverter controls torque, speed, and braking in ac induction motors

NASA Technical Reports Server (NTRS)

Nola, F. J.

1974-01-01

Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.

Efficient Low-Lift Cooling with Radiant Distribution, Thermal Storage and Variable-Speed Chiller Controls Part I: Component and Subsystem Models

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

Armstrong, Peter; Jiang, Wei; Winiarski, David W.

2009-03-31

this paper develops component and subsystem models used to evaluat4e the performance of a low-lift cooling system with an air-colled chiller optimized for variable-speed and low-pressure-ratio operation, a hydronic radient distribution system, variable-speed transport miotor controls, and peak-shifting controls.

Speed and Torque Control Strategies for Loss Reduction of Vertical Axis Wind Turbines

NASA Astrophysics Data System (ADS)

Argent, Michael; McDonald, Alasdair; Leithead, Bill; Giles, Alexander

2016-09-01

This paper builds on the work into modelling the generator losses for Vertical Axis Wind Turbines from their intrinsic torque cycling to investigate the effects of aerodynamic inefficiencies caused by the varying rotational speed resulting from different torque control strategies to the cyclic torque. This is achieved by modelling the wake that builds up from the rotation of the VAWT rotor to investigate how the wake responds to a changing rotor speed and how this in turn affects the torque produced by the blades as well as the corresponding change in generator losses and any changes to the energy extracted by the wind turbine rotor.

A one year pay-as-you-speed trial with economic incentives for not speeding.

PubMed

Stigson, Helena; Hagberg, Jan; Kullgren, Anders; Krafft, Maria

2014-01-01

The objective was to identify whether it was possible to change driver behavior by economic incentives and thereby reduce crash risk. Furthermore, the objective was to evaluate the participants' attitudes toward the pay-as-you-speed (PAYS) concept. A one-year PAYS trial with economic incentives for keeping speed limits using intelligent speed assistance (ISA) was conducted in Sweden during 2011-2012. The full incentive was a 30 percent discount off the insurance premium. The participants were private insurance customers and were randomized into a test group (initial n = 152, final n = 128) and a control group (initial n = 98, final n = 68). When driving, the drivers in the test group were informed and warned visually when the speed limit was exceeded. They could also follow their driving results on a personal website. The control group was not given any feedback at all. To reflect the impact of the PAYS concept the proportion of distance driven above the speed limit was compared between the 2 groups. The introduction of a PAYS concept shows that the test group significantly reduced the proportion of distance driven above the speed limit. The proportion of driving at a speed exceeding 5 km/h over the speed limit was 6 percent for the test group and 14 percent for the control group. It also showed that the effect was higher the higher the violation of speed. The result remained constant over time. It was shown that a PAYS concept is an effective way to reduce speed violations. Hence, it has the possibility to reduce crash severity and thereby to save lives. This could be an important step toward a safer road transport system. The majority of the participants were in favor of the concept, which indicates the potential of a new insurance product in the future.

Modern control concepts in hydrology. [parameter identification in adaptive stochastic control approach

NASA Technical Reports Server (NTRS)

Duong, N.; Winn, C. B.; Johnson, G. R.

1975-01-01

Two approaches to an identification problem in hydrology are presented, based upon concepts from modern control and estimation theory. The first approach treats the identification of unknown parameters in a hydrologic system subject to noisy inputs as an adaptive linear stochastic control problem; the second approach alters the model equation to account for the random part in the inputs, and then uses a nonlinear estimation scheme to estimate the unknown parameters. Both approaches use state-space concepts. The identification schemes are sequential and adaptive and can handle either time-invariant or time-dependent parameters. They are used to identify parameters in the Prasad model of rainfall-runoff. The results obtained are encouraging and confirm the results from two previous studies; the first using numerical integration of the model equation along with a trial-and-error procedure, and the second using a quasi-linearization technique. The proposed approaches offer a systematic way of analyzing the rainfall-runoff process when the input data are imbedded in noise.

Control of Groundwater Remediation Process as Distributed Parameter System

NASA Astrophysics Data System (ADS)

Mendel, M.; Kovács, T.; Hulkó, G.

2014-12-01

Pollution of groundwater requires the implementation of appropriate solutions which can be deployed for several years. The case of local groundwater contamination and its subsequent spread may result in contamination of drinking water sources or other disasters. This publication aims to design and demonstrate control of pumping wells for a model task of groundwater remediation. The task consists of appropriately spaced soil with input parameters, pumping wells and control system. Model of controlled system is made in the program MODFLOW using the finitedifference method as distributed parameter system. Control problem is solved by DPS Blockset for MATLAB & Simulink.

Locomotor Recovery in Spinal Cord Injury: Insights Beyond Walking Speed and Distance.

PubMed

Awai, Lea; Curt, Armin

2016-08-01

Recovery of locomotor function after incomplete spinal cord injury (iSCI) is clinically assessed through walking speed and distance, while improvements in these measures might not be in line with a normalization of gait quality and are, on their own, insensitive at revealing potential mechanisms underlying recovery. The objective of this study was to relate changes of gait parameters to the recovery of walking speed while distinguishing between parameters that rather reflect speed improvements from factors contributing to overall recovery. Kinematic data of 16 iSCI subjects were repeatedly recorded during in-patient rehabilitation. The responsiveness of gait parameters to walking speed was assessed by linear regression. Principal component analysis (PCA) was applied on the multivariate data across time to identify factors that contribute to recovery after iSCI. Parameters of gait cycle and movement dynamics were both responsive and closely related to the recovery of walking speed, which increased by 96%. Multivariate analysis revealed specific gait parameters (intralimb shape normality and consistency) that, although less related to speed increments, loaded highly on principal component one (PC1) (58.6%) explaining the highest proportion of variance (i.e., recovery of outcome over time). Interestingly, measures of hip, knee, and ankle range of motion showed varying degrees of responsiveness (from very high to very low) while not contributing to gait recovery as revealed by PCA. The conjunct application of two analysis methods distinguishes gait parameters that simply reflect increased walking speed from parameters that actually contribute to gait recovery in iSCI. This distinction may be of value for the evaluation of interventions for locomotor recovery.

Sensorless FOC Performance Improved with On-Line Speed and Rotor Resistance Estimator Based on an Artificial Neural Network for an Induction Motor Drive

PubMed Central

Gutierrez-Villalobos, Jose M.; Rodriguez-Resendiz, Juvenal; Rivas-Araiza, Edgar A.; Martínez-Hernández, Moisés A.

2015-01-01

Three-phase induction motor drive requires high accuracy in high performance processes in industrial applications. Field oriented control, which is one of the most employed control schemes for induction motors, bases its function on the electrical parameter estimation coming from the motor. These parameters make an electrical machine driver work improperly, since these electrical parameter values change at low speeds, temperature changes, and especially with load and duty changes. The focus of this paper is the real-time and on-line electrical parameters with a CMAC-ADALINE block added in the standard FOC scheme to improve the IM driver performance and endure the driver and the induction motor lifetime. Two kinds of neural network structures are used; one to estimate rotor speed and the other one to estimate rotor resistance of an induction motor. PMID:26131677

Compensator design for improved counterbalancing in high speed atomic force microscopy

PubMed Central

Bozchalooi, I. S.; Youcef-Toumi, K.; Burns, D. J.; Fantner, G. E.

2011-01-01

High speed atomic force microscopy can provide the possibility of many new scientific observations and applications ranging from nano-manufacturing to the study of biological processes. However, the limited imaging speed has been an imperative drawback of the atomic force microscopes. One of the main reasons behind this limitation is the excitation of the AFM dynamics at high scan speeds, severely undermining the reliability of the acquired images. In this research, we propose a piezo based, feedforward controlled, counter actuation mechanism to compensate for the excited out-of-plane scanner dynamics. For this purpose, the AFM controller output is properly filtered via a linear compensator and then applied to a counter actuating piezo. An effective algorithm for estimating the compensator parameters is developed. The information required for compensator design is extracted from the cantilever deflection signal, hence eliminating the need for any additional sensors. The proposed approach is implemented and experimentally evaluated on the dynamic response of a custom made AFM. It is further assessed by comparing the imaging performance of the AFM with and without the application of the proposed technique and in comparison with the conventional counterbalancing methodology. The experimental results substantiate the effectiveness of the method in significantly improving the imaging performance of AFM at high scan speeds. PMID:22128989

Compensator design for improved counterbalancing in high speed atomic force microscopy

NASA Astrophysics Data System (ADS)

Bozchalooi, I. S.; Youcef-Toumi, K.; Burns, D. J.; Fantner, G. E.

2011-11-01

High speed atomic force microscopy can provide the possibility of many new scientific observations and applications ranging from nano-manufacturing to the study of biological processes. However, the limited imaging speed has been an imperative drawback of the atomic force microscopes. One of the main reasons behind this limitation is the excitation of the AFM dynamics at high scan speeds, severely undermining the reliability of the acquired images. In this research, we propose a piezo based, feedforward controlled, counter actuation mechanism to compensate for the excited out-of-plane scanner dynamics. For this purpose, the AFM controller output is properly filtered via a linear compensator and then applied to a counter actuating piezo. An effective algorithm for estimating the compensator parameters is developed. The information required for compensator design is extracted from the cantilever deflection signal, hence eliminating the need for any additional sensors. The proposed approach is implemented and experimentally evaluated on the dynamic response of a custom made AFM. It is further assessed by comparing the imaging performance of the AFM with and without the application of the proposed technique and in comparison with the conventional counterbalancing methodology. The experimental results substantiate the effectiveness of the method in significantly improving the imaging performance of AFM at high scan speeds.