Modification of the azimuth control system in the LLMC

NASA Astrophysics Data System (ADS)

Li, Binhua; Yang, Lei; Chen, Linfei; Mao, Wei

2000-10-01

A new control system of the azimuth transmission mechanism used in the Lower Latitude Meridian Circle (LLMC) is described in this paper. Because the original azimuth transmission mechanism causes too much vibration during the transposition of the horizontal axis of the instrument, we decided to modify the original system by two ways. One is to modify the lift mechanism and the azimuth transmission mechanism. The other is to replace the original stepper motors with a new type of stepper motor. According to the requirement of the new motor and its sine subdivided microstep driver, the original control system has been modified. The new system has an expansion output board and a new control program compared with the original one. The hardware architecture of the new system is described. The program in the single chip microcontroller is written in ASM, which is composed of 10 subroutines. The program in a host PC is written in C++. The methods using in controlling motors and skills in designing these programs are discussed. Two sketch flow charts of the control program are presented in the paper. Modification of the lift mechanism is also introduced. All this works make the vibration very slight.

Analysis of Access Control Policies in Operating Systems

ERIC Educational Resources Information Center

Chen, Hong

2009-01-01

Operating systems rely heavily on access control mechanisms to achieve security goals and defend against remote and local attacks. The complexities of modern access control mechanisms and the scale of policy configurations are often overwhelming to system administrators and software developers. Therefore, mis-configurations are common, and the…

Flight control systems properties and problems, volume 1

NASA Technical Reports Server (NTRS)

Mcruer, D. T.; Johnston, D. E.

1975-01-01

This volume contains a delineation of fundamental and mechanization-specific flight control characteristics and problems gleaned from many sources and spanning a period of over two decades. It is organized to present and discuss first some fundamental, generic problems of closed-loop flight control systems involving numerator characteristics (quadratic dipoles, non-minimum phase roots, and intentionally introduced zeros). Next the principal elements of the largely mechanical primary flight control system are reviewed with particular emphasis on the influence of nonlinearities. The characteristics and problems of augmentation (damping, stability, and feel) system mechanizations are then dealt with. The particular idiosyncracies of automatic control actuation and command augmentation schemes are stressed, because they constitute the major interfaces with the primary flight control system and an often highly variable vehicle response.

Control of mechanical systems with rolling constraints: Application to dynamic control of mobile robots

NASA Technical Reports Server (NTRS)

Sarkar, Nilanjan; Yun, Xiaoping; Kumar, Vijay

1994-01-01

There are many examples of mechanical systems that require rolling contacts between two or more rigid bodies. Rolling contacts engender nonholonomic constraints in an otherwise holonomic system. In this article, we develop a unified approach to the control of mechanical systems subject to both holonomic and nonholonomic constraints. We first present a state space realization of a constrained system. We then discuss the input-output linearization and zero dynamics of the system. This approach is applied to the dynamic control of mobile robots. Two types of control algorithms for mobile robots are investigated: trajectory tracking and path following. In each case, a smooth nonlinear feedback is obtained to achieve asymptotic input-output stability and Lagrange stability of the overall system. Simulation results are presented to demonstrate the effectiveness of the control algorithms and to compare the performane of trajectory-tracking and path-following algorithms.

Mechanization of and experience with a triplex fly-by-wire backup control system

NASA Technical Reports Server (NTRS)

Lock, W. P.; Petersen, W. R.; Whitman, G. B.

1976-01-01

A redundant three axis analog control system was designed and developed to back up a digital fly by wire control system for an F-8C airplane. The mechanization and operational experience with the backup control system, the problems involved in synchronizing it with the primary system, and the reliability of the system are discussed. The backup control system was dissimilar to the primary system, and it provided satisfactory handling through the flight envelope evaluated. Limited flight tests of a variety of control tasks showed that control was also satisfactory when the backup control system was controlled by a minimum displacement (force) side stick. The operational reliability of the F-8 digital fly by wire control system was satisfactory, with no unintentional downmodes to the backup control system in flight. The ground and flight reliability of the system's components is discussed.

Firmware Development Improves System Efficiency

NASA Technical Reports Server (NTRS)

Chern, E. James; Butler, David W.

1993-01-01

Most manufacturing processes require physical pointwise positioning of the components or tools from one location to another. Typical mechanical systems utilize either stop-and-go or fixed feed-rate procession to accomplish the task. The first approach achieves positional accuracy but prolongs overall time and increases wear on the mechanical system. The second approach sustains the throughput but compromises positional accuracy. A computer firmware approach has been developed to optimize this point wise mechanism by utilizing programmable interrupt controls to synchronize engineering processes 'on the fly'. This principle has been implemented in an eddy current imaging system to demonstrate the improvement. Software programs were developed that enable a mechanical controller card to transmit interrupts to a system controller as a trigger signal to initiate an eddy current data acquisition routine. The advantages are: (1) optimized manufacturing processes, (2) increased throughput of the system, (3) improved positional accuracy, and (4) reduced wear and tear on the mechanical system.

Mechanical code comparator

DOEpatents

Peter, Frank J.; Dalton, Larry J.; Plummer, David W.

2002-01-01

A new class of mechanical code comparators is described which have broad potential for application in safety, surety, and security applications. These devices can be implemented as micro-scale electromechanical systems that isolate a secure or otherwise controlled device until an access code is entered. This access code is converted into a series of mechanical inputs to the mechanical code comparator, which compares the access code to a pre-input combination, entered previously into the mechanical code comparator by an operator at the system security control point. These devices provide extremely high levels of robust security. Being totally mechanical in operation, an access control system properly based on such devices cannot be circumvented by software attack alone.

The 18th Aerospace Mechanisms Symposium

NASA Technical Reports Server (NTRS)

1984-01-01

Topics concerning aerospace mechanisms, their functional performance, and design specifications are presented. Discussed subjects include the design and development of release mechanisms, actuators, linear driver/rate controllers, antenna and appendage deployment systems, position control systems, and tracking mechanisms for antennas and solar arrays. Engine design, spaceborne experiments, and large space structure technology are also examined.

Robust control of multi-jointed arm with a decentralized autonomous control mechanism

NASA Technical Reports Server (NTRS)

Kimura, Shinichi; Miyazaki, Ken; Suzuki, Yoshiaki

1994-01-01

A decentralized autonomous control mechanism applied to the control of three dimensional manipulators and its robustness to partial damage was assessed by computer simulation. Decentralized control structures are believed to be quite robust to time delay between the operator and the target system. A 10-jointed manipulator based on our control mechanism was able to continue its positioning task in three-dimensional space without revision of the control program, even after some of its joints were damaged. These results suggest that this control mechanism can be effectively applied to space telerobots, which are associated with serious time delay between the operator and the target system, and which cannot be easily repaired after being partially damaged.

Computation and Communication Evaluation of an Authentication Mechanism for Time-Triggered Networked Control Systems

PubMed Central

Martins, Goncalo; Moondra, Arul; Dubey, Abhishek; Bhattacharjee, Anirban; Koutsoukos, Xenofon D.

2016-01-01

In modern networked control applications, confidentiality and integrity are important features to address in order to prevent against attacks. Moreover, network control systems are a fundamental part of the communication components of current cyber-physical systems (e.g., automotive communications). Many networked control systems employ Time-Triggered (TT) architectures that provide mechanisms enabling the exchange of precise and synchronous messages. TT systems have computation and communication constraints, and with the aim to enable secure communications in the network, it is important to evaluate the computational and communication overhead of implementing secure communication mechanisms. This paper presents a comprehensive analysis and evaluation of the effects of adding a Hash-based Message Authentication (HMAC) to TT networked control systems. The contributions of the paper include (1) the analysis and experimental validation of the communication overhead, as well as a scalability analysis that utilizes the experimental result for both wired and wireless platforms and (2) an experimental evaluation of the computational overhead of HMAC based on a kernel-level Linux implementation. An automotive application is used as an example, and the results show that it is feasible to implement a secure communication mechanism without interfering with the existing automotive controller execution times. The methods and results of the paper can be used for evaluating the performance impact of security mechanisms and, thus, for the design of secure wired and wireless TT networked control systems. PMID:27463718

Computation and Communication Evaluation of an Authentication Mechanism for Time-Triggered Networked Control Systems.

PubMed

Martins, Goncalo; Moondra, Arul; Dubey, Abhishek; Bhattacharjee, Anirban; Koutsoukos, Xenofon D

2016-07-25

In modern networked control applications, confidentiality and integrity are important features to address in order to prevent against attacks. Moreover, network control systems are a fundamental part of the communication components of current cyber-physical systems (e.g., automotive communications). Many networked control systems employ Time-Triggered (TT) architectures that provide mechanisms enabling the exchange of precise and synchronous messages. TT systems have computation and communication constraints, and with the aim to enable secure communications in the network, it is important to evaluate the computational and communication overhead of implementing secure communication mechanisms. This paper presents a comprehensive analysis and evaluation of the effects of adding a Hash-based Message Authentication (HMAC) to TT networked control systems. The contributions of the paper include (1) the analysis and experimental validation of the communication overhead, as well as a scalability analysis that utilizes the experimental result for both wired and wireless platforms and (2) an experimental evaluation of the computational overhead of HMAC based on a kernel-level Linux implementation. An automotive application is used as an example, and the results show that it is feasible to implement a secure communication mechanism without interfering with the existing automotive controller execution times. The methods and results of the paper can be used for evaluating the performance impact of security mechanisms and, thus, for the design of secure wired and wireless TT networked control systems.

The Intersystem - Internetworking for space systems

NASA Astrophysics Data System (ADS)

Landauer, C.

This paper is a description of the Intersystem, which is a mechanism for internetworking among existing and planned military satellite communication systems. The communication systems interconnected with this mechanism are called member systems, and the interconnected set of communication systems is called the Intersystem. The Intersystem is implemented with higher layer protocols that impose a common organization on the different signaling conventions, so that end users of different systems can communicate with each other. The Intersystem provides its coordination of member system access and resource requests with Intersystem Resource Controllers (IRCs), which are processors that implement the Intersystem protocols and have interfaces to the member systems' own access and resource control mechanisms. The IRCs are connected to each other to form the IRC Subnetwork. Terminals request services from the IRC Subnetwork using the Intersystem Access Control Protocols, and the IRC Subnetwork responses to the requests are coordinated using the RCRC (Resource Controller to Resource Controller) Protocols.

A Mechanical Coil Insertion System for Endovascular Coil Embolization of Intracranial Aneurysms

PubMed Central

Haraguchi, K.; Miyachi, S.; Matsubara, N.; Nagano, Y.; Yamada, H.; Marui, N.; Sano, A.; Fujimoto, H.; Izumi, T.; Yamanouchi, T.; Asai, T.; Wakabayashi, T.

2013-01-01

Summary Like other fields of medicine, robotics and mechanization might be introduced into endovascular coil embolization of intracranial aneurysms for effective treatment. We have already reported that coil insertion force could be smaller and more stable when the coil delivery wire is driven mechanically at a constant speed. Another background is the difficulty in synchronizing operators' minds and hands when two operators control the microcatheter and the coil respectively. We have therefore developed a mechanical coil insertion system enabling a single operator to insert coils at a fixed speed while controlling the microcatheter. Using our new system, the operator manipulated the microcatheter with both hands and drove the coil using foot switches simultaneously. A delivery wire force sensor previously reported was used concurrently, allowing the operator to detect excessive stress on the wire. In vitro coil embolization was performed using three methods: simple mechanical advance of the coil; simple mechanical advance of the coil with microcatheter control; and driving (forward and backward) of the coil using foot switches in addition to microcatheter control. The system worked without any problems, and did not interfere with any procedures. In experimental coil embolization, delivery wire control using the foot switches as well as microcatheter manipulation helped to achieve successful insertion of coils. This system could offer the possibility of developing safer and more efficient coil embolization. Although we aim at total mechanization and automation of procedures in the future, microcatheter manipulation and synchronized delivery wire control are still indispensable using this system. PMID:23693038

Force reflecting hand controller for manipulator teleoperation

NASA Technical Reports Server (NTRS)

Bryfogle, Mark D.

1991-01-01

A force reflecting hand controller based upon a six degree of freedom fully parallel mechanism, often termed a Stewart Platform, has been designed, constructed, and tested as an integrated system with a slave robot manipulator test bed. A force reflecting hand controller comprises a kinesthetic device capable of transmitting position and orientation commands to a slave robot manipulator while simultaneously representing the environmental interaction forces of the slave manipulator back to the operator through actuators driving the hand controller mechanism. The Stewart Platform was chosen as a novel approach to improve force reflecting teleoperation because of its inherently high ratio of load generation capability to system mass content and the correspondingly high dynamic bandwidth. An additional novelty of the program was to implement closed loop force and torque control about the hand controller mechanism by equipping the handgrip with a six degree of freedom force and torque measuring cell. The mechanical, electrical, computer, and control systems are discussed and system tests are presented.

System precisely controls oscillation of vibrating mass

NASA Technical Reports Server (NTRS)

Hancock, D. J.

1967-01-01

System precisely controls the sinusoidal amplitude of a vibrating mechanical mass. Using two sets of coils, the system regulates the drive signal amplitude at the precise level to maintain the mechanical mass when it reaches the desired vibration amplitude.

Control design based on dead-zone and leakage adaptive laws for artificial swarm mechanical systems

NASA Astrophysics Data System (ADS)

Zhao, Xiaomin; Chen, Y. H.; Zhao, Han

2017-05-01

We consider the control design of artificial swarm systems with emphasis on four characteristics. First, the agent is made of mechanical components. As a result, the motion of each agent is subject to physical laws that govern mechanical systems. Second, both nonlinearity and uncertainty of the mechanical system are taken into consideration. Third, the ideal agent kinematic performance is treated as a desired d'Alembert constraint. This in turn suggests a creative way of embedding the constraint into the control design. Fourth, two types of adaptive robust control schemes are designed. They both contain leakage and dead-zone. However, one design suggests a trade-off between the amount of leakage and the size of dead-zone, in exchange for a simplified dead-zone structure.

Modelling of long-term and short-term mechanisms of arterial pressure control in the cardiovascular system: an object-oriented approach.

PubMed

Fernandez de Canete, J; Luque, J; Barbancho, J; Munoz, V

2014-04-01

A mathematical model that provides an overall description of both the short- and long-term mechanisms of arterial pressure regulation is presented. Short-term control is exerted through the baroreceptor reflex while renal elimination plays a role in long-term control. Both mechanisms operate in an integrated way over the compartmental model of the cardiovascular system. The whole system was modelled in MODELICA, which uses a hierarchical object-oriented modelling strategy, under the DYMOLA simulation environment. The performance of the controlled system was analysed by simulation in light of the existing hypothesis and validation tests previously performed with physiological data, demonstrating the effectiveness of both regulation mechanisms under physiological and pathological conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Design and Integration for High Performance Robotic Systems Based on Decomposition and Hybridization Approaches

PubMed Central

Zhang, Dan; Wei, Bin

2017-01-01

Currently, the uses of robotics are limited with respect to performance capabilities. Improving the performance of robotic mechanisms is and still will be the main research topic in the next decade. In this paper, design and integration for improving performance of robotic systems are achieved through three different approaches, i.e., structure synthesis design approach, dynamic balancing approach, and adaptive control approach. The purpose of robotic mechanism structure synthesis design is to propose certain mechanism that has better kinematic and dynamic performance as compared to the old ones. For the dynamic balancing design approach, it is normally accomplished based on employing counterweights or counter-rotations. The potential issue is that more weight and inertia will be included in the system. Here, reactionless based on the reconfiguration concept is put forward, which can address the mentioned problem. With the mechanism reconfiguration, the control system needs to be adapted thereafter. One way to address control system adaptation is by applying the “divide and conquer” methodology. It entails modularizing the functionalities: breaking up the control functions into small functional modules, and from those modules assembling the control system according to the changing needs of the mechanism. PMID:28075360

Development of a 3D parallel mechanism robot arm with three vertical-axial pneumatic actuators combined with a stereo vision system.

PubMed

Chiang, Mao-Hsiung; Lin, Hao-Ting

2011-01-01

This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel mechanism robot. In the mechanical system, a 3D parallel mechanism robot contains three serial chains, a fixed base, a movable platform and a pneumatic servo system. The parallel mechanism are designed and analyzed first for realizing a 3D motion in the X-Y-Z coordinate system of the robot's end-effector. The inverse kinematics and the forward kinematics of the parallel mechanism robot are investigated by using the Denavit-Hartenberg notation (D-H notation) coordinate system. The pneumatic actuators in the three vertical motion axes are modeled. In the control system, the Fourier series-based adaptive sliding-mode controller with H(∞) tracking performance is used to design the path tracking controllers of the three vertical servo pneumatic actuators for realizing 3D path tracking control of the end-effector. Three optical linear scales are used to measure the position of the three pneumatic actuators. The 3D position of the end-effector is then calculated from the measuring position of the three pneumatic actuators by means of the kinematics. However, the calculated 3D position of the end-effector cannot consider the manufacturing and assembly tolerance of the joints and the parallel mechanism so that errors between the actual position and the calculated 3D position of the end-effector exist. In order to improve this situation, sensor collaboration is developed in this paper. A stereo vision system is used to collaborate with the three position sensors of the pneumatic actuators. The stereo vision system combining two CCD serves to measure the actual 3D position of the end-effector and calibrate the error between the actual and the calculated 3D position of the end-effector. Furthermore, to verify the feasibility of the proposed parallel mechanism robot driven by three vertical pneumatic servo actuators, a full-scale test rig of the proposed parallel mechanism pneumatic robot is set up. Thus, simulations and experiments for different complex 3D motion profiles of the robot end-effector can be successfully achieved. The desired, the actual and the calculated 3D position of the end-effector can be compared in the complex 3D motion control.

Development of a 3D Parallel Mechanism Robot Arm with Three Vertical-Axial Pneumatic Actuators Combined with a Stereo Vision System

PubMed Central

Chiang, Mao-Hsiung; Lin, Hao-Ting

2011-01-01

This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel mechanism robot. In the mechanical system, a 3D parallel mechanism robot contains three serial chains, a fixed base, a movable platform and a pneumatic servo system. The parallel mechanism are designed and analyzed first for realizing a 3D motion in the X-Y-Z coordinate system of the robot’s end-effector. The inverse kinematics and the forward kinematics of the parallel mechanism robot are investigated by using the Denavit-Hartenberg notation (D-H notation) coordinate system. The pneumatic actuators in the three vertical motion axes are modeled. In the control system, the Fourier series-based adaptive sliding-mode controller with H∞ tracking performance is used to design the path tracking controllers of the three vertical servo pneumatic actuators for realizing 3D path tracking control of the end-effector. Three optical linear scales are used to measure the position of the three pneumatic actuators. The 3D position of the end-effector is then calculated from the measuring position of the three pneumatic actuators by means of the kinematics. However, the calculated 3D position of the end-effector cannot consider the manufacturing and assembly tolerance of the joints and the parallel mechanism so that errors between the actual position and the calculated 3D position of the end-effector exist. In order to improve this situation, sensor collaboration is developed in this paper. A stereo vision system is used to collaborate with the three position sensors of the pneumatic actuators. The stereo vision system combining two CCD serves to measure the actual 3D position of the end-effector and calibrate the error between the actual and the calculated 3D position of the end-effector. Furthermore, to verify the feasibility of the proposed parallel mechanism robot driven by three vertical pneumatic servo actuators, a full-scale test rig of the proposed parallel mechanism pneumatic robot is set up. Thus, simulations and experiments for different complex 3D motion profiles of the robot end-effector can be successfully achieved. The desired, the actual and the calculated 3D position of the end-effector can be compared in the complex 3D motion control. PMID:22247676

SMAP Instrument Mechanical System Engineering

NASA Technical Reports Server (NTRS)

Slimko, Eric; French, Richard; Riggs, Benjamin

2013-01-01

The Soil Moisture Active Passive (SMAP) mission, scheduled for launch by the end of 2014, is being developed to measure the soil moisture and soil freeze/thaw state on a global scale over a three-year period. The accuracy, resolution, and global coverage of SMAP measurements are invaluable across many science and applications disciplines including hydrology, climate, carbon cycle, and the meteorological, environment, and ecology applications communities. The SMAP observatory is composed of a despun bus and a spinning instrument platform that includes both a deployable 6 meter aperture low structural frequency Astromesh reflector and a spin control system. The instrument section has engendered challenging mechanical system issues associated with the antenna deployment, flexible antenna pointing in the context of a multitude of disturbances, spun section mass properties, spin control system development, and overall integration with the flight system on both mechanical and control system levels. Moreover, the multitude of organizations involved, including two major vendors providing the spin subsystem and reflector boom assembly plus the flight system mechanical and guidance, navigation, and control teams, has led to several unique system engineering challenges. Capturing the key physics associated with the function of the flight system has been challenging due to the many different domains that are applicable. Key interfaces and operational concepts have led to complex negotiations because of the large number of organizations that integrate with the instrument mechanical system. Additionally, the verification and validation concerns associated with the mechanical system have had required far-reaching involvement from both the flight system and other subsystems. The SMAP instrument mechanical systems engineering issues and their solutions are described in this paper.

Practical homeostasis lighting control system using sensor agent robots for office space

NASA Astrophysics Data System (ADS)

Tokiwa, Momoko; Mita, Akira

2014-03-01

The comfortable space can be changed by season, age, physical condition and the like. However, the current systems are not able to resolve them absolutely. This research proposes the Homeostasis lighting control system based on the mechanism of biotic homeostasis for making the algorithms of apparatus control. Homeostasis are kept by the interaction of the three systems, endocrine system, immune system, and nervous system[1]. By the gradual reaction in the endocrine system, body's protective response in the immune system, and the electrical reaction in the nerve system, we can keep the environments against variable changes. The new lighting control system utilizes this mechanism. Firstly, we focused on legibility and comfort in the office space to construct the control model learning from the endocrine and immune systems. The mechanism of the endocrine system is used for ambient lights in the space is used considering circadian rhythm for comfort. For the legibility, the immune system is used to control considering devices near the human depending on the distance between the human. Simulations and the demonstration were conducted to show the feasibility. Finally, the nerve system was intruded to enhance the system.

Investigation of efficiency of electric drive control system of excavator traction mechanism based on feedback on load

NASA Astrophysics Data System (ADS)

Kuznetsov, N. K.; Iov, I. A.; Iov, A. A.

2018-05-01

The article presents the results of a study of the efficiency of the electric drive control system of the traction mechanism of a dragline based on the use of feedback on load in the traction cable. The investigations were carried out using a refined electromechanical model of the traction mechanism, which took into account not only the elastic elements of the gearbox, the backlashes in it and the changes in the kinematic parameters of the mechanism during operation, but also the mechanical characteristics of the electric drive and the features of its control system. By mathematical modeling of the transient processes of the electromechanical system, it is shown that the introduction of feedback on the load in the elastic element allows one to reduce the dynamic loads in the traction mechanism and to limit the elastic oscillations of the actuating mechanism in comparison with the standard control system. Fixed as a general decrease in the dynamic load of the nodes of traction mechanism in the modes of loading and latching of the bucket, and a decrease the operating time of the mechanism at maximum load. At the same time, undesirable phenomena in the operation of the electric drive were also associated with the increase in the recovery time of the steady-state value of the speed of the actuating mechanism under certain operating conditions, which can lead to a decrease in the reliability of the mechanical part and the productivity of the traction mechanism.

Engine Performance (Section C: Emission Control Systems). Auto Mechanics Curriculum Guide. Module 3. Instructor's Guide.

ERIC Educational Resources Information Center

Rains, Larry

This engine performance (emission control systems) module is one of a series of competency-based modules in the Missouri Auto Mechanics Curriculum Guide. Topics of this module's five units are: positive crankcase ventilation (PCV) and evaporative emission control systems; exhaust gas recirculation (EGR); air injection and catalytic converters;…

Mechanization of and experience with a triplex fly-by-wire backup control system

NASA Technical Reports Server (NTRS)

Lock, W. P.; Petersen, W. R.; Whitman, G. B.

1975-01-01

A redundant three-axis analog control system was designed and developed to back up a digital fly-by-wire control system for an F-8C airplane. Forty-two flights, involving 58 hours of flight time, were flown by six pilots. The mechanization and operational experience with the backup control system, the problems involved in synchronizing it with the primary system, and the reliability of the system are discussed. The backup control system was dissimilar to the primary system, and it provided satisfactory handling through the flight envelope evaluated. Limited flight tests of a variety of control tasks showed that control was also satisfactory when the backup control system was controlled by a minimum-displacement (force) side stick. The operational reliability of the F-8 digital fly-by-wire control system was satisfactory, with no unintentional downmodes to the backup control system in flight. The ground and flight reliability of the system's components is discussed.

Microgravity experiments of nano-satellite docking mechanism for final rendezvous approach and docking phase

NASA Astrophysics Data System (ADS)

Ui, Kyoichi; Matunaga, Saburo; Satori, Shin; Ishikawa, Tomohiro

2005-09-01

Laboratory for Space Systems (LSS), Tokyo Institute of Technology (Tokyo Tech) conducted three-dimensional microgravity environment experiments about a docking mechanism for mothership-daughtership (MS-DS) nano-satellite using the facility of Japan Micro Gravity Center (JAMIC) with Hokkaido Institute of Technology (HIT). LSS has studied and developed a docking mechanism for MS-DS nano-satellite system in final rendezvous approach and docking phase since 2000. Consideration of the docking mechanism is to mate a nano-satellite stably while remaining control error of relative velocity and attitude because it is difficult for nano-satellite to have complicated attitude control and mating systems. Objective of the experiments is to verify fundamental grasping function based on our proposed docking methodology. The proposed docking sequence is divided between approach/grasping phase and guiding phase. In the approach/grasping phase, the docking mechanism grasps the nano-satellite even though the nano-satellite has relative position and attitude control errors as well as relative velocity in a docking space. In the guiding function, the docking mechanism guides the nano-satellite to a docking port while adjusting its attitude in order to transfer electrical power and fuel to the nano-satellite. In the paper, we describe the experimental system including the docking mechanism, control system, the daughtership system and the release mechanism, and describe results of microgravity experiments in JAMIC.

Flight Investigation of a Mechanical Feel Device in an Irreversible Elevator Control System of a Large Airplane

NASA Technical Reports Server (NTRS)

Brown, B Porter; Chilton, Robert G; Whitten, James B

1952-01-01

Report presents the results of measurements of the longitudinal stability and control characteristics of a large airplane using a mechanical feel device in combination with a booster incorporated in the elevator-control system. Tests were made to investigate the feasibility of eliminating the aerodynamic control forces through use of a booster and of providing control-feel forces mechanically. The feel device consisted of a centering spring which restrained the control stick through a linkage which was changed as a function of the dynamic pressure. Provisions were made for trimming and for manual adjustment of the force gradient. The system was designed to approximate the control-force characteristics that would result with a conventional elevator control with linear hinge-moment characteristics.

Switched Fuzzy-PD Control of Contact Forces in Robotic Microbiomanipulation.

PubMed

Zhang, Weize; Dong, Xianke; Liu, Xinyu

2017-05-01

Force sensing and control are of paramount importance in robotic micromanipulation. A contact force regulator capable of accurately applying mechanical stimuli to a live Drosophila larva could greatly facilitate mechanobiology research on Drosophila and may eventually lead to novel discoveries in mechanotransduction mechanisms of neuronal circuitries. In this paper, we present a novel contact force control scheme implemented in an automated Drosophila larvae micromanipulation system, featuring a switched fuzzy to proportional-differential (PD) controller and a noise-insensitive extended high gain observer (EHGO). The switched fuzzy-PD control law inherits the fast convergence of fuzzy control and overcomes its drawbacks such as large overshoot and steady-state oscillation. The noise-insensitive EHGO can reliably estimate system modeling errors and is robust to force measurement noises, which is advantageous over conventional high gain observers (sensitive to signal noises). Force control experiments show that, compared to a proportional-integral-differential (PID) controller, this new force control scheme significantly enhances the system dynamic performance in terms of rising time, overshoot, and oscillation. The developed robotic system and the force control scheme will be applied to mechanical stimulation and fluorescence imaging of Drosophila larvae for identifying new mechanotransduction mechanisms.

Man-vehicle systems research facility advanced aircraft flight simulator throttle mechanism

NASA Technical Reports Server (NTRS)

Kurasaki, S. S.; Vallotton, W. C.

1985-01-01

The Advanced Aircraft Flight Simulator is equipped with a motorized mechanism that simulates a two engine throttle control system that can be operated via a computer driven performance management system or manually by the pilots. The throttle control system incorporates features to simulate normal engine operations and thrust reverse and vary the force feel to meet a variety of research needs. While additional testing to integrate the work required is principally now in software design, since the mechanical aspects function correctly. The mechanism is an important part of the flight control system and provides the capability to conduct human factors research of flight crews with advanced aircraft systems under various flight conditions such as go arounds, coupled instrument flight rule approaches, normal and ground operations and emergencies that would or would not normally be experienced in actual flight.

An Analytical Dynamics Approach to the Control of Mechanical Systems

NASA Astrophysics Data System (ADS)

Mylapilli, Harshavardhan

A new and novel approach to the control of nonlinear mechanical systems is presented in this study. The approach is inspired by recent results in analytical dynamics that deal with the theory of constrained motion. The control requirements on the dynamical system are viewed from an analytical dynamics perspective and the theory of constrained motion is used to recast these control requirements as constraints on the dynamical system. Explicit closed form expressions for the generalized nonlinear control forces are obtained by using the fundamental equation of mechanics. The control so obtained is optimal at each instant of time and causes the constraints to be exactly satisfied. No linearizations and/or approximations of the nonlinear dynamical system are made, and no a priori structure is imposed on the nature of nonlinear controller. Three examples dealing with highly nonlinear complex dynamical systems that are chosen from diverse areas of discrete and continuum mechanics are presented to demonstrate the control approach. The first example deals with the energy control of underactuated inhomogeneous nonlinear lattices (or chains), the second example deals with the synchronization of the motion of multiple coupled slave gyros with that of a master gyro, and the final example deals with the control of incompressible hyperelastic rubber-like thin cantilever beams. Numerical simulations accompanying these examples show the ease, simplicity and the efficacy with which the control methodology can be applied and the accuracy with which the desired control objectives can be met.

Engine Tune-up Service. Unit 6: Emission Control Systems. Student Guide. Automotive Mechanics Curriculum.

ERIC Educational Resources Information Center

Bacon, E. Miles

This student guide is for Unit 6, Emission Control Systems, in the Engine Tune-Up Service portion of the Automotive Mechanics Curriculum. It deals with inspecting, testing, and servicing an emission control system. A companion review exercise book and posttests are available separately as CE 031 221-222. An introduction tells how this unit fits…

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.

A piezoelectric transformer

NASA Technical Reports Server (NTRS)

Won, C. C.

1993-01-01

This work describes a modeling and design method whereby a piezoelectric system is formulated by two sets of second-order equations, one for the mechanical system, and the other for the electrical system, coupled through the piezoelectric effect. The solution to this electromechanical coupled system gives a physical interpretation of the piezoelectric effect as a piezoelectric transformer that is a part of the piezoelectric system, which transfers the applied mechanical force into a force-controlled current source, and short circuit mechanical compliance into capacitance. It also transfers the voltage source into a voltage-controlled relative velocity input, and free motional capacitance into mechanical compliance. The formulation and interpretation simplify the modeling of smart structures and lead to physical insight that aids the designer. Due to its physical realization, the smart structural system can be unconditional stable and effectively control responses. This new concept has been demonstrated in three numerical examples for a simple piezoelectric system.

System and method for bidirectional flow and controlling fluid flow in a conduit

DOEpatents

Ortiz, Marcos German

1999-01-01

A system for measuring bidirectional flow, including backflow, of fluid in a conduit. The system utilizes a structural mechanism to create a pressure differential in the conduit. Pressure sensors are positioned upstream from the mechanism, at the mechanism, and downstream from the mechanism. Data from the pressure sensors are transmitted to a microprocessor or computer, and pressure differential detected between the pressure sensors is then used to calculate the backflow. Control signals may then be generated by the microprocessor or computer to shut off valves located in the conduit, upon the occurrence of backflow, or to control flow, total material dispersed, etc. in the conduit.

Design of Control System for Flexible Packaging Bags Palletizing Production Line Based on PLC

NASA Astrophysics Data System (ADS)

Zheng, Huiping; Chen, Lin; Zhao, Xiaoming; Liu, Zhanyang

Flexible packaging bags palletizing production line is to put the bags in the required area according to particular order and size, in order to finish handling, storage, loading and unloading, transportation and other logistics work of goods. Flexible packaging bags palletizing line is composed of turning bags mechanism, shaping mechanism, indexing mechanism, marshalling mechanism, pushing bags mechanism, pressing bags mechanism, laminating mechanism, elevator, tray warehouse, tray conveyor and loaded tray conveyor. Whether the whole production line can smoothly run depends on each of the above equipment and precision control among them. In this paper the technological process and the control logic of flexible packaging bags palletizing production line is introduced. Palletizing process of the production line realized automation by means of a control system based on programmable logic controller (PLC). It has the advantages of simple structure, reliable and easy maintenance etc.

14 CFR 27.923 - Rotor drive system and control mechanism tests.

Code of Federal Regulations, 2011 CFR

2011-01-01

... purpose of this paragraph, an affected power input includes all parts of the rotor drive system which can... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Rotor drive system and control mechanism... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27...

14 CFR 27.923 - Rotor drive system and control mechanism tests.

Code of Federal Regulations, 2013 CFR

2013-01-01

... purpose of this paragraph, an affected power input includes all parts of the rotor drive system which can... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Rotor drive system and control mechanism... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27...

A computerized test system for thermal-mechanical fatigue crack growth

NASA Technical Reports Server (NTRS)

Marchand, N.; Pelloux, R. M.

1986-01-01

A computerized testing system to measure fatigue crack growth under thermal-mechanical fatigue conditions is described. Built around a servohydraulic machine, the system is capable of a push-pull test under stress-controlled or strain-controlled conditions in the temperature range of 25 to 1050 C. Temperature and mechanical strain are independently controlled by the closed-loop system to simulate the complex inservice strain-temperature relationship. A d-c electrical potential method is used to measure crack growth rates. The correction procedure of the potential signal to take into account powerline and RF-induced noises and thermal changes is described. It is shown that the potential drop technique can be used for physical mechanism studies and for modelling crack tip processes.

Adaptive mechanism-based congestion control for networked systems

NASA Astrophysics Data System (ADS)

Liu, Zhi; Zhang, Yun; Chen, C. L. Philip

2013-03-01

In order to assure the communication quality in network systems with heavy traffic and limited bandwidth, a new ATRED (adaptive thresholds random early detection) congestion control algorithm is proposed for the congestion avoidance and resource management of network systems. Different to the traditional AQM (active queue management) algorithms, the control parameters of ATRED are not configured statically, but dynamically adjusted by the adaptive mechanism. By integrating with the adaptive strategy, ATRED alleviates the tuning difficulty of RED (random early detection) and shows a better control on the queue management, and achieve a more robust performance than RED under varying network conditions. Furthermore, a dynamic transmission control protocol-AQM control system using ATRED controller is introduced for the systematic analysis. It is proved that the stability of the network system can be guaranteed when the adaptive mechanism is finely designed. Simulation studies show the proposed ATRED algorithm achieves a good performance in varying network environments, which is superior to the RED and Gentle-RED algorithm, and providing more reliable service under varying network conditions.

ATS-6 engineering performance report. Volume:Program and systems summaries: Mechanical and thermal details

NASA Technical Reports Server (NTRS)

Wales, R. O. (Editor)

1981-01-01

The overall mission and spacecraft systems, testing, and operations are summarized. The mechanical subsystems are reviewed, encompassing mechanical design requirements; separation and deployment mechanisms; design and performance evaluation; and the television camera reflector monitor. Thermal control and contamination are discussed in terms of thermal control subsystems, design validation, subsystems performance, the advanced flight experiment, and the quartz-crystal microbalance contamination monitor.

An overview of neural function and feedback control in human communication.

PubMed

Hood, L J

1998-01-01

The speech and hearing mechanisms depend on accurate sensory information and intact feedback mechanisms to facilitate communication. This article provides a brief overview of some components of the nervous system important for human communication and some electrophysiological methods used to measure cortical function in humans. An overview of automatic control and feedback mechanisms in general and as they pertain to the speech motor system and control of the hearing periphery is also presented, along with a discussion of how the speech and auditory systems interact.

Controlled Quantum Packets

NASA Technical Reports Server (NTRS)

DeMartino, Salvatore; DeSiena, Silvio

1996-01-01

We look at time evolution of a physical system from the point of view of dynamical control theory. Normally we solve motion equation with a given external potential and we obtain time evolution. Standard examples are the trajectories in classical mechanics or the wave functions in Quantum Mechanics. In the control theory, we have the configurational variables of a physical system, we choose a velocity field and with a suited strategy we force the physical system to have a well defined evolution. The evolution of the system is the 'premium' that the controller receives if he has adopted the right strategy. The strategy is given by well suited laboratory devices. The control mechanisms are in many cases non linear; it is necessary, namely, a feedback mechanism to retain in time the selected evolution. Our aim is to introduce a scheme to obtain Quantum wave packets by control theory. The program is to choose the characteristics of a packet, that is, the equation of evolution for its centre and a controlled dispersion, and to give a building scheme from some initial state (for example a solution of stationary Schroedinger equation). It seems natural in this view to use stochastic approach to Quantum Mechanics, that is, Stochastic Mechanics [S.M.]. It is a quantization scheme different from ordinary ones only formally. This approach introduces in quantum theory the whole mathematical apparatus of stochastic control theory. Stochastic Mechanics, in our view, is more intuitive when we want to study all the classical-like problems. We apply our scheme to build two classes of quantum packets both derived generalizing some properties of coherent states.

Dynamic processes in regulation and some implications for biofeedback and biobehavioral interventions.

PubMed

Lehrer, Paul; Eddie, David

2013-06-01

Systems theory has long been used in psychology, biology, and sociology. This paper applies newer methods of control systems modeling for assessing system stability in health and disease. Control systems can be characterized as open or closed systems with feedback loops. Feedback produces oscillatory activity, and the complexity of naturally occurring oscillatory patterns reflects the multiplicity of feedback mechanisms, such that many mechanisms operate simultaneously to control the system. Unstable systems, often associated with poor health, are characterized by absence of oscillation, random noise, or a very simple pattern of oscillation. This modeling approach can be applied to a diverse range of phenomena, including cardiovascular and brain activity, mood and thermal regulation, and social system stability. External system stressors such as disease, psychological stress, injury, or interpersonal conflict may perturb a system, yet simultaneously stimulate oscillatory processes and exercise control mechanisms. Resonance can occur in systems with negative feedback loops, causing high-amplitude oscillations at a single frequency. Resonance effects can be used to strengthen modulatory oscillations, but may obscure other information and control mechanisms, and weaken system stability. Positive as well as negative feedback loops are important for system function and stability. Examples are presented of oscillatory processes in heart rate variability, and regulation of autonomic, thermal, pancreatic and central nervous system processes, as well as in social/organizational systems such as marriages and business organizations. Resonance in negative feedback loops can help stimulate oscillations and exercise control reflexes, but also can deprive the system of important information. Empirical hypotheses derived from this approach are presented, including that moderate stress may enhance health and functioning.

Self-Contained Avionics Sensing and Flight Control System for Small Unmanned Aerial Vehicle

NASA Technical Reports Server (NTRS)

Ingham, John C. (Inventor); Shams, Qamar A. (Inventor); Logan, Michael J. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Melanie L. (Inventor); Kuhn, III, Theodore R. (Inventor); Babel, III, Walter C. (Inventor); Fox, legal representative, Christopher L. (Inventor); Adams, James K. (Inventor); Laughter, Sean A. (Inventor)

2011-01-01

A self-contained avionics sensing and flight control system is provided for an unmanned aerial vehicle (UAV). The system includes sensors for sensing flight control parameters and surveillance parameters, and a Global Positioning System (GPS) receiver. Flight control parameters and location signals are processed to generate flight control signals. A Field Programmable Gate Array (FPGA) is configured to provide a look-up table storing sets of values with each set being associated with a servo mechanism mounted on the UAV and with each value in each set indicating a unique duty cycle for the servo mechanism associated therewith. Each value in each set is further indexed to a bit position indicative of a unique percentage of a maximum duty cycle for the servo mechanism associated therewith. The FPGA is further configured to provide a plurality of pulse width modulation (PWM) generators coupled to the look-up table. Each PWM generator is associated with and adapted to be coupled to one of the servo mechanisms.

Engineering stategies and implications of using higher plants for throttling gas and water exchange in a controlled ecological life support system

NASA Technical Reports Server (NTRS)

Chamberland, Dennis; Wheeler, Raymond M.; Corey, Kenneth A.

1993-01-01

Engineering stategies for advanced life support systems to be used on Lunar and Mars bases involve a wide spectrum of approaches. These range from purely physical-chemical life support strategies to purely biological approaches. Within the context of biological based systems, a bioengineered system can be devised that would utilize the metabolic mechanisms of plants to control the rates of CO2 uptake and O2 evolution (photosynthesis) and water production (transpiration). Such a mechanism of external engineering control has become known as throttling. Research conducted at the John F. Kennedy Space Center's Controlled Ecological Life Support System Breadboard Project has demonstrated the potential of throttling these fluxes by changing environmental parameters affecting the plant processes. Among the more effective environmental throttles are: light and CO2 concentration for controllingthe rate of photsynthesis and humidity and CO2 concentration for controlling transpiration. Such a bioengineered strategy implies control mechanisms that in the past have not been widely attributed to life support systems involving biological components and suggests a broad range of applications in advanced life support system design.

System and method for bidirectional flow and controlling fluid flow in a conduit

DOEpatents

Ortiz, M.G.

1999-03-23

A system for measuring bidirectional flow, including backflow, of fluid in a conduit is disclosed. The system utilizes a structural mechanism to create a pressure differential in the conduit. Pressure sensors are positioned upstream from the mechanism, at the mechanism, and downstream from the mechanism. Data from the pressure sensors are transmitted to a microprocessor or computer, and pressure differential detected between the pressure sensors is then used to calculate the backflow. Control signals may then be generated by the microprocessor or computer to shut off valves located in the conduit, upon the occurrence of backflow, or to control flow, total material dispersed, etc. in the conduit. 3 figs.

Logical Access Control Mechanisms in Computer Systems.

ERIC Educational Resources Information Center

Hsiao, David K.

The subject of access control mechanisms in computer systems is concerned with effective means to protect the anonymity of private information on the one hand, and to regulate the access to shareable information on the other hand. Effective means for access control may be considered on three levels: memory, process and logical. This report is a…

Nonlinear frequency response based adaptive vibration controller design for a class of nonlinear systems

NASA Astrophysics Data System (ADS)

Thenozhi, Suresh; Tang, Yu

2018-01-01

Frequency response functions (FRF) are often used in the vibration controller design problems of mechanical systems. Unlike linear systems, the FRF derivation for nonlinear systems is not trivial due to their complex behaviors. To address this issue, the convergence property of nonlinear systems can be studied using convergence analysis. For a class of time-invariant nonlinear systems termed as convergent systems, the nonlinear FRF can be obtained. The present paper proposes a nonlinear FRF based adaptive vibration controller design for a mechanical system with cubic damping nonlinearity and a satellite system. Here the controller gains are tuned such that a desired closed-loop frequency response for a band of harmonic excitations is achieved. Unlike the system with cubic damping, the satellite system is not convergent, therefore an additional controller is utilized to achieve the convergence property. Finally, numerical examples are provided to illustrate the effectiveness of the proposed controller.

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project. ACT/Control/Guidance System study, volume 1

NASA Technical Reports Server (NTRS)

1982-01-01

The active control technology (ACT) control/guidance system task of the integrated application of active controls (IAAC) technology project within the NASA energy efficient transport program was documented. The air traffic environment of navigation and air traffic control systems and procedures were extrapolated. An approach to listing flight functions which will be performed by systems and crew of an ACT configured airplane of the 1990s, and a determination of function criticalities to safety of flight, are the basis of candidate integrated ACT/Control/Guidance System architecture. The system mechanizes five active control functions: pitch augmented stability, angle of attack limiting, lateral/directional augmented stability, gust load alleviation, and maneuver load control. The scope and requirements of a program for simulating the integrated ACT avionics and flight deck system, with pilot in the loop, are defined, system and crew interface elements are simulated, and mechanization is recommended. Relationships between system design and crew roles and procedures are evaluated.

Accuracy analysis of pointing control system of solar power station

NASA Technical Reports Server (NTRS)

Hung, J. C.; Peebles, P. Z., Jr.

1978-01-01

The first-phase effort concentrated on defining the minimum basic functions that the retrodirective array must perform, identifying circuits that are capable of satisfying the basic functions, and looking at some of the error sources in the system and how they affect accuracy. The initial effort also examined three methods for generating torques for mechanical antenna control, performed a rough analysis of the flexible body characteristics of the solar collector, and defined a control system configuration for mechanical pointing control of the array.

Designing Crane Controls with Applied Mechanical and Electrical Safety Features

NASA Technical Reports Server (NTRS)

Lytle, Bradford P.; Walczak, Thomas A.

2002-01-01

The use of overhead traveling bridge cranes in many varied applications is common practice. In particular, the use of cranes in the nuclear, military, commercial, aerospace, and other industries can involve safety critical situations. Considerations for Human Injury or Casualty, Loss of Assets, Endangering the Environment, or Economic Reduction must be addressed. Traditionally, in order to achieve additional safety in these applications, mechanical systems have been augmented with a variety of devices. These devices assure that a mechanical component failure shall reduce the risk of a catastrophic loss of the correct and/or safe load carrying capability. ASME NOG-1-1998, (Rules for Construction of Overhead and Gantry Cranes, Top Running Bridge, and Multiple Girder), provides design standards for cranes in safety critical areas. Over and above the minimum safety requirements of todays design standards, users struggle with obtaining a higher degree of reliability through more precise functional specifications while attempting to provide "smart" safety systems. Electrical control systems also may be equipped with protective devices similar to the mechanical design features. Demands for improvement of the cranes "control system" is often recognized, but difficult to quantify for this traditionally "mechanically" oriented market. Finite details for each operation must be examined and understood. As an example, load drift (or small motions) at close tolerances can be unacceptable (and considered critical). To meet these high functional demands encoders and other devices are independently added to control systems to provide motion and velocity feedback to the control drive. This paper will examine the implementation of Programmable Electronic Systems (PES). PES is a term this paper will use to describe any control system utilizing any programmable electronic device such as Programmable Logic Controllers (PLC), or an Adjustable Frequency Drive (AID) 'smart' programmable motion controller. Therefore the use of the term Programmable Electronic Systems (PES) is an encompassing description for a large spectrum of programmable electronic control devices.

Quasivelocities and Optimal Control for underactuated Mechanical Systems

NASA Astrophysics Data System (ADS)

Colombo, L.; de Diego, D. Martín

2010-07-01

This paper is concerned with the application of the theory of quasivelocities for optimal control for underactuated mechanical systems. Using this theory, we convert the original problem in a variational second-order lagrangian system subjected to constraints. The equations of motion are geometrically derived using an adaptation of the classical Skinner and Rusk formalism.

Quasivelocities and Optimal Control for underactuated Mechanical Systems

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

Colombo, L.; Martin de Diego, D.

2010-07-28

This paper is concerned with the application of the theory of quasivelocities for optimal control for underactuated mechanical systems. Using this theory, we convert the original problem in a variational second-order lagrangian system subjected to constraints. The equations of motion are geometrically derived using an adaptation of the classical Skinner and Rusk formalism.

Alstom Francis Turbine Ring Gates: from Retrofitting to Commissioning

NASA Astrophysics Data System (ADS)

A, Nguyen P.; G, Labrecque; M-O, Thibault; M, Bergeron; A, Steinhilber; D, Havard

2014-03-01

The Ring Gate synchronisation system developed by Alstom is new and patented. It uses hydraulic cylinders connected in pairs by a serial connection. The new hydraulic synchronisation system, when compared to the previous mechanical synchronisation system, has several advantages. It is a compact design; it reduces the number of mechanical components as well as maintenance costs. The new system maintains the Ring Gates robustness. The new approach is an evolution from mechanical to hydraulic synchronization assisted by electronic control. The new synchronization system eliminates several mechanical components that used to add wear and friction and which are usually difficult to adjust during maintenance. Tension chains and sprockets and associated controls are eliminated. Through the position sensors, the redundancy of the ring gate synchronization system makes it predictable and reliable. The electronic control compensates for any variation in operation, for example a leak in the hydraulic system. An emergency closing is possible without the electronic control system due to the stiffness of hydraulic serial connection in the hydraulic cylinder pairs. The Ring Gate can work safely against uneven loads and frictions. The development will be reviewed and its application discussed through commissioning results.

Control of mechanical systems by the mixed "time and expenditure" criterion

NASA Astrophysics Data System (ADS)

Alesova, I. M.; Babadzanjanz, L. K.; Pototskaya, I. Yu.; Pupysheva, Yu. Yu.; Saakyan, A. T.

2018-05-01

The optimal controlled motion of a mechanical system, that is determined by the linear system ODE with constant coefficients and piecewise constant control components, is considered. The number of control switching points and the heights of control steps are considered as preset. The optimized functional is combination of classical time criteria and "Expenditure criteria", that is equal to the total area of all steps of all control components. In the absence of control, the solution of the system is equal to the sum of components (frequency components) corresponding to different eigenvalues of the matrix of the ODE system. Admissible controls are those that turn to zero (at a non predetermined time moment) the previously chosen frequency components of the solution. An algorithm for the finding of control switching points, based on the necessary minimum conditions for mixed criteria, is proposed.

Dynamic Processes in Regulation and Some Implications for Biofeedback and Biobehavioral Interventions

PubMed Central

Lehrer, Paul; Eddie, David

2013-01-01

Systems theory has long been applied in psychology, biology, and sociology. This paper applies newer methods of control systems modeling to the assessment of system stability in health and disease. Control systems can be characterized as open or closed systems with feedback loops. Feedback produces oscillatory activity, and the complexity of naturally occurring oscillatory patterns reflects the multiplicity of feedback mechanisms, such that many mechanisms operate simultaneously to control the system. Unstable systems, often associated with poor health, are characterized by absence of oscillation, random noise, or a very simple pattern of oscillation. This modeling approach can be applied to a diverse range of phenomena, including cardiovascular and brain activity, mood and thermal regulation, and social system stability. External system stressors such as disease, psychological stress, injury, or interpersonal conflict may perturb a system, yet simultaneously stimulate oscillatory processes and exercise control mechanisms. Resonance can occur in systems with negative feedback loops, causing high-amplitude oscillations at a single frequency. Resonance effects can be used to strengthen modulatory oscillations, but may obscure other information and control mechanisms, and weaken system stability. Positive as well as negative feedback loops are important for system function and stability. Examples are presented of oscillatory processes in heart rate variability, and regulation of autonomic, thermal, pancreatic and central nervous system processes, as well as in social/organizational systems such as marriages and business organizations. Resonance in negative feedback loops can help stimulate oscillations and exercise control reflexes, but also can deprive the system of important information. Empirical hypotheses derived from this approach are presented, including that moderate stress may enhance health and functioning. PMID:23572244

A patient transfer apparatus between bed and stretcher.

PubMed

Wang, Hongbo; Kasagami, Fumio

2008-02-01

This paper presents a patient transfer apparatus between bed and stretcher. This apparatus makes it possible for the nurse to move weak, injured, or paralyzed patient from bed to stretcher, or vice versa, alone. Moreover, the suffering, stress, and uneasy feeling of the patient can be alleviated. This paper describes the specification, mechanical design, control system, and motion control of the apparatus. A special devised mechanism is developed, and a new servo system is used in this control system. The control principle and algorithm of the new servo system are proposed, and the motion-control method and safety function of the apparatus are described. The experimental results and evaluation indicated the effectiveness of this system.

Integration of a mechanical forebody vortex control system into the F-15

NASA Technical Reports Server (NTRS)

Boalbey, Richard E.; Citurs, Kevin D.; Ely, Wayne L.; Harbaugh, Stephen P.; Hollingsworth, William B.; Phillips, Ronald L.

1994-01-01

The goal of the F-15 Forebody Vortex Control (FVC) program is to develop a production FVC system for the F-15. The system may consist of either a mechanically actuated device such as the strakes developed for the HARV program, or a pneumatic device such as the port blowing system being tested on the X-29. Both types of systems are being evaluated under this program. Background information on the F-15 and a description and overview of forebody vortex controls (FVC) will be presented.

Serotonin Affects Movement Gain Control in the Spinal Cord

PubMed Central

Glaser, Joshua I.; Deng, Linna; Thompson, Christopher K.; Stevenson, Ian H.; Wang, Qining; Hornby, Thomas George; Heckman, Charles J.; Kording, Konrad P.

2014-01-01

A fundamental challenge for the nervous system is to encode signals spanning many orders of magnitude with neurons of limited bandwidth. To meet this challenge, perceptual systems use gain control. However, whether the motor system uses an analogous mechanism is essentially unknown. Neuromodulators, such as serotonin, are prime candidates for gain control signals during force production. Serotonergic neurons project diffusely to motor pools, and, therefore, force production by one muscle should change the gain of others. Here we present behavioral and pharmaceutical evidence that serotonin modulates the input–output gain of motoneurons in humans. By selectively changing the efficacy of serotonin with drugs, we systematically modulated the amplitude of spinal reflexes. More importantly, force production in different limbs interacts systematically, as predicted by a spinal gain control mechanism. Psychophysics and pharmacology suggest that the motor system adopts gain control mechanisms, and serotonin is a primary driver for their implementation in force production. PMID:25232107

Optimal integral force feedback for active vibration control

NASA Astrophysics Data System (ADS)

Teo, Yik R.; Fleming, Andrew J.

2015-11-01

This paper proposes an improvement to Integral Force Feedback (IFF), which is a popular method for active vibration control of structures and mechanical systems. Benefits of IFF include robustness, guaranteed stability and simplicity. However, the maximum damping performance is dependent on the stiffness of the system; hence, some systems cannot be adequately controlled. In this paper, an improvement to the classical force feedback control scheme is proposed. The improved method achieves arbitrary damping for any mechanical system by introducing a feed-through term. The proposed improvement is experimentally demonstrated by actively damping an objective lens assembly for a high-speed confocal microscope.

Performance of Control System Using Microcontroller for Sea Water Circulation

NASA Astrophysics Data System (ADS)

Indriani, A.; Witanto, Y.; Pratama, A. S.; Supriyadi; Hendra; Tanjung, A.

2018-02-01

Now a day control system is very important rule for any process. Control system have been used in the automatic system. Automatic system can be seen in the industrial filed, mechanical field, electrical field and etc. In industrial and mechanical field, control system are used for control of motion component such as motor, conveyor, machine, control of process made of product, control of system and soon. In electrical field, control system can met for control of electrical system as equipment or part electrical like fan, rice cooker, refrigerator, air conditioner and etc. Control system are used for control of temperature and circulation gas, air and water. Control system of temperature and circulation of water also can be used for fisher community. Control system can be create by using microcontroller, PLC and other automatic program [1][2]. In this paper we will focus on the close loop system by using microcontroller Arduino Mega to control of temperature and circulation of sea water for fisher community. Performance control system is influenced by control equipment, sensor sensitivity, test condition, environment and others. The temperature sensor is measured using the DS18S20 and the sea water clarity sensor for circulation indicator with turbidity sensor. From the test results indicated that this control system can circulate sea water and maintain the temperature and clarity of seawater in a short time.

Balanced bridge feedback control system

NASA Technical Reports Server (NTRS)

Lurie, Boris J. (Inventor)

1990-01-01

In a system having a driver, a motor, and a mechanical plant, a multiloop feedback control apparatus for controlling the movement and/or positioning of a mechanical plant, the control apparatus has a first local bridge feedback loop for feeding back a signal representative of a selected ratio of voltage and current at the output driver, and a second bridge feedback loop for feeding back a signal representative of a selected ratio of force and velocity at the output of the motor. The control apparatus may further include an outer loop for feeding back a signal representing the angular velocity and/or position of the mechanical plant.

Vertical-angle control system in the LLMC

NASA Astrophysics Data System (ADS)

Li, Binhua; Yang, Lei; Tie, Qiongxian; Mao, Wei

2000-10-01

A control system of the vertical angle transmission used in the Lower Latitude Meridian Circle (LLMC) is described in this paper. The transmission system can change the zenith distance of the tube quickly and precisely. It works in three modes: fast motion, slow motion and lock mode. The fast motion mode and the slow motion mode are that the tube of the instrument is driven by a fast motion stepper motor and a slow motion one separately. The lock mode is running for lock mechanism that is driven by a lock stepper motor. These three motors are controlled together by a single chip microcontroller, which is controlled in turn by a host personal computer. The slow motion mechanism and its rotational step angle are fully discussed because the mechanism is not used before. Then the hardware structure of this control system based on a microcontroller is described. Control process of the system is introduced during a normal observation, which is divided into eleven steps. All the steps are programmed in our control software in C++ and/or in ASM. The C++ control program is set up in the host PC, while the ASM control program is in the microcontroller system. Structures and functions of these rprograms are presented. Some details and skills for programming are discussed in the paper too.

System identification of closed-loop cardiovascular control: effects of posture and autonomic blockade

NASA Technical Reports Server (NTRS)

Mullen, T. J.; Appel, M. L.; Mukkamala, R.; Mathias, J. M.; Cohen, R. J.

1997-01-01

We applied system identification to the analysis of fluctuations in heart rate (HR), arterial blood pressure (ABP), and instantaneous lung volume (ILV) to characterize quantitatively the physiological mechanisms responsible for the couplings between these variables. We characterized two autonomically mediated coupling mechanisms [the heart rate baroreflex (HR baroreflex) and respiratory sinus arrhythmia (ILV-HR)] and two mechanically mediated coupling mechanisms [the blood pressure wavelet generated with each cardiac contraction (circulatory mechanics) and the direct mechanical effects of respiration on blood pressure (ILV-->ABP)]. We evaluated the method in humans studied in the supine and standing postures under control conditions and under conditions of beta-sympathetic and parasympathetic pharmacological blockades. Combined beta-sympathetic and parasympathetic blockade abolished the autonomically mediated couplings while preserving the mechanically mediated coupling. Selective autonomic blockade and postural changes also altered the couplings in a manner consistent with known physiological mechanisms. System identification is an "inverse-modeling" technique that provides a means for creating a closed-loop model of cardiovascular regulation for an individual subject without altering the underlying physiological control mechanisms.

REACTOR CONTROL ROD OPERATING SYSTEM

DOEpatents

Miller, G.

1961-12-12

A nuclear reactor control rod mechanism is designed which mechanically moves the control rods into and out of the core under normal conditions but rapidly forces the control rods into the core by catapultic action in the event of an emergency. (AEC)

Mechanism synthesis and 2-D control designs of an active three cable crane

NASA Technical Reports Server (NTRS)

Yang, Li-Farn; Mikulas, Martin M., Jr.

1992-01-01

A Lunar Crane with a suspension system based on a three cable mechanism is investigated to provide a stable end-effector for hoisting, positioning, and assembling large components during construction and servicing of a Lunar Base. The three cable suspension mechanism consists of a structural framework of three cables pointing to a common point that closely coincides with the suspended payload's center of gravity. The vibrational characteristics of this three cable suspension system are investigated by comparing a simple 2-D symmetric suspension model and a swinging pendulum in terms of their analytical natural frequency equations. A study is also made of actively controlling the dynamics of the crane using two different actuator concepts. Also, Lyapunov-based control algorithms are developed to determine two regulator-type control laws performing the system vibrational suppression for both system dynamics. Simulations including initial-valued dynamic responses as well as control performances for two different system dynamics are also presented.

Active-passive vibration absorber of beam-cart-seesaw system with piezoelectric transducers

NASA Astrophysics Data System (ADS)

Lin, J.; Huang, C. J.; Chang, Julian; Wang, S.-W.

2010-09-01

In contrast with fully controllable systems, a super articulated mechanical system (SAMS) is a controlled underactuated mechanical system in which the dimensions of the configuration space exceed the dimensions of the control input space. The objectives of the research are to develop a novel SAMS model which is called beam-cart-seesaw system, and renovate a novel approach for achieving a high performance active-passive piezoelectric vibration absorber for such system. The system consists of two mobile carts, which are coupled via rack and pinion mechanics to two parallel tracks mounted on pneumatic rodless cylinders. One cart carries an elastic beam, and the other cart acts as a counterbalance. One adjustable counterweight mass is also installed underneath the seesaw to serve as a passive damping mechanism to absorb impact and shock energy. The motion and control of a Bernoulli-Euler beam subjected to the modified cart/seesaw system are analyzed first. Moreover, gray relational grade is utilized to investigate the sensitivity of tuning the active proportional-integral-derivative (PID) controller to achieve desired vibration suppression performance. Consequently, it is shown that the active-passive vibration absorber can not only provide passive damping, but can also enhance the active action authority. The proposed software/hardware platform can also be profitable for the standardization of laboratory equipment, as well as for the development of entertainment tools.

Performance-based maintenance of gas turbines for reliable control of degraded power systems

NASA Astrophysics Data System (ADS)

Mo, Huadong; Sansavini, Giovanni; Xie, Min

2018-03-01

Maintenance actions are necessary for ensuring proper operations of control systems under component degradation. However, current condition-based maintenance (CBM) models based on component health indices are not suitable for degraded control systems. Indeed, failures of control systems are only determined by the controller outputs, and the feedback mechanism compensates the control performance loss caused by the component deterioration. Thus, control systems may still operate normally even if the component health indices exceed failure thresholds. This work investigates the CBM model of control systems and employs the reduced control performance as a direct degradation measure for deciding maintenance activities. The reduced control performance depends on the underlying component degradation modelled as a Wiener process and the feedback mechanism. To this aim, the controller features are quantified by developing a dynamic and stochastic control block diagram-based simulation model, consisting of the degraded components and the control mechanism. At each inspection, the system receives a maintenance action if the control performance deterioration exceeds its preventive-maintenance or failure thresholds. Inspired by realistic cases, the component degradation model considers random start time and unit-to-unit variability. The cost analysis of maintenance model is conducted via Monte Carlo simulation. Optimal maintenance strategies are investigated to minimize the expected maintenance costs, which is a direct consequence of the control performance. The proposed framework is able to design preventive maintenance actions on a gas power plant, to ensuring required load frequency control performance against a sudden load increase. The optimization results identify the trade-off between system downtime and maintenance costs as a function of preventive maintenance thresholds and inspection frequency. Finally, the control performance-based maintenance model can reduce maintenance costs as compared to CBM and pre-scheduled maintenance.

Acceleration control system for semi-active in-car crib with joint application of regular and inverted pendulum mechanisms

NASA Astrophysics Data System (ADS)

Kawashima, T.

2016-09-01

To reduce the risk of injury to an infant in an in-car crib (or in a child safety bed) collision shock during a car crash, it is necessary to maintain a constant force acting on the crib below a certain allowable value. To realize this objective, we propose a semi-active in-car crib system with the joint application of regular and inverted pendulum mechanisms. The arms of the proposed crib system support the crib like a pendulum while the pendulum system itself is supported like an inverted pendulum by the arms. In addition, the friction torque of each arm is controlled using a brake mechanism that enables the proposed in-car crib to decrease the acceleration of the crib gradually and maintain it around the target value. This system not only reduces the impulsive force but also transfers the force to the infant's back using a spin control system, i.e., the impulse force acts is made to act perpendicularly on the crib. The spin control system was developed in our previous work. This work focuses on the acceleration control system. A semi-active control law with acceleration feedback is introduced, and the effectiveness of the system is demonstrated using numerical simulation and model experiment.

The MOD-OA 200 kilowatt wind turbine generator design and analysis report

NASA Astrophysics Data System (ADS)

Andersen, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.; Lipner, M. H.; Schornhorst, J. R.

1980-08-01

The project requirements, approach, system description, design requirements, design, analysis, system tests, installation safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the MOD-OA 200 kw wind turbine generator are discussed. The components, the rotor, driven train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electrical system, and control systems are presented. The rotor includes the blades, hub and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control and Dynamic loads and fatigue are analyzed.

The MOD-OA 200 kilowatt wind turbine generator design and analysis report

NASA Technical Reports Server (NTRS)

Andersen, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.; Lipner, M. H.; Schornhorst, J. R.

1980-01-01

The project requirements, approach, system description, design requirements, design, analysis, system tests, installation safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the MOD-OA 200 kw wind turbine generator are discussed. The components, the rotor, driven train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electrical system, and control systems are presented. The rotor includes the blades, hub and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control and Dynamic loads and fatigue are analyzed.

Intelligent control and adaptive systems; Proceedings of the Meeting, Philadelphia, PA, Nov. 7, 8, 1989

NASA Technical Reports Server (NTRS)

Rodriguez, Guillermo (Editor)

1990-01-01

Various papers on intelligent control and adaptive systems are presented. Individual topics addressed include: control architecture for a Mars walking vehicle, representation for error detection and recovery in robot task plans, real-time operating system for robots, execution monitoring of a mobile robot system, statistical mechanics models for motion and force planning, global kinematics for manipulator planning and control, exploration of unknown mechanical assemblies through manipulation, low-level representations for robot vision, harmonic functions for robot path construction, simulation of dual behavior of an autonomous system. Also discussed are: control framework for hand-arm coordination, neural network approach to multivehicle navigation, electronic neural networks for global optimization, neural network for L1 norm linear regression, planning for assembly with robot hands, neural networks in dynamical systems, control design with iterative learning, improved fuzzy process control of spacecraft autonomous rendezvous using a genetic algorithm.

Adaptive Control Strategies for Interlimb Coordination in Legged Robots: A Review

PubMed Central

Aoi, Shinya; Manoonpong, Poramate; Ambe, Yuichi; Matsuno, Fumitoshi; Wörgötter, Florentin

2017-01-01

Walking animals produce adaptive interlimb coordination during locomotion in accordance with their situation. Interlimb coordination is generated through the dynamic interactions of the neural system, the musculoskeletal system, and the environment, although the underlying mechanisms remain unclear. Recently, investigations of the adaptation mechanisms of living beings have attracted attention, and bio-inspired control systems based on neurophysiological findings regarding sensorimotor interactions are being developed for legged robots. In this review, we introduce adaptive interlimb coordination for legged robots induced by various factors (locomotion speed, environmental situation, body properties, and task). In addition, we show characteristic properties of adaptive interlimb coordination, such as gait hysteresis and different time-scale adaptations. We also discuss the underlying mechanisms and control strategies to achieve adaptive interlimb coordination and the design principle for the control system of legged robots. PMID:28878645

Neural systems for preparatory control of imitation.

PubMed

Cross, Katy A; Iacoboni, Marco

2014-01-01

Humans have an automatic tendency to imitate others. Previous studies on how we control these tendencies have focused on reactive mechanisms, where inhibition of imitation is implemented after seeing an action. This work suggests that reactive control of imitation draws on at least partially specialized mechanisms. Here, we examine preparatory imitation control, where advance information allows control processes to be employed before an action is observed. Drawing on dual route models from the spatial compatibility literature, we compare control processes using biological and non-biological stimuli to determine whether preparatory imitation control recruits specialized neural systems that are similar to those observed in reactive imitation control. Results indicate that preparatory control involves anterior prefrontal, dorsolateral prefrontal, posterior parietal and early visual cortices regardless of whether automatic responses are evoked by biological (imitative) or non-biological stimuli. These results indicate both that preparatory control of imitation uses general mechanisms, and that preparatory control of imitation draws on different neural systems from reactive imitation control. Based on the regions involved, we hypothesize that preparatory control is implemented through top-down attentional biasing of visual processing.

How does a specific learning and memory system in the mammalian brain gain control of behavior?

PubMed

McDonald, Robert J; Hong, Nancy S

2013-11-01

This review addresses a fundamental, yet poorly understood set of issues in systems neuroscience. The issues revolve around conceptualizations of the organization of learning and memory in the mammalian brain. One intriguing, and somewhat popular, conceptualization is the idea that there are multiple learning and memory systems in the mammalian brain and they interact in different ways to influence and/or control behavior. This approach has generated interesting empirical and theoretical work supporting this view. One issue that needs to be addressed is how these systems influence or gain control of voluntary behavior. To address this issue, we clearly specify what we mean by a learning and memory system. We then review two types of processes that might influence which memory system gains control of behavior. One set of processes are external factors that can affect which system controls behavior in a given situation including task parameters like the kind of information available to the subject, types of training experience, and amount of training. The second set of processes are brain mechanisms that might influence what memory system controls behavior in a given situation including executive functions mediated by the prefrontal cortex; switching mechanisms mediated by ascending neurotransmitter systems, the unique role of the hippocampus during learning. The issue of trait differences in control of different learning and memory systems will also be considered in which trait differences in learning and memory function are thought to potentially emerge from differences in level of prefrontal influence, differences in plasticity processes, differences in ascending neurotransmitter control, differential access to effector systems like motivational and motor systems. Finally, we present scenarios in which different mechanisms might interact. This review was conceived to become a jumping off point for new work directed at understanding these issues. The outcome of this work, in combination with other approaches, might improve understanding of the mechanisms of volition in human and non-human animals. Copyright © 2013 Wiley Periodicals, Inc.

Effectiveness and efficiency of the two trolley system as an infection control mechanism in the operating theatre.

PubMed

Tuisawana, Viliame

2009-11-01

A good infection control manager understands the need to prevent a complete cycle of infection. The Infection Control Working Group Manual of Fiji, emphasised that the Cycle of Infection is the series of stage in which infection is spread. Operating theatres have infection control protocols. Most equipments and instruments used in operating theatre circulate within the theatre. The theatre trolleys are a main component in managing an operating theatre but the least recognised. This paper reviews the effectiveness and efficiency of the current two-trolley system as an infection control mechanism in theatre. The paper will discuss infection control using the current trolley system in relation to the layout of Labasa Hospital operating theatre, human resource, equipment standard and random swab results. The following are random swab results of theatre equipments taken by the Infection Control Nurse from 2006 to 2008. The Labasa Hospital Infection Committee have discouraged random swab sample from mid 2008 based on new guidelines on infection control. The two trolley system, in which an allocated outside trolley transports patients from the ward to a semi-sterile area in theatre. The inside trolley which transports the patient to the operating table. The two trolley system means more trolleys, extra staffs for lifting, additional handling of very sick patients, congestion and delay in taking patients to operating table in theatres should be considered. The one-trolley system in theatre greatly reduces the chances of manually lifting patients, thus reducing the risk of patient injury from fall and risk of back injuries to nurses. There are other evident based practices which can compliment the one trolley system for an effective infection control mechanism in theatres. The Fiji Infection Control Manual (2002) emphases the importance of regularly cleaning the environment and equipments in theatre but there is never a mention about using a two trolley system as an infection control mechanism for theatre.

Design and implementation of robust controllers for a gait trainer.

PubMed

Wang, F C; Yu, C H; Chou, T Y

2009-08-01

This paper applies robust algorithms to control an active gait trainer for children with walking disabilities. Compared with traditional rehabilitation procedures, in which two or three trainers are required to assist the patient, a motor-driven mechanism was constructed to improve the efficiency of the procedures. First, a six-bar mechanism was designed and constructed to mimic the trajectory of children's ankles in walking. Second, system identification techniques were applied to obtain system transfer functions at different operating points by experiments. Third, robust control algorithms were used to design Hinfinity robust controllers for the system. Finally, the designed controllers were implemented to verify experimentally the system performance. From the results, the proposed robust control strategies are shown to be effective.

Adaptive tracking control of a wheeled mobile robot via an uncalibrated camera system.

PubMed

Dixon, W E; Dawson, D M; Zergeroglu, E; Behal, A

2001-01-01

This paper considers the problem of position/orientation tracking control of wheeled mobile robots via visual servoing in the presence of parametric uncertainty associated with the mechanical dynamics and the camera system. Specifically, we design an adaptive controller that compensates for uncertain camera and mechanical parameters and ensures global asymptotic position/orientation tracking. Simulation and experimental results are included to illustrate the performance of the control law.

Computational Methods for Nonlinear Dynamic Problems in Solid and Structural Mechanics: Progress in the Theory and Modeling of Friction and in the Control of Dynamical Systems with Frictional Forces

DTIC Science & Technology

1989-03-31

present several numerical studies designed to reveal the effect that some of the governing parameters have on the behavior of the system and, whenever...Friction and in the Control of Dynamical Systems with Frictional Forces FINAL TECHNICAL REPORT March 31, 1989 _ -- I -.7: .-.- - : AFOSR Contract F49620...SOLID AND STRUCTURAL MECHANICS: Progress in the Theory and Modeling of Friction and in the Control of Dynamical Systems with Frictional Forces I I * FINAL

Modeling and control design of a wind tunnel model support

NASA Technical Reports Server (NTRS)

Howe, David A.

1990-01-01

The 12-Foot Pressure Wind Tunnel at Ames Research Center is being restored. A major part of the restoration is the complete redesign of the aircraft model supports and their associated control systems. An accurate trajectory control servo system capable of positioning a model (with no measurable overshoot) is needed. Extremely small errors in scaled-model pitch angle can increase airline fuel costs for the final aircraft configuration by millions of dollars. In order to make a mechanism sufficiently accurate in pitch, a detailed structural and control-system model must be created and then simulated on a digital computer. The model must contain linear representations of the mechanical system, including masses, springs, and damping in order to determine system modes. Electrical components, both analog and digital, linear and nonlinear must also be simulated. The model of the entire closed-loop system must then be tuned to control the modes of the flexible model-support structure. The development of a system model, the control modal analysis, and the control-system design are discussed.

Methods, systems and apparatus for controlling operation of two alternating current (AC) machines

DOEpatents

Gallegos-Lopez, Gabriel [Torrance, CA; Nagashima, James M [Cerritos, CA; Perisic, Milun [Torrance, CA; Hiti, Silva [Redondo Beach, CA

2012-06-05

A system is provided for controlling two alternating current (AC) machines via a five-phase PWM inverter module. The system comprises a first control loop, a second control loop, and a current command adjustment module. The current command adjustment module operates in conjunction with the first control loop and the second control loop to continuously adjust current command signals that control the first AC machine and the second AC machine such that they share the input voltage available to them without compromising the target mechanical output power of either machine. This way, even when the phase voltage available to either one of the machines decreases, that machine outputs its target mechanical output power.

Redox sensing: Orthogonal control in cell cycle and apoptosis signaling

PubMed Central

Jones, Dean P.

2010-01-01

Living systems have three major types of cell signaling systems that are dependent upon high-energy chemicals, redox environment and transmembranal ion gating mechanisms. Development of integrated systems biology descriptions of cell signaling require conceptual models incorporating all three. Recent advances in redox biology show that thiol/disulfide redox systems are regulated under dynamic, non-equilibrium conditions, progressively oxidized with the life cycle of cells and distinct in terms of redox potentials among subcellular compartments. The present article uses these observations as a basis to distinguish “redox-sensing” mechanisms, which are more global biologic redox control mechanisms, from “redox signaling”, which involves conveyance of discrete activating or inactivating signals. Both redox sensing and redox signaling use sulfur switches, especially cysteine (Cys) residues in proteins which are sensitive to reversible oxidation, nitrosylation, glutathionylation, acylation, sulfhydration or metal binding. Unlike specific signaling mechanisms, the redox-sensing mechanisms provide means to globally affect the rates and activities of the high-energy, ion gating and redox-signaling systems by controlling sensitivity, distribution, macromolecular interactions and mobility of signaling proteins. Effects mediated through Cys residues not directly involved in signaling means redox-sensing control can be orthogonal to the signaling mechanisms. This provides a capability to integrate signals according to cell cycle and physiologic state without fundamentally altering the signaling mechanisms. Recent findings that thiol/disulfide pools in humans are oxidized with age, environmental exposures and disease risk suggest that redox-sensing thiols could provide a central mechanistic link in disease development and progression. PMID:20964735

Identifying a cooperative control mechanism between an applied field and the environment of open quantum systems

NASA Astrophysics Data System (ADS)

Gao, Fang; Rey-de-Castro, Roberto; Wang, Yaoxiong; Rabitz, Herschel; Shuang, Feng

2016-05-01

Many systems under control with an applied field also interact with the surrounding environment. Understanding the control mechanisms has remained a challenge, especially the role played by the interaction between the field and the environment. In order to address this need, here we expand the scope of the Hamiltonian-encoding and observable-decoding (HE-OD) technique. HE-OD was originally introduced as a theoretical and experimental tool for revealing the mechanism induced by control fields in closed quantum systems. The results of open-system HE-OD analysis presented here provide quantitative mechanistic insights into the roles played by a Markovian environment. Two model open quantum systems are considered for illustration. In these systems, transitions are induced by either an applied field linked to a dipole operator or Lindblad operators coupled to the system. For modest control yields, the HE-OD results clearly show distinct cooperation between the dynamics induced by the optimal field and the environment. Although the HE-OD methodology introduced here is considered in simulations, it has an analogous direct experimental formulation, which we suggest may be applied to open systems in the laboratory to reveal mechanistic insights.

DACS II - A distributed thermal/mechanical loads data acquisition and control system

NASA Technical Reports Server (NTRS)

Zamanzadeh, Behzad; Trover, William F.; Anderson, Karl F.

1987-01-01

A distributed data acquisition and control system has been developed for the NASA Flight Loads Research Facility. The DACS II system is composed of seven computer systems and four array processors configured as a main computer system, three satellite computer systems, and 13 analog input/output systems interconnected through three independent data networks. Up to three independent heating and loading tests can be run concurrently on different test articles or the entire system can be used on a single large test such as a full scale hypersonic aircraft. Thermal tests can include up to 512 independent adaptive closed loop control channels. The control system can apply up to 20 MW of heating to a test specimen while simultaneously applying independent mechanical loads. Each thermal control loop is capable of heating a structure at rates of up to 150 F per second over a temperature range of -300 to +2500 F. Up to 64 independent mechanical load profiles can be commanded along with thermal control. Up to 1280 analog inputs monitor temperature, load, displacement and strain on the test specimens with real time data displayed on up to 15 terminals as color plots and tabular data displays. System setup and operation is accomplished with interactive menu-driver displays with extensive facilities to assist the users in all phases of system operation.

Environmental Control System Installer/Servicer (Residential Air Conditioning Mechanic). V-TECS Guide.

ERIC Educational Resources Information Center

Meyer, Calvin F.; Benson, Robert T.

This guide provides job relevant tasks, performance objectives, performance guides, resources, learning activitites, evaluation standards, and achievement testing in the occupation of environmental control system installer/servicer (residential air conditioning mechanic). It is designed to be used with any chosen teaching method. The course…

Integral force feedback control with input shaping: Application to piezo-based scanning systems in ECDLs.

PubMed

Zhang, Meng; Liu, Zhigang; Zhu, Yu; Bu, Mingfan; Hong, Jun

2017-07-01

In this paper, a hybrid control system is developed by integrating the closed-loop force feedback and input shaping method to overcome the problem of the hysteresis and dynamic behavior in piezo-based scanning systems and increase the scanning speed of tunable external cavity diode lasers. The flexible hinge and piezoelectric actuators are analyzed, and a dynamic model of the scanning systems is established. A force sensor and an integral controller are utilized in integral force feedback (IFF) to directly augment the damping of the piezoelectric scanning systems. Hysteresis has been effectively eliminated, but the mechanical resonance is still evident. Noticeable residual vibration occurred after the inflection points and then gradually disappeared. For the further control of mechanical resonance, based on the theory of minimum-acceleration trajectory planning, the time-domain input shaping method was developed. The turning sections of a scanning trajectory are replaced by smooth curves, while the linear sections are retained. The IFF method is combined with the input shaping method to control the non-linearity and mechanical resonance in high-speed piezo-based scanning systems. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

Concept and realization of unmanned aerial system with different modes of operation

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

Czyba, Roman; Szafrański, Grzegorz; Janusz, Wojciech

2014-12-10

In this paper we describe the development process of unmanned aerial system, its mechanical components, electronics and software solutions. During the stage of design, we have formulated some necessary requirements for the multirotor vehicle and ground control station in order to build an optimal system which can be used for the reconnaissance missions. Platform is controlled by use of the ground control station (GCS) and has possibility of accomplishing video based observation tasks. In order to fulfill this requirement the on-board payload consists of mechanically stabilized camera augmented with machine vision algorithms to enable object tracking tasks. Novelty of themore » system are four modes of flight, which give full functionality of the developed UAV system. Designed ground control station is consisted not only of the application itself, but also a built-in dedicated components located inside the chassis, which together creates an advanced UAV system supporting the control and management of the flight. Mechanical part of quadrotor is designed to ensure its robustness while meeting objectives of minimizing weight of the platform. Finally the designed electronics allows for implementation of control and estimation algorithms without the needs for their excessive computational optimization.« less

Integral force feedback control with input shaping: Application to piezo-based scanning systems in ECDLs

NASA Astrophysics Data System (ADS)

Zhang, Meng; Liu, Zhigang; Zhu, Yu; Bu, Mingfan; Hong, Jun

2017-07-01

In this paper, a hybrid control system is developed by integrating the closed-loop force feedback and input shaping method to overcome the problem of the hysteresis and dynamic behavior in piezo-based scanning systems and increase the scanning speed of tunable external cavity diode lasers. The flexible hinge and piezoelectric actuators are analyzed, and a dynamic model of the scanning systems is established. A force sensor and an integral controller are utilized in integral force feedback (IFF) to directly augment the damping of the piezoelectric scanning systems. Hysteresis has been effectively eliminated, but the mechanical resonance is still evident. Noticeable residual vibration occurred after the inflection points and then gradually disappeared. For the further control of mechanical resonance, based on the theory of minimum-acceleration trajectory planning, the time-domain input shaping method was developed. The turning sections of a scanning trajectory are replaced by smooth curves, while the linear sections are retained. The IFF method is combined with the input shaping method to control the non-linearity and mechanical resonance in high-speed piezo-based scanning systems. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

A force-controllable macro-micro manipulator and its application to medical robots

NASA Technical Reports Server (NTRS)

Marzwell, Neville I.; Uecker, Darrin R.; Wang, Yulun

1994-01-01

This paper describes an 8-degrees-of-freedom macro-micro robot. This robot is capable of performing tasks that require accurate force control, such as polishing, finishing, grinding, deburring, and cleaning. The design of the macro-micro mechanism, the control algorithms, and the hardware/software implementation of the algorithms are described in this paper. Initial experimental results are reported. In addition, this paper includes a discussion of medical surgery and the role that force control may play. We introduce a new class of robotic systems collectively called Robotic Enhancement Technology (RET). RET systems introduce the combination of robotic manipulation with human control to perform manipulation tasks beyond the individual capability of either human or machine. The RET class of robotic systems offers new challenges in mechanism design, control-law development, and man/machine interface design. We believe force-controllable mechanisms such as the macro-micro structure we have developed are a necessary part of RET. Work in progress in the area of RET systems and their application to minimally invasive surgery is presented, along with future research directions.

Adaptive kanban control mechanism for a single-stage hybrid system

NASA Astrophysics Data System (ADS)

Korugan, Aybek; Gupta, Surendra M.

2002-02-01

In this paper, we consider a hybrid manufacturing system with two discrete production lines. Here the output of either production line can satisfy the demand for the same type of product without any penalties. The interarrival times for demand occurrences and service completions are exponentially distributed i.i.d. variables. In order to control this type of manufacturing system we suggest a single stage pull type control mechanism with adaptive kanbans and state independent routing of the production information.

10 CFR 55.41 - Written examination: Operators.

Code of Federal Regulations, 2013 CFR

2013-01-01

... elements, control rods, core instrumentation, and coolant flow. (3) Mechanical components and design..., and functions of reactivity control mechanisms and instrumentation. (7) Design, components, and functions of control and safety systems, including instrumentation, signals, interlocks, failure modes, and...

10 CFR 55.41 - Written examination: Operators.

Code of Federal Regulations, 2014 CFR

2014-01-01

... elements, control rods, core instrumentation, and coolant flow. (3) Mechanical components and design..., and functions of reactivity control mechanisms and instrumentation. (7) Design, components, and functions of control and safety systems, including instrumentation, signals, interlocks, failure modes, and...

Proportional and Integral Thermal Control System for Large Scale Heating Tests

NASA Technical Reports Server (NTRS)

Fleischer, Van Tran

2015-01-01

The National Aeronautics and Space Administration Armstrong Flight Research Center (Edwards, California) Flight Loads Laboratory is a unique national laboratory that supports thermal, mechanical, thermal/mechanical, and structural dynamics research and testing. A Proportional Integral thermal control system was designed and implemented to support thermal tests. A thermal control algorithm supporting a quartz lamp heater was developed based on the Proportional Integral control concept and a linearized heating process. The thermal control equations were derived and expressed in terms of power levels, integral gain, proportional gain, and differences between thermal setpoints and skin temperatures. Besides the derived equations, user's predefined thermal test information generated in the form of thermal maps was used to implement the thermal control system capabilities. Graphite heater closed-loop thermal control and graphite heater open-loop power level were added later to fulfill the demand for higher temperature tests. Verification and validation tests were performed to ensure that the thermal control system requirements were achieved. This thermal control system has successfully supported many milestone thermal and thermal/mechanical tests for almost a decade with temperatures ranging from 50 F to 3000 F and temperature rise rates from -10 F/s to 70 F/s for a variety of test articles having unique thermal profiles and test setups.

Animation of multi-flexible body systems and its use in control system design

NASA Technical Reports Server (NTRS)

Juengst, Carl; Stahlberg, Ron

1993-01-01

Animation can greatly assist the structural dynamicist and control system analyst with better understanding of how multi-flexible body systems behave. For multi-flexible body systems, the structural characteristics (mode frequencies, mode shapes, and damping) change, sometimes dramatically with large angles of rotation between bodies. With computer animation, the analyst can visualize these changes and how the system responds to active control forces and torques. A characterization of the type of system we wish to animate is presented. The lack of clear understanding of the above effects was a key element leading to the development of a multi-flexible body animation software package. The resulting animation software is described in some detail here, followed by its application to the control system analyst. Other applications of this software can be determined on an individual need basis. A number of software products are currently available that make the high-speed rendering of rigid body mechanical system simulation possible. However, such options are not available for use in rendering flexible body mechanical system simulations. The desire for a high-speed flexible body visualization tool led to the development of the Flexible Or Rigid Mechanical System (FORMS) software. This software was developed at the Center for Simulation and Design Optimization of Mechanical Systems at the University of Iowa. FORMS provides interactive high-speed rendering of flexible and/or rigid body mechanical system simulations, and combines geometry and motion information to produce animated output. FORMS is designed to be both portable and flexible, and supports a number of different user interfaces and graphical display devices. Additional features have been added to FORMS that allow special visualization results related to the nature of the flexible body geometric representations.

Hydraulic actuator mechanism to control aircraft spoiler movements through dual input commands

NASA Technical Reports Server (NTRS)

Irick, S. C. (Inventor)

1981-01-01

An aircraft flight spoiler control mechanism is described. The invention enables the conventional, primary spoiler control system to retain its operational characteristics while accommodating a secondary input controlled by a conventional computer system to supplement the settings made by the primary input. This is achieved by interposing springs between the primary input and the spoiler control unit. The springs are selected to have a stiffness intermediate to the greater force applied by the primary control linkage and the lesser resistance offered by the spoiler control unit. Thus, operation of the primary input causes the control unit to yield before the springs, yet, operation of the secondary input, acting directly on the control unit, causes the springs to yield and absorb adjustments before they are transmitted into the primary control system.

Overhead Crane Computer Model

NASA Astrophysics Data System (ADS)

Enin, S. S.; Omelchenko, E. Y.; Fomin, N. V.; Beliy, A. V.

2018-03-01

The paper has a description of a computer model of an overhead crane system. The designed overhead crane system consists of hoisting, trolley and crane mechanisms as well as a payload two-axis system. With the help of the differential equation of specified mechanisms movement derived through Lagrange equation of the II kind, it is possible to build an overhead crane computer model. The computer model was obtained using Matlab software. Transients of coordinate, linear speed and motor torque of trolley and crane mechanism systems were simulated. In addition, transients of payload swaying were obtained with respect to the vertical axis. A trajectory of the trolley mechanism with simultaneous operation with the crane mechanism is represented in the paper as well as a two-axis trajectory of payload. The designed computer model of an overhead crane is a great means for studying positioning control and anti-sway control systems.

The development of small-scale mechanization means positioning algorithm using radio frequency identification technology in industrial plants

NASA Astrophysics Data System (ADS)

Astafiev, A.; Orlov, A.; Privezencev, D.

2018-01-01

The article is devoted to the development of technology and software for the construction of positioning and control systems for small mechanization in industrial plants based on radio frequency identification methods, which will be the basis for creating highly efficient intelligent systems for controlling the product movement in industrial enterprises. The main standards that are applied in the field of product movement control automation and radio frequency identification are considered. The article reviews modern publications and automation systems for the control of product movement developed by domestic and foreign manufacturers. It describes the developed algorithm for positioning of small-scale mechanization means in an industrial enterprise. Experimental studies in laboratory and production conditions have been conducted and described in the article.

Kinematics Analysis of End Effector for Carrier Robot of Feeding Broiler Chicken System

NASA Astrophysics Data System (ADS)

Syam, Rafiuddin; Arsyad, Hairul; Bauna, Ruslan; Renreng, Ilyas; Bakhri, Syaiful

2018-02-01

The demand for commodities, especially Broiler chicken farms are increasing, the volume of feed requirements Broiler chickens increased with age up to the age of 30-57 days required feed 3,829 grams/day/head, so if the chicken population is 3,000 needed transporting feed 11 487 kg/day, This research aims to produce a robot capable of transporting feed in the top of the cage by using a control system so as to make efficient use of manpower. Design robot performed using software design three-dimensional Solidworks2010, process of making the robot is started with the design manufacture three (3) units of mechanical systems (mechanical system for holder feed, mechanical systems for lifter feed and mechanical systems for transporting feed), then do the design process framework as a component buffer so that the mechanical system will work properly and safely when the robot operates. Furthermore, the manufacture of electronic circuits and control are using Arduino Mega microcontroller. After assembling all components mechanical systems and installation of electronic systems and control, then experiments to evaluate the performance of the robot have been made. The results of experiments showed that all components work well according to plan, in particular the speed and acceleration of end effector motion so it can hold and release the feed well. This strongly supports the robots perform tasks in accordance with the intent, i.e., holding, lifting and moving feed.

Mechanism controller system for the optical spectroscopic and infrared remote imaging system instrument on board the Rosetta space mission

NASA Astrophysics Data System (ADS)

Castro Marín, J. M.; Brown, V. J. G.; López Jiménez, A. C.; Rodríguez Gómez, J.; Rodrigo, R.

2001-05-01

The optical, spectroscopic infrared remote imaging system (OSIRIS) is an instrument carried on board the European Space Agency spacecraft Rosetta that will be launched in January 2003 to study in situ the comet Wirtanen. The electronic design of the mechanism controller board (MCB) system of the two OSIRIS optical cameras, the narrow angle camera, and the wide angle camera, is described here. The system is comprised of two boards mounted on an aluminum frame as part of an electronics box that contains the power supply and the digital processor unit of the instrument. The mechanisms controlled by the MCB for each camera are the front door assembly and a filter wheel assembly. The front door assembly for each camera is driven by a four phase, permanent magnet stepper motor. Each filter wheel assembly consists of two, eight filter wheels. Each wheel is driven by a four phase, variable reluctance stepper motor. Each motor, for all the assemblies, also contains a redundant set of four stator phase windings that can be energized separately or in parallel with the main windings. All stepper motors are driven in both directions using the full step unipolar mode of operation. The MCB also performs general housekeeping data acquisition of the OSIRIS instrument, i.e., mechanism position encoders and temperature measurements. The electronic design application used is quite new due to use of a field programmable gate array electronic devices that avoid the use of the now traditional system controlled by microcontrollers and software. Electrical tests of the engineering model have been performed successfully and the system is ready for space qualification after environmental testing. This system may be of interest to institutions involved in future space experiments with similar needs for mechanisms control.

Man-equivalent telepresence through four fingered human-like hand system

NASA Technical Reports Server (NTRS)

Jau, Bruno M.

1992-01-01

The author describes a newly developed mechanical hand system. The robot hand is in human-like configuration with a thumb and three fingers, a palm, a wrist, and the forearm in which the hand and wrist actuators are located. Each finger and the wrist has its own active electromechanical compliance system, allowing the joint drive trains to be stiffened or loosened. This mechanism imitates the human muscle dual function of positioner and stiffness controller. This is essential for soft grappling operations. The hand-wrist assembly has 16 finger joints, three wrist joints, and five compliance mechanisms for a total of 24 degrees of freedom. The strength of the hand is roughly half that of the human hand and its size is comparable to a male hand. The hand is controlled through an exoskeleton glove controller that the operator wears. The glove provides the man-machine interface in telemanipulation control mode: it senses the operator's inputs to guide the mechanical hand in hybrid position and force control. The hand system is intended for dexterous manipulations in structured environments. Typical applications will include work in hostile environment such as space operations and nuclear power plants.

Non-mechanical beam control for entry, descent and landing laser radar (Conference Presentation)

NASA Astrophysics Data System (ADS)

Stockley, Jay E.; Kluttz, Kelly; Hosting, Lance; Serati, Steve; Bradley, Cullen P.; McManamon, Paul F.; Amzajerdian, Farzin

2017-05-01

Laser radar for entry, descent, and landing (EDL) applications as well as the space docking problem could benefit from a low size, weight, and power (SWaP) beam control system. Moreover, an inertia free approach employing non-mechanical beam control is also attractive for laser radar that is intended to be employed aboard space platforms. We are investigating a non-mechanical beam steering (NMBS) sub-system based on liquid crystal polarization grating (LCPG) technology with emphasis placed on improved throughput and significant weight reduction by combining components and drastically reducing substrate thicknesses. In addition to the advantages of non-mechanical, gimbal free beam control, and greatly improved SWaP, our approach also enables wide area scanning using a scalable architecture. An extraterrestrial application entails additional environmental constraints, consequently an environmental test plan tailored to an EDL mission will also be discussed. In addition, we will present advances in continuous fine steering technology which would complement the coarse steering LCPG technology. A low-SWaP, non-mechanical beam control system could be used in many laser radar remote sensing applications including meteorological studies and agricultural or environmental surveys in addition to the entry, descent, and landing application.

SMS engineering design report

NASA Technical Reports Server (NTRS)

1976-01-01

The engineering design for the Shuttle Missions Simulator is presented in sections, with each section representing a subsystem development activity. Subsystems covered include: electrical power system; mechanical power system; main propellant and external tank; solid rocket booster; reaction control system; orbital maneuvering system; guidance, navigation, and control; data processing system; mission control center interface; and image display system.

Vibration control of uncertain multiple launch rocket system using radial basis function neural network

NASA Astrophysics Data System (ADS)

Li, Bo; Rui, Xiaoting

2018-01-01

Poor dispersion characteristics of rockets due to the vibration of Multiple Launch Rocket System (MLRS) have always restricted the MLRS development for several decades. Vibration control is a key technique to improve the dispersion characteristics of rockets. For a mechanical system such as MLRS, the major difficulty in designing an appropriate control strategy that can achieve the desired vibration control performance is to guarantee the robustness and stability of the control system under the occurrence of uncertainties and nonlinearities. To approach this problem, a computed torque controller integrated with a radial basis function neural network is proposed to achieve the high-precision vibration control for MLRS. In this paper, the vibration response of a computed torque controlled MLRS is described. The azimuth and elevation mechanisms of the MLRS are driven by permanent magnet synchronous motors and supposed to be rigid. First, the dynamic model of motor-mechanism coupling system is established using Lagrange method and field-oriented control theory. Then, in order to deal with the nonlinearities, a computed torque controller is designed to control the vibration of the MLRS when it is firing a salvo of rockets. Furthermore, to compensate for the lumped uncertainty due to parametric variations and un-modeled dynamics in the design of the computed torque controller, a radial basis function neural network estimator is developed to adapt the uncertainty based on Lyapunov stability theory. Finally, the simulated results demonstrate the effectiveness of the proposed control system and show that the proposed controller is robust with regard to the uncertainty.

Motion planning in velocity affine mechanical systems

NASA Astrophysics Data System (ADS)

Jakubiak, Janusz; Tchoń, Krzysztof; Magiera, Władysław

2010-09-01

We address the motion planning problem in specific mechanical systems whose linear and angular velocities depend affinely on control. The configuration space of these systems encompasses the rotation group, and the motion planning involves the system orientation. Derivation of the motion planning algorithm for velocity affine systems has been inspired by the continuation method. Performance of this algorithm is illustrated with examples of the kinematics of a serial nonholonomic manipulator, the plate-ball kinematics and the attitude control of a rigid body.

Design of transplanting mechanism for system of rice intensification (SRI) transplanter in Kedah, Malaysia

NASA Astrophysics Data System (ADS)

Imran, M. S.; Manan, M. S. Abdul; Khalil, A. N. M.; MdNaim, M. K.; Ahmad, R. N.

2017-08-01

There is a demand to develop transplanter specifically for system of rice intensification (SRI) cultivation in Malaysia. This SRI transplanter is different from conventional transplanter as it is required special requirements for transplanting. The work focused on transplanting mechanism design which can be later attached to SRI transplanter. The mechanical design was established using linkage mechanism, having a wheel that act as timing wheel that will control the distance between transplanted seedlings. The linkage mechanism also control the opening of the flapper that allow the seedling together with its nursery soil to be dropped, and control the stopper to prevent next seedling from sliding down the tray. The use of simple mechanism will have low cost for fabrication. The design was analysed using motion analysis software. Results show the design is perfectly good and can be fabricated without any problem. The animation successfully shows the perfect movement of the mechanism and transplanting process.

Mechanical Systems Versus Smoking Bans for Secondhand Smoke Control

PubMed Central

Barrientos-Gutierrez, Tonatiuh; Amick, Benjamin C.; Gimeno, David; Reynales-Shigematsu, Luz M.; Delclos, George L.; Harrist, Ronald B.; Kelder, Steven H.; Lazcano-Ponce, Eduardo; Hernandez-Ávila, Mauricio

2012-01-01

Introduction: Despite international efforts to implement smoking bans, several national legislations still allow smoking and recommend mechanical systems, such as ventilation and air extraction, to eliminate secondhand smoke (SHS) health-related risks. We aimed to quantify the relative contribution of mechanical systems and smoking bans to SHS elimination. Methods: A cross-sectional study was conducted in randomly selected establishments from 4 Mexican cities (3 with no ban). SHS exposure was assessed using nicotine passive monitors. Establishment characteristics, presence of mechanical systems, and enforcement of smoking policies were obtained through direct observation and self-report. Multilevel models were used to assess relative contributions to SHS reduction. Results: Compared with Mexico City, nicotine concentrations were 3.8 times higher in Colima, 5.4 in Cuernavaca, and 6.4 in Toluca. Mechanical systems were not associated with reduced nicotine concentrations. Concentration differences between cities were largely explained by the presence of smoking bans (69.1% difference reduction) but not by mechanical systems (−5.7% difference reduction). Conclusions: Smoking bans represent the only effective approach to reduce SHS. Tobacco control regulations should stop considering mechanical systems as advisable means for SHS reduction and opt for complete smoking bans in public places. PMID:21994338

49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

Code of Federal Regulations, 2011 CFR

2011-10-01

... INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Rules and.... Contact element of automatic train stop device of the mechanical trip type shall be maintained at a height...

Space Shuttle Technical Conference, Part 2

NASA Technical Reports Server (NTRS)

Chaffee, Norman (Compiler)

1985-01-01

The retrospective presentation provides technical disciplinary focus in the following technical areas: (1) integrated avionics; (2) guidance, navigation, and control; (3) aerodynamics; (4) structures; (5) life support, environmental control, and crew station; (6) ground operations; (7) propulsion and power; (8) communications and tracking; (9) mechanics and mechanical systems; and (10) thermal and contamination environments and protection systems.

SPS flexible system control assessment analysis

NASA Technical Reports Server (NTRS)

Balas, M. J.

1981-01-01

Active control of the Satellite Power System (SPS0, a large mechanically flexible aerospace structure is addressed. The control algorithm is the principle component in the feedback link from sensors to actuators. An analysis of the interaction of the SPS structure and its active control system is presented.

Mechatronics by Analogy and Application to Legged Locomotion

NASA Astrophysics Data System (ADS)

Ragusila, Victor

A new design methodology for mechatronic systems, dubbed as Mechatronics by Analogy (MbA), is introduced and applied to designing a leg mechanism. The new methodology argues that by establishing a similarity relation between a complex system and a number of simpler models it is possible to design the former using the analysis and synthesis means developed for the latter. The methodology provides a framework for concurrent engineering of complex systems while maintaining the transparency of the system behaviour through making formal analogies between the system and those with more tractable dynamics. The application of the MbA methodology to the design of a monopod robot leg, called the Linkage Leg, is also studied. A series of simulations show that the dynamic behaviour of the Linkage Leg is similar to that of a combination of a double pendulum and a spring-loaded inverted pendulum, based on which the system kinematic, dynamic, and control parameters can be designed concurrently. The first stage of Mechatronics by Analogy is a method of extracting significant features of system dynamics through simpler models. The goal is to determine a set of simpler mechanisms with similar dynamic behaviour to that of the original system in various phases of its motion. A modular bond-graph representation of the system is determined, and subsequently simplified using two simplification algorithms. The first algorithm determines the relevant dynamic elements of the system for each phase of motion, and the second algorithm finds the simple mechanism described by the remaining dynamic elements. In addition to greatly simplifying the controller for the system, using simpler mechanisms with similar behaviour provides a greater insight into the dynamics of the system. This is seen in the second stage of the new methodology, which concurrently optimizes the simpler mechanisms together with a control system based on their dynamics. Once the optimal configuration of the simpler system is determined, the original mechanism is optimized such that its dynamic behaviour is analogous. It is shown that, if this analogy is achieved, the control system designed based on the simpler mechanisms can be directly implemented to the more complex system, and their dynamic behaviours are close enough for the system performance to be effectively the same. Finally it is shown that, for the employed objective of fast legged locomotion, the proposed methodology achieves a better design than Reduction-by-Feedback, a competing methodology that uses control layers to simplify the dynamics of the system.

Deducing growth mechanisms for minerals from the shapes of crystal size distributions

USGS Publications Warehouse

Eberl, D.D.; Drits, V.A.; Srodon, J.

1998-01-01

Crystal size distributions (CSDs) of natural and synthetic samples are observed to have several distinct and different shapes. We have simulated these CSDs using three simple equations: the Law of Proportionate Effect (LPE), a mass balance equation, and equations for Ostwald ripening. The following crystal growth mechanisms are simulated using these equations and their modifications: (1) continuous nucleation and growth in an open system, during which crystals nucleate at either a constant, decaying, or accelerating nucleation rate, and then grow according to the LPE; (2) surface-controlled growth in an open system, during which crystals grow with an essentially unlimited supply of nutrients according to the LPE; (3) supply-controlled growth in an open system, during which crystals grow with a specified, limited supply of nutrients according to the LPE; (4) supply- or surface-controlled Ostwald ripening in a closed system, during which the relative rate of crystal dissolution and growth is controlled by differences in specific surface area and by diffusion rate; and (5) supply-controlled random ripening in a closed system, during which the rate of crystal dissolution and growth is random with respect to specific surface area. Each of these mechanisms affects the shapes of CSDs. For example, mechanism (1) above with a constant nucleation rate yields asymptotically-shaped CSDs for which the variance of the natural logarithms of the crystal sizes (??2) increases exponentially with the mean of the natural logarithms of the sizes (??). Mechanism (2) yields lognormally-shaped CSDs, for which ??2 increases linearly with ??, whereas mechanisms (3) and (5) do not change the shapes of CSDs, with ??2 remaining constant with increasing ??. During supply-controlled Ostwald ripening (4), initial lognormally-shaped CSDs become more symmetric, with ??2 decreasing with increasing ??. Thus, crystal growth mechanisms often can be deduced by noting trends in ?? versus ??2 of CSDs for a series of related samples.

Research Technology

NASA Image and Video Library

2001-08-01

The electro-mechanical actuator, a new electronics technology, is an electronic system that provides the force needed to move valves that control the flow of propellant to the engine. It is proving to be advantageous for the main propulsion system plarned for a second generation reusable launch vehicle. Hydraulic actuators have been used successfully in rocket propulsion systems. However, they can leak when high pressure is exerted on such a fluid-filled hydraulic system. Also, hydraulic systems require significant maintenance and support equipment. The electro-mechanical actuator is proving to be low maintenance and the system weighs less than a hydraulic system. The electronic controller is a separate unit powering the actuator. Each actuator has its own control box. If a problem is detected, it can be replaced by simply removing one defective unit. The hydraulic systems must sustain significant hydraulic pressures in a rocket engine regardless of demand. The electro-mechanical actuator utilizes power only when needed. A goal of the Second Generation Reusable Launch Vehicle Program is to substantially improve safety and reliability while reducing the high cost of space travel. The electro-mechanical actuator was developed by the Propulsion Projects Office of the Second Generation Reusable Launch Vehicle Program at the Marshall Space Flight Center.

An opto-electro-mechanical system based on evanescently-coupled optical microbottle and electromechanical resonator

NASA Astrophysics Data System (ADS)

Asano, Motoki; Ohta, Ryuichi; Yamamoto, Takashi; Okamoto, Hajime; Yamaguchi, Hiroshi

2018-05-01

Evanescent coupling between a high-Q silica optical microbottle and a GaAs electromechanical resonator is demonstrated. This coupling offers an opto-electro-mechanical system which possesses both cavity-enhanced optical sensitivity and electrical controllability of the mechanical motion. Cooling and heating of the mechanical mode are demonstrated based on optomechanical detection via the radiation pressure and electromechanical feedback via the piezoelectric effect. This evanescent approach allows for individual design of optical, mechanical, and electrical systems, which could lead to highly sensitive and functionalized opto-electro-mechanical systems.

Adaptively Adjusted Event-Triggering Mechanism on Fault Detection for Networked Control Systems.

PubMed

Wang, Yu-Long; Lim, Cheng-Chew; Shi, Peng

2016-12-08

This paper studies the problem of adaptively adjusted event-triggering mechanism-based fault detection for a class of discrete-time networked control system (NCS) with applications to aircraft dynamics. By taking into account the fault occurrence detection progress and the fault occurrence probability, and introducing an adaptively adjusted event-triggering parameter, a novel event-triggering mechanism is proposed to achieve the efficient utilization of the communication network bandwidth. Both the sensor-to-control station and the control station-to-actuator network-induced delays are taken into account. The event-triggered sensor and the event-triggered control station are utilized simultaneously to establish new network-based closed-loop models for the NCS subject to faults. Based on the established models, the event-triggered simultaneous design of fault detection filter (FDF) and controller is presented. A new algorithm for handling the adaptively adjusted event-triggering parameter is proposed. Performance analysis verifies the effectiveness of the adaptively adjusted event-triggering mechanism, and the simultaneous design of FDF and controller.

Technical Evaluation Report on the Flight Mechanics Panel Symposium on the Flight Mechanics Panel Symposium on Space Vehicle Flight Mechanics (La Mecanique du Vol des Vehicules Spatiaux)

DTIC Science & Technology

1990-11-01

control and including final recovery for a wide range of space vehicles from tethered satellite systems and flexible space structures to the space plane...flight mechanics, members from the Fluid Dynamics Panel, the Guidance and Control Panel, the Propulsion and Energetics Panel and the Structures and... Structures and Materials which should be overcome for a successful realization of a human Space Transportation System in the 21st century. He

High efficiency and simple technique for controlling mechanisms by EMG signals

NASA Astrophysics Data System (ADS)

Dugarte, N.; Álvarez, A.; Balacco, J.; Mercado, G.; Gonzalez, A.; Dugarte, E.; Javier, F.; Ceballos, G.; Olivares, A.

2016-04-01

This article reports the development of a simple and efficient system that allows control of mechanisms through electromyography (EMG) signals. The novelty about this instrument is focused on individual control of each motion vector mechanism through independent electronic circuits. Each of electronic circuit does positions a motor according to intensity of EMG signal captured. This action defines movement in one mechanical axis considered from an initial point, based on increased muscle tension. The final displacement of mechanism depends on individual’s ability to handle the levels of muscle tension at different body parts. This is the design of a robotic arm where each degree of freedom is handled with a specific microcontroller that responds to signals taken from a defined muscle. The biophysical interaction between the person and the final positioning of the robotic arm is used as feedback. Preliminary tests showed that the control operates with minimal positioning error margins. The constant use of system with the same operator showed that the person adapts and progressively improves at control technique.

Delay times of a LiDAR-guided precision sprayer control system

USDA-ARS?s Scientific Manuscript database

Accurate flow control systems in triggering sprays against detected targets are needed for precision variable-rate sprayer development. System delay times due to the laser-sensor data buffer, software operation, and hydraulic-mechanical component response were determined for a control system used fo...

XRF inductive bead fusion and PLC based control system

NASA Astrophysics Data System (ADS)

Zhu, Jin-hong; Wang, Ying-jie; Shi, Hong-xin; Chen, Qing-ling; Chen, Yu-xi

2009-03-01

In order to ensure high-quality X-ray fluorescence spectrometry (XRF) analysis, an inductive bead fusion machine was developed. The prototype consists of super-audio IGBT induction heating power supply, rotation and swing mechanisms, and programmable logic controller (PLC). The system can realize sequence control, mechanical movement control, output current and temperature control. Experimental results show that the power supply can operate at an ideal quasi-resonant state, in which the expected power output and the required temperature can be achieved for rapid heating and the uniform formation of glass beads respectively.

Attitude controls for VTOL aircraft

NASA Technical Reports Server (NTRS)

Pauli, F. A.

1971-01-01

Systems consist of single duct system with two sets of reaction control nozzles, one linked mechanically to pilot's controls, and other set driven by electric servomotors commanded by preselected combinations of electrical signals.

Progressing quality control in environmental impact assessment beyond legislative compliance: An evaluation of the IEMA EIA Quality Mark certification scheme

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

Bond, Alan, E-mail: alan.bond@uea.ac.uk; Research Unit for Environmental Sciences and Management, North-West University; Fischer, Thomas B, E-mail: fischer@liverpool.ac.uk

The effectiveness of Environmental Impact Assessment (EIA) systems is contingent on a number of control mechanisms: procedural; judicial; evaluative; public and government agency; professional; and development aid agency. If we assume that procedural and judicial controls are guaranteed in developed EIA systems, then progressing effectiveness towards an acceptable level depends on improving the performance of other control mechanisms over time. These other control mechanisms are either absent, or are typically centrally controlled, requiring public finances; this we argue is an unpopular model in times of greater Government austerity. Here we evaluate a market-based mechanism for improving the performance of evaluativemore » and professional control mechanisms, the UK Institute of Environmental Management and Assessments' EIA Quality Mark. We do this by defining dimensions of effectiveness for the purposes of our evaluation, and by identifying international examples of the approaches taken to delivering the other control measures to validate the approach taken in the EIA Quality Mark. We then evaluate the EIA Quality Mark, when used in combination with legal procedures and an active judiciary, against the effectiveness dimensions and use time-series analysis of registrant data to examine its ability to progress practice. We conclude that the EIA Quality Mark has merit as a model for a market-based mechanism, and may prove a more financially palatable approach for delivering effective EIA in mature systems in countries that lack centralised agency oversight. It may, therefore, be of particular interest to some Member States of the European Union for ensuring forthcoming certification requirements stemming from recent amendments to the EIA Directive. - Highlights: • Quality control mechanisms in EIA are identified. • Effectiveness of EIA is conceptualised for evaluation purposes. • The UK IEMA EIA Quality Mark is introduced as a market-based mechanism. • The EIA Quality Mark is found to progress quality in many, but not all, areas.« less

Digital flight control actuation system study

NASA Technical Reports Server (NTRS)

Rossing, R.; Hupp, R.

1974-01-01

Flight control actuators and feedback sensors suitable for use in a redundant digital flight control system were examined. The most appropriate design approach for an advanced digital flight control actuation system for development and use in a fly-by-wire system was selected. The concept which was selected consisted of a PM torque motor direct drive. The selected system is compatible with concurrent and independent development efforts on the computer system and the control law mechanizations.

A reducing of a chaotic movement to a periodic orbit, of a micro-electro-mechanical system, by using an optimal linear control design

NASA Astrophysics Data System (ADS)

Chavarette, Fábio Roberto; Balthazar, José Manoel; Felix, Jorge L. P.; Rafikov, Marat

2009-05-01

This paper analyzes the non-linear dynamics, with a chaotic behavior of a particular micro-electro-mechanical system. We used a technique of the optimal linear control for reducing the irregular (chaotic) oscillatory movement of the non-linear systems to a periodic orbit. We use the mathematical model of a (MEMS) proposed by Luo and Wang.

The application of hydraulics in the 2,000 kW wind turbine generator

NASA Technical Reports Server (NTRS)

Onufreiczuk, S.

1978-01-01

A 2000 kW turbine generator using hydraulic power in two of its control systems is being built under the management of NASA Lewis Research Center. The hydraulic systems providing the control torques and forces for the yaw and blade pitch control systems are discussed. The yaw-drive-system hydraulic supply provides the power for positioning the nacelle so that the rotary axis is kept in line with the direction of the prevailing wind, as well as pressure to the yaw and high speed shaft brakes. The pitch-change-mechanism hydraulic system provides the actuation to the pitch change mechanism and permits feathering of the blades during an emergency situation. It operates in conjunction with the overall windmill computer system, with the feather control permitting slewing control flow to pass from the servo valve to the actuators without restriction.

Design of rapid prototype of UAV line-of-sight stabilized control system

NASA Astrophysics Data System (ADS)

Huang, Gang; Zhao, Liting; Li, Yinlong; Yu, Fei; Lin, Zhe

2018-01-01

The line-of-sight (LOS) stable platform is the most important technology of UAV (unmanned aerial vehicle), which can reduce the effect to imaging quality from vibration and maneuvering of the aircraft. According to the requirement of LOS stability system (inertial and optical-mechanical combined method) and UAV's structure, a rapid prototype is designed using based on industrial computer using Peripheral Component Interconnect (PCI) and Windows RTX to exchange information. The paper shows the control structure, and circuit system including the inertial stability control circuit with gyro and voice coil motor driven circuit, the optical-mechanical stability control circuit with fast-steering-mirror (FSM) driven circuit and image-deviation-obtained system, outer frame rotary follower, and information-exchange system on PC. Test results show the stability accuracy reaches 5μrad, and prove the effectiveness of the combined line-of-sight stabilization control system, and the real-time rapid prototype runs stable.

Tank waste remediation system immobilized high-level waste storage project configuration management implementation plan

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

Burgard, K.G.

This Configuration Management Implementation Plan was developed to assist in the management of systems, structures, and components, to facilitate the effective control and statusing of changes to systems, structures, and components; and to ensure technical consistency between design, performance, and operational requirements. Its purpose is to describe the approach Project W-464 will take in implementing a configuration management control, to determine the rigor of control, and to identify the mechanisms for imposing that control.This Configuration Management Implementation Plan was developed to assist in the management of systems, structures, and components, to facilitate the effective control and statusing of changes tomore » systems, structures, and components; and to ensure technical consistency between design, performance, and operational requirements. Its purpose is to describe the approach Project W-464 will take in implementing a configuration management control, to determine the rigor of control, and to identify the mechanisms for imposing that control.« less

Neural robust stabilization via event-triggering mechanism and adaptive learning technique.

PubMed

Wang, Ding; Liu, Derong

2018-06-01

The robust control synthesis of continuous-time nonlinear systems with uncertain term is investigated via event-triggering mechanism and adaptive critic learning technique. We mainly focus on combining the event-triggering mechanism with adaptive critic designs, so as to solve the nonlinear robust control problem. This can not only make better use of computation and communication resources, but also conduct controller design from the view of intelligent optimization. Through theoretical analysis, the nonlinear robust stabilization can be achieved by obtaining an event-triggered optimal control law of the nominal system with a newly defined cost function and a certain triggering condition. The adaptive critic technique is employed to facilitate the event-triggered control design, where a neural network is introduced as an approximator of the learning phase. The performance of the event-triggered robust control scheme is validated via simulation studies and comparisons. The present method extends the application domain of both event-triggered control and adaptive critic control to nonlinear systems possessing dynamical uncertainties. Copyright © 2018 Elsevier Ltd. All rights reserved.

Asynchronous sampled-data approach for event-triggered systems

NASA Astrophysics Data System (ADS)

Mahmoud, Magdi S.; Memon, Azhar M.

2017-11-01

While aperiodically triggered network control systems save a considerable amount of communication bandwidth, they also pose challenges such as coupling between control and event-condition design, optimisation of the available resources such as control, communication and computation power, and time-delays due to computation and communication network. With this motivation, the paper presents separate designs of control and event-triggering mechanism, thus simplifying the overall analysis, asynchronous linear quadratic Gaussian controller which tackles delays and aperiodic nature of transmissions, and a novel event mechanism which compares the cost of the aperiodic system against a reference periodic implementation. The proposed scheme is simulated on a linearised wind turbine model for pitch angle control and the results show significant improvement against the periodic counterpart.

An investigation on the electrochemical behavior of the Co/Cu multilayer system.

PubMed

Mahshid, S S; Dolati, A

2010-09-01

Co/Cu multilayers were deposited in a sulfate solution by controlling the current and potential for the deposition of cobalt and copper layer respectively. The electrochemical behavior of these multilayers was studied by cyclic voltammetry and current transients. In addition, a mathematical analysis was used to characterize the electrodeposition system. Simultaneously, the nucleation and growth mechanisms were monitored by these techniques. In this case, the results clearly showed that electrodeposition of cobalt layers was a kinetically controlled process while the reduction of copper ions was a diffusion-control process. Although nucleation mechanism of the single Co deposit was found as a progressive system, it was found as an instantaneous system with three-dimensional growth mechanism in the Co/Cu bilayer deposition. Atomic Forced Microscopy images of the Co/Cu multilayer also confirmed the aforementioned nucleation mechanism, where it was expected that the growth of multilayer films would form a laminar-type structure containing a large number of equally-sized rounded grains in each layer.

UNIX security in a supercomputing environment

NASA Technical Reports Server (NTRS)

Bishop, Matt

1989-01-01

The author critiques some security mechanisms in most versions of the Unix operating system and suggests more effective tools that either have working prototypes or have been implemented, for example in secure Unix systems. Although no computer (not even a secure one) is impenetrable, breaking into systems with these alternate mechanisms will cost more, require more skill, and be more easily detected than penetrations of systems without these mechanisms. The mechanisms described fall into four classes (with considerable overlap). User authentication at the local host affirms the identity of the person using the computer. The principle of least privilege dictates that properly authenticated users should have rights precisely sufficient to perform their tasks, and system administration functions should be compartmentalized; to this end, access control lists or capabilities should either replace or augment the default Unix protection system, and mandatory access controls implementing multilevel security models and integrity mechanisms should be available. Since most users access supercomputing environments using networks, the third class of mechanisms augments authentication (where feasible). As no security is perfect, the fourth class of mechanism logs events that may indicate possible security violations; this will allow the reconstruction of a successful penetration (if discovered), or possibly the detection of an attempted penetration.

Power and energy ratios in mechanical CVT drive control

NASA Astrophysics Data System (ADS)

Balakin, P. D.; Stripling, L. O.

2017-06-01

Being based on the principle of providing the systems with adaptation property to the real parameters and operational condition, the mechanical system capable to control automatically the components of convertible power is offered and this allows providing stationary operation of the vehicle engine in the terms of variable external loading. This is achieved by drive control integrated in the power transmission, which implements an additional degree of freedom and operates on the basis of the laws of motion, with the energy of the main power flow by changing automatically the kinematic characteristics of the power transmission, this system being named CVT. The power and energy ratios found allow performing the necessary design calculations of the sections and the links of the mechanical CVT scheme.

Mechanical Impedance Modeling of Human Arm: A survey

NASA Astrophysics Data System (ADS)

Puzi, A. Ahmad; Sidek, S. N.; Sado, F.

2017-03-01

Human arm mechanical impedance plays a vital role in describing motion ability of the upper limb. One of the impedance parameters is stiffness which is defined as the ratio of an applied force to the measured deformation of the muscle. The arm mechanical impedance modeling is useful in order to develop a better controller for system that interacts with human as such an automated robot-assisted platform for automated rehabilitation training. The aim of the survey is to summarize the existing mechanical impedance models of human upper limb so to justify the need to have an improved version of the arm model in order to facilitate the development of better controller of such systems with ever increase in complexity. In particular, the paper will address the following issue: Human motor control and motor learning, constant and variable impedance models, methods for measuring mechanical impedance and mechanical impedance modeling techniques.

New Concepts in Indexing *

PubMed Central

Shank, Russell

1965-01-01

Recent trends in indexing emphasize mechanical, not intellectual, developments. Mechanized operations have produced indexes in depth (1) of information on limited areas of science or (2) utilizing limited parameters for analysis. These indexes may include only citations or both useful data and citations of source literature. Both keyword-in-context and citation indexing seem to be passing the test of the marketplace. Mechanical equipment has also been successfully used to manipulate EAM cards for production of index copy. Information centers are increasingly being used as control devices in narrowly defined subject areas. Authors meet growing pressures to participate in information control work by preparing abstracts of their own articles. Mechanized image systems persist, although large systems are scarce and the many small systems may bring only limited relief for information control and retrieval problems. Experimentation and limited development continue on theory and technique of automatic indexing and abstracting. PMID:14306025

Impact of inertia, friction, and backlash upon force control in telemanipulation

NASA Technical Reports Server (NTRS)

Duffie, Neil A.; Zik, John J.; Wiker, Steven F.; Gale, Karen L.

1991-01-01

The mechanical behavior of master controllers of telemanipulators has been a concern of both designers and implementors of telerobotic systems. In general, the literature recommends that telemanipulator systems be constructed that minimize inertia, friction, and backlash in an effort to improve telemanipulative performance. For the most part, these recommendations are founded upon theoretical analysis or simply intuition. Although these recommendations are not challenged on their merit, the material results are measured of building and fielding telemanipulators that possess less than ideal mechanical behaviors. Experiments are described in which forces in a mechanical system with human input are evaluated as a function of mechanical characteristics such as inertia, friction, and backlash. Results indicate that the ability of the human to maintain gripping forces was relatively unaffected by dynamic characteristics in the range studied, suggesting that telemanipulator design in this range should be based on task level force control requirements rather than human factors.

Terminal Sliding Mode-Based Consensus Tracking Control for Networked Uncertain Mechanical Systems on Digraphs.

PubMed

Chen, Gang; Song, Yongduan; Guan, Yanfeng

2018-03-01

This brief investigates the finite-time consensus tracking control problem for networked uncertain mechanical systems on digraphs. A new terminal sliding-mode-based cooperative control scheme is developed to guarantee that the tracking errors converge to an arbitrarily small bound around zero in finite time. All the networked systems can have different dynamics and all the dynamics are unknown. A neural network is used at each node to approximate the local unknown dynamics. The control schemes are implemented in a fully distributed manner. The proposed control method eliminates some limitations in the existing terminal sliding-mode-based consensus control methods and extends the existing analysis methods to the case of directed graphs. Simulation results on networked robot manipulators are provided to show the effectiveness of the proposed control algorithms.

Closed-form solutions for linear regulator design of mechanical systems including optimal weighting matrix selection

NASA Technical Reports Server (NTRS)

Hanks, Brantley R.; Skelton, Robert E.

1991-01-01

Vibration in modern structural and mechanical systems can be reduced in amplitude by increasing stiffness, redistributing stiffness and mass, and/or adding damping if design techniques are available to do so. Linear Quadratic Regulator (LQR) theory in modern multivariable control design, attacks the general dissipative elastic system design problem in a global formulation. The optimal design, however, allows electronic connections and phase relations which are not physically practical or possible in passive structural-mechanical devices. The restriction of LQR solutions (to the Algebraic Riccati Equation) to design spaces which can be implemented as passive structural members and/or dampers is addressed. A general closed-form solution to the optimal free-decay control problem is presented which is tailored for structural-mechanical system. The solution includes, as subsets, special cases such as the Rayleigh Dissipation Function and total energy. Weighting matrix selection is a constrained choice among several parameters to obtain desired physical relationships. The closed-form solution is also applicable to active control design for systems where perfect, collocated actuator-sensor pairs exist.

Parasitic load control system for exhaust temperature control

DOEpatents

Strauser, Aaron D.; Coleman, Gerald N.; Coldren, Dana R.

2009-04-28

A parasitic load control system is provided. The system may include an exhaust producing engine and a fuel pumping mechanism configured to pressurize fuel in a pressure chamber. The system may also include an injection valve configured to cause fuel pressure to build within the pressure chamber when in a first position and allow injection of fuel from the pressure chamber into one or more combustion chambers of the engine when in a second position. The system may further include a controller configured to independently regulate the pressure in the pressure chamber and the injection of fuel into the one or more combustion chambers, to increase a load on the fuel pumping mechanism, increasing parasitic load on the engine, thereby increasing a temperature of the exhaust produced by the engine.

14 CFR Appendix I to Part 25 - Installation of an Automatic Takeoff Thrust Control System (ATTCS)

Code of Federal Regulations, 2010 CFR

2010-01-01

...) This appendix specifies additional requirements for installation of an engine power control system that... crew to increase thrust or power. I25.2Definitions. (a) Automatic Takeoff Thrust Control System (ATTCS... mechanical and electrical, that sense engine failure, transmit signals, actuate fuel controls or power levers...

Torque sensor

NASA Astrophysics Data System (ADS)

Fgeppert, E.

1984-09-01

Mechanical means for sensing turning torque generated by the load forces in a rotary drive system is described. The sensing means is designed to operate with minimal effect on normal operation of the drive system. The invention can be employed in various drive systems, e.g., automotive engine-transmission power plants, electric motor-operated tools, and metal cutting machines. In such drive systems, the torque-sensing feature may be useful for actuation of various control devices, such as electric switches, mechanical clutches, brake actuators, fluid control valves, or audible alarms. The torque-sensing function can be used for safety overload relief, motor de-energization, engine fuel control transmission clutch actuation, remote alarm signal, tool breakage signal, etc.

Spacecraft automatic umbilical system

NASA Technical Reports Server (NTRS)

Goldin, R. W.; Jacquemin, G. G.; Johnson, W. H.

1981-01-01

An umbilical system design is described that incorporates all the features specified for a power system to payload interconnect capability. A proof-of-concept prototype of the umbilical system was built to determine experimentally the suitability of the threading characteristics of the ram mechanism and to verify freedom from cross threading. It is concluded that Berthing systems that utilize remote manipulator systems (RMS) can be simplified by using RMS targets, closed circuit TV cameras, tie into the RMS control system, and grapple-fixture and end-effector-like capture and secure mechanisms. To effect a remotely controlled umbilical interconnect in proximity with a manned spacecraft and to provide for extravehicular activity backup and maintenance capabilities, 18 different mechanisms are found to be necessary. The weight impact of proving for maintenance capability in a large multiple connector umbilical system was found to be in the order of +60 percent.

Development of the Software for 30 inch Telescope Control System at KHAO

NASA Astrophysics Data System (ADS)

Mun, B.-S.; Kim, S.-J.; Jang, M.; Min, S.-W.; Seol, K.-H.; Moon, K.-S.

2006-12-01

Even though 30inch optical telescope at Kyung Hee Astronomy Observatory has been used to produce a series of scientific achievements since its first light in 1992, numerous difficulties in the operation of the telescope have hindered the precise observations needed for further researches. Since the currently used PC-TCS (Personal Computer based Telescope Control system) software based on ISA-bus type is outdated, it doesn't have a user friendly interface and make it impossible to scale. Also accumulated errors which are generated by discordance from input and output signals into a motion controller required new control system. Thus we have improved the telescope control system by updating software and modifying mechanical parts. We applied a new BLDC (brushless DC) servo motor system to the mechanical parts of the telescope and developed a control software using Visual Basic 6.0. As a result, we could achieve a high accuracy in controlling of the telescope and use the userfriendly GUI (Graphic User Interface).

Mechanical Engineering Design Project report: Enabler control systems

NASA Technical Reports Server (NTRS)

Cullen, Christian; Delvecchio, Dave; Scarborough, Alan; Havics, Andrew A.

1992-01-01

The Controls Group was assigned the responsibility for designing the Enabler's control system. The requirement for the design was that the control system must provide a simple user interface to control the boom articulation joints, chassis articulation joints, and the wheel drive. The system required controlling hydraulic motors on the Enabler by implementing 8-bit microprocessor boards. In addition, feedback to evaluate positions and velocities must be interfaced to provide the operator with confirmation as well as control.

A Novel Approach for Enhancement of Automobile Clutch Engagement Quality Using Mechatronics Based Automated Clutch System

NASA Astrophysics Data System (ADS)

Tripathi, K.

2013-01-01

In automated manual clutch (AMC) a mechatronic system controls clutch force trajectory through an actuator governed by a control system. The present study identifies relevant characteristics of this trajectory and their effects on driveline dynamics and engagement quality. A new type of force trajectory is identified which gives the good engagement quality. However this trajectory is not achievable through conventional clutch control mechanism. But in AMC a mechatronic system based on electro-hydraulic or electro-mechanical elements can make it feasible. A mechatronic system is presented in which a mechatronic add-on system can be used to implement the novel force trajectory, without the requirement of replacing the traditional diaphragm spring based clutch in a vehicle with manual transmission.

Dysfunctions of decision-making and cognitive control as transdiagnostic mechanisms of mental disorders: advances, gaps, and needs in current research.

PubMed

Goschke, Thomas

2014-01-01

Disadvantageous decision-making and impaired volitional control over actions, thoughts, and emotions are characteristics of a wide range of mental disorders such as addiction, eating disorders, depression, and anxiety disorders and may reflect transdiagnostic core mechanisms and possibly vulnerability factors. Elucidating the underlying neurocognitive mechanisms is a precondition for moving from symptom-based to mechanism-based disorder classifications and ultimately mechanism-targeted interventions. However, despite substantial advances in basic research on decision-making and cognitive control, there are still profound gaps in our current understanding of dysfunctions of these processes in mental disorders. Central unresolved questions are: (i) to which degree such dysfunctions reflect transdiagnostic mechanisms or disorder-specific patterns of impairment; (ii) how phenotypical features of mental disorders relate to dysfunctional control parameter settings and aberrant interactions between large-scale brain systems involved in habit and reward-based learning, performance monitoring, emotion regulation, and cognitive control; (iii) whether cognitive control impairments are consequences or antecedent vulnerability factors of mental disorders; (iv) whether they reflect generalized competence impairments or context-specific performance failures; (v) whether not only impaired but also chronic over-control contributes to mental disorders. In the light of these gaps, needs for future research are: (i) an increased focus on basic cognitive-affective mechanisms underlying decision and control dysfunctions across disorders; (ii) longitudinal-prospective studies systematically incorporating theory-driven behavioural tasks and neuroimaging protocols to assess decision-making and control dysfunctions and aberrant interactions between underlying large-scale brain systems; (iii) use of latent-variable models of cognitive control rather than single tasks; (iv) increased focus on the interplay of implicit and explicit cognitive-affective processes; (v) stronger focus on computational models specifying neurocognitive mechanisms underlying phenotypical expressions of mental disorders. Copyright © 2013 John Wiley & Sons, Ltd.

Mechanical capacitor

NASA Technical Reports Server (NTRS)

Kirk, J. A.; Studer, P. A.; Evans, H. E.

1976-01-01

A new energy storage system (the mechanical capacitor), using a spokeless magnetically levitated composite ring rotor, is described and design formulas for sizing the components are presented. This new system is configured around a permanent magnet (flux biased) suspension which has active servo control in the radial direction and passive control in the axial direction. The storage ring is used as a moving rotor and electronic commutation of the stationary armature coils is proposed. There is no mechanical contact with the rotating spokeless ring; therefore, long life and near zero rundown losses are projected. A 7-kW h system is sized to demonstrate feasibility. A literature review of flywheel energy storage systems is also presented and general formulas are developed for comparing rotor geometries.

Performance Guaranteed Inertia Emulation forDiesel-Wind System Feed Microgrid via ModelReference Control

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

Melin, Alexander M.; Zhang, Yichen; Djouadi, Seddik

In this paper, a model reference control based inertia emulation strategy is proposed. Desired inertia can be precisely emulated through this control strategy so that guaranteed performance is ensured. A typical frequency response model with parametrical inertia is set to be the reference model. A measurement at a specific location delivers the information of disturbance acting on the diesel-wind system to the referencemodel. The objective is for the speed of the diesel-wind system to track the reference model. Since active power variation is dominantly governed by mechanical dynamics and modes, only mechanical dynamics and states, i.e., a swing-engine-governor system plusmore » a reduced-order wind turbine generator, are involved in the feedback control design. The controller is implemented in a three-phase diesel-wind system feed microgrid. The results show exact synthetic inertia is emulated, leading to guaranteed performance and safety bounds.« less

Aircraft Landing Gear, Ice and Rain Control Systems (Course Outline), Aviation Mechanics 3 (Air Frame):9067.02.

ERIC Educational Resources Information Center

Dade County Public Schools, Miami, FL.

This document presents an outline for a 135-hour course designed to familiarize the student with operation, inspection, troubleshooting, and repair of aircraft landing gear, ice and rain control systems. It is designed to help the trainee master the knowledge and skills necessary to become an aviation airframe mechanic. The aviation airframe…

Service-oriented architecture for the ARGOS instrument control software

NASA Astrophysics Data System (ADS)

Borelli, J.; Barl, L.; Gässler, W.; Kulas, M.; Rabien, Sebastian

2012-09-01

The Advanced Rayleigh Guided ground layer Adaptive optic System, ARGOS, equips the Large Binocular Telescope (LBT) with a constellation of six rayleigh laser guide stars. By correcting atmospheric turbulence near the ground, the system is designed to increase the image quality of the multi-object spectrograph LUCIFER approximately by a factor of 3 over a field of 4 arc minute diameter. The control software has the critical task of orchestrating several devices, instruments, and high level services, including the already existing adaptive optic system and the telescope control software. All these components are widely distributed over the telescope, adding more complexity to the system design. The approach used by the ARGOS engineers is to write loosely coupled and distributed services under the control of different ownership systems, providing a uniform mechanism to offer, discover, interact and use these distributed capabilities. The control system counts with several finite state machines, vibration and flexure compensation loops, and safety mechanism, such as interlocks, aircraft, and satellite avoidance systems.

Automatic control system for uniformly paving iron ore pellets

NASA Astrophysics Data System (ADS)

Wang, Bowen; Qian, Xiaolong

2014-05-01

In iron and steelmaking industry, iron ore pellet qualities are crucial to end-product properties, manufacturing costs and waste emissions. Uniform pellet pavements on the grate machine are a fundamental prerequisite to ensure even heat-transfer and pellet induration successively influences performance of the following metallurgical processes. This article presents an automatic control system for uniformly paving green pellets on the grate, via a mechanism mainly constituted of a mechanical linkage, a swinging belt, a conveyance belt and a grate. Mechanism analysis illustrates that uniform pellet pavements demand the frontend of the swinging belt oscillate at a constant angular velocity. Subsequently, kinetic models are formulated to relate oscillatory movements of the swinging belt's frontend to rotations of a crank link driven by a motor. On basis of kinetic analysis of the pellet feeding mechanism, a cubic B-spline model is built for numerically computing discrete frequencies to be modulated during a motor rotation. Subsequently, the pellet feeding control system is presented in terms of compositional hardware and software components, and their functional relationships. Finally, pellet feeding experiments are carried out to demonstrate that the control system is effective, reliable and superior to conventional methods.

Predictor-based control for an inverted pendulum subject to networked time delay.

PubMed

Ghommam, J; Mnif, F

2017-03-01

The inverted pendulum is considered as a special class of underactuated mechanical systems with two degrees of freedom and a single control input. This mechanical configuration allows to transform the underactuated system into a nonlinear system that is referred to as the normal form, whose control design techniques for stabilization are well known. In the presence of time delays, these control techniques may result in inadequate behavior and may even cause finite escape time in the controlled system. In this paper, a constructive method is presented to design a controller for an inverted pendulum characterized by a time-delayed balance control. First, the partial feedback linearization control for the inverted pendulum is modified and coupled with a state predictor to compensate for the delay. Several coordinate transformations are processed to transform the estimated partial linearized system into an upper-triangular form. Second, nested saturation and backstepping techniques are combined to derive the control law of the transformed system that would complete the design of the whole control input. The effectiveness of the proposed technique is illustrated by numerical simulations. Copyright © 2017 ISA. Published by 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.

Controllability of Free-piston Stirling Engine/linear Alternator Driving a Dynamic Load

NASA Technical Reports Server (NTRS)

Kankam, M. David; Rauch, Jeffrey S.

1994-01-01

This paper presents the dynamic behavior of a Free-Piston Stirling Engine/linear alternator (FPSE/LA) driving a single-phase fractional horse-power induction motor. The controllability and dynamic stability of the system are discussed by means of sensitivity effects of variations in system parameters, engine controller, operating conditions, and mechanical loading on the induction motor. The approach used expands on a combined mechanical and thermodynamic formulation employed in a previous paper. The application of state-space technique and frequency domain analysis enhances understanding of the dynamic interactions. Engine-alternator parametric sensitivity studies, similar to those of the previous paper, are summarized. Detailed discussions are provided for parametric variations which relate to the engine controller and system operating conditions. The results suggest that the controllability of a FPSE-based power system is enhanced by proper operating conditions and built-in controls.

ARM-based control system for terry rapier loom

NASA Astrophysics Data System (ADS)

Shi, Weimin; Gu, Yeqing; Wu, Zhenyu; Wang, Fan

2007-12-01

In this paper, a novel ARM-based mechatronics control technique applied in terry rapier loom was presented. Electronic weft selection, electronic fluff, electronic let-off and take-up motions system, which consists of position and speedcontrolled servomechanisms, were studied. The control system configuration, operation principle, and mathematical models of electronic drives system were analyzed. The synchronism among all mechanical motions and an improved intelligent control algorithm for the warp let-off tension control was discussed. The result indict that, by applying electronic and embedded control techniques and the individual servomechanisms, the electronic weft selection, electronic let-off device and electronic take-up device in HGA732T terry rapier loom have greatly simplified the initial complicated mechanism, kept the warp tension constant from full to empty beam, set the variable weft density, eliminated the start mark effectively, promoted its flexibility, reliability and properties, and improved the fabric quality.

Decoherence control mechanisms of a charged magneto-oscillator in contact with different environments

NASA Astrophysics Data System (ADS)

Rajesh, Asam; Bandyopadhyay, Malay; Jayannavar, Arun M.

2017-12-01

In this work, we consider two different techniques based on reservoir engineering process and quantum Zeno control method to analyze the decoherence control mechanism of a charged magneto-oscillator in contact with different type of environment. Our analysis reveals that both the control mechanisms are very much sensitive on the details of different environmental spectrum (J (ω)), and also on different system and reservoir parameters, e.g., external magnetic field (rc), confinement length (r0), temperature (T), cut-off frequency of reservoir spectrum (ωcut), and measurement interval (τ). We also demonstrate the manipulation scheme of the continuous passage from decay suppression to decay acceleration by tuning the above mentioned system or reservoir parameters, e.g., rc, r0, T and τ.

Dynamics of cochlear nonlinearity: Automatic gain control or instantaneous damping?

PubMed

Altoè, Alessandro; Charaziak, Karolina K; Shera, Christopher A

2017-12-01

Measurements of basilar-membrane (BM) motion show that the compressive nonlinearity of cochlear mechanical responses is not an instantaneous phenomenon. For this reason, the cochlear amplifier has been thought to incorporate an automatic gain control (AGC) mechanism characterized by a finite reaction time. This paper studies the effect of instantaneous nonlinear damping on the responses of oscillatory systems. The principal results are that (i) instantaneous nonlinear damping produces a noninstantaneous gain control that differs markedly from typical AGC strategies; (ii) the kinetics of compressive nonlinearity implied by the finite reaction time of an AGC system appear inconsistent with the nonlinear dynamics measured on the gerbil basilar membrane; and (iii) conversely, those nonlinear dynamics can be reproduced using an harmonic oscillator with instantaneous nonlinear damping. Furthermore, existing cochlear models that include instantaneous gain-control mechanisms capture the principal kinetics of BM nonlinearity. Thus, an AGC system with finite reaction time appears neither necessary nor sufficient to explain nonlinear gain control in the cochlea.

PID position regulation in one-degree-of-freedom Euler-Lagrange systems actuated by a PMSM

NASA Astrophysics Data System (ADS)

Verastegui-Galván, J.; Hernández-Guzmán, V. M.; Orrante-Sakanassi, J.

2018-02-01

This paper is concerned with position regulation in one-degree-of-freedom Euler-Lagrange Systems. We consider that the mechanical subsystem is actuated by a permanent magnet synchronous motor (PMSM). Our proposal consists of a Proportional-Integral-Derivative (PID) controller for the mechanical subsystem and a slight variation of field oriented control for the PMSM. We take into account the motor electric dynamics during the stability analysis. We present, for the first time, a global asymptotic stability proof for such a control scheme without requiring the mechanical subsystem to naturally possess viscous friction. Finally, as a corollary of our main result we prove global asymptotic stability for output feedback PID regulation of one-degree-of-freedom Euler-Lagrange systems when generated torque is considered as the system input, i.e. when the electric dynamics of PMSM's is not taken into account.

Verification of Security Policy Enforcement in Enterprise Systems

NASA Astrophysics Data System (ADS)

Gupta, Puneet; Stoller, Scott D.

Many security requirements for enterprise systems can be expressed in a natural way as high-level access control policies. A high-level policy may refer to abstract information resources, independent of where the information is stored; it controls both direct and indirect accesses to the information; it may refer to the context of a request, i.e., the request’s path through the system; and its enforcement point and enforcement mechanism may be unspecified. Enforcement of a high-level policy may depend on the system architecture and the configurations of a variety of security mechanisms, such as firewalls, host login permissions, file permissions, DBMS access control, and application-specific security mechanisms. This paper presents a framework in which all of these can be conveniently and formally expressed, a method to verify that a high-level policy is enforced, and an algorithm to determine a trusted computing base for each resource.

Engineering science and mechanics; Proceedings of the International Symposium, Tainan, Republic of China, December 29-31, 1981. Parts 1 & 2

NASA Astrophysics Data System (ADS)

Hsia, H.-M.; Chou, Y.-L.; Longman, R. W.

1983-07-01

The topics considered are related to measurements and controls in physical systems, the control of large scale and distributed parameter systems, chemical engineering systems, aerospace science and technology, thermodynamics and fluid mechanics, and computer applications. Subjects in structural dynamics are discussed, taking into account finite element approximations in transient analysis, buckling finite element analysis of flat plates, dynamic analysis of viscoelastic structures, the transient analysis of large frame structures by simple models, large amplitude vibration of an initially stressed thick plate, nonlinear aeroelasticity, a sensitivity analysis of a combined beam-spring-mass structure, and the optimal design and aeroelastic investigation of segmented windmill rotor blades. Attention is also given to dynamics and control of mechanical and civil engineering systems, composites, and topics in materials. For individual items see A83-44002 to A83-44061

Mechanical design and driving mechanism of an isokinetic functional electrical stimulation-based leg stepping trainer.

PubMed

Hamzaid, N A; Fornusek, C; Ruys, A; Davis, G M

2007-12-01

The mechanical design of a constant velocity (isokinetic) leg stepping trainer driven by functional electrical stimulation-evoked muscle contractions was the focus of this paper. The system was conceived for training the leg muscles of neurologically-impaired patients. A commercially available slider crank mechanism for elliptical stepping exercise was adapted to a motorized isokinetic driving mechanism. The exercise system permits constant-velocity pedalling at cadences of 1-60 rev x min(-1). The variable-velocity feature allows low pedalling forces for individuals with very weak leg muscles, yet provides resistance to higher pedalling effort in stronger patients. In the future, the system will be integrated with a computer-controlled neuromuscular stimulator and a feedback control unit to monitor training responses of spinal cord-injured, stroke and head injury patients.

Integrated orbital servicing study follow-on. Volume 3: Engineering test unit and controls

NASA Technical Reports Server (NTRS)

1978-01-01

A one-g servicing demonstration system which can be used to investigate and develop, in a real time hands-on situation, a wide variety of the mechanism and control system aspects of orbital servicing in the form of module exchange is described including the engineering test unit and the servicer servo drive console. A series of recommendations for future work is given concerning the control problem and more efficient module exchanges, mechanical elements, and electronics.

Embedding of electrodes within a microchannel interfacing a permselective medium for sensing and active control of the concentration-polarization layer

NASA Astrophysics Data System (ADS)

Yossifon, Gilad; Park, Sinwook

2016-11-01

Previously, it has been shown that for a prescribed system, the diffusion length may be affected by any number of mechanisms including natural and forced convection, electroosmotic flow of the second kind and electro-convective instability. In all of the above mentioned cases the length of the diffusion layer is indirectly prescribed by the complicated competition between several mechanisms which are primarily dictated by the various system parameters and applied voltage. In contrast, we suggest that by embedding electrodes/heaters within a microchannel interfacing a permselective medium, the diffusion layer length may be controlled regardless of the dominating overlimiting current mechanism and system parameters. As well as demonstrating that the simple presence of electrodes can enhance mixing via induced-charge electrokinetic effects, we also offer a means of externally activating embedded electrodes and heaters to maintain external, dynamic control of the diffusion length. Such control is particularly important in applications requiring intense ion transport, such as electrodialysis. At the same time, we will also investigate means of suppressing these mechanisms which is of fundamental importance for sensing applications.

Sample Manipulation System for Sample Analysis at Mars

NASA Technical Reports Server (NTRS)

Mumm, Erik; Kennedy, Tom; Carlson, Lee; Roberts, Dustyn

2008-01-01

The Sample Analysis at Mars (SAM) instrument will analyze Martian samples collected by the Mars Science Laboratory Rover with a suite of spectrometers. This paper discusses the driving requirements, design, and lessons learned in the development of the Sample Manipulation System (SMS) within SAM. The SMS stores and manipulates 74 sample cups to be used for solid sample pyrolysis experiments. Focus is given to the unique mechanism architecture developed to deliver a high packing density of sample cups in a reliable, fault tolerant manner while minimizing system mass and control complexity. Lessons learned are presented on contamination control, launch restraint mechanisms for fragile sample cups, and mechanism test data.

V-TECS Guide for Automobile Engine Performance Technician.

ERIC Educational Resources Information Center

Meyer, Calvin F.; Benson, Robert T.

This guide is intended to assist teachers responsible for instructing future auto engine performance technicians. The following topics are covered: diagnosing engine performance problems, ignition system problems, fuel system problems, mechanically related performance problems, emission control system problems, and electronic control systems;…

General Purpose Vehicle Mechanic Career Ladder, AFSCs 47232, 47252, and 47275.

DTIC Science & Technology

1983-03-01

general-purpose vehicles; gasoline and diesel engines; automotive electrical and emission control systems maintenance; drive trains and brake systems...OR HYDRAULIC PRESSES ELECTRONIC IGNITION TESTERS HEADLIGHT TESTERS OSCILLOSCOPES DYNAMOMETERS EXHAUST EMISSION TESTERS GAS SHIELD WELDING...collection forms; man-hour accounting forms and reports; corrosion control procedures; troubleshooting exhaust systems, and emission control systems

Integrated System Design for Air Revitalization in Next Generation Crewed Spacecraft

NASA Technical Reports Server (NTRS)

Mulloth, Lila; Perry, Jay; LeVan, Douglas

2004-01-01

The capabilities of NASA's existing environmental control and life support (ECLS) system designs are inadequate for future human space initiatives that involve long-duration space voyages and interplanetary missions. This paper discusses the concept of an integrated system of CO2 removal and trace contaminant control units that utilizes novel gas separation and purification techniques and optimized thermal and mechanical design, for future spacecraft. The integration process will enhance the overall life and economics of the existing systems by eliminating multiple mechanical devices with moving parts.

Industrial Control Systems/SCADA systems risk assessment in the energy sector

NASA Astrophysics Data System (ADS)

Falodun, Babatunde

The energy sector is one of the most critical components of our national infrastructure. It not only provides the electrical power and petroleum required to run day-to-day operations and mechanisms in society, it's also an important element that directly impacts the economy with regard to growth and stability. Industrial Control Systems (ICS) /Supervisory Control and Data Acquisition Systems (SCADA) are computerized mechanisms, they are both software and hardware that are used to control real time processes and operations in power plants and oil production facilities. A significant attack on these control systems that leads to widespread disruption of energy could result in catastrophic consequences for any major city and even the nation. This research paper explores cyber threats and vulnerabilities faced by ICS/SCADA systems in the energy sector and also highlights possible outcomes of a successful breach. Furthermore, the research underscores mitigation strategies that could be used to prevent and respond to an attack. Keywords: Cybersecurity, SCADA, Cyber Attacks, Threats, Vulnerabilities, Risk Assessment, Dr. Albert Orbinati.

Operational Management of Area Environment.

ERIC Educational Resources Information Center

Sprague, George W.

Three phases leading to the automation of the mechanical building systems on the Harvard campus are described. The systems allow a single operator to monitor and control all the mechanical systems, plus fire, flood, and security alarms, for all buildings in a large area of the campus. (JT)

Design and control of a high precision drive mechanism

NASA Astrophysics Data System (ADS)

Pan, Bo; He, Yongqiang; Wang, Haowei; Zhang, Shuyang; Zhang, Donghua; Wei, Xiaorong; Jiang, Zhihong

2017-01-01

This paper summarizes the development of a high precision drive mechanism (HPDM) for space application, such as the directional antenna, the laser communication device, the mobile camera and other pointing mechanisms. In view of the great practical significance of high precision drive system, control technology for permanent magnet synchronous motor (PMSM) servo system is also studied and a PMSM servo controller is designed in this paper. And the software alignment was applied to the controller to eliminate the steady error of the optical encoder, which helps to realize the 1 arcsec (1σ) control precision. To assess its capabilities, the qualification environment testing including the thermal vacuum cycling testing, and the sinusoidal and random vibration were carried out. The testing results show that the performance of the HPDM is almost the same between the former and the end of each testing.

117. PNEUMATIC SUPPLY PANEL IN CENTER OF VEHICLE MECHANICAL SYSTEMS ...

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

117. PNEUMATIC SUPPLY PANEL IN CENTER OF VEHICLE MECHANICAL SYSTEMS ROOM (111), LSB (BLDG. 770), FACING NORTH. CONTROLS FOR FLOW AND PRESSURE REGULATION OF HELIUM ON LEFT SIDE OF PANEL; CONTROLS FOR NITROGEN ON RIGHT SIDE OF PANEL (AT RIGHT EDGE OF PHOTO). - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

116. PNEUMATIC SUPPLY PANEL IN CENTER OF VEHICLE MECHANICAL SYSTEMS ...

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

116. PNEUMATIC SUPPLY PANEL IN CENTER OF VEHICLE MECHANICAL SYSTEMS ROOM (111) OF LSB (BLDG. 770), FACING NORTH. CONTROLS FOR FLOW AND PRESSURE REGULATION OF NITROGEN ON RIGHT SIDE OF PANEL; CONTROLS FOR HELIUM ON LEFT SIDE OF PANEL (AT LEFT EDGE OF PHOTO). - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Acceptance test procedure for the L-070 project mechanical equipment and instrumentation

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

Loll, C.M.

1996-04-19

This document contains the acceptance test procedure for the mechanical equipment and instrumentation installed per the L-070 Project. The specific system to be tested are the pump controls for the 3906 Lift Station and 350-A Lift Station. In addition, verification that signals are being received by the 300 Area Treated Effluent Disposal Facility control system, is also performed.

Observation of optomechanical buckling transitions

PubMed Central

Xu, H.; Kemiktarak, U.; Fan, J.; Ragole, S.; Lawall, J.; Taylor, J. M.

2017-01-01

Correlated phases of matter provide long-term stability for systems as diverse as solids, magnets and potential exotic quantum materials. Mechanical systems, such as buckling transition spring switches, can have engineered, stable configurations whose dependence on a control variable is reminiscent of non-equilibrium phase transitions. In hybrid optomechanical systems, light and matter are strongly coupled, allowing engineering of rapid changes in the force landscape, storing and processing information, and ultimately probing and controlling behaviour at the quantum level. Here we report the observation of first- and second-order buckling transitions between stable mechanical states in an optomechanical system, in which full control of the nature of the transition is obtained by means of the laser power and detuning. The underlying multiwell confining potential we create is highly tunable, with a sub-nanometre distance between potential wells. Our results enable new applications in photonics and information technology, and may enable explorations of quantum phase transitions and macroscopic quantum tunnelling in mechanical systems. PMID:28248293

High pressure water electrolysis for space station EMU recharge

NASA Technical Reports Server (NTRS)

Lance, Nick; Puskar, Michael; Moulthrop, Lawrence; Zagaja, John

1988-01-01

A high pressure oxygen recharge system (HPORS), is being developed for application on board the Space Station. This electrolytic system can provide oxygen at up to 6000 psia without a mechanical compressor. The Hamilton standard HPORS based on a solid polymer electrolyte system is an extension of the much larger and succesful 3000 psia system of the U.S. Navy. Cell modules have been successfully tested under conditions beyond which spacecraft may encounter during launch. The control system with double redundancy and mechanical backups for all electronically controlled components is designed to ensure a safe shutdown.

Outboard Repair.

ERIC Educational Resources Information Center

Hardway, Jack

This consortium-developed instructor's manual for small engine repair (with focus on outboard motors) consists of the following nine instructional units: electrical remote control assembly, mechanical remote control assembly, tilt assemblies, exhaust housing, propeller and trim tabs, cooling system, mechanical gearcase, electrical gearcase, and…

Interactive simulation system for artificial ventilation on the internet: virtual ventilator.

PubMed

Takeuchi, Akihiro; Abe, Tadashi; Hirose, Minoru; Kamioka, Koichi; Hamada, Atsushi; Ikeda, Noriaki

2004-12-01

To develop an interactive simulation system "virtual ventilator" that demonstrates the dynamics of pressure and flow in the respiratory system under the combination of spontaneous breathing, ventilation modes, and ventilator options. The simulation system was designed to be used by unexperienced health care professionals as a self-training tool. The system consists of a simulation controller and three modules: respiratory, spontaneous breath, and ventilator. The respiratory module models the respiratory system by three resistances representing the main airway, the right and left lungs, and two compliances also representing the right and left lungs. The spontaneous breath module generates inspiratory negative pressure produced by a patient. The ventilator module generates driving force of pressure or flow according to the combination of the ventilation mode and options. These forces are given to the respiratory module through the simulation controller. The simulation system was developed using HTML, VBScript (3000 lines, 100 kB) and ActiveX control (120 kB), and runs on Internet Explorer (5.5 or higher). The spontaneous breath is defined by a frequency, amplitude and inspiratory patterns in the spontaneous breath module. The user can construct a ventilation mode by setting a control variable, phase variables (trigger, limit, and cycle), and options. Available ventilation modes are: controlled mechanical ventilation (CMV), continuous positive airway pressure, synchronized intermittent mandatory ventilation (SIMV), pressure support ventilation (PSV), SIMV + PSV, pressure-controlled ventilation (PCV), pressure-regulated volume control (PRVC), proportional assisted ventilation, mandatory minute ventilation (MMV), bilevel positive airway pressure (BiPAP). The simulation system demonstrates in a graph and animation the airway pressure, flow, and volume of the respiratory system during mechanical ventilation both with and without spontaneous breathing. We developed a web application that demonstrated the respiratory mechanics and the basic theory of ventilation mode.

Transient Oscilliations in Mechanical Systems of Automatic Control with Random Parameters

NASA Astrophysics Data System (ADS)

Royev, B.; Vinokur, A.; Kulikov, G.

2018-04-01

Transient oscillations in mechanical systems of automatic control with random parameters is a relevant but insufficiently studied issue. In this paper, a modified spectral method was applied to investigate the problem. The nature of dynamic processes and the phase portraits are analyzed depending on the amplitude and frequency of external influence. It is evident from the obtained results, that the dynamic phenomena occurring in the systems with random parameters under external influence are complex, and their study requires further investigation.

Biofluid mechanics of special organs and the issue of system control. Sixth International Bio-Fluid Mechanics Symposium and Workshop, March 28-30, 2008 Pasadena, California.

PubMed

Zamir, Mair; Moore, James E; Fujioka, Hideki; Gaver, Donald P

2010-03-01

In the field of fluid flow within the human body, focus has been placed on the transportation of blood in the systemic circulation since the discovery of that system; but, other fluids and fluid flow phenomena pervade the body. Some of the most fascinating fluid flow phenomena within the human body involve fluids other than blood and a service other than transport--the lymphatic and pulmonary systems are two striking examples. While transport is still involved in both cases, this is not the only service which they provide and blood is not the only fluid involved. In both systems, filtration, extraction, enrichment, and in general some "treatment" of the fluid itself is the primary function. The study of the systemic circulation has also been conventionally limited to treating the system as if it were an open-loop system governed by the laws of fluid mechanics alone, independent of physiological controls and regulations. This implies that system failures can be explained fully in terms of the laws of fluid mechanics, which of course is not the case. In this paper we examine the clinical implications of these issues and of the special biofluid mechanics issues involved in the lymphatic and pulmonary systems.

Focal Plane Array Shutter Mechanism of the JWST NIRSpec Detector System

NASA Technical Reports Server (NTRS)

Hale, Kathleen; Sharma, Rajeev

2006-01-01

This viewgraph presentation reviews the requirements, chamber location, shutter system design, stepper motor specifications, dry lubrication, control system, the environmental cryogenic function testing and the test results of the Focal Plane Array Shutter mechanism for the James Webb Space Telescope Near Infrared Spectrum Detector system. Included are design views of the location for the Shutter Mechanism, lubricant (lubricated with Molybdenum Di Sulfide) thickness, and information gained from the cryogenic testing.

Cognitive Control Mechanisms, Emotion & Memory: A neural perspective with implications for psychopathology

PubMed Central

Banich, Marie T.; Mackiewicz, Kristen L.; Depue, Brendan E.; Whitmer, Anson; Miller, Gregory A.; Heller, Wendy

2009-01-01

In this paper we provide a focused review of the literature examining neural mechanisms involved in cognitive control over memory processes that can influence, and in turn are influenced, by emotional processes. The review is divided into two parts, the first focusing on working memory and the second on long-term memory. With regard to working memory, we discuss the neural bases of 1) control mechanisms that can select against distracting emotional information, 2) mechanisms that can regulate emotional reactions or responses, 3) how mood state influences cognitive control, and 4) individual differences in control mechanisms. For long-term memory, we briefly review 1) the neural substrates of emotional memory, 2) the cognitive and neural mechanisms that are involved in controlling emotional memories and 3) how these systems are altered in post-traumatic stress disorder. Finally, we consider tentative generalizations that can be drawn from this relatively unexplored conjunction of research endeavors. PMID:18948135

Adaptive displays and controllers using alternative feedback.

PubMed

Repperger, D W

2004-12-01

Investigations on the design of haptic (force reflecting joystick or force display) controllers were conducted by viewing the display of force information within the context of several different paradigms. First, using analogies from electrical and mechanical systems, certain schemes of the haptic interface were hypothesized which may improve the human-machine interaction with respect to various criteria. A discussion is given on how this interaction benefits the electrical and mechanical system. To generalize this concept to the design of human-machine interfaces, three studies with haptic mechanisms were then synthesized and analyzed.

MOD-0A 200 kW wind turbine generator design and analysis report

NASA Astrophysics Data System (ADS)

Anderson, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.; Lipner, M. H.; Schornhorst, J. R.

1980-08-01

The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. The project requirements, approach, system description, design requirements, design, analysis, system tests, installation, safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl system, and control systems are presented. The rotor includes the blades, hub, and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control are discussed. Systems analyses on dynamic loads and fatigue are presented.

MOD-0A 200 kW wind turbine generator design and analysis report

NASA Technical Reports Server (NTRS)

Anderson, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.; Lipner, M. H.; Schornhorst, J. R.

1980-01-01

The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. The project requirements, approach, system description, design requirements, design, analysis, system tests, installation, safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl system, and control systems are presented. The rotor includes the blades, hub, and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control are discussed. Systems analyses on dynamic loads and fatigue are presented.

On Decision-Making Among Multiple Rule-Bases in Fuzzy Control Systems

NASA Technical Reports Server (NTRS)

Tunstel, Edward; Jamshidi, Mo

1997-01-01

Intelligent control of complex multi-variable systems can be a challenge for single fuzzy rule-based controllers. This class of problems cam often be managed with less difficulty by distributing intelligent decision-making amongst a collection of rule-bases. Such an approach requires that a mechanism be chosen to ensure goal-oriented interaction between the multiple rule-bases. In this paper, a hierarchical rule-based approach is described. Decision-making mechanisms based on generalized concepts from single-rule-based fuzzy control are described. Finally, the effects of different aggregation operators on multi-rule-base decision-making are examined in a navigation control problem for mobile robots.

Linear and non-linear systems identification for adaptive control in mechanical applications vibration suppression

NASA Astrophysics Data System (ADS)

Cazzulani, Gabriele; Resta, Ferruccio; Ripamonti, Francesco

2012-04-01

During the last years, more and more mechanical applications saw the introduction of active control strategies. In particular, the need of improving the performances and/or the system health is very often associated to vibration suppression. This goal can be achieved considering both passive and active solutions. In this sense, many active control strategies have been developed, such as the Independent Modal Space Control (IMSC) or the resonant controllers (PPF, IRC, . . .). In all these cases, in order to tune and optimize the control strategy, the knowledge of the system dynamic behaviour is very important and it can be achieved both considering a numerical model of the system or through an experimental identification process. Anyway, dealing with non-linear or time-varying systems, a tool able to online identify the system parameters becomes a key-point for the control logic synthesis. The aim of the present work is the definition of a real-time technique, based on ARMAX models, that estimates the system parameters starting from the measurements of piezoelectric sensors. These parameters are returned to the control logic, that automatically adapts itself to the system dynamics. The problem is numerically investigated considering a carbon-fiber plate model forced through a piezoelectric patch.

Coal gasification vessel

DOEpatents

Loo, Billy W.

1982-01-01

A vessel system (10) comprises an outer shell (14) of carbon fibers held in a binder, a coolant circulation mechanism (16) and control mechanism (42) and an inner shell (46) comprised of a refractory material and is of light weight and capable of withstanding the extreme temperature and pressure environment of, for example, a coal gasification process. The control mechanism (42) can be computer controlled and can be used to monitor and modulate the coolant which is provided through the circulation mechanism (16) for cooling and protecting the carbon fiber and outer shell (14). The control mechanism (42) is also used to locate any isolated hot spots which may occur through the local disintegration of the inner refractory shell (46).

Pressure Dynamic Characteristics of Pressure Controlled Ventilation System of a Lung Simulator

PubMed Central

Shi, Yan; Ren, Shuai; Cai, Maolin; Xu, Weiqing; Deng, Qiyou

2014-01-01

Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems. PMID:25197318

The analysis on nonlinear control of the aircraft arresting system

NASA Astrophysics Data System (ADS)

Song, Jinchun; Du, Tianrong

2005-12-01

The aircraft arresting system is a complicated nonlinear system. This paper analyzes the mechanical-hydraulic structure of aircraft arresting system composed of electro hydraulic valve and establishes the dynamic equation of the aircraft arresting system. Based on the state-feedback linearization of nonlinear system, a PD-based controller is synthesized. Simulation studies indicate, while arresting the different type aircraft, the proposed controller has fast response, good tracking performance and strong robustness. By tuning the parameters of the PD controller, a satisfactory control performance can be guaranteed.

A hybrid system of a membrane oscillator coupled to ultracold atoms

NASA Astrophysics Data System (ADS)

Kampschulte, Tobias

2015-05-01

The control over micro- and nanomechanical oscillators has recently made impressive progress. First experiments demonstrated ground-state cooling and single-phonon control of high-frequency oscillators using cryogenic cooling and techniques of cavity optomechanics. Coupling engineered mechanical structures to microscopic quantum system with good coherence properties offers new possibilities for quantum control of mechanical vibrations, precision sensing and quantum-level signal transduction. Ultracold atoms are an attractive choice for such hybrid systems: Mechanical can either be coupled to the motional state of trapped atoms, which can routinely be ground-state cooled, or to the internal states, for which a toolbox of coherent manipulation and detection exists. Furthermore, atomic collective states with non-classical properties can be exploited to infer the mechanical motion with reduced quantum noise. Here we use trapped ultracold atoms to sympathetically cool the fundamental vibrational mode of a Si3N4 membrane. The coupling of membrane and atomic motion is mediated by laser light over a macroscopic distance and enhanced by an optical cavity around the membrane. The observed cooling of the membrane from room temperature to 650 +/- 230 mK shows that our hybrid mechanical-atomic system operates at a large cooperativity. Our scheme could provide ground-state cooling and quantum control of low-frequency oscillators such as levitated nanoparticles, in a regime where purely optomechanical techniques cannot reach the ground state. Furthermore, we will present a scheme where an optomechanical system is coupled to internal states of ultracold atoms. The mechanical motion is translated into a polarization rotation which drives Raman transitions between atomic ground states. Compared to the motional-state coupling, the new scheme enables to couple atoms to high-frequency structures such as optomechanical crystals.

Concept of planetary gear system to control fluid mixture ratio

NASA Technical Reports Server (NTRS)

Mcgroarty, J. D.

1966-01-01

Mechanical device senses and corrects for fluid flow departures from the selected flow ratio of two fluids. This system has been considered for control of rocket engine propellant mixture control but could find use wherever control of the flow ratio of any two fluids is desired.

Concept for Highly Mechanized Data Processing, Project 111.

DTIC Science & Technology

A concept is developed for a highly mechanized maintenance data processing system capable of deriving factors, influences, and correlations to raise...the level of logistics knowledge and lead to the design of a management-control system. (Author)

A characteristic length scale causes anomalous size effects and boundary programmability in mechanical metamaterials

NASA Astrophysics Data System (ADS)

Coulais, Corentin; Kettenis, Chris; van Hecke, Martin

2018-01-01

The architecture of mechanical metamaterials is designed to harness geometry, nonlinearity and topology to obtain advanced functionalities such as shape morphing, programmability and one-way propagation. Although a purely geometric framework successfully captures the physics of small systems under idealized conditions, large systems or heterogeneous driving conditions remain essentially unexplored. Here we uncover strong anomalies in the mechanics of a broad class of metamaterials, such as auxetics, shape changers or topological insulators; a non-monotonic variation of their stiffness with system size, and the ability of textured boundaries to completely alter their properties. These striking features stem from the competition between rotation-based deformations--relevant for small systems--and ordinary elasticity, and are controlled by a characteristic length scale which is entirely tunable by the architectural details. Our study provides new vistas for designing, controlling and programming the mechanics of metamaterials.

Integrating conflict detection and attentional control mechanisms.

PubMed

Walsh, Bong J; Buonocore, Michael H; Carter, Cameron S; Mangun, George R

2011-09-01

Human behavior involves monitoring and adjusting performance to meet established goals. Performance-monitoring systems that act by detecting conflict in stimulus and response processing have been hypothesized to influence cortical control systems to adjust and improve performance. Here we used fMRI to investigate the neural mechanisms of conflict monitoring and resolution during voluntary spatial attention. We tested the hypothesis that the ACC would be sensitive to conflict during attentional orienting and influence activity in the frontoparietal attentional control network that selectively modulates visual information processing. We found that activity in ACC increased monotonically with increasing attentional conflict. This increased conflict detection activity was correlated with both increased activity in the attentional control network and improved speed and accuracy from one trial to the next. These results establish a long hypothesized interaction between conflict detection systems and neural systems supporting voluntary control of visual attention.

Damage-mitigating control of aerospace systems for high performance and extended life

NASA Technical Reports Server (NTRS)

Ray, Asok; Wu, Min-Kuang; Carpino, Marc; Lorenzo, Carl F.; Merrill, Walter C.

1992-01-01

The concept of damage-mitigating control is to minimize fatigue (as well as creep and corrosion) damage of critical components of mechanical structures while simultaneously maximizing the system dynamic performance. Given a dynamic model of the plant and the specifications for performance and stability robustness, the task is to synthesize a control law that would meet the system requirements and, at the same time, satisfy the constraints that are imposed by the material and structural properties of the critical components. The authors present the concept of damage-mitigating control systems design with the following objectives: (1) to achieve high performance with a prolonged life span; and (2) to systematically update the controller as the new technology of advanced materials evolves. The major challenge is to extract the information from the material properties and then utilize this information in a mathematical form so that it can be directly applied to robust control synthesis for mechanical systems. The basic concept of damage-mitigating control is illustrated using a relatively simplified model of a space shuttle main engine.

A microcomputer controlled snow ski binding system--I. Instrumentation and field evaluation.

PubMed

MacGregor, D; Hull, M L; Dorius, L K

1985-01-01

This paper presents the design and field evaluation of the first microcomputer controlled ski binding system. This system incorporates an Intel 8086 microcomputer controller and an integral binding/dynamometer. This instrumentation system not only undertakes real time control, but also it records dynamometer data via a miniature digital cassette tape recorder. The integral binding/dynamometer offers the same operational and mounting convenience of commercially available mechanical bindings. The binding may be released either manually or electrically via the controller. Comprised of four octagonal half strain rings, the strain gage dynamometer measures the three moment load components at the boot. To enable the user to conveniently operate the computer, extensive operating software was developed. The operating software is discussed in relation to both the acquisition and storage of data from the dynamometer and the control of the electro-mechanical snow ski binding. The binding system has been used successfully to both record boot moment components and control ski binding release during actual skiing maneuvers. Moment histories typical of three common recreational skiing maneuvers are presented.

Mechanical perturbation control of cardiac alternans

NASA Astrophysics Data System (ADS)

Hazim, Azzam; Belhamadia, Youssef; Dubljevic, Stevan

2018-05-01

Cardiac alternans is a disturbance in heart rhythm that is linked to the onset of lethal cardiac arrhythmias. Mechanical perturbation control has been recently used to suppress alternans in cardiac tissue of relevant size. In this control strategy, cardiac tissue mechanics are perturbed via active tension generated by the heart's electrical activity, which alters the tissue's electric wave profile through mechanoelectric coupling. We analyze the effects of mechanical perturbation on the dynamics of a map model that couples the membrane voltage and active tension systems at the cellular level. Therefore, a two-dimensional iterative map of the heart beat-to-beat dynamics is introduced, and a stability analysis of the system of coupled maps is performed in the presence of a mechanical perturbation algorithm. To this end, a bidirectional coupling between the membrane voltage and active tension systems in a single cardiac cell is provided, and a discrete form of the proposed control algorithm, that can be incorporated in the coupled maps, is derived. In addition, a realistic electromechanical model of cardiac tissue is employed to explore the feasibility of suppressing alternans at cellular and tissue levels. Electrical activity is represented in two detailed ionic models, the Luo-Rudy 1 and the Fox models, while two active contractile tension models, namely a smooth variant of the Nash-Panfilov model and the Niederer-Hunter-Smith model, are used to represent mechanical activity in the heart. The Mooney-Rivlin passive elasticity model is employed to describe passive mechanical behavior of the myocardium.

To react or not to react? Intrinsic stochasticity of human control in virtual stick balancing

PubMed Central

Zgonnikov, Arkady; Lubashevsky, Ihor; Kanemoto, Shigeru; Miyazawa, Toru; Suzuki, Takashi

2014-01-01

Understanding how humans control unstable systems is central to many research problems, with applications ranging from quiet standing to aircraft landing. Increasingly, much evidence appears in favour of event-driven control hypothesis: human operators only start actively controlling the system when the discrepancy between the current and desired system states becomes large enough. The event-driven models based on the concept of threshold can explain many features of the experimentally observed dynamics. However, much still remains unclear about the dynamics of human-controlled systems, which likely indicates that humans use more intricate control mechanisms. This paper argues that control activation in humans may be not threshold-driven, but instead intrinsically stochastic, noise-driven. Specifically, we suggest that control activation stems from stochastic interplay between the operator's need to keep the controlled system near the goal state, on the one hand, and the tendency to postpone interrupting the system dynamics, on the other hand. We propose a model capturing this interplay and show that it matches the experimental data on human balancing of virtual overdamped stick. Our results illuminate that the noise-driven activation mechanism plays a crucial role at least in the considered task, and, hypothetically, in a broad range of human-controlled processes. PMID:25056217

Development of an Upper Limb Power Assist System Using Pneumatic Actuators for Farming Lift-up Motion

NASA Astrophysics Data System (ADS)

Yagi, Eiichi; Harada, Daisuke; Kobayashi, Masaaki

A power assist system has lately attracted considerable attention to lifting-up an object without low back pain. We have been developing power assist systems with pneumatic actuators for the elbow and shoulder to farming support of lifting-up a bag of rice weighing 30kg. This paper describes the mechanism and control method of this power assist system. The pneumatic rotary actuator supports shoulder motion, and the air cylinder supports elbow motion. In this control method, the surface electromyogram(EMG) signals are used as input information of the controller. The joint support torques of human are calculated based on the antigravity term of necessary joint torques, which are estimated on the dynamics of a human approximated link model. The experimental results show the effectiveness of the proposed mechanism and control method of the power assist system.

Parametric optimization in virtual prototyping environment of the control device for a robotic system used in thin layers deposition

NASA Astrophysics Data System (ADS)

Enescu (Balaş, M. L.; Alexandru, C.

2016-08-01

The paper deals with the optimal design of the control system for a 6-DOF robot used in thin layers deposition. The optimization is based on parametric technique, by modelling the design objective as a numerical function, and then establishing the optimal values of the design variables so that to minimize the objective function. The robotic system is a mechatronic product, which integrates the mechanical device and the controlled operating device.The mechanical device of the robot was designed in the CAD (Computer Aided Design) software CATIA, the 3D-model being then transferred to the MBS (Multi-Body Systems) environment ADAMS/View. The control system was developed in the concurrent engineering concept, through the integration with the MBS mechanical model, by using the DFC (Design for Control) software solution EASY5. The necessary angular motions in the six joints of the robot, in order to obtain the imposed trajectory of the end-effector, have been established by performing the inverse kinematic analysis. The positioning error in each joint of the robot is used as design objective, the optimization goal being to minimize the root mean square during simulation, which is a measure of the magnitude of the positioning error varying quantity.

A System for Delivering Mechanical Stimulation and Robot-Assisted Therapy to the Rat Whisker Pad during Facial Nerve Regeneration

PubMed Central

Heaton, James T.; Knox, Christopher; Malo, Juan; Kobler, James B.; Hadlock, Tessa A.

2013-01-01

Functional recovery is typically poor after facial nerve transection and surgical repair. In rats, whisking amplitude remains greatly diminished after facial nerve regeneration, but can recover more completely if the whiskers are periodically mechanically stimulated during recovery. Here we present a robotic “whisk assist” system for mechanically driving whisker movement after facial nerve injury. Movement patterns were either pre-programmed to reflect natural amplitudes and frequencies, or movements of the contralateral (healthy) side of the face were detected and used to control real-time mirror-like motion on the denervated side. In a pilot study, twenty rats were divided into nine groups and administered one of eight different whisk assist driving patterns (or control) for 5–20 minutes, five days per week, across eight weeks of recovery after unilateral facial nerve cut and suture repair. All rats tolerated the mechanical stimulation well. Seven of the eight treatment groups recovered average whisking amplitudes that exceeded controls, although small group sizes precluded statistical confirmation of group differences. The potential to substantially improve facial nerve recovery through mechanical stimulation has important clinical implications, and we have developed a system to control the pattern and dose of stimulation in the rat facial nerve model. PMID:23475376

A Hierarchical Model Predictive Tracking Control for Independent Four-Wheel Driving/Steering Vehicles with Coaxial Steering Mechanism

NASA Astrophysics Data System (ADS)

Itoh, Masato; Hagimori, Yuki; Nonaka, Kenichiro; Sekiguchi, Kazuma

2016-09-01

In this study, we apply a hierarchical model predictive control to omni-directional mobile vehicle, and improve the tracking performance. We deal with an independent four-wheel driving/steering vehicle (IFWDS) equipped with four coaxial steering mechanisms (CSM). The coaxial steering mechanism is a special one composed of two steering joints on the same axis. In our previous study with respect to IFWDS with ideal steering, we proposed a model predictive tracking control. However, this method did not consider constraints of the coaxial steering mechanism which causes delay of steering. We also proposed a model predictive steering control considering constraints of this mechanism. In this study, we propose a hierarchical system combining above two control methods for IFWDS. An upper controller, which deals with vehicle kinematics, runs a model predictive tracking control, and a lower controller, which considers constraints of coaxial steering mechanism, runs a model predictive steering control which tracks the predicted steering angle optimized an upper controller. We verify the superiority of this method by comparing this method with the previous method.

Subscription merging in filter-based publish/subscribe systems

NASA Astrophysics Data System (ADS)

Zhang, Shengdong; Shen, Rui

2013-03-01

Filter-based publish/subscribe systems suffer from high subscription maintenance cost for each broker in the system stores a large number of subscriptions. Advertisement and covering are not sufficient to conquer such problem. Thus, subscription merging is proposed. However, current researches lack of an efficient and practical merging mechanism. In this paper, we propose a novel subscription merging mechanism. The mechanism is both time and space efficient, and can flexibly control the merging granularity. The merging mechanism has been verified through both theoretical and simulation-based evaluation.

Relatchable launch restraint mechanism for deployable booms

NASA Technical Reports Server (NTRS)

Warden, Robert M.

1990-01-01

A new Relatchable Launch Mechanism was developed which enables a deployable system to be restrained and released repeatedly rather than the normal one shot release systems of the past. The deployable systems are of the self extending type which rely on a lanyard attached to a drive motor to control the deployment and retraction. The Relatch Mechanism uses the existing drive motor to also actuate the latch. The design and kinematics of the Relatch Mechanism as used on two flight programs are described.

Mechatronics as a Technological Basis for an Innovative Learning Environment in Engineering

ERIC Educational Resources Information Center

Garner, Gavin Thomas

2009-01-01

Mechatronic systems that couple mechanical and electrical systems with the help of computer control are forcing a paradigm shift in the design, manufacture, and implementation of mechanical devices. The inherently interdisciplinary nature of these systems generates exciting new opportunities for developing a hands-on, inventive, and…

F-8 DFBW simulating STS contro l system - Pilot-induced oscillation (PIO) on landing

NASA Technical Reports Server (NTRS)

1978-01-01

From 1972 to 1985 the NASA Dryden Flight Research Center conducted flight research with an F-8C employing the first digital fly-by-wire flight control system without a mechanical back up. The decision to replace all mechanical control linkages to rudder, ailerons, and other flight control surfaces was made for two reasons. First, it forced the research engineers to focus on the technology and issues that were truly critical for a production fly-by-wire aircraft. Secondly, it would give industry the confidence it needed to apply the technology--confidence it would not have had if the experimental system relied on a mechanical back up. In the first few decades of flight, pilots had controlled aircraft through direct force--moving control sticks and rudder pedals linked to cables and pushrods that pivoted control surfaces on the wings and tails. As engine power and speeds increased, more force was needed and hydraulically boosted controls emerged. Soon, all high-performance and large aircraft had hydraulic-mechanical flight-control systems. These conventional flight control systems restricted designers in the configuration and design of aircraft because of the need for flight stability. As the electronic era grew in the 1960s, so did the idea of aircraft with electronic flight-control systems. Wires replacing mechanical devices would give designers greater flexibility in configuration and in the size and placement of components such as tail surfaces and wings. A fly-by-wire system also would be smaller, more reliable, and in military aircraft, much less vulnerable to battle damage. A fly-by-wire aircraft would also be much more responsive to pilot control inputs. The result would be more efficient, safer aircraft with improved performance and design. The Aircraft By the late 1960s, engineers at Dryden began discussing how to modify an aircraft and create a fly-by-wire testbed. Support for the concept at NASA Headquarters came from Neil Armstrong, former research pilot at Dryden. He served in the Office of Advanced Research and Technology following his historic Apollo 11 lunar landing and knew electronic control systems from his days training in and operating the lunar module. Armstrong supported the proposed Dryden project and backed the transfer of an F-8C Crusader from the U.S. Navy to NASA to become the Digital Fly-By-Wire (DFBW) research aircraft. It was given the tail number 'NASA 802.' Wires from the control stick in the cockpit to the control surfaces on the wings and tail surfaces replaced the entire mechanical flight-control system in the F-8. The heart of the system was an off-the-shelf backup Apollo digital flight-control computer and inertial sensing unit, which transmitted pilot inputs to the actuators on the control surfaces. On May 25, 1972, the highly modified F-8 became the first aircraft to fly completely dependent upon an electronic flight-control system without any mechanical backup. The pilot was Gary Krier. The first phase of the DFBW program validated the fly-by-wire concept and quickly showed that a refined system, especially in large aircraft, would greatly enhance flying qualities by sensing motion changes and applying pilot inputs instantaneously. The Phase 1 system had a backup analog fly-by-wire system in the event of a failure in the Apollo computer unit, but it was never necessary to use the system in flight. In a joint program carried out with the Langley Research Center in the second phase of research, the original Apollo system was replaced with a triply redundant digital system. It would provide backup computer capabilities if a failure occurred. The DFBW program lasted 13 years. The final research flight, the 210th of the program, was made April 2, 1985, with Dryden Research Pilot Ed Schneider at the controls. Research Benefits The F-8 DFBW validated the principal concepts of the all-electric flight control systems now used in a variety of airplanes ranging from the F/A-18 to the Boeing 777 and the space shuttles. A DFBW flight control system also is used on the space shuttles. NASA 802 was the testbed for the sidestick-controller used in the F-16 fighter, the second U.S. high performance aircraft with a DFBW system. In addition to pioneering the space shuttle's fly-by-wire flight-control system, NASA 802 was the testbed that explored Pilot Induced Oscillations (PIO) and validated methods to suppress them. PIOs occur when a pilot over-controls an aircraft and a sustained oscillation results. On the last of five free flights of the prototype Space Shuttle Enterprise during approach and landing tests in l977, a PIO developed as the vehicle settled onto the runway. The problem was duplicated with the F-8 DFBW and a series of PIO suppression filters was developed and tested on the aircraft for the shuttle program office. DFBW research carried out with NASA 802 at Dryden is now considered one of the most significant and successful aeronautical programs in NASA history. In this clip we see NASA research pilot John Manke at the controls of Dryden's F-8 Digital Fly-By-Wire aircraft as it enters a severe pilot induced oscillation or PIO just after completion of a touch-and-go landing while testing for a signal-delay-related problem that occurred during an approach to landing on the shuttle prototype Enterprise.

Developing an interactive teleradiology system for SARS diagnosis

NASA Astrophysics Data System (ADS)

Sun, Jianyong; Zhang, Jianguo; Zhuang, Jun; Chen, Xiaomeng; Yong, Yuanyuan; Tan, Yongqiang; Chen, Liu; Lian, Ping; Meng, Lili; Huang, H. K.

2004-04-01

Severe acute respiratory syndrome (SARS) is a respiratory illness that had been reported in Asia, North America, and Europe in last spring. Most of the China cases of SARS have occurred by infection in hospitals or among travelers. To protect the physicians, experts and nurses from the SARS during the diagnosis and treatment procedures, the infection control mechanisms were built in SARS hospitals. We built a Web-based interactive teleradiology system to assist the radiologists and physicians both in side and out side control area to make image diagnosis. The system consists of three major components: DICOM gateway (GW), Web-based image repository server (Server), and Web-based DICOM viewer (Viewer). This system was installed and integrated with CR, CT and the hospital information system (HIS) in Shanghai Xinhua hospital to provide image-based ePR functions for SARS consultation between the radiologists, physicians and experts inside and out side control area. The both users inside and out side the control area can use the system to process and manipulate the DICOM images interactively, and the system provide the remote control mechanism to synchronize their operations on images and display.

Development of a Wearable Assist Robot for Walk Rehabilitation After Knee Arthroplasty Surgery

NASA Astrophysics Data System (ADS)

Terada, H.; Zhu, Y.; Horiguchi, K.; Nakamura, M.; Takahashi, R.

In Japan, it is popular that the disease knee joints will be replaced to artificial joints by surgery. And we have to assist so many patients for walk rehabilitation. So, the wearable assist robot has been developed. This robot includes the knee motion assist mechanism and the hip joint support mechanism. Especially, the knee motion assist mechanism consists of a non-circular gear and grooved cams. This mechanism rotates and slides simultaneously, which has two degree-of-freedom. Also, the hip joint support mechanism consists of a hip brace and a ball-joint. This mechanism can avoid motion constraints which are the internal or external rotation and the adduction or abduction. Then, the control algorithm, which considers an assisting timing for the walk rehabilitation, has been proposed. A sensing system of a walk state for this control system uses a heel contacts sensor and knee and hip joint rotation angle sensors. Also, the prototype robot has been tested. And it is confirmed that the assisting system is useful.

Therapeutic Opportunities for Self-Control Repair in Addiction and Related Disorders: Change and the Limits of Change in Trans-Disease Processes

PubMed Central

Bickel, Warren K.; Quisenberry, Amanda J.; Moody, Lara; Wilson, A. George

2014-01-01

Contemporary neuro-economic approaches hypothesize that self-control failure results from drugs annexing normal learning mechanisms that produce pathological reward processing and distort decision-making as a result from the dysregulation of two valuation systems. An emphasis on processes shared across different diseases and disorders is at odds with the contemporary approach that assumes unique disease etiologies and treatments. Studying trans-disease processes can identify mechanisms that operate in multiple disease states and ascertain if factors that influence processes in one disease state may be applicable to all disease states. In this paper we review the dual model of self-control failure, the Competing Neurobehavioral Decision Systems approach, the relationship of delay discounting to the relative control of these two systems, and evidence that the executive system can be strengthened. Future research that could result in more potent interventions for executive system improvement and potential constraints on the repair of self-control failure are discussed. PMID:25664226

Separable Roles for Attentional Control Sub-Systems in Reading Tasks: A Combined Behavioral and fMRI Study

PubMed Central

Ihnen, S.K.Z.; Petersen, Steven E.; Schlaggar, Bradley L.

2015-01-01

Attentional control is important both for learning to read and for performing difficult reading tasks. A previous study invoked 2 mechanisms to explain reaction time (RT) differences between reading tasks with variable attentional demands. The present study combined behavioral and neuroimaging measures to test the hypotheses that there are 2 mechanisms of interaction between attentional control and reading; that these mechanisms are dissociable both behaviorally and neuro-anatomically; and that the 2 mechanisms involve functionally separable control systems. First, RT evidence was found in support of the 2-mechanism model, corroborating the previous study. Next, 2 sets of brain regions were identified as showing functional magnetic resonance imaging blood oxygen level-dependent activity that maps onto the 2-mechanism distinction. One set included bilateral Cingulo-opercular regions and mostly right-lateralized Dorsal Attention regions (CO/DA+). This CO/DA+ region set showed response properties consistent with a role in reporting which processing pathway (phonological or lexical) was biased for a particular trial. A second set was composed primarily of left-lateralized Frontal-parietal (FP) regions. Its signal properties were consistent with a role in response checking. These results demonstrate how the subcomponents of attentional control interact with subcomponents of reading processes in healthy young adults. PMID:24275830

A federated capability-based access control mechanism for internet of things (IoTs)

NASA Astrophysics Data System (ADS)

Xu, Ronghua; Chen, Yu; Blasch, Erik; Chen, Genshe

2018-05-01

The prevalence of Internet of Things (IoTs) allows heterogeneous embedded smart devices to collaboratively provide intelligent services with or without human intervention. While leveraging the large-scale IoT-based applications like Smart Gird and Smart Cities, IoT also incurs more concerns on privacy and security. Among the top security challenges that IoTs face is that access authorization is critical in resource and information protection over IoTs. Traditional access control approaches, like Access Control Lists (ACL), Role-based Access Control (RBAC) and Attribute-based Access Control (ABAC), are not able to provide a scalable, manageable and efficient mechanisms to meet requirement of IoT systems. The extraordinary large number of nodes, heterogeneity as well as dynamicity, necessitate more fine-grained, lightweight mechanisms for IoT devices. In this paper, a federated capability-based access control (FedCAC) framework is proposed to enable an effective access control processes to devices, services and information in large scale IoT systems. The federated capability delegation mechanism, based on a propagation tree, is illustrated for access permission propagation. An identity-based capability token management strategy is presented, which involves registering, propagation and revocation of the access authorization. Through delegating centralized authorization decision-making policy to local domain delegator, the access authorization process is locally conducted on the service provider that integrates situational awareness (SAW) and customized contextual conditions. Implemented and tested on both resources-constrained devices, like smart sensors and Raspberry PI, and non-resource-constrained devices, like laptops and smart phones, our experimental results demonstrate the feasibility of the proposed FedCAC approach to offer a scalable, lightweight and fine-grained access control solution to IoT systems connected to a system network.

Power Management Based Current Control Technique for Photovoltaic-Battery Assisted Wind-Hydro Hybrid System

NASA Astrophysics Data System (ADS)

Ram Prabhakar, J.; Ragavan, K.

2013-07-01

This article proposes new power management based current control strategy for integrated wind-solar-hydro system equipped with battery storage mechanism. In this control technique, an indirect estimation of load current is done, through energy balance model, DC-link voltage control and droop control. This system features simpler energy management strategy and necessitates few power electronic converters, thereby minimizing the cost of the system. The generation-demand (G-D) management diagram is formulated based on the stochastic weather conditions and demand, which would likely moderate the gap between both. The features of management strategy deploying energy balance model include (1) regulating DC-link voltage within specified tolerances, (2) isolated operation without relying on external electric power transmission network, (3) indirect current control of hydro turbine driven induction generator and (4) seamless transition between grid-connected and off-grid operation modes. Furthermore, structuring of the hybrid system with appropriate selection of control variables enables power sharing among each energy conversion systems and battery storage mechanism. By addressing these intricacies, it is viable to regulate the frequency and voltage of the remote network at load end. The performance of the proposed composite scheme is demonstrated through time-domain simulation in MATLAB/Simulink environment.

Optimal control of underactuated mechanical systems: A geometric approach

NASA Astrophysics Data System (ADS)

Colombo, Leonardo; Martín De Diego, David; Zuccalli, Marcela

2010-08-01

In this paper, we consider a geometric formalism for optimal control of underactuated mechanical systems. Our techniques are an adaptation of the classical Skinner and Rusk approach for the case of Lagrangian dynamics with higher-order constraints. We study a regular case where it is possible to establish a symplectic framework and, as a consequence, to obtain a unique vector field determining the dynamics of the optimal control problem. These developments will allow us to develop a new class of geometric integrators based on discrete variational calculus.

An analytic-numerical method for the construction of the reference law of operation for a class of mechanical controlled systems

NASA Astrophysics Data System (ADS)

Mizhidon, A. D.; Mizhidon, K. A.

2017-04-01

An analytic-numerical method for the construction of a reference law of operation for a class of dynamic systems describing vibrations in controlled mechanical systems is proposed. By the reference law of operation of a system, we mean a law of the system motion that satisfies all the requirements for the quality and design features of the system under permanent external disturbances. As disturbances, we consider polyharmonic functions with known amplitudes and frequencies of the harmonics but unknown initial phases. For constructing the reference law of motion, an auxiliary optimal control problem is solved in which the cost function depends on a weighting coefficient. The choice of the weighting coefficient ensures the design of the reference law. Theoretical foundations of the proposed method are given.

Flight control systems properties and problems. Volume 2: Block diagram compendium

NASA Technical Reports Server (NTRS)

Johnston, D. E.

1975-01-01

A compendium of stability augmentation system and autopilot block diagrams is presented. Descriptive materials for 48 different types of aircraft systems are provided. A broad representation of the many mechanical approaches which have been used for aircraft control is developed.

Analysis and testing of aeroelastic model stability augmentation systems. [for supersonic transport aircraft wing and B-52 aircraft control system

NASA Technical Reports Server (NTRS)

Sevart, F. D.; Patel, S. M.

1973-01-01

Testing and evaluation of a stability augmentation system for aircraft flight control were performed. The flutter suppression system and synthesis conducted on a scale model of a supersonic wing for a transport aircraft are discussed. Mechanization and testing of the leading and trailing edge surface actuation systems are described. The ride control system analyses for a 375,000 pound gross weight B-52E aircraft are presented. Analyses of the B-52E aircraft maneuver load control system are included.

75 FR 16648 - Airworthiness Directives; The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-02

.... Subsequent investigation revealed extensive damage to the elevator tab control system. Severe vibration in... and right elevator control tab mechanisms for gaps between the swage ring and the aft attach lug, and... replacing any discrepant elevator tab control mechanism, including performing the detailed inspection on the...

A summary of the mechanical design, testing and performance of the IMP-H and J attitude control systems

NASA Technical Reports Server (NTRS)

Metzger, J. R.

1974-01-01

The main aspects of the attitude control system used on both the IMP-H and J spacecraft are presented. The mechanical configuration is described. Information on all the specific components comprising the flight system is provided. The acceptance and qualification testing of both individual components and the installed system are summarized. Functional information regarding the operation and performance in relation to the orbiting spacecraft and its mission is included. Related topics which are discussed are: (1) safety requirements, (2) servicing procedures, (3) anomalous behavior, and (4) pyrotechnic devices.

A/E/C CAD Standard, Release 5.0

DTIC Science & Technology

2012-12-01

System Control Panels Halon System Inert Gas Smoke/Pressurization Control Egress Requirements Fire Protection System Appendix A ... System Natural Gas System Miter Gates Makeup Air System Appendix A Model File Level/Layer Assignment Tables A54 Discipline: Mechanical Model...SWITCHES Element type: Symbol Electrical: STP14B SURFACE 1X4 STRIP BATTERY Element type: Symbol Electrical: SUBST A

Controlling Mackey-Glass chaos.

PubMed

Kiss, Gábor; Röst, Gergely

2017-11-01

The Mackey-Glass equation is the representative example of delay induced chaotic behavior. Here, we propose various control mechanisms so that otherwise erratic solutions are forced to converge to the positive equilibrium or to a periodic orbit oscillating around that equilibrium. We take advantage of some recent results of the delay differential literature, when a sufficiently large domain of the phase space has been shown to be attractive and invariant, where the system is governed by monotone delayed feedback and chaos is not possible due to some Poincaré-Bendixson type results. We systematically investigate what control mechanisms are suitable to drive the system into such a situation and prove that constant perturbation, proportional feedback control, Pyragas control, and state dependent delay control can all be efficient to control Mackey-Glass chaos with properly chosen control parameters.

Controlling Mackey-Glass chaos

NASA Astrophysics Data System (ADS)

Kiss, Gábor; Röst, Gergely

2017-11-01

The Mackey-Glass equation is the representative example of delay induced chaotic behavior. Here, we propose various control mechanisms so that otherwise erratic solutions are forced to converge to the positive equilibrium or to a periodic orbit oscillating around that equilibrium. We take advantage of some recent results of the delay differential literature, when a sufficiently large domain of the phase space has been shown to be attractive and invariant, where the system is governed by monotone delayed feedback and chaos is not possible due to some Poincaré-Bendixson type results. We systematically investigate what control mechanisms are suitable to drive the system into such a situation and prove that constant perturbation, proportional feedback control, Pyragas control, and state dependent delay control can all be efficient to control Mackey-Glass chaos with properly chosen control parameters.

Adaptive backstepping sliding mode control with fuzzy monitoring strategy for a kind of mechanical system.

PubMed

Song, Zhankui; Sun, Kaibiao

2014-01-01

A novel adaptive backstepping sliding mode control (ABSMC) law with fuzzy monitoring strategy is proposed for the tracking-control of a kind of nonlinear mechanical system. The proposed ABSMC scheme combining the sliding mode control and backstepping technique ensure that the occurrence of the sliding motion in finite-time and the trajectory of tracking-error converge to equilibrium point. To obtain a better perturbation rejection property, an adaptive control law is employed to compensate the lumped perturbation. Furthermore, we introduce fuzzy monitoring strategy to improve adaptive capacity and soften the control signal. The convergence and stability of the proposed control scheme are proved by using Lyaponov's method. Finally, numerical simulations demonstrate the effectiveness of the proposed control scheme. © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

On-line pulse control for structural and mechanical systems

NASA Technical Reports Server (NTRS)

Udwadia, F. E.; Garba, J. A.; Tabaie, S.

1981-01-01

This paper studies the feasibility of using open-loop adaptive on-line pulse control for limiting the response of large linear multidegree of freedom systems subjected to general dynamic loading environments. Pulses of short durations are used to control the system when the system response exceeds a given threshold level. The pulse magnitudes are obtained in closed form, leading to large computational efficiencies when compared with optimal control theoretic methods. The technique is illustrated for a structural system subjected to earthquake-like base excitations.

Engine Tune-up Service. Unit 6: Emission Control Systems. Posttests. Automotive Mechanics Curriculum.

ERIC Educational Resources Information Center

Morse, David T.; May, Theodore R.

This book of posttests is designed to accompany the Engine Tune-Up Service Student Guide for Unit 6, Emission Control Systems, available separately as CE 031 220. Focus of the posttests is inspecting, testing, and servicing emission control systems. One multiple choice posttest is provided that covers the seven performance objectives contained in…

Overview of the GRC Stirling Convertor System Dynamic Model

NASA Technical Reports Server (NTRS)

Lewandowski, Edward J.; Regan, Timothy F.

2004-01-01

A Stirling Convertor System Dynamic Model has been developed at the Glenn Research Center for controls, dynamics, and systems development of free-piston convertor power systems. It models the Stirling cycle thermodynamics, heat flow, gas, mechanical, and mounting dynamics, the linear alternator, and the controller. The model's scope extends from the thermal energy input to thermal, mechanical dynamics, and electrical energy out, allowing one to study complex system interactions among subsystems. The model is a non-linear time-domain model containing sub-cycle dynamics, allowing it to simulate transient and dynamic phenomena that other models cannot. The model details and capability are discussed.

Analysis of achievable disturbance attenuation in a precision magnetically-suspended motion control system

NASA Technical Reports Server (NTRS)

Kuzin, Alexander V.; Holmes, Michael L.; Behrouzjou, Roxana; Trumper, David L.

1994-01-01

The results of the analysis of the achievable disturbance attenuation to get an Angstrom motion control resolution and macroscopic travel in a precision magnetically-suspended motion control system are presented in this paper. Noise sources in the transducers, electronics, and mechanical vibrations are used to develop the control design.

Exact controllability for a Thermodiffusion System with locally distributed controls

NASA Astrophysics Data System (ADS)

de Moraes, F. G.; Schulz, R. A.; Soriano, J. A.

2018-03-01

In this work we establish a exact controllability result for a thermodiffusion system, modeled by Cattaneo's law, posed in a one-dimensional domain. In the present model the control mechanisms are effective in a small subinterval of the domain. To obtain the desired results, we prove an observability inequality for the adjoint system which, together with the multiplier methods and the Hilbert Uniqueness Method (HUM) developed by J.L. Lions, gives the controllability.

A throat-bypass stability system for a YF-12 aircraft research inlet using self-acting mechanical valves

NASA Technical Reports Server (NTRS)

Cole, G. L.; Dustin, M. O.; Neiner, G. H.

1975-01-01

Results of a wind tunnel investigation are presented. The inlet was modified so that airflow can be removed through a porous cowl-bleed region in the vicinity of the throat. Bleed plenum exit flow area is controlled by relief type mechanical valves. Unlike valves in previous systems, these are made for use in a high Mach flight environment and include refinements so that the system could be tested on a NASA YF-12 aircraft. The valves were designed to provide their own reference pressure. The results show that the system can absorb internal-airflow-transients that are too fast for a conventional bypass door control system and that the two systems complement each other quite well. Increased tolerance to angle of attack and Mach number changes is indicated. The valves should provide sufficient time for the inlet control system to make geometry changes required to keep the inlet started.

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study

NASA Technical Reports Server (NTRS)

1982-01-01

The Current and Advanced Technology ACT control system definition tasks of the Integrated Application of Active Controls (IAAC) Technology project within the Energy Efficient Transport Program are summarized. The systems mechanize six active control functions: (1) pitch augmented stability; (2) angle of attack limiting; (3) lateral/directional augmented stability; (4) gust load alleviation; (5) maneuver load control; and (6) flutter mode control. The redundant digital control systems meet all function requirements with required reliability and declining weight and cost as advanced technology is introduced.

Development of hand rehabilitation system for paralysis patient - universal design using wire-driven mechanism.

PubMed

Yamaura, Hiroshi; Matsushita, Kojiro; Kato, Ryu; Yokoi, Hiroshi

2009-01-01

We have developed a hand rehabilitation system for patients suffering from paralysis or contracture. It consists of two components: a hand rehabilitation machine, which moves human finger joints with motors, and a data glove, which provides control of the movement of finger joints attached to the rehabilitation machine. The machine is based on the arm structure type of hand rehabilitation machine; a motor indirectly moves a finger joint via a closed four-link mechanism. We employ a wire-driven mechanism and develop a compact design that can control all three joints (i.e., PIP, DIP and MP ) of a finger and that offers a wider range of joint motion than conventional systems. Furthermore, we demonstrate the hand rehabilitation process, finger joints of the left hand attached to the machine are controlled by the finger joints of the right hand wearing the data glove.

Modeling of short-term mechanism of arterial pressure control in the cardiovascular system: object-oriented and acausal approach.

PubMed

Kulhánek, Tomáš; Kofránek, Jiří; Mateják, Marek

2014-11-01

This letter introduces an alternative approach to modeling the cardiovascular system with a short-term control mechanism published in Computers in Biology and Medicine, Vol. 47 (2014), pp. 104-112. We recommend using abstract components on a distinct physical level, separating the model into hydraulic components, subsystems of the cardiovascular system and individual subsystems of the control mechanism and scenario. We recommend utilizing an acausal modeling feature of Modelica language, which allows model variables to be expressed declaratively. Furthermore, the Modelica tool identifies which are the dependent and independent variables upon compilation. An example of our approach is introduced on several elementary components representing the hydraulic resistance to fluid flow and the elastic response of the vessel, among others. The introduced model implementation can be more reusable and understandable for the general scientific community. Copyright © 2014 Elsevier Ltd. All rights reserved.

A novel open-loop tracking strategy for photovoltaic systems.

PubMed

Alexandru, Cătălin

2013-01-01

This paper approaches a dual-axis equatorial tracking system that is used to increase the photovoltaic efficiency by maximizing the degree of use of the solar radiation. The innovative aspect in the solar tracker design consists in considering the tracking mechanism as a perturbation for the DC motors. The goal is to control the DC motors, which are perturbed with the motor torques whose computation is based on the dynamic model of the mechanical structure on which external forces act. The daily and elevation angles of the PV module represent the input parameters in the mechanical device, while the outputs transmitted to the controller are the motor torques. The controller tuning is approached by a parametric optimization process, using design of experiments and response surface methodology techniques, in a multiple regression. The simulation and experimental results demonstrate the operational performance of the tracking system.

A Novel Open-Loop Tracking Strategy for Photovoltaic Systems

PubMed Central

Alexandru, Cătălin

2013-01-01

This paper approaches a dual-axis equatorial tracking system that is used to increase the photovoltaic efficiency by maximizing the degree of use of the solar radiation. The innovative aspect in the solar tracker design consists in considering the tracking mechanism as a perturbation for the DC motors. The goal is to control the DC motors, which are perturbed with the motor torques whose computation is based on the dynamic model of the mechanical structure on which external forces act. The daily and elevation angles of the PV module represent the input parameters in the mechanical device, while the outputs transmitted to the controller are the motor torques. The controller tuning is approached by a parametric optimization process, using design of experiments and response surface methodology techniques, in a multiple regression. The simulation and experimental results demonstrate the operational performance of the tracking system. PMID:24327803

Genomic imprinting—an epigenetic gene-regulatory model

PubMed Central

Koerner, Martha V; Barlow, Denise P

2010-01-01

Epigenetic mechanisms (Box 1) are considered to play major gene-regulatory roles in development, differentiation and disease. However, the relative importance of epigenetics in defining the mammalian transcriptome in normal and disease states is unknown. The mammalian genome contains only a few model systems where epigenetic gene regulation has been shown to play a major role in transcriptional control. These model systems are important not only to investigate the biological function of known epigenetic modifications but also to identify new and unexpected epigenetic mechanisms in the mammalian genome. Here we review recent progress in understanding how epigenetic mechanisms control imprinted gene expression. PMID:20153958

Peripheral mechanisms for vocal production in birds - differences and similarities to human speech and singing.

PubMed

Riede, Tobias; Goller, Franz

2010-10-01

Song production in songbirds is a model system for studying learned vocal behavior. As in humans, bird phonation involves three main motor systems (respiration, vocal organ and vocal tract). The avian respiratory mechanism uses pressure regulation in air sacs to ventilate a rigid lung. In songbirds sound is generated with two independently controlled sound sources, which reside in a uniquely avian vocal organ, the syrinx. However, the physical sound generation mechanism in the syrinx shows strong analogies to that in the human larynx, such that both can be characterized as myoelastic-aerodynamic sound sources. Similarities include active adduction and abduction, oscillating tissue masses which modulate flow rate through the organ and a layered structure of the oscillating tissue masses giving rise to complex viscoelastic properties. Differences in the functional morphology of the sound producing system between birds and humans require specific motor control patterns. The songbird vocal apparatus is adapted for high speed, suggesting that temporal patterns and fast modulation of sound features are important in acoustic communication. Rapid respiratory patterns determine the coarse temporal structure of song and maintain gas exchange even during very long songs. The respiratory system also contributes to the fine control of airflow. Muscular control of the vocal organ regulates airflow and acoustic features. The upper vocal tract of birds filters the sounds generated in the syrinx, and filter properties are actively adjusted. Nonlinear source-filter interactions may also play a role. The unique morphology and biomechanical system for sound production in birds presents an interesting model for exploring parallels in control mechanisms that give rise to highly convergent physical patterns of sound generation. More comparative work should provide a rich source for our understanding of the evolution of complex sound producing systems. Copyright © 2009 Elsevier Inc. All rights reserved.

93. TEMPERATURE AND FLOW RATE CONTROLS FOR SYSTEM 1 AND ...

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

93. TEMPERATURE AND FLOW RATE CONTROLS FOR SYSTEM 1 AND SYSTEM 2, FACING WEST IN MECHANICAL EQUIPMENT ROOM (101), LSB (BLDG. 770) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

29 CFR 1910.217 - Mechanical power presses.

Code of Federal Regulations, 2012 CFR

2012-07-01

... against unintentional operation and have the individual operator's hand controls arranged by design and... trip the press. (b) The control system shall be designed to permit an adjustment which will require... shall incorporate an antirepeat feature. (d) The control systems shall be designed to require release of...

29 CFR 1910.217 - Mechanical power presses.

Code of Federal Regulations, 2011 CFR

2011-07-01

... against unintentional operation and have the individual operator's hand controls arranged by design and... trip the press. (b) The control system shall be designed to permit an adjustment which will require... shall incorporate an antirepeat feature. (d) The control systems shall be designed to require release of...

29 CFR 1910.217 - Mechanical power presses.

Code of Federal Regulations, 2010 CFR

2010-07-01

... against unintentional operation and have the individual operator's hand controls arranged by design and... trip the press. (b) The control system shall be designed to permit an adjustment which will require... shall incorporate an antirepeat feature. (d) The control systems shall be designed to require release of...

29 CFR 1910.217 - Mechanical power presses.

Code of Federal Regulations, 2014 CFR

2014-07-01

... against unintentional operation and have the individual operator's hand controls arranged by design and... trip the press. (b) The control system shall be designed to permit an adjustment which will require... shall incorporate an antirepeat feature. (d) The control systems shall be designed to require release of...

29 CFR 1910.217 - Mechanical power presses.

Code of Federal Regulations, 2013 CFR

2013-07-01

... against unintentional operation and have the individual operator's hand controls arranged by design and... trip the press. (b) The control system shall be designed to permit an adjustment which will require... shall incorporate an antirepeat feature. (d) The control systems shall be designed to require release of...

A control system formulation of the mechanism that controls the secretions of serum group hormone in humans during sleep

NASA Technical Reports Server (NTRS)

Howard, J. C.; Young, D. R.

1975-01-01

Plasma growth hormone concentrations during sleep were determined experimentally. An elevated level of plasma growth hormone was observed during the initial phase of sleep and remained elevated for approximately 3 hr before returning to the steady-state level. Moreover, subsequent to a prolonged interruption of sleep, of the order of 2-3 hr, an elevated level of plasma growth hormone was again observed during the initial phase of resumed sleep. A control system formulation of the mechanism that controls the secretions of serum growth hormone in humans was used to account for the growth hormone responses observed.

Bilingual Language Control and General Purpose Cognitive Control among Individuals with Bilingual Aphasia: Evidence Based on Negative Priming and Flanker Tasks

PubMed Central

Dash, Tanya; Kar, Bhoomika R.

2014-01-01

Background. Bilingualism results in an added advantage with respect to cognitive control. The interaction between bilingual language control and general purpose cognitive control systems can also be understood by studying executive control among individuals with bilingual aphasia. Objectives. The current study examined the subcomponents of cognitive control in bilingual aphasia. A case study approach was used to investigate whether cognitive control and language control are two separate systems and how factors related to bilingualism interact with control processes. Methods. Four individuals with bilingual aphasia performed a language background questionnaire, picture description task, and two experimental tasks (nonlinguistic negative priming task and linguistic and nonlinguistic versions of flanker task). Results. A descriptive approach was used to analyse the data using reaction time and accuracy measures. The cumulative distribution function plots were used to visualize the variations in performance across conditions. The results highlight the distinction between general purpose cognitive control and bilingual language control mechanisms. Conclusion. All participants showed predominant use of the reactive control mechanism to compensate for the limited resources system. Independent yet interactive systems for bilingual language control and general purpose cognitive control were postulated based on the experimental data derived from individuals with bilingual aphasia. PMID:24982591

Evaluation of passive and active vibration control mechanisms in a microgravity environment

NASA Technical Reports Server (NTRS)

Ellison, J.; Ahmadi, G.; Grodsinsky, C.

1993-01-01

The behavior of equipment and their light secondary attachments in large space structures under orbital excitation is studied. The equipment is modeled as a shear beam and its secondary attachment is treated as a single-degree-of-freedom lumped mass system. Peak responses of the equipment and its secondary system for a variety of vibration control mechanisms are evaluated. A novel active friction control mechanism, by varying the normal force, is suggested. The device uses a magnetic field control to minimize the stick condition, thereby reducing the overall structural response. The results show that the use of the passive vibration control devices could reduce the peak equipment responses to a certain extent. However, major reduction of vibration levels could be achieved only by the use of active devices. Using active control of the interface normal force, the peak responses of the equipment and its attachment are reduced by a factor of 10 over the fixed-base equipment response.

EBSD characterization of twinning in cold-rolled CP-Ti

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

Li, X., E-mail: csulixu@hotmail.com; Duan, Y.L., E-mail: 876270744@qq.com; Xu, G.F., E-mail: csuxgf66@csu.edu.cn

2013-10-15

This work presents the use of a mechanical testing system and the electron backscatter diffraction technique to study the mechanical properties and twinning systems of cold-rolled commercial purity titanium, respectively. The dependence of twinning on the matrix orientation is analyzed by the distribution map of Schmid factor. The results showed that the commercial purity titanium experienced strong strain hardening and had excellent formability during rolling. Both the (112{sup ¯}2)<112{sup ¯}3{sup ¯}> compressive twins and (101{sup ¯}2)<101{sup ¯}1{sup ¯}> tensile twins were dependent on the matrix orientation. The Schmid factor of a grain influenced the activation of a particular twinning system.more » The specific rolling deformation of commercial purity titanium controlled the number and species of twinning systems and further changed the mechanical properties. - Highlights: • CP-Ti experienced strain hardening and had excellent formability. • Twins were dependent on the matrix orientation. • Schmid factor of a grain influenced the activation of a twinning system. • Rolling deformation controlled twinning systems and mechanical properties.« less

The JPL telerobotic Manipulator Control and Mechanization (MCM) subsystem

NASA Technical Reports Server (NTRS)

Hayati, Samad; Lee, Thomas S.; Tso, Kam; Backes, Paul; Kan, Edwin; Lloyd, J.

1989-01-01

The Manipulator Control and Mechanization (MCM) subsystem of the telerobot system provides the real-time control of the robot manipulators in autonomous and teleoperated modes and real time input/output for a variety of sensors and actuators. Substantial hardware and software are included in this subsystem which interfaces in the hierarchy of the telerobot system with the other subsystems. The other subsystems are: run time control, task planning and reasoning, sensing and perception, and operator control subsystem. The architecture of the MCM subsystem, its capabilities, and details of various hardware and software elements are described. Important improvements in the MCM subsystem over the first version are: dual arm coordinated trajectory generation and control, addition of integrated teleoperation, shared control capability, replacement of the ultimate controllers with motor controllers, and substantial increase in real time processing capability.

Analysis and testing of stability augmentation systems. [for supersonic transport aircraft wing and B-52 aircraft control system

NASA Technical Reports Server (NTRS)

Sevart, F. D.; Patel, S. M.; Wattman, W. J.

1972-01-01

Testing and evaluation of stability augmentation systems for aircraft flight control were conducted. The flutter suppression system analysis of a scale supersonic transport wing model is described. Mechanization of the flutter suppression system is reported. The ride control synthesis for the B-52 aeroelastic model is discussed. Model analyses were conducted using equations of motion generated from generalized mass and stiffness data.

Artificial neural networks for control of a grid-connected rectifier/inverter under disturbance, dynamic and power converter switching conditions.

PubMed

Li, Shuhui; Fairbank, Michael; Johnson, Cameron; Wunsch, Donald C; Alonso, Eduardo; Proaño, Julio L

2014-04-01

Three-phase grid-connected converters are widely used in renewable and electric power system applications. Traditionally, grid-connected converters are controlled with standard decoupled d-q vector control mechanisms. However, recent studies indicate that such mechanisms show limitations in their applicability to dynamic systems. This paper investigates how to mitigate such restrictions using a neural network to control a grid-connected rectifier/inverter. The neural network implements a dynamic programming algorithm and is trained by using back-propagation through time. To enhance performance and stability under disturbance, additional strategies are adopted, including the use of integrals of error signals to the network inputs and the introduction of grid disturbance voltage to the outputs of a well-trained network. The performance of the neural-network controller is studied under typical vector control conditions and compared against conventional vector control methods, which demonstrates that the neural vector control strategy proposed in this paper is effective. Even in dynamic and power converter switching environments, the neural vector controller shows strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy control requirements for a faulted power system.

Nonlinear effects of respiration on the crosstalk between cardiovascular and cerebrovascular control systems

NASA Astrophysics Data System (ADS)

Bari, Vlasta; Marchi, Andrea; De Maria, Beatrice; Rossato, Gianluca; Nollo, Giandomenico; Faes, Luca; Porta, Alberto

2016-05-01

Cardiovascular and cerebrovascular regulatory systems are vital control mechanisms responsible for guaranteeing homeostasis and are affected by respiration. This work proposes the investigation of cardiovascular and cerebrovascular control systems and the nonlinear influences of respiration on both regulations through joint symbolic analysis (JSA), conditioned or unconditioned on respiration. Interactions between cardiovascular and cerebrovascular regulatory systems were evaluated as well by performing correlation analysis between JSA indexes describing the two control systems. Heart period, systolic and mean arterial pressure, mean cerebral blood flow velocity and respiration were acquired on a beat-to-beat basis in 13 subjects experiencing recurrent syncope episodes (SYNC) and 13 healthy individuals (non-SYNC) in supine resting condition and during head-up tilt test at 60° (TILT). Results showed that JSA distinguished conditions and groups, whereas time domain parameters detected only the effect of TILT. Respiration affected cardiovascular and cerebrovascular regulatory systems in a nonlinear way and was able to modulate the interactions between the two control systems with different outcome in non-SYNC and SYNC groups, thus suggesting that the analysis of the impact of respiration on cardiovascular and cerebrovascular regulatory systems might improve our understanding of the mechanisms underpinning the development of postural-related syncope.

Congestion and flow control in signaling system no. 7: Impacts of intelligent networks and new services

NASA Astrophysics Data System (ADS)

Zepf, Joachim; Rufa, Gerhard

1994-04-01

This paper focuses on the transient performance analysis of the congestion and flow control mechanisms in CCITT Signaling System No. 7 (SS7). Special attention is directed to the impacts of the introduction of intelligent services and new applications, e.g., Freephone, credit card services, user-to-user signaling, etc. In particular, we show that signaling traffic characteristics like signaling scenarios or signaling message length as well as end-to-end signaling capabilities have a significant influence on the congestion and flow control and, therefore, on the real-time signaling performance. One important result of our performance studies is that if, e.g., intelligent services are introduced, the SS7 congestion and flow control does not work correctly. To solve this problem, some reinvestigations into these mechanisms would be necessary. Therefore, some approaches, e.g., modification of the Signaling Connection Control Part (SCCP) congestion control, usage of the SCCP relay function, or a redesign of the MTP flow control procedures are discussed in order to guarantee the efficacy of the congestion and flow control mechanisms also in the future.

Research a Novel Integrated and Dynamic Multi-object Trade-Off Mechanism in Software Project

NASA Astrophysics Data System (ADS)

Jiang, Weijin; Xu, Yuhui

Aiming at practical requirements of present software project management and control, the paper presented to construct integrated multi-object trade-off model based on software project process management, so as to actualize integrated and dynamic trade-oil of the multi-object system of project. Based on analyzing basic principle of dynamic controlling and integrated multi-object trade-off system process, the paper integrated method of cybernetics and network technology, through monitoring on some critical reference points according to the control objects, emphatically discussed the integrated and dynamic multi- object trade-off model and corresponding rules and mechanism in order to realize integration of process management and trade-off of multi-object system.

Validation of a robotic balance system for investigations in the control of human standing balance.

PubMed

Luu, Billy L; Huryn, Thomas P; Van der Loos, H F Machiel; Croft, Elizabeth A; Blouin, Jean-Sébastien

2011-08-01

Previous studies have shown that human body sway during standing approximates the mechanics of an inverted pendulum pivoted at the ankle joints. In this study, a robotic balance system incorporating a Stewart platform base was developed to provide a new technique to investigate the neural mechanisms involved in standing balance. The robotic system, programmed with the mechanics of an inverted pendulum, controlled the motion of the body in response to a change in applied ankle torque. The ability of the robotic system to replicate the load properties of standing was validated by comparing the load stiffness generated when subjects balanced their own body to the robot's mechanical load programmed with a low (concentrated-mass model) or high (distributed-mass model) inertia. The results show that static load stiffness was not significantly (p > 0.05) different for standing and the robotic system. Dynamic load stiffness for the robotic system increased with the frequency of sway, as predicted by the mechanics of an inverted pendulum, with the higher inertia being accurately matched to the load properties of the human body. This robotic balance system accurately replicated the physical model of standing and represents a useful tool to simulate the dynamics of a standing person. © 2011 IEEE

High-throughput state-machine replication using software transactional memory.

PubMed

Zhao, Wenbing; Yang, William; Zhang, Honglei; Yang, Jack; Luo, Xiong; Zhu, Yueqin; Yang, Mary; Luo, Chaomin

2016-11-01

State-machine replication is a common way of constructing general purpose fault tolerance systems. To ensure replica consistency, requests must be executed sequentially according to some total order at all non-faulty replicas. Unfortunately, this could severely limit the system throughput. This issue has been partially addressed by identifying non-conflicting requests based on application semantics and executing these requests concurrently. However, identifying and tracking non-conflicting requests require intimate knowledge of application design and implementation, and a custom fault tolerance solution developed for one application cannot be easily adopted by other applications. Software transactional memory offers a new way of constructing concurrent programs. In this article, we present the mechanisms needed to retrofit existing concurrency control algorithms designed for software transactional memory for state-machine replication. The main benefit for using software transactional memory in state-machine replication is that general purpose concurrency control mechanisms can be designed without deep knowledge of application semantics. As such, new fault tolerance systems based on state-machine replications with excellent throughput can be easily designed and maintained. In this article, we introduce three different concurrency control mechanisms for state-machine replication using software transactional memory, namely, ordered strong strict two-phase locking, conventional timestamp-based multiversion concurrency control, and speculative timestamp-based multiversion concurrency control. Our experiments show that speculative timestamp-based multiversion concurrency control mechanism has the best performance in all types of workload, the conventional timestamp-based multiversion concurrency control offers the worst performance due to high abort rate in the presence of even moderate contention between transactions. The ordered strong strict two-phase locking mechanism offers the simplest solution with excellent performance in low contention workload, and fairly good performance in high contention workload.

High-throughput state-machine replication using software transactional memory

PubMed Central

Yang, William; Zhang, Honglei; Yang, Jack; Luo, Xiong; Zhu, Yueqin; Yang, Mary; Luo, Chaomin

2017-01-01

State-machine replication is a common way of constructing general purpose fault tolerance systems. To ensure replica consistency, requests must be executed sequentially according to some total order at all non-faulty replicas. Unfortunately, this could severely limit the system throughput. This issue has been partially addressed by identifying non-conflicting requests based on application semantics and executing these requests concurrently. However, identifying and tracking non-conflicting requests require intimate knowledge of application design and implementation, and a custom fault tolerance solution developed for one application cannot be easily adopted by other applications. Software transactional memory offers a new way of constructing concurrent programs. In this article, we present the mechanisms needed to retrofit existing concurrency control algorithms designed for software transactional memory for state-machine replication. The main benefit for using software transactional memory in state-machine replication is that general purpose concurrency control mechanisms can be designed without deep knowledge of application semantics. As such, new fault tolerance systems based on state-machine replications with excellent throughput can be easily designed and maintained. In this article, we introduce three different concurrency control mechanisms for state-machine replication using software transactional memory, namely, ordered strong strict two-phase locking, conventional timestamp-based multiversion concurrency control, and speculative timestamp-based multiversion concurrency control. Our experiments show that speculative timestamp-based multiversion concurrency control mechanism has the best performance in all types of workload, the conventional timestamp-based multiversion concurrency control offers the worst performance due to high abort rate in the presence of even moderate contention between transactions. The ordered strong strict two-phase locking mechanism offers the simplest solution with excellent performance in low contention workload, and fairly good performance in high contention workload. PMID:29075049

Study of Mechanization in DOD Libraries and Information Centers.

ERIC Educational Resources Information Center

Booz, Allen Applied Research, Inc., Bethesda, MD.

This report summarizes the on-site study of mechanization in DoD libraries and information centers. Included are presentations and evaluations on thesaurus building, file structure, input processing, serial control, selective dissemination of information, circulation control, equipments being used, recommendations on information retrieval systems,…

Stable propagation of mechanical signals in soft media using stored elastic energy.

PubMed

Raney, Jordan R; Nadkarni, Neel; Daraio, Chiara; Kochmann, Dennis M; Lewis, Jennifer A; Bertoldi, Katia

2016-08-30

Soft structures with rationally designed architectures capable of large, nonlinear deformation present opportunities for unprecedented, highly tunable devices and machines. However, the highly dissipative nature of soft materials intrinsically limits or prevents certain functions, such as the propagation of mechanical signals. Here we present an architected soft system composed of elastomeric bistable beam elements connected by elastomeric linear springs. The dissipative nature of the polymer readily damps linear waves, preventing propagation of any mechanical signal beyond a short distance, as expected. However, the unique architecture of the system enables propagation of stable, nonlinear solitary transition waves with constant, controllable velocity and pulse geometry over arbitrary distances. Because the high damping of the material removes all other linear, small-amplitude excitations, the desired pulse propagates with high fidelity and controllability. This phenomenon can be used to control signals, as demonstrated by the design of soft mechanical diodes and logic gates.

Stable propagation of mechanical signals in soft media using stored elastic energy

PubMed Central

Raney, Jordan R.; Nadkarni, Neel; Daraio, Chiara; Lewis, Jennifer A.; Bertoldi, Katia

2016-01-01

Soft structures with rationally designed architectures capable of large, nonlinear deformation present opportunities for unprecedented, highly tunable devices and machines. However, the highly dissipative nature of soft materials intrinsically limits or prevents certain functions, such as the propagation of mechanical signals. Here we present an architected soft system composed of elastomeric bistable beam elements connected by elastomeric linear springs. The dissipative nature of the polymer readily damps linear waves, preventing propagation of any mechanical signal beyond a short distance, as expected. However, the unique architecture of the system enables propagation of stable, nonlinear solitary transition waves with constant, controllable velocity and pulse geometry over arbitrary distances. Because the high damping of the material removes all other linear, small-amplitude excitations, the desired pulse propagates with high fidelity and controllability. This phenomenon can be used to control signals, as demonstrated by the design of soft mechanical diodes and logic gates. PMID:27519797

The effects of spaceflight on open-loop and closed-loop postural control mechanisms: human neurovestibular studies on SLS-2

NASA Technical Reports Server (NTRS)

Collins, J. J.; De Luca, C. J.; Pavlik, A. E.; Roy, S. H.; Emley, M. S.; Young, L. R. (Principal Investigator)

1995-01-01

Stabilogram-diffusion analysis was used to examine how prolonged periods in microgravity affect the open-loop and closed-loop postural control mechanisms. It was hypothesized that following spaceflight: (1) the effective stochastic activity of the open-loop postural control schemes in astronauts is increased; (2) the effective stochastic activity and uncorrelated behavior, respectively, of the closed-loop postural control mechanisms in astronauts are increased; and (3) astronauts utilized open-loop postural controls schemes for shorter time intervals and smaller displacements. Four crew members and two alternates from the 14-day Spacelab Life Sciences 2 Mission were included in the study. Each subject was tested under eyes-open, quiet-standing conditions on multiple preflight and postflight days. The subjects' center-of-pressure trajectories were measured with a force platform and analyzed according to stabilogram-diffusion analysis. It was found that the effective stochastic activity of the open-loop postural control schemes in three of the four crew members was increased following spaceflight. This result is interpreted as an indication that there may be in-flight adaptations to higher-level descending postural control pathways, e.g., a postflight increase in the tonic activation of postural muscles. This change may also be the consequence of a compensatory (e.g., "stiffening") postural control strategy that is adopted by astronauts to account for general feeling of postflight unsteadiness. The crew members, as a group, did not exhibit any consistent preflight/postflight differences in the steady-state behavior of their closed-loop postural control mechanisms or in the functional interaction of their open-loop and closed-loop postural control mechanisms. These results are interpreted as indications that although there may be in-flight adaptations to the vestibular system and/or proprioceptive system, input from the visual system can compensate for such changes during undisturbed stance.

The Los Alamos National Laboratory precision double crystal spectrometer

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

Morgan, D.V.; Stevens, C.J.; Liefield, R.J.

1994-03-01

This report discusses the following topics on the LANL precision double crystal X-ray spectrometer: Motivation for construction of the instrument; a brief history of the instrument; mechanical systems; motion control systems; computer control system; vacuum system; alignment program; scan programs; observations of the copper K{alpha} lines; and characteristics and specifications.

Aircraft Instrument, Fire Protection, Warning, Communication, Navigation and Cabin Atmosphere Control System (Course Outline), Aviation Mechanics 3 (Air Frame): 9067.04.

ERIC Educational Resources Information Center

Dade County Public Schools, Miami, FL.

This document presents an outline for a 135-hour course designed to familiarize the student with manipulative skills and theoretical knowledge concerning aircraft instrument systems like major flight and engine instruments; fire protection and fire fighting systems; warning systems and navigation systems; aircraft cabin control systems, such as…

[Research on the Clinical Alarm Management Mechanism Based on Closed-loop Control Theory].

PubMed

Lin, Zhongkuan; Zheng, Kun; Shen, Yunming; Wu, Yunyun

2018-05-30

This paper proposes a clinical alarm management system based on the theory of the closed loop control. The alarm management mechanism can be divided into the expected standard, improving execution rule, rule execution, medical devices with alarm functions, results analysis strategy and the output link. And, we make relevant application and discussion. Results showed that the mechanism can be operable and effective.

ROBOCAL: Gamma-ray isotopic hardware/software interface

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

Hurd, J.R.; Bonner, C.A.; Ostenak, C.A.

1989-01-01

ROBOCAL, presently being developed at the Los Alamos National Laboratory, is a full-scale prototypical robotic system for remotely performing calorimetric and gamma-ray isotopics measurements of nuclear materials. It features a fully automated vertical stacker-retriever for storing and retrieving packaged nuclear materials from a multi-drawer system, and a fully automated, uniquely integrated gantry robot for programmable selection and transfer of nuclear materials to calorimetric and gamma-ray isotopic measurement stations. Since ROBOCAL is to require almost no operator intervention, a mechanical control system is required in addition to a totally automated assay system. The assay system must be a completely integrated datamore » acquisition and isotopic analysis package fully capable of performing state-of-the-art homogeneous and heterogeneous analyses on many varied matrices. The TRIFID assay system being discussed at this conference by J. G. Fleissner of the Rocky Flats Plant has been adopted because of its many automated features. These include: MCA/ADC setup and acquisition; spectral storage and analysis utilizing an expert system formalism; report generation with internal measurement control printout; user friendly screens and menus. The mechanical control portion consists primarily of two detector platforms and a sample platform, each with independent movement. Some minor modifications and additions are needed with TRIFID to interface the assay and mechanical portions with the CimRoc 4000 software controlling the robot. 6 refs., 5 figs., 3 tabs.« less

The system controlling the composition of clastic sediments

USGS Publications Warehouse

Johnsson, Mark J.

1993-01-01

The composition of clastic sediments and rocks is controlled by a complex suite of parameters operating during pedogenesis, erosion, transport, deposition, and burial. The principal first-order parameters include source rock composition, modification by chemical weathering, mechanical disaggregation and abrasion, authigenic inputs, hydrodynamic sorting, and diagenesis. Each of these first-order parameters is influenced to varying degrees by such factors as the tectonic settings of the source region, transportational system and depositional environment, climate, vegetation, relief, slope, and the nature and energy of transportational and depositional systems. These factors are not independent; rather a complicated web of interrelationships and feedback mechanisms causes many factors to be modulated by others. Accordingly, processes controlling the composition of clastic sediments are best viewed as constituting a system, and in evaluating compositional information the dynamics of the system must be considered as whole.

Traffic signal control enhancements under vehicle infrastructure integration systems.

DOT National Transportation Integrated Search

2011-12-01

Most current traffic signal systems are operated using a very archaic traffic-detection simple binary : logic (vehicle presence/non presence information). The logic was originally developed to provide input for old : electro-mechanical controllers th...

Engine Tune-up Service. Unit 6: Emission Control Systems. Review Exercise Book. Automotive Mechanics Curriculum.

ERIC Educational Resources Information Center

Bacon, E. Miles

This book of pretests and review exercises is designed to accompany the Engine Tune-Up Service Student Guide for Unit 6, Emission Control Systems, available separately as CE 031 220. Focus of the exercises and pretests is inspecting, testing, and servicing emission control systems. Pretests and performance checklists are provided for each of the…

Stability and Performance Robustness Assessment of Multivariable Control Systems

DTIC Science & Technology

1993-04-01

00- STABILITY AND PERFORMANCE ROBUSTNESS ASSESSMENT OF MULTIVARIABLE CONTROL SYSTEMS Asok Ray , Jenny I. Shen, and Chen-Kuo Weng Mechanical...Office of Naval Research Assessment of Multivariable Control Systems Grant No. N00014-90-J- 1513 6. AUTHOR(S) (Extension) Professor Asok Ray , Dr...20 The Pennsylvania State University University Park, PA 16802 (20 for Professor Asok Ray ) Naval Postgraduate School

Development of an evolutionary simulator and an overall control system for intelligent wheelchair

NASA Astrophysics Data System (ADS)

Imai, Makoto; Kawato, Koji; Hamagami, Tomoki; Hirata, Hironori

The goal of this research is to develop an intelligent wheelchair (IWC) system which aids an indoor safe mobility for elderly and disabled people with a new conceptual architecture which realizes autonomy, cooperativeness, and a collaboration behavior. In order to develop the IWC system in real environment, we need design-tools and flexible architecture. In particular, as more significant ones, this paper describes two key techniques which are an evolutionary simulation and an overall control mechanism. The evolutionary simulation technique corrects the error between the virtual environment in a simulator and real one in during the learning of an IWC agent, and coevolves with the agent. The overall control mechanism is implemented with subsumption architecture which is employed in an autonomous robot controller. By using these techniques in both simulations and experiments, we confirm that our IWC system acquires autonomy, cooperativeness, and a collaboration behavior efficiently.

CRPS: A contingent hypothesis with prostaglandins as crucial conversion factor.

PubMed

van der Veen, Phe

2015-11-01

CRPS is an acute pain disease expressed as chronic pain with a severe loss of tissue and function. CRPS usually occurs after minor injuries and then progresses in a way that is scarcely controllable, or completely uncontrollable. This article addresses the functional control mechanism of a biological organism, a comparison of techniques, and the way the negative feedback mechanisms fail in regulated feedback systems. The measurement and regulation system is controlled at the local, regional, and central levels in a biological system. Locally generated substances such as prostaglandins and hormones, as well as the central nervous system, play important roles in this process. Prostaglandins fulfil many conversion functions and are involved in vasoactive processes, pain, and inflammation. They play an intermediating role between the activity of the autonomic nervous system and local occurrences. The insufficiently explored conversion function of prostaglandins as a ubiquitously present cofactor may be related to the development of CRPS at sites which have had minor injuries in the past. Chronic Regional Pain Syndrome (CRPS) is a moderately prevalent disease, which occurs more frequently with age. Even though there are diseases known to have a precipitating effect on the aetiology of CRPS, for example Carpal tunnel syndrome, the mechanism of onset is unknown. The disease falls under the category of chronic pain, and seldom has an effective treatment based on scientific research. The economic and psychosocial aspects of the disease are substantial. CRPS is the final position of a positive feedback measurement and control system. Homoeostasis is directed by measurement and control processes. In electronics, a rapid conversion system, which quickly adapts to changing circumstances, superimposed with a delayed conversion system, which ensures a stable basis of homoeostasis. Measured changes are compensatorily controlled. An analogy is expected for a Complex Adaptive System such as a living organism. Hormonal systems are slow systems, suitable for stabilising activity. Neural reflex systems function quickly. Prostaglandins that come from local tissue may be the link between the slow and rapid control. In electronics, negative feedback can convert into a feedback loop which results in the dysregulation, which is what prostaglandins do in biochemistry. A dysregulated feedback control mechanism only has two positions: a zero position and a final position. The process is not easily influenced by other factors. Only phase shifting and signal weakness can affect the feedback process. Theoretically, prostaglandins can also affect this process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Security Policies for Mitigating the Risk of Load Altering Attacks on Smart Grid Systems

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

Ryutov, Tatyana; AlMajali, Anas; Neuman, Clifford

2015-04-01

While demand response programs implement energy efficiency and power quality objectives, they bring potential security threats to the Smart Grid. The ability to influence load in a system enables attackers to cause system failures and impacts the quality and integrity of power delivered to customers. This paper presents a security mechanism to monitor and control load according to a set of security policies during normal system operation. The mechanism monitors, detects, and responds to load altering attacks. We examined the security requirements of Smart Grid stakeholders and constructed a set of load control policies enforced by the mechanism. We implementedmore » a proof of concept prototype and tested it using the simulation environment. By enforcing the proposed policies in this prototype, the system is maintained in a safe state in the presence of load drop attacks.« less

Inhaled nano- and microparticles for drug delivery

PubMed Central

El-Sherbiny, Ibrahim M.; El-Baz, Nancy M.; Yacoub, Magdi H.

2015-01-01

The 21st century has seen a paradigm shift to inhaled therapy, for both systemic and local drug delivery, due to the lung's favourable properties of a large surface area and high permeability. Pulmonary drug delivery possesses many advantages, including non-invasive route of administration, low metabolic activity, control environment for systemic absorption and avoids first bypass metabolism. However, because the lung is one of the major ports of entry, it has multiple clearance mechanisms, which prevent foreign particles from entering the body. Although these clearance mechanisms maintain the sterility of the lung, clearance mechanisms can also act as barriers to the therapeutic effectiveness of inhaled drugs. This effectiveness is also influenced by the deposition site and delivered dose. Particulate-based drug delivery systems have emerged as an innovative and promising alternative to conventional inhaled drugs to circumvent pulmonary clearance mechanisms and provide enhanced therapeutic efficiency and controlled drug release. The principle of multiple pulmonary clearance mechanisms is reviewed, including mucociliary, alveolar macrophages, absorptive, and metabolic degradation. This review also discusses the current approaches and formulations developed to achieve optimal pulmonary drug delivery systems. PMID:26779496

The concept of the mechanically active guideway as a novel approach to maglev

NASA Technical Reports Server (NTRS)

Horwath, T. G.

1992-01-01

A maglev system that is suitable for operation in the United States will have to meet unique requirements which determine the major systems characteristics. Maglev configurations presently developed in Germany and Japan are based on conventional maglev concepts and as such do not meet all of the requirements. A novel maglev guideway concept is introduced as a solution. This concept, the mechanically active guideway, is articulated in three degrees of freedom and assumes system functions which normally reside in the maglev vehicle. The mechanically active guideway contains spatially distributed actuators which are energized under computer control at the time of vehicle passage to achieve bank angle adjustment and ride quality control. A typical realization of the concept is outlined.

Collaboration Mechanism for Equipment Instruction of Multiple Energy Systems

NASA Astrophysics Data System (ADS)

Wang, Dong; Wang, Tuo; Wang, Qi; Zhang, Zhao; Zhao, Mingyu; Wang, Yinghui

2018-01-01

When multiple energy systems execute optimization instructions simultaneously, and the same equipment is Shared, the instruction conflict may occur. Aiming at the above problems, taking into account the control objectives of each system, the characteristics of different systems, such as comprehensive clean energy, energy efficiency, and peak filling, etc., designed the instruction coordination mechanism for the daemon. This mechanism mainly acts on the main station of the system, and form a final optimization instruction. For some specific scenarios, the collaboration mechanism of unlocking the terminal is supplemented. The mechanism determines the specific execution instructions based on the arrival time of the instruction. Finally, the experiment in Tianjin eco-city shows that this algorithm can meet the instruction and collaboration requirements of multi-energy systems, and ensure the safe operation of the equipment.

Mechanisms for Robust Cognition.

PubMed

Walsh, Matthew M; Gluck, Kevin A

2015-08-01

To function well in an unpredictable environment using unreliable components, a system must have a high degree of robustness. Robustness is fundamental to biological systems and is an objective in the design of engineered systems such as airplane engines and buildings. Cognitive systems, like biological and engineered systems, exist within variable environments. This raises the question, how do cognitive systems achieve similarly high degrees of robustness? The aim of this study was to identify a set of mechanisms that enhance robustness in cognitive systems. We identify three mechanisms that enhance robustness in biological and engineered systems: system control, redundancy, and adaptability. After surveying the psychological literature for evidence of these mechanisms, we provide simulations illustrating how each contributes to robust cognition in a different psychological domain: psychomotor vigilance, semantic memory, and strategy selection. These simulations highlight features of a mathematical approach for quantifying robustness, and they provide concrete examples of mechanisms for robust cognition. © 2014 Cognitive Science Society, Inc.

Requirements for implementing real-time control functional modules on a hierarchical parallel pipelined system

NASA Technical Reports Server (NTRS)

Wheatley, Thomas E.; Michaloski, John L.; Lumia, Ronald

1989-01-01

Analysis of a robot control system leads to a broad range of processing requirements. One fundamental requirement of a robot control system is the necessity of a microcomputer system in order to provide sufficient processing capability.The use of multiple processors in a parallel architecture is beneficial for a number of reasons, including better cost performance, modular growth, increased reliability through replication, and flexibility for testing alternate control strategies via different partitioning. A survey of the progression from low level control synchronizing primitives to higher level communication tools is presented. The system communication and control mechanisms of existing robot control systems are compared to the hierarchical control model. The impact of this design methodology on the current robot control systems is explored.

Development and Integration of Control System Models

NASA Technical Reports Server (NTRS)

Kim, Young K.

1998-01-01

The computer simulation tool, TREETOPS, has been upgraded and used at NASA/MSFC to model various complicated mechanical systems and to perform their dynamics and control analysis with pointing control systems. A TREETOPS model of Advanced X-ray Astrophysics Facility - Imaging (AXAF-1) dynamics and control system was developed to evaluate the AXAF-I pointing performance for Normal Pointing Mode. An optical model of Shooting Star Experiment (SSE) was also developed and its optical performance analysis was done using the MACOS software.

A Hierarchical Learning Control Framework for an Aerial Manipulation System

NASA Astrophysics Data System (ADS)

Ma, Le; Chi, yanxun; Li, Jiapeng; Li, Zhongsheng; Ding, Yalei; Liu, Lixing

2017-07-01

A hierarchical learning control framework for an aerial manipulation system is proposed. Firstly, the mechanical design of aerial manipulation system is introduced and analyzed, and the kinematics and the dynamics based on Newton-Euler equation are modeled. Secondly, the framework of hierarchical learning for this system is presented, in which flight platform and manipulator are controlled by different controller respectively. The RBF (Radial Basis Function) neural networks are employed to estimate parameters and control. The Simulation and experiment demonstrate that the methods proposed effective and advanced.

Validation of an in vitro 3D bone culture model with perfused and mechanically stressed ceramic scaffold.

PubMed

Bouet, G; Cruel, M; Laurent, C; Vico, L; Malaval, L; Marchat, D

2015-05-15

An engineered three dimensional (3D) in vitro cell culture system was designed with the goal of inducing and controlling in vitro osteogenesis in a reproducible manner under conditions more similar to the in vivo bone microenvironment than traditional two-dimensional (2D) models. This bioreactor allows efficient mechanical loading and perfusion of an original cubic calcium phosphate bioceramic of highly controlled composition and structure. This bioceramic comprises an internal portion containing homogeneously interconnected macropores surrounded by a dense layer, which minimises fluid flow bypass around the scaffold. This dense and flat layer permits the application of a homogeneous loading on the bioceramic while also enhancing its mechanical strength. Numerical modelling of constraints shows that the system provides direct mechanical stimulation of cells within the scaffold. Experimental results establish that under perfusion at a steady flow of 2 µL/min, corresponding to 3 ≤ Medium velocity ≤ 23 µm/s, mouse calvarial cells grow and differentiate as osteoblasts in a reproducible manner, and lay down a mineralised matrix. Moreover, cells respond to mechanical loading by increasing C-fos expression, which demonstrates the effective mechanical stimulation of the culture within the scaffold. In summary, we provide a "proof-of-concept" for osteoblastic cell culture in a controlled 3D culture system under perfusion and mechanical loading. This model will be a tool to analyse bone cell functions in vivo, and will provide a bench testing system for the clinical assessment of bioactive bone-targeting molecules under load.

Control electronics for a multi-laser/multi-detector scanning system

NASA Technical Reports Server (NTRS)

Kennedy, W.

1980-01-01

The Mars Rover Laser Scanning system uses a precision laser pointing mechanism, a photodetector array, and the concept of triangulation to perform three dimensional scene analysis. The system is used for real time terrain sensing and vision. The Multi-Laser/Multi-Detector laser scanning system is controlled by a digital device called the ML/MD controller. A next generation laser scanning system, based on the Level 2 controller, is microprocessor based. The new controller capabilities far exceed those of the ML/MD device. The first draft circuit details and general software structure are presented.

49 CFR 236.809 - Signal, slotted mechanical.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Signal, slotted mechanical. 236.809 Section 236..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

49 CFR 236.809 - Signal, slotted mechanical.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Signal, slotted mechanical. 236.809 Section 236..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

49 CFR 236.809 - Signal, slotted mechanical.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Signal, slotted mechanical. 236.809 Section 236..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

49 CFR 236.809 - Signal, slotted mechanical.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Signal, slotted mechanical. 236.809 Section 236..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

Next generation control system for reflexive aerostructures

NASA Astrophysics Data System (ADS)

Maddux, Michael R.; Meents, Elizabeth P.; Barnell, Thomas J.; Cable, Kristin M.; Hemmelgarn, Christopher; Margraf, Thomas W.; Havens, Ernie

2010-04-01

Cornerstone Research Group Inc. (CRG) has developed and demonstrated a composite structural solution called reflexive composites for aerospace applications featuring CRG's healable shape memory polymer (SMP) matrix. In reflexive composites, an integrated structural health monitoring (SHM) system autonomously monitors the structural health of composite aerospace structures, while integrated intelligent controls monitor data from the SHM system to characterize damage and initiate healing when damage is detected. Development of next generation intelligent controls for reflexive composites were initiated for the purpose of integrating prognostic health monitoring capabilities into the reflexive composite structural solution. Initial efforts involved data generation through physical inspections and mechanical testing. Compression after impact (CAI) testing was conducted on composite-reinforced shape memory polymer samples to induce damage and investigate the effectiveness of matrix healing on mechanical performance. Non-destructive evaluation (NDE) techniques were employed to observe and characterize material damage. Restoration of mechanical performance was demonstrated through healing, while NDE data showed location and size of damage and verified mitigation of damage post-healing. Data generated was used in the development of next generation reflexive controls software. Data output from the intelligent controls could serve as input to Integrated Vehicle Health Management (IVHM) systems and Integrated Resilient Aircraft Controls (IRAC). Reflexive composite technology has the ability to reduce maintenance required on composite structures through healing, offering potential to significantly extend service life of aerospace vehicles and reduce operating and lifecycle costs.

Control mechanism of double-rotator-structure ternary optical computer

NASA Astrophysics Data System (ADS)

Kai, SONG; Liping, YAN

2017-03-01

Double-rotator-structure ternary optical processor (DRSTOP) has two characteristics, namely, giant data-bits parallel computing and reconfigurable processor, which can handle thousands of data bits in parallel, and can run much faster than computers and other optical computer systems so far. In order to put DRSTOP into practical application, this paper established a series of methods, namely, task classification method, data-bits allocation method, control information generation method, control information formatting and sending method, and decoded results obtaining method and so on. These methods form the control mechanism of DRSTOP. This control mechanism makes DRSTOP become an automated computing platform. Compared with the traditional calculation tools, DRSTOP computing platform can ease the contradiction between high energy consumption and big data computing due to greatly reducing the cost of communications and I/O. Finally, the paper designed a set of experiments for DRSTOP control mechanism to verify its feasibility and correctness. Experimental results showed that the control mechanism is correct, feasible and efficient.

Real-time pair-feeding of animals

NASA Technical Reports Server (NTRS)

Leon, H. A.; Connolly, J. P.; Hitchman, M. J.; Humbert, J. E.

1972-01-01

Automatic pair-feeding system was developed which immediately dispenses same amount of food to control animal as has been consumed by experimental animal that has free access to food. System consists of: master feeding system; slave feeding station; and control mechanism. Technique performs real time pair-feeding without attendant time lag.

MOCAD: A Tool for Graphical and Interactive Calculation and Optimization of Cam Mechanisms and Motion Control Systems

NASA Astrophysics Data System (ADS)

Heine, A.; Berger, M.

The classical meaning of motion design is the usage of laws of motion with convenient characteristic values. Whereas the software MOCAD supports a graphical and interactive mode of operation, among others by using an automatic polynomial interpolation. Besides a direct coupling for motion control systems, different file formats for data export are offered. The calculation of plane and spatial cam mechanisms is also based on the data, generated in the motion design module. Drawing on an example of an intermittent cam mechanism with an inside cam profile used as a new drive concept for indexing tables, the influence of motion design on the transmission properties is shown. Another example gives an insight into the calculation and export of envelope curves for cylindrical cam mechanisms. The gained geometry data can be used for generating realistic 3D-models in the CAD-system Pro/ENGINEER, using a special data exchange format.

A review of adaptive change in musculoskeletal impedance during space flight and associated implications for postflight head movement control

NASA Technical Reports Server (NTRS)

McDonald, P. V.; Bloomberg, J. J.; Layne, C. S.

1997-01-01

We present a review of converging sources of evidence which suggest that the differences between loading histories experienced in 1-g and weightlessness are sufficient to stimulate adaptation in mechanical impedance of the musculoskeletal system. As a consequence of this adaptive change we argue that we should observe changes in the ability to attenuate force transmission through the musculoskeletal system both during and after space flight. By focusing attention on the relation between human sensorimotor activity and support surfaces, the importance of controlling mechanical energy flow through the musculoskeletal system is demonstrated. The implications of such control are discussed in light of visual-vestibular function in the specific context of head and gaze control during postflight locomotion. Evidence from locomotory biomechanics, visual-vestibular function, ergonomic evaluations of human vibration, and specific investigations of locomotion and head and gaze control after space flight, is considered.

Acquisition of Mechanically Assisted Spark Plasma Sintering System for Advanced Research and Education on Functionally Graded Hybrid Materials

DTIC Science & Technology

2012-03-14

Institute. The proposed effort offers a multidisciplinary research program to achieve the topic goals by coupling thermal- acoustic - mechanical flight...optional optical pyrometer .  Single port for standard (mechanical vacuum pump) and high vacuum system. POWER SUPPLY  10,000 amp, 10 VDC pulsed...Amperage TEMPERATURE CONTROL SYSTEM  Ten (10) Type K and five (5) Type C thermocouples with protective flexible sheaths.  Optical Pyrometer

SYSTEMS APPROACH TO CHARACTERIZING AND PREDICTING THYROID TOXICITY

EPA Science Inventory

A systems approach is being undertaken in which in vivo and in vitro assays are integrated to understand the mechanisms of thyroid hormone mediated pathways controlling frog metamorphosis, and more generally the regulation and control of the HPT axis.

MOD-OA 200 kW wind turbine generator engineeringing

NASA Technical Reports Server (NTRS)

Andersen, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.

1980-01-01

Engineering drawings and the detailed mechanical and electrical design of a horizontal-axis wind turbine designed for DOE at the NASA Lewis Research Center and installed in Clayton, New Mexico are discussed. The drawings show the hub, pitch change mechanism, drive train, nacelle equipment, yaw drive system, tower, foundation, electrical power systems, and the control and safety systems.

A weed compaction roller system for use with mechanical herbicide application

Treesearch

Adam H. Wiese; Daniel A. Netzer; Don E. Riemenschneider; Ronald S., Jr. Zalesny

2006-01-01

We designed, constructed, and field-tested a versatile and unique weed compaction roller system that can be used with mechanical herbicide application for invasive weed control in tree plantations, agronomic settings, and areas where localized flora and fauna are in danger of elimination from the landscape. The weed compaction roller system combined with herbicide...

Dynamic Inversion based Control of a Docking Mechanism

NASA Technical Reports Server (NTRS)

Kulkarni, Nilesh V.; Ippolito, Corey; Krishnakumar, Kalmanje

2006-01-01

The problem of position and attitude control of the Stewart platform based docking mechanism is considered motivated by its future application in space missions requiring the autonomous docking capability. The control design is initiated based on the framework of the intelligent flight control architecture being developed at NASA Ames Research Center. In this paper, the baseline position and attitude control system is designed using dynamic inversion with proportional-integral augmentation. The inverse dynamics uses a Newton-Euler formulation that includes the platform dynamics, the dynamics of the individual legs along with viscous friction in the joints. Simulation results are presented using forward dynamics simulated by a commercial physics engine that builds the system as individual elements with appropriate joints and uses constrained numerical integration,

Autonomous Operations System: Development and Application

NASA Technical Reports Server (NTRS)

Toro Medina, Jaime A.; Wilkins, Kim N.; Walker, Mark; Stahl, Gerald M.

2016-01-01

Autonomous control systems provides the ability of self-governance beyond the conventional control system. As the complexity of mechanical and electrical systems increases, there develops a natural drive for developing robust control systems to manage complicated operations. By closing the bridge between conventional automated systems to knowledge based self-awareness systems, nominal control of operations can evolve into relying on safe critical mitigation processes to support any off-nominal behavior. Current research and development efforts lead by the Autonomous Propellant Loading (APL) group at NASA Kennedy Space Center aims to improve cryogenic propellant transfer operations by developing an automated control and health monitoring system. As an integrated systems, the center aims to produce an Autonomous Operations System (AOS) capable of integrating health management operations with automated control to produce a fully autonomous system.

Flutter suppression for the Active Flexible Wing - Control system design and experimental validation

NASA Technical Reports Server (NTRS)

Waszak, M. R.; Srinathkumar, S.

1992-01-01

The synthesis and experimental validation of a control law for an active flutter suppression system for the Active Flexible Wing wind-tunnel model is presented. The design was accomplished with traditional root locus and Nyquist methods using interactive computer graphics tools and with extensive use of simulation-based analysis. The design approach relied on a fundamental understanding of the flutter mechanism to formulate understanding of the flutter mechanism to formulate a simple control law structure. Experimentally, the flutter suppression controller succeeded in simultaneous suppression of two flutter modes, significantly increasing the flutter dynamic pressure despite errors in the design model. The flutter suppression controller was also successfully operated in combination with a rolling maneuver controller to perform flutter suppression during rapid rolling maneuvers.

[Advanced Development for Space Robotics With Emphasis on Fault Tolerance Technology

NASA Technical Reports Server (NTRS)

Tesar, Delbert

1997-01-01

This report describes work developing fault tolerant redundant robotic architectures and adaptive control strategies for robotic manipulator systems which can dynamically accommodate drastic robot manipulator mechanism, sensor or control failures and maintain stable end-point trajectory control with minimum disturbance. Kinematic designs of redundant, modular, reconfigurable arms for fault tolerance were pursued at a fundamental level. The approach developed robotic testbeds to evaluate disturbance responses of fault tolerant concepts in robotic mechanisms and controllers. The development was implemented in various fault tolerant mechanism testbeds including duality in the joint servo motor modules, parallel and serial structural architectures, and dual arms. All have real-time adaptive controller technologies to react to mechanism or controller disturbances (failures) to perform real-time reconfiguration to continue the task operations. The developments fall into three main areas: hardware, software, and theoretical.

Precision displacement reference system

DOEpatents

Bieg, Lothar F.; Dubois, Robert R.; Strother, Jerry D.

2000-02-22

A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

Application of Calspan pitch rate control system to the Space Shuttle for approach and landing

NASA Technical Reports Server (NTRS)

Weingarten, N. C.; Chalk, C. R.

1983-01-01

A pitch rate control system designed for use in the shuttle during approach and landing was analyzed and compared with a revised control system developed by NASA and the existing OFT control system. The design concept control system uses filtered pitch rate feedback with proportional plus integral paths in the forward loop. Control system parameters were designed as a function of flight configuration. Analysis included time and frequency domain techniques. Results indicate that both the Calspan and NASA systems significantly improve the flying qualities of the shuttle over the OFT. Better attitude and flight path control and less time delay are the primary reasons. The Calspan system is preferred because of reduced time delay and simpler mechanization. Further testing of the improved flight control systems in an in-flight simulator is recommended.

Integrating end-to-end threads of control into object-oriented analysis and design

NASA Technical Reports Server (NTRS)

Mccandlish, Janet E.; Macdonald, James R.; Graves, Sara J.

1993-01-01

Current object-oriented analysis and design methodologies fall short in their use of mechanisms for identifying threads of control for the system being developed. The scenarios which typically describe a system are more global than looking at the individual objects and representing their behavior. Unlike conventional methodologies that use data flow and process-dependency diagrams, object-oriented methodologies do not provide a model for representing these global threads end-to-end. Tracing through threads of control is key to ensuring that a system is complete and timing constraints are addressed. The existence of multiple threads of control in a system necessitates a partitioning of the system into processes. This paper describes the application and representation of end-to-end threads of control to the object-oriented analysis and design process using object-oriented constructs. The issue of representation is viewed as a grouping problem, that is, how to group classes/objects at a higher level of abstraction so that the system may be viewed as a whole with both classes/objects and their associated dynamic behavior. Existing object-oriented development methodology techniques are extended by adding design-level constructs termed logical composite classes and process composite classes. Logical composite classes are design-level classes which group classes/objects both logically and by thread of control information. Process composite classes further refine the logical composite class groupings by using process partitioning criteria to produce optimum concurrent execution results. The goal of these design-level constructs is to ultimately provide the basis for a mechanism that can support the creation of process composite classes in an automated way. Using an automated mechanism makes it easier to partition a system into concurrently executing elements that can be run in parallel on multiple processors.

Variability in cardiovascular control: the baroreflex reconsidered.

PubMed

Karemaker, John M; Wesseling, Karel H

2008-03-01

Although blood pressure control is often viewed as a paradigmatic example of a "homeostatic" biological control system, blood pressure levels can fluctuate considerably over shorter and longer time scales. In modern signal analysis, coherence between heart rate and blood pressure variability is used to estimate baroreflex gain. However, the shorter the measurement period, the more variability this gain factor reveals. We review evidence that this variability is not due to the technique used for the estimation, but may be an intrinsic property of the circulatory control mechanisms. The baroreflex is reviewed from its evolutionary origin, starting in fishes as a reflex mechanism to protect the gills from excessively high pressures by slowing the heart via the (parasympathetic) vagus nerve. Baroreflex inhibition of cardiovascular sympathetic nervous outflow is a later development; the maximally possible extent of sympathetic activity probably being set in the central nervous system by mechanisms other than blood pressure per se. In the sympathetic outflow tract not only baroreflex inhibition but also as yet unidentified, stochastic mechanisms decide to pass or not pass on the sympathetic activity to the periphery. In this short essay, the "noisiness" of the baroreflex as nervous control system is stressed. This property is observed in all elements of the reflex, even at the--supposedly--most basic relation between afferent receptor nerve input and efferent--vagus--nerve output signal.

Fault Detection and Isolation for Hydraulic Control

NASA Technical Reports Server (NTRS)

1987-01-01

Pressure sensors and isolation valves act to shut down defective servochannel. Redundant hydraulic system indirectly senses failure in any of its electrical control channels and mechanically isolates hydraulic channel controlled by faulty electrical channel so flat it cannot participate in operating system. With failure-detection and isolation technique, system can sustains two failed channels and still functions at full performance levels. Scheme useful on aircraft or other systems with hydraulic servovalves where failure cannot be tolerated.

ROMPS critical design review data package

NASA Technical Reports Server (NTRS)

Dobbs, M. E.

1992-01-01

The design elements of the Robot-Operated Material Processing in Space (ROMPS) system are described in outline and graphical form. The following subsystems/topics are addressed: servo system, testbed and simulation results, System V Controller, robot module, furnace module, SCL experiment supervisor and script sample processing control, battery system, watchdog timers, mechanical/thermal considerations, and fault conditions and recovery.

46 CFR 154.1200 - Mechanical ventilation system: General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... gas-safe space in the cargo area. (4) Each space that contains inert gas generators, except main...) Each cargo compressor room, pump room, gas-dangerous cargo control station, and space that contains... following must have a supply-type mechanical ventilation system: (1) Each space that contains electric...

Software control and system configuration management: A systems-wide approach

NASA Technical Reports Server (NTRS)

Petersen, K. L.; Flores, C., Jr.

1984-01-01

A comprehensive software control and system configuration management process for flight-crucial digital control systems of advanced aircraft has been developed and refined to insure efficient flight system development and safe flight operations. Because of the highly complex interactions among the hardware, software, and system elements of state-of-the-art digital flight control system designs, a systems-wide approach to configuration control and management has been used. Specific procedures are implemented to govern discrepancy reporting and reconciliation, software and hardware change control, systems verification and validation testing, and formal documentation requirements. An active and knowledgeable configuration control board reviews and approves all flight system configuration modifications and revalidation tests. This flexible process has proved effective during the development and flight testing of several research aircraft and remotely piloted research vehicles with digital flight control systems that ranged from relatively simple to highly complex, integrated mechanizations.

An Intelligent Catheter System Robotic Controlled Catheter System

PubMed Central

Negoro, M.; Tanimoto, M.; Arai, F.; Fukuda, T.; Fukasaku, K.; Takahashi, I.; Miyachi, S.

2001-01-01

Summary We have developed a novel catheter system, an intelligent catheter system, which is able to control a catheter by an externally-placed controller. This system has made from master-slave mechanism and has following three components; 1) a joy stick as a master (for operators) 2)a catheter controller as a slave (for a patient),3)a micro force sensor as a sensing device. This catheter tele-guiding system has abilities to perform intravascular procedures from the distant places. It may help to reduce the radiation exposures to the operators and also to help train young doctors. PMID:20663387

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transpot project-demonstration act system definition

NASA Technical Reports Server (NTRS)

Hanks, G. W.; Shomber, H. A.; Crumb, C. B.; Flora, C. C.; Macdonald, K. A. B.; Smith, R. D.; Sassi, A. P.; Dorwart, R. J.

1982-01-01

The 1985 ACT airplane is the Final Active Controls Technology (ACT) Airplane with the addition of three-axis fly by wire. Thus it retains all the efficiency features of the full ACT system plus the weight and cost savings accruing from deletion of the mechanical control system. The control system implements the full IAAC spectrum of active controls except flutter-mode control, judged essentially nonbeneficial, and incorporates new control surfaces called flaperons to make the most of wing-load alleviation. This redundant electronic system is conservatively designed to preserve the extreme reliability required of crucial short-period pitch augmentation, which provides more than half of the fuel savings.

Proceedings of the NATO-Advanced Study Institute on Computer Aided Analysis of Rigid and Flexible Mechanical Systems. Volume 1: Main lectures

NASA Astrophysics Data System (ADS)

Pereira, Manuel S.; Ambrosio, Jorge A. C.

1993-07-01

During the last few years, major scientific progress has been achieved in fields related to computer aided analysis of multibody systems. In view of this progress and recent developments of computer hardware and general purpose software, there is a need to access the current state of art and results from different schools of thought, with the objective of focussing trends in future research. Going back to 1983 when an important NATO-NSF-ARO Advanced Study Institute on Computer Aided Analysis and Optimization of Mechanical Systems was held at the University of Iowa, one may notice that less then 10 years ago the state of art was mainly dwelling on rigid body dynamics. The interest in the dynamic simulation of mechanical systems has steadily increased in recent years coming mainly from the aerospace and automative industries. The development of multibody system analysis formulations have been more recently motivated with the need to include several features such as: real-time simulation capabilities, highly non-linear control devices, work space path planing, active control of machine flexibilities and reliability and accuracy in the analysis results. The need for accurate and efficient analysis tools for design of large and lightweight mechanical systems has driven many research groups in the challenging problem of flexible systems with an increasing interaction with finite element methodologies. Basic approaches to mechanical systems dynamic analysis have recently been presented in several new text books. These publications demonstrate that both recursive and absolute methods still have their proponents to resolve the redundancy encountered in most mechanical systems.

Quantum acoustics with superconducting qubits

NASA Astrophysics Data System (ADS)

Chu, Yiwen

2017-04-01

The ability to engineer and manipulate different types of quantum mechanical objects allows us to take advantage of their unique properties and create useful hybrid technologies. Thus far, complex quantum states and exquisite quantum control have been demonstrated in systems ranging from trapped ions to superconducting resonators. Recently, there have been many efforts to extend these demonstrations to the motion of complex, macroscopic objects. These mechanical objects have important applications as quantum memories or transducers for measuring and connecting different types of quantum systems. In particular, there have been a few experiments that couple motion to nonlinear quantum objects such as superconducting qubits. This opens up the possibility of creating, storing, and manipulating non-Gaussian quantum states in mechanical degrees of freedom. However, before sophisticated quantum control of mechanical motion can be achieved, we must realize systems with long coherence times while maintaining a sufficient interaction strength. These systems should be implemented in a simple and robust manner that allows for increasing complexity and scalability in the future. In this talk, I will describe our recent experiments demonstrating a high frequency bulk acoustic wave resonator that is strongly coupled to a superconducting qubit using piezoelectric transduction. In contrast to previous experiments with qubit-mechanical systems, our device requires only simple fabrication methods, extends coherence times to many microseconds, and provides controllable access to a multitude of phonon modes. We use this system to demonstrate basic quantum operations on the coupled qubit-phonon system. Straightforward improvements to the current device will allow for advanced protocols analogous to what has been shown in optical and microwave resonators, resulting in a novel resource for implementing hybrid quantum technologies.

Design and implementation of new control room system in Damavand tokamak

NASA Astrophysics Data System (ADS)

Rasouli, H.; Zamanian, H.; Gheidi, M.; Kheiri-Fard, M.; Kouhi, A.

2017-07-01

The aim of this paper is design and implementation of an up-to-date control room. The previous control room had a lot of constraints and it was not apposite to the sophisticated diagnostic systems as well as to the modern control and multivariable systems. Although it provided the best output for the considered experiments and implementing offline algorithms among all similar plants, it needed to be developed to provide more capability for complex algorithm mechanisms and this work introduces our efforts in this area. Accordingly, four leading systems were designed and implemented, including real-time control system, online Data Acquisition System (DAS), offline DAS, monitoring and data transmission system. In the control system, three real-time control modules were established based on Digital Signal Processor (DSP). Thanks to them, implementation of the classic and linear and nonlinear intelligent controllers was possible to control the plasma position and its elongation. Also, online DAS was constructed in two modules. Using them, voltages and currents of charge for the capacitor banks and pressure of different parts in vacuum vessel were measured and monitored. Likewise, by real-time processing of the online data, the safety protocol of plant performance was accomplished. In addition, the offline DAS was organized in 13 modules based on Field Programmable Gate Array (FPGA). This system can be used for gathering all diagnostic, control, and performance data in 156 channels. Data transmission system and storing mechanism in the server was provided by data transmitting network and MDSplus standard protocol. Moreover, monitoring software was designed so that it could display the required plots for physical analyses. Taking everything into account, this new platform can improve the quality and quantity of research activities in plasma physics for Damavand tokamak.

Noise Reduction Through Circulation Control

NASA Technical Reports Server (NTRS)

Munro, Scott E.; Ahuja, K. K.; Englar, Robert J.

2005-01-01

Circulation control technology uses tangential blowing around a rounded trailing edge or a leading edge to change the force and moment characteristics of an aerodynamic body. This technology has been applied to circular cylinders, wings, helicopter rotors, and even to automobiles for improved aerodynamic performance. Only limited research has been conducted on the acoustic of this technology. Since wing flaps contribute to the environmental noise of an aircraft, an alternate blown high lift system without complex mechanical flaps could prove beneficial in reducing the noise of an approaching aircraft. Thus, in this study, a direct comparison of the acoustic characteristics of high lift systems employing a circulation control wing configuration and a conventional wing flapped configuration has been made. These results indicate that acoustically, a circulation control wing high lift system could be considerably more acceptable than a wing with conventional mechanical flaps.

The Brain in its Body: Motor Control and Sensing in a Biomechanical Context

PubMed Central

Chiel, Hillel J.; Ting, Lena H.; Ekeberg, Orjan; Hartmann, Mitra J. Z.

2009-01-01

Although it is widely recognized that adaptive behavior emerges from the ongoing interactions among the nervous system, the body, and the environment, it has only become possible in recent years to experimentally study and to simulate these interacting systems. We briefly review work on molluscan feeding, maintenance of postural control in cats and humans, simulations of locomotion in lamprey, insect, cat and salamander, and active vibrissal sensing in rats to illustrate the insights that can be derived from studies of neural control and sensing within a biomechanical context. These studies illustrate that control may be shared between the nervous system and the periphery, that neural activity organizes degrees of freedom into biomechanically meaningful subsets, that mechanics alone may play crucial roles in enforcing gait patterns, and that mechanics of sensors is crucial for their function. PMID:19828793

Electro-mechanical energy conversion system having a permanent magnet machine with stator, resonant transfer link and energy converter controls

DOEpatents

Skeist, S. Merrill; Baker, Richard H.

2006-01-10

An electro-mechanical energy conversion system coupled between an energy source and an energy load comprising an energy converter device including a permanent magnet induction machine coupled between the energy source and the energy load to convert the energy from the energy source and to transfer the converted energy to the energy load and an energy transfer multiplexer to control the flow of power or energy through the permanent magnetic induction machine.

Controlling molecular transport in minimal emulsions

NASA Astrophysics Data System (ADS)

Gruner, Philipp; Riechers, Birte; Semin, Benoît; Lim, Jiseok; Johnston, Abigail; Short, Kathleen; Baret, Jean-Christophe

2016-01-01

Emulsions are metastable dispersions in which molecular transport is a major mechanism driving the system towards its state of minimal energy. Determining the underlying mechanisms of molecular transport between droplets is challenging due to the complexity of a typical emulsion system. Here we introduce the concept of `minimal emulsions', which are controlled emulsions produced using microfluidic tools, simplifying an emulsion down to its minimal set of relevant parameters. We use these minimal emulsions to unravel the fundamentals of transport of small organic molecules in water-in-fluorinated-oil emulsions, a system of great interest for biotechnological applications. Our results are of practical relevance to guarantee a sustainable compartmentalization of compounds in droplet microreactors and to design new strategies for the dynamic control of droplet compositions.

An anticipative escape system for vehicles in water crashes

NASA Astrophysics Data System (ADS)

Shen, Chuanliang; Wang, Jiawei; Yin, Qi; Zhu, Yantao; Yang, Jiawei; Liao, Mengdi; Yang, Liming

2017-07-01

In this article, it designs an escape system for vehicles in water crashes. The structure mainly contains sensors, control organs and actuating mechanism for both doors and windows. Sensors judge whether the vehicle falls into water or is in the falling process. The actuating mechanism accepts the signal delivered by the control organs, then open the electronic central lock on doors and meanwhile lower the window. The water escape system is able to anticipate drowning situations for vehicles and controls both doors and windows in such an emergency. Under the premise of doors staying in an undamaged state, it is for sure that people in the vehicle can open the door while drowning in the water and safely escape.

Virtual reality robotic telesurgery simulations using MEMICA haptic system

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Mavroidis, Constantinos; Bouzit, Mourad; Dolgin, Benjamin; Harm, Deborah L.; Kopchok, George E.; White, Rodney

2001-01-01

The authors conceived a haptic mechanism called MEMICA (Remote Mechanical Mirroring using Controlled stiffness and Actuators) that can enable the design of high dexterity, rapid response, and large workspace haptic system. The development of a novel MEMICA gloves and virtual reality models are being explored to allow simulation of telesurgery and other applications. The MEMICA gloves are being designed to provide intuitive mirroring of the conditions at a virtual site where a robot simulates the presence of a human operator. The key components of MEMICA are miniature electrically controlled stiffness (ECS) elements and electrically controlled force and stiffness (ECFS) actuators that are based on the use of Electro-Rheological Fluids (ERF. In this paper the design of the MEMICA system and initial experimental results are presented.

MEMS device for spacecraft thermal control applications

NASA Technical Reports Server (NTRS)

Swanson, Theordore D. (Inventor)

2003-01-01

A micro-electromechanical device that comprises miniaturized mechanical louvers, referred to as Micro Electro-Mechanical Systems (MEMS) louvers are employed to achieve a thermal control function for spacecraft and instruments. The MEMS louvers are another form of a variable emittance control coating and employ micro-electromechanical technology. In a function similar to traditional, macroscopic thermal louvers, the MEMS louvers of the present invention change the emissivity of a surface. With the MEMS louvers, as with the traditional macroscopic louvers, a mechanical vane or window is opened and closed to allow an alterable radiative view to space.

Addressing Production System Failures Using Multi-agent Control

NASA Astrophysics Data System (ADS)

Gautam, Rajesh; Miyashita, Kazuo

Output in high-volume production facilities is limited by bottleneck machines. We propose a control mechanism by modeling workstations as agents that pull jobs from other agents based on their current WIP level and requirements. During failures, when flows of some jobs are disrupted, the agents pull alternative jobs to maintain utilization of their capacity at a high level. In this paper, we empirically demonstrate that the proposed mechanism can react to failures more appropriately than other control mechanisms using a benchmark problem of a semiconductor manufacturing process.

Neural control of muscle

NASA Technical Reports Server (NTRS)

Max, S. R.; Markelonis, G. J.

1983-01-01

Cholinergic innervation regulates the physiological and biochemical properties of skeletal muscle. The mechanisms that appear to be involved in this regulation include soluble, neurally-derived polypeptides, transmitter-evoked muscle activity and the neurotransmitter, acetylcholine, itself. Despite extensive research, the interacting neural mechanisms that control such macromolecules as acetylcholinesterase, the acetylcholine receptor and glucose 6-phosphate dehydrogenase remain unclear. It may be that more simplified in vitro model systems coupled with recent dramatic advances in the molecular biology of neurally-regulated proteins will begin to allow researchers to unravel the mechanisms controlling the expression and maintenance of these macromolecules.

An architecture for heuristic control of real-time processes

NASA Technical Reports Server (NTRS)

Raulefs, P.; Thorndyke, P. W.

1987-01-01

Abstract Process management combines complementary approaches of heuristic reasoning and analytical process control. Management of a continuous process requires monitoring the environment and the controlled system, assessing the ongoing situation, developing and revising planned actions, and controlling the execution of the actions. For knowledge-intensive domains, process management entails the potentially time-stressed cooperation among a variety of expert systems. By redesigning a blackboard control architecture in an object-oriented framework, researchers obtain an approach to process management that considerably extends blackboard control mechanisms and overcomes limitations of blackboard systems.

An in-plane nano-mechanics approach to achieve reversible resonance control of photonic crystal nanocavities.

PubMed

Chew, Xiongyeu; Zhou, Guangya; Yu, Hongbin; Chau, Fook Siong; Deng, Jie; Loke, Yee Chong; Tang, Xiaosong

2010-10-11

Control of photonic crystal resonances in conjunction with large spectral shifting is critical in achieving reconfigurable photonic crystal devices. We propose a simple approach to achieve nano-mechanical control of photonic crystal resonances within a compact integrated on-chip approach. Three different tip designs utilizing an in-plane nano-mechanical tuning approach are shown to achieve reversible and low-loss resonance control on a one-dimensional photonic crystal nanocavity. The proposed nano-mechanical approach driven by a sub-micron micro-electromechanical system integrated on low loss suspended feeding nanowire waveguide, achieved relatively large resonance spectral shifts of up to 18 nm at a driving voltage of 25 V. Such designs may potentially be used as tunable optical filters or switches.

Software control and system configuration management - A process that works

NASA Technical Reports Server (NTRS)

Petersen, K. L.; Flores, C., Jr.

1983-01-01

A comprehensive software control and system configuration management process for flight-crucial digital control systems of advanced aircraft has been developed and refined to insure efficient flight system development and safe flight operations. Because of the highly complex interactions among the hardware, software, and system elements of state-of-the-art digital flight control system designs, a systems-wide approach to configuration control and management has been used. Specific procedures are implemented to govern discrepancy reporting and reconciliation, software and hardware change control, systems verification and validation testing, and formal documentation requirements. An active and knowledgeable configuration control board reviews and approves all flight system configuration modifications and revalidation tests. This flexible process has proved effective during the development and flight testing of several research aircraft and remotely piloted research vehicles with digital flight control systems that ranged from relatively simple to highly complex, integrated mechanizations.

Microwave power transmission system studies. Volume 3, section 8: Mechanical systems and flight operations

NASA Technical Reports Server (NTRS)

Maynard, O. E.; Brown, W. C.; Edwards, A.; Haley, J. T.; Meltz, G.; Howell, J. M.; Nathan, A.

1975-01-01

The efforts and recommendations associated with preliminary design and concept definition for mechanical systems and flight operations are presented. Technical discussion in the areas of mission analysis, antenna structural concept, configuration analysis, assembly and packaging with associated costs are presented. Technology issues for the control system, structural system, thermal system and assembly including cost and man's role in assembly and maintenance are identified. Background and desired outputs for future efforts are discussed.

Equipment modifications for perennial nutsedge control in fallow organic transition

USDA-ARS?s Scientific Manuscript database

Perennial nutsedges are extremely difficult to control in organic crop transition and production systems. Herbicides suitable for use in certified organic production do not adequately control perennial nutsedges. Cultural and mechanical control are partially effective in controlling perennial nuts...

Titan 3E/Centaur D-1T Systems Summary

NASA Technical Reports Server (NTRS)

1973-01-01

A systems and operational summary of the Titan 3E/Centaur D-1T program is presented which describes vehicle assembly facilities, launch facilities, and management responsibilities, and also provides detailed information on the following separate systems: (1) mechanical systems, including structural components, insulation, propulsion units, reaction control, thrust vector control, hydraulic systems, and pneumatic equipment; (2) astrionics systems, such as instrumentation and telemetry, navigation and guidance, C-Band tracking system, and range safety command system; (3) digital computer unit software; (4) flight control systems; (5) electrical/electronic systems; and (6) ground support equipment, including checkout equipment.

Stochastic resonant damping in a noisy monostable system: theory and experiment.

PubMed

Volpe, Giovanni; Perrone, Sandro; Rubi, J Miguel; Petrov, Dmitri

2008-05-01

Usually in the presence of a background noise an increased effort put in controlling a system stabilizes its behavior. Rarely it is thought that an increased control of the system can lead to a looser response and, therefore, to a poorer performance. Strikingly there are many systems that show this weird behavior; examples can be drawn form physical, biological, and social systems. Until now no simple and general mechanism underlying such behaviors has been identified. Here we show that such a mechanism, named stochastic resonant damping, can be provided by the interplay between the background noise and the control exerted on the system. We experimentally verify our prediction on a physical model system based on a colloidal particle held in an oscillating optical potential. Our result adds a tool for the study of intrinsically noisy phenomena, joining the many constructive facets of noise identified in the past decades-for example, stochastic resonance, noise-induced activation, and Brownian ratchets.

Test bed experiments for various telerobotic system characteristics and configurations

NASA Technical Reports Server (NTRS)

Duffie, Neil A.; Wiker, Steven F.; Zik, John J.

1990-01-01

Dexterous manipulation and grasping in telerobotic systems depends on the integration of high-performance sensors, displays, actuators and controls into systems in which careful consideration has been given to human perception and tolerance. Research underway at the Wisconsin Center for Space Automation and Robotics (WCSAR) has the objective of enhancing the performance of these systems and their components, and quantifying the effects of the many electrical, mechanical, control, and human factors that affect their performance. This will lead to a fundamental understanding of performance issues which will in turn allow designers to evaluate sensor, actuator, display, and control technologies with respect to generic measures of dexterous performance. As part of this effort, an experimental test bed was developed which has telerobotic components with exceptionally high fidelity in master/slave operation. A Telerobotic Performance Analysis System has also been developed which allows performance to be determined for various system configurations and electro-mechanical characteristics. Both this performance analysis system and test bed experiments are described.

Investigating the Relationship between Governance Mechanisms and the Disclosure of IT Control Weaknesses

ERIC Educational Resources Information Center

Hamdan, Basil

2012-01-01

The current research is concerned with exploring the quality of information technology (IT) control over financial reporting systems as reported under Section 404 of the Sarbanes-Oxley Act of 2002. More specifically, this dissertation examines the association between organizational governance mechanisms and the occurrence and subsequent disclosure…

46 CFR 111.106-15 - Ventilation of hazardous locations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... its operational controls outside the ventilated space, if the system is mechanical; and (3) Have a... opening. (c) The mechanical ventilation of enclosed flammable or combustible liquid cargo handling or.... The power ventilation system must be designed to remove vapors from the bottom of the space at points...

109. EAST WALL OF MECHANICAL EQUIPMENT ROOM (201), LSB (BLDG. ...

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

109. EAST WALL OF MECHANICAL EQUIPMENT ROOM (201), LSB (BLDG. 751): TEMPERATURE, FLOW RATE, AND HUMIDITY MONITORING CONTROLS FOR SYSTEM 1 AND SYSTEM 2 AIR HANDLING - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

92. EAST WALL OF MECHANICAL EQUIPMENT ROOM (101), LSB (BLDG. ...

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

92. EAST WALL OF MECHANICAL EQUIPMENT ROOM (101), LSB (BLDG. 770). TEMPERATURE, FLOW RATE, AND HUMIDITY MONITORING CONTROLS FOR SYSTEM 1 AND SYSTEM 2 AIR HANDLING. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

K- and Ka-band mobile-vehicular satellite-tracking reflector antenna system for the NASA ACTS mobile terminal

NASA Technical Reports Server (NTRS)

Densmore, Art; Jamnejad, Vahraz; Wu, T. K.; Woo, Ken

1993-01-01

This paper describes the development of the K- and Ka-band mobile-vehicular satellite-tracking reflector antenna system for NASA's ACTS Mobile Terminal (AMT) project. ACTS is NASA's Advanced Communications Technology Satellites. The AMT project will make the first experimental use of ACTS soon after the satellite is operational, to demonstrate mobile communications via the satellite from a van on the road. The AMT antenna system consists of a mechanically steered small reflector antenna, using a shared aperture for both frequency bands and fitting under a radome of 23 cm diameter and 10 cm height, and a microprocessor controlled antenna controller that tracks the satellite as the vehicle moves about. The RF and mechanical characteristics of the antenna and the antenna tracking control system are discussed. Measurements of the antenna performance are presented.

Periodic motion planning and control for underactuated mechanical systems

NASA Astrophysics Data System (ADS)

Wang, Zeguo; Freidovich, Leonid B.; Zhang, Honghua

2018-06-01

We consider the problem of periodic motion planning and of designing stabilising feedback control laws for such motions in underactuated mechanical systems. A novel periodic motion planning method is proposed. Each state is parametrised by a truncated Fourier series. Then we use numerical optimisation to search for the parameters of the trigonometric polynomial exploiting the measure of discrepancy in satisfying the passive dynamics equations as a performance index. Thus an almost feasible periodic motion is found. Then a linear controller is designed and stability analysis is given to verify that solutions of the closed-loop system stay inside a tube around the planned approximately feasible periodic trajectory. Experimental results for a double rotary pendulum are shown, while numerical simulations are given for models of a spacecraft with liquid sloshing and of a chain of mass spring system.

REVIEW: Internal models in sensorimotor integration: perspectives from adaptive control theory

NASA Astrophysics Data System (ADS)

Tin, Chung; Poon, Chi-Sang

2005-09-01

Internal models and adaptive controls are empirical and mathematical paradigms that have evolved separately to describe learning control processes in brain systems and engineering systems, respectively. This paper presents a comprehensive appraisal of the correlation between these paradigms with a view to forging a unified theoretical framework that may benefit both disciplines. It is suggested that the classic equilibrium-point theory of impedance control of arm movement is analogous to continuous gain-scheduling or high-gain adaptive control within or across movement trials, respectively, and that the recently proposed inverse internal model is akin to adaptive sliding control originally for robotic manipulator applications. Modular internal models' architecture for multiple motor tasks is a form of multi-model adaptive control. Stochastic methods, such as generalized predictive control, reinforcement learning, Bayesian learning and Hebbian feedback covariance learning, are reviewed and their possible relevance to motor control is discussed. Possible applicability of a Luenberger observer and an extended Kalman filter to state estimation problems—such as sensorimotor prediction or the resolution of vestibular sensory ambiguity—is also discussed. The important role played by vestibular system identification in postural control suggests an indirect adaptive control scheme whereby system states or parameters are explicitly estimated prior to the implementation of control. This interdisciplinary framework should facilitate the experimental elucidation of the mechanisms of internal models in sensorimotor systems and the reverse engineering of such neural mechanisms into novel brain-inspired adaptive control paradigms in future.

Experimental and numerical investigation of a phase-only control mechanism in the linear intensity regime.

PubMed

Brühl, Elisabeth; Buckup, Tiago; Motzkus, Marcus

2018-06-07

Mechanisms and optimal experimental conditions in coherent control still intensely stimulate debates. In this work, a phase-only control mechanism in an open quantum system is investigated experimentally and numerically. Several parameterizations for femtosecond pulse shaping (combination of chirp and multipulses) are exploited in transient absorption of a prototype organic molecule to control population and vibrational coherence in ground and excited states. Experimental results are further numerically simulated and corroborated with a four-level density-matrix model, which reveals a phase-only control mechanism based on the interaction between the tailored phase of the excitation pulse and the induced transient absorption. In spite of performing experiment and numerical simulations in the linear regime of excitation, the control effect amplitude depends non-linearly on the excitation energy and is explained as a pump-dump control mechanism. No evidence of single-photon control is observed with the model. Moreover, our results also show that the control effect on the population and vibrational coherence is highly dependent on the spectral detuning of the excitation spectrum. Contrary to the popular belief in coherent control experiments, spectrally resonant tailored excitation will lead to the control of the excited state only for very specific conditions.

Actively controlled shaft seals for aerospace applications

NASA Astrophysics Data System (ADS)

Salant, Richard F.

The objective of years 4 and 5 of this project (1992 and 1993) is to determine experimentally the behavior and operating characteristics of a controllable mechanical seal, and to identify potential problem areas. A controllable mechanical seal is one in which the thickness of the lubricating film separating the sealing surfaces is adjustable, and can be controlled by an electronic control system, based on information supplied by sensors that monitor the condition of the film. This work builds upon work done during years 1-3, in which a controllable mechanical seal was designed, analyzed, and fabricated. At the beginning of year 4, the mechanical seal and test rig was assembled, and preliminary testing begun. The five major tasks of years 4 and 5 encompass instrumentation, configuration changes of the mechanical seal to optimize its performance, systematic steady state tests, systematic transient tests, and a final report. During this reporting period, significant progress was made on instrumenting the test rig and modifying the design to optimize the seal's performance. Initial steady state tests were also performed.

Double loaded self-decomposable SiO2 nanoparticles for sustained drug release

NASA Astrophysics Data System (ADS)

Zhao, Saisai; Zhang, Silu; Ma, Jiang; Fan, Li; Yin, Chun; Lin, Ge; Li, Quan

2015-10-01

Sustained drug release for a long duration is a desired feature of modern drugs. Using double-loaded self-decomposable SiO2 nanoparticles, we demonstrated sustained drug release in a controllable manner. The double loading of the drugs was achieved using two different mechanisms--the first one via a co-growth mechanism, and the second one by absorption. A two-phase sustained drug release was firstly revealed in an in vitro system, and then further demonstrated in mice. After a single intravenous injection, the drug was controllably released from the nanoparticles into blood circulation with a Tmax of about 8 h, afterwards a long lasting release pattern was achieved to maintain drug systemic exposure with a plasma elimination half-life of approximately 28 h. We disclosed that the absorbed drug molecules contributed to the initial fast release for quickly reaching the therapeutic level with relatively higher plasma concentrations, while the ``grown-in'' drugs were responsible for maintaining the therapeutic level via the later controlled slow and sustained release. The present nanoparticle carrier drug configuration and the loading/maintenance release mechanisms provide a promising platform that ensures a prolonged therapeutic effect by controlling drug concentrations within the therapeutic window--a sustained drug delivery system with a great impact on improving the management of chronic diseases.Sustained drug release for a long duration is a desired feature of modern drugs. Using double-loaded self-decomposable SiO2 nanoparticles, we demonstrated sustained drug release in a controllable manner. The double loading of the drugs was achieved using two different mechanisms--the first one via a co-growth mechanism, and the second one by absorption. A two-phase sustained drug release was firstly revealed in an in vitro system, and then further demonstrated in mice. After a single intravenous injection, the drug was controllably released from the nanoparticles into blood circulation with a Tmax of about 8 h, afterwards a long lasting release pattern was achieved to maintain drug systemic exposure with a plasma elimination half-life of approximately 28 h. We disclosed that the absorbed drug molecules contributed to the initial fast release for quickly reaching the therapeutic level with relatively higher plasma concentrations, while the ``grown-in'' drugs were responsible for maintaining the therapeutic level via the later controlled slow and sustained release. The present nanoparticle carrier drug configuration and the loading/maintenance release mechanisms provide a promising platform that ensures a prolonged therapeutic effect by controlling drug concentrations within the therapeutic window--a sustained drug delivery system with a great impact on improving the management of chronic diseases. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03029c

33 CFR 154.2100 - Vapor control system, general.

Code of Federal Regulations, 2014 CFR

2014-07-01

... be constructed to acceptable engineering standards and have the appropriate mechanical strength to... hazards, sources of ignition, and mechanical damage to the maximum practicable extent. Each remaining...

The Moisture Menace.

ERIC Educational Resources Information Center

Chivetta, Christopher

2001-01-01

Discusses how to control an indoor pool environment by understanding the mechanics of water evaporation, condensation, and migration. Stresses the need for a properly designed, installed, operated, and maintained mechanical system. (GR)

Role of the Renin-Angiotensin-Aldosterone System beyond Blood Pressure Regulation: Molecular and Cellular Mechanisms Involved in End-Organ Damage during Arterial Hypertension

PubMed Central

Muñoz-Durango, Natalia; Fuentes, Cristóbal A.; Castillo, Andrés E.; González-Gómez, Luis Martín; Vecchiola, Andrea; Fardella, Carlos E.; Kalergis, Alexis M.

2016-01-01

Arterial hypertension is a common condition worldwide and an important predictor of several complicated diseases. Arterial hypertension can be triggered by many factors, including physiological, genetic, and lifestyle causes. Specifically, molecules of the renin-angiotensin-aldosterone system not only play important roles in the control of blood pressure, but they are also associated with the genesis of arterial hypertension, thus constituting a need for pharmacological interventions. Chronic high pressure generates mechanical damage along the vascular system, heart, and kidneys, which are the principal organs affected in this condition. In addition to mechanical stress, hypertension-induced oxidative stress, chronic inflammation, and the activation of reparative mechanisms lead to end-organ damage, mainly due to fibrosis. Clinical trials have demonstrated that renin-angiotensin-aldosterone system intervention in hypertensive patients lowers morbidity/mortality and inflammatory marker levels as compared to placebo patients, evidencing that this system controls more than blood pressure. This review emphasizes the detrimental effects that a renin-angiotensin-aldosterone system (RAAS) imbalance has on health considerations above and beyond high blood pressure, such as fibrotic end-organ damage. PMID:27347925

Role of the Renin-Angiotensin-Aldosterone System beyond Blood Pressure Regulation: Molecular and Cellular Mechanisms Involved in End-Organ Damage during Arterial Hypertension.

PubMed

Muñoz-Durango, Natalia; Fuentes, Cristóbal A; Castillo, Andrés E; González-Gómez, Luis Martín; Vecchiola, Andrea; Fardella, Carlos E; Kalergis, Alexis M

2016-06-23

Arterial hypertension is a common condition worldwide and an important predictor of several complicated diseases. Arterial hypertension can be triggered by many factors, including physiological, genetic, and lifestyle causes. Specifically, molecules of the renin-angiotensin-aldosterone system not only play important roles in the control of blood pressure, but they are also associated with the genesis of arterial hypertension, thus constituting a need for pharmacological interventions. Chronic high pressure generates mechanical damage along the vascular system, heart, and kidneys, which are the principal organs affected in this condition. In addition to mechanical stress, hypertension-induced oxidative stress, chronic inflammation, and the activation of reparative mechanisms lead to end-organ damage, mainly due to fibrosis. Clinical trials have demonstrated that renin-angiotensin-aldosterone system intervention in hypertensive patients lowers morbidity/mortality and inflammatory marker levels as compared to placebo patients, evidencing that this system controls more than blood pressure. This review emphasizes the detrimental effects that a renin-angiotensin-aldosterone system (RAAS) imbalance has on health considerations above and beyond high blood pressure, such as fibrotic end-organ damage.

Modelling Systemic Iron Regulation during Dietary Iron Overload and Acute Inflammation: Role of Hepcidin-Independent Mechanisms.

PubMed

Enculescu, Mihaela; Metzendorf, Christoph; Sparla, Richard; Hahnel, Maximilian; Bode, Johannes; Muckenthaler, Martina U; Legewie, Stefan

2017-01-01

Systemic iron levels must be maintained in physiological concentrations to prevent diseases associated with iron deficiency or iron overload. A key role in this process plays ferroportin, the only known mammalian transmembrane iron exporter, which releases iron from duodenal enterocytes, hepatocytes, or iron-recycling macrophages into the blood stream. Ferroportin expression is tightly controlled by transcriptional and post-transcriptional mechanisms in response to hypoxia, iron deficiency, heme iron and inflammatory cues by cell-autonomous and systemic mechanisms. At the systemic level, the iron-regulatory hormone hepcidin is released from the liver in response to these cues, binds to ferroportin and triggers its degradation. The relative importance of individual ferroportin control mechanisms and their interplay at the systemic level is incompletely understood. Here, we built a mathematical model of systemic iron regulation. It incorporates the dynamics of organ iron pools as well as regulation by the hepcidin/ferroportin system. We calibrated and validated the model with time-resolved measurements of iron responses in mice challenged with dietary iron overload and/or inflammation. The model demonstrates that inflammation mainly reduces the amount of iron in the blood stream by reducing intracellular ferroportin transcription, and not by hepcidin-dependent ferroportin protein destabilization. In contrast, ferroportin regulation by hepcidin is the predominant mechanism of iron homeostasis in response to changing iron diets for a big range of dietary iron contents. The model further reveals that additional homeostasis mechanisms must be taken into account at very high dietary iron levels, including the saturation of intestinal uptake of nutritional iron and the uptake of circulating, non-transferrin-bound iron, into liver. Taken together, our model quantitatively describes systemic iron metabolism and generated experimentally testable predictions for additional ferroportin-independent homeostasis mechanisms.

Modelling Systemic Iron Regulation during Dietary Iron Overload and Acute Inflammation: Role of Hepcidin-Independent Mechanisms

PubMed Central

Sparla, Richard; Hahnel, Maximilian; Bode, Johannes; Muckenthaler, Martina U.; Legewie, Stefan

2017-01-01

Systemic iron levels must be maintained in physiological concentrations to prevent diseases associated with iron deficiency or iron overload. A key role in this process plays ferroportin, the only known mammalian transmembrane iron exporter, which releases iron from duodenal enterocytes, hepatocytes, or iron-recycling macrophages into the blood stream. Ferroportin expression is tightly controlled by transcriptional and post-transcriptional mechanisms in response to hypoxia, iron deficiency, heme iron and inflammatory cues by cell-autonomous and systemic mechanisms. At the systemic level, the iron-regulatory hormone hepcidin is released from the liver in response to these cues, binds to ferroportin and triggers its degradation. The relative importance of individual ferroportin control mechanisms and their interplay at the systemic level is incompletely understood. Here, we built a mathematical model of systemic iron regulation. It incorporates the dynamics of organ iron pools as well as regulation by the hepcidin/ferroportin system. We calibrated and validated the model with time-resolved measurements of iron responses in mice challenged with dietary iron overload and/or inflammation. The model demonstrates that inflammation mainly reduces the amount of iron in the blood stream by reducing intracellular ferroportin transcription, and not by hepcidin-dependent ferroportin protein destabilization. In contrast, ferroportin regulation by hepcidin is the predominant mechanism of iron homeostasis in response to changing iron diets for a big range of dietary iron contents. The model further reveals that additional homeostasis mechanisms must be taken into account at very high dietary iron levels, including the saturation of intestinal uptake of nutritional iron and the uptake of circulating, non-transferrin-bound iron, into liver. Taken together, our model quantitatively describes systemic iron metabolism and generated experimentally testable predictions for additional ferroportin-independent homeostasis mechanisms. PMID:28068331

Controlling mechanisms over the internet

NASA Astrophysics Data System (ADS)

Lumia, Ronald

1997-01-01

The internet, widely available throughout the world, can be used to control robots, machine tools, and other mechanisms. This paper will describe a low-cost virtual collaborative environment (VCE) which will connect users with distant equipment. The system is based on PC technology, and incorporates off-line-programming with on-line execution. A remote user programs the systems graphically and simulates the motions and actions of the mechanism until satisfied with the functionality of the program. The program is then transferred from the remote site to the local site where the real equipment exists. At the local site, the simulation is run again to check the program from a safety standpoint. Then, the local user runs the program on the real equipment. During execution, a camera in the real workspace provides an image back to the remote user through a teleconferencing system. The system costs approximately 12,500 dollars and represents a low-cost alternative to the Sandia National Laboratories VCE.

Experience with synchronous and asynchronous digital control systems

NASA Technical Reports Server (NTRS)

Regenie, V. A.; Chacon, C. V.; Lock, W. P.

1986-01-01

Flight control systems have undergone a revolution since the days of simple mechanical linkages; presently the most advanced systems are full-authority, full-time digital systems controlling unstable aircraft. With the use of advanced control systems, the aerodynamic design can incorporate features that allow greater performance and fuel savings, as can be seen on the new Airbus design and advanced tactical fighter concepts. These advanced aircraft will be and are relying on the flight control system to provide the stability and handling qualities required for safe flight and to allow the pilot to control the aircraft. Various design philosophies have been proposed and followed to investigate system architectures for these advanced flight control systems. One major area of discussion is whether a multichannel digital control system should be synchronous or asynchronous. This paper addressed the flight experience at the Dryden Flight Research Facility of NASA's Ames Research Center with both synchronous and asynchronous digital flight control systems. Four different flight control systems are evaluated against criteria such as software reliability, cost increases, and schedule delays.

77 FR 50577 - Airworthiness Directives; The Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-22

... the drive mechanism of the horizontal stabilizer trim actuator. This AD requires repetitive detailed... horizontal stabilizer trim control system; repetitive measurements for discrepancies of the ballscrew to... lubrication of the horizontal stabilizer trim control system; repetitive measurements for discrepancies of the...

Congestion and flow control in signaling system No. 7: Impacts of intelligent networks and new services

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

Zepf, J.; Rufa, G.

1994-04-01

This paper focuses on the transient performance analysis of the congestion and flow control mechanisms in CCITT Signaling System No. 7 (SS7). Special attention is directed to the impacts of the introduction of intelligent services and new applications, e.g., Freephone, credit card services, user-to-user signaling, etc. In particular, we show that signaling traffic characteristics like signaling scenarios or signaling message length as well as end-to-end signaling capabilities have a significant influence on the congestion and flow control and, therefore, on the real-time signaling performance. One important result of our performance studies is that if, e.g., intelligent services are introduced, themore » SS7 congestion and flow control does not work correctly. To solve this problem, some reinvestigations into these mechanisms would be necessary. Therefore, some approaches, e.g., modification of the Signaling Connection Control Part (SCCP) congestion control, usage of the SCCP relay function, or a redesign of the MTP flow control procedures are discussed in order to guarantee the efficacy of the congestion and flow control mechanisms also in the future. 16 refs.« less

Measurement of control system response using an analog operational circuit

NASA Technical Reports Server (NTRS)

Lalli, V. R.

1978-01-01

Ten basic steps are established for an analog method that measures control system response parameters. An example shows how these steps were used on a speed control portion of an auxiliary power unit. The equations and calculations necessary to describe this subsystem are given. The mechanization schematic and simulation diagram for obtaining the measured response parameters of the control system using an analog circuit are explained. Methods for investigating the various effects of the control parameters are described. It is concluded that the optimum system should be underdamped enough to be slightly oscillatory during transients.

The modeling of an automotive electronic control system and the application of optimizing methods

NASA Astrophysics Data System (ADS)

Zhang, Yansheng; Yang, Zhigang; Zhang, Xiang

2005-12-01

Now, MATLAB/SIMULINK software is popularly used by automotive electronic control designers to develop automotive electronic control systems and perform numerical simulations. But they will face problems, such as value initialization in the "integrator" block, conversion among different data types, selection of "if" block and "switch" block, realization of the "if-clause" under multiple options and the auto-switching control, etc. Taking as an example the designing of an Automated Mechanical Transmission (AMT) system, this paper discusses some techniques and methods for modeling the automotive electronic control system with MATLAB/SIMULINK, offering designers some successful examples.

Impact of end effector technology on telemanipulation performance

NASA Technical Reports Server (NTRS)

Bejczy, A. K.; Szakaly, Z.; Ohm, T.

1990-01-01

Generic requirements for end effector design are briefly summarized as derived from generic functional and operational requirements. Included is a brief summary of terms and definitions related to end effector technology. The second part contains a brief overview of end effector technology work as JPL during the past ten years, with emphasis on the evolution of new mechanical, sensing and control capabilities of end effectors. The third and major part is devoted to the description of current end effector technology. The ongoing work addresses mechanical, sensing and control details with emphasis on mechanical ruggedness, increased resolution in sensing, and close electronic and control integration with overall telemanipulator control system.

B-52 stability augmentation system reliability

NASA Technical Reports Server (NTRS)

Bowling, T. C.; Key, L. W.

1976-01-01

The B-52 SAS (Stability Augmentation System) was developed and retrofitted to nearly 300 aircraft. It actively controls B-52 structural bending, provides improved yaw and pitch damping through sensors and electronic control channels, and puts complete reliance on hydraulic control power for rudder and elevators. The system has experienced over 300,000 flight hours and has exhibited service reliability comparable to the results of the reliability test program. Development experience points out numerous lessons with potential application in the mechanization and development of advanced technology control systems of high reliability.

System and method of active vibration control for an electro-mechanically cooled device

DOEpatents

Lavietes, Anthony D.; Mauger, Joseph; Anderson, Eric H.

2000-01-01

A system and method of active vibration control of an electro-mechanically cooled device is disclosed. A cryogenic cooling system is located within an environment. The cooling system is characterized by a vibration transfer function, which requires vibration transfer function coefficients. A vibration controller generates the vibration transfer function coefficients in response to various triggering events. The environments may differ by mounting apparatus, by proximity to vibration generating devices, or by temperature. The triggering event may be powering on the cooling system, reaching an operating temperature, or a reset action. A counterbalance responds to a drive signal generated by the vibration controller, based on the vibration signal and the vibration transfer function, which adjusts vibrations. The method first places a cryogenic cooling system within a first environment and then generates a first set of vibration transfer function coefficients, for a vibration transfer function of the cooling system. Next, the cryogenic cooling system is placed within a second environment and a second set of vibration transfer function coefficients are generated. Then, a counterbalance is driven, based on the vibration transfer function, to reduce vibrations received by a vibration sensitive element.

Precision gimballed mirror control in remote sensing LIDAR for environmental monitoring

NASA Astrophysics Data System (ADS)

Singh, Ravindra; Mudgil, Ashwani; Prakash, Chandra; Pal, Suranjan

2006-12-01

Differential Absorption Lidar (DIAL) Systems are advantageously used to detect and measure very small concentrations of trace gases in the atmosphere. There is a requirement to interrogate and search for the presence of one or more of toxic agents out of a large number (about 20 or so) of possible agents at distances up to several kilometers with the help of a ground-based multi-wavelength DIAL system employing pulsed, tunable laser sources in the wavelength bands of 2-5 micron and 9.2-10.8 micron. The Laser beams from the two sources are directed in the atmosphere with a predefined divergence to scan the atmosphere. Two methodologies can be implemented to provide the beam steering, one is to mount the entire telescope of transmitting and receiving channel on to a motorized gimbal platform and second is to keep the optical telescope stationary and use a slewing mirror to steer the beam in required direction. The first scheme is named as mass control and second scheme is called mirror control. Both the schemes have relative advantages and disadvantages and in the present DIAL application second scheme is being adopted. The present opto-mechanical configuration of DIAL system employs a 700 x 500 mm 2 (Elliptical) steering mirror for transmitting the collimated beams in a required direction and receiving the reflected beam as well. In the receiving channel a Telescope is used which collects the return beam and focuses the same on to a detector. The slewing mirror is housed in a gimbal mount having a sufficient FOR (Field of Regard) in Azimuth and elevation plane. The paper describes the modeling and simulation of Opto-mechanical and servo-mechanical subsystems of precision gimbaled mirror and also discusses the issues related to design of control system. The requirement specifications in regard to field of regard, slew rates 5°/s, scanning rates 1°/s are to be met with stringent beam pointing and scanning accuracies. The design of this system is categorized as multidisciplinary problem. The design parameters obtained from opto-mechanical analysis forms the input for control system design. The design of control system is carried out using conventional design methodologies.

Formalization of the Access Control on ARM-Android Platform with the B Method

NASA Astrophysics Data System (ADS)

Ren, Lu; Wang, Wei; Zhu, Xiaodong; Man, Yujia; Yin, Qing

2018-01-01

ARM-Android is a widespread mobile platform with multi-layer access control mechanisms, security-critical in the system. Many access control vulnerabilities still exist due to the course-grained policy and numerous engineering defects, which have been widely studied. However, few researches focus on the mechanism formalization, including the Android permission framework, kernel process management and hardware isolation. This paper first develops a comprehensive formal access control model on the ARM-Android platform using the B method, from the Android middleware to hardware layer. All the model specifications are type checked and proved to be well-defined, with 75%of proof obligations demonstrated automatically. The results show that the proposed B model is feasible to specify and verify access control schemes in the ARM-Android system, and capable of implementing a practical control module.

Control and automation of the Pegasus multi-point Thomson scattering system

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

Bodner, G. M., E-mail: gbodner@wisc.edu; Bongard, M. W.; Fonck, R. J.

A new control system for the Pegasus Thomson scattering diagnostic has recently been deployed to automate the laser operation, data collection process, and interface with the system-wide Pegasus control code. Automation has been extended to areas outside of data collection, such as manipulation of beamline cameras and remotely controlled turning mirror actuators to enable intra-shot beam alignment. Additionally, the system has been upgraded with a set of fast (∼1 ms) mechanical shutters to mitigate contamination from background light. Modification and automation of the Thomson system have improved both data quality and diagnostic reliability.

Control and automation of the Pegasus multi-point Thomson scattering system

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

Bodner, Grant M.; Bongard, Michael W.; Fonck, Raymond J.

A new control system for the Pegasus Thomson scattering diagnostic has recently been deployed to automate the laser operation, data collection process, and interface with the system-wide Pegasus control code. Automation has been extended to areas outside of data collection, such as manipulation of beamline cameras and remotely controlled turning mirror actuators to enable intra-shot beam alignment. In addition, the system has been upgraded with a set of fast (~1 ms) mechanical shutters to mitigate contamination from background light. Modification and automation of the Thomson system have improved both data quality and diagnostic reliability.

Control and automation of the Pegasus multi-point Thomson scattering system

DOE PAGES

Bodner, Grant M.; Bongard, Michael W.; Fonck, Raymond J.; ...

2016-08-12

A new control system for the Pegasus Thomson scattering diagnostic has recently been deployed to automate the laser operation, data collection process, and interface with the system-wide Pegasus control code. Automation has been extended to areas outside of data collection, such as manipulation of beamline cameras and remotely controlled turning mirror actuators to enable intra-shot beam alignment. In addition, the system has been upgraded with a set of fast (~1 ms) mechanical shutters to mitigate contamination from background light. Modification and automation of the Thomson system have improved both data quality and diagnostic reliability.

A nonlinear control method based on ANFIS and multiple models for a class of SISO nonlinear systems and its application.

PubMed

Zhang, Yajun; Chai, Tianyou; Wang, Hong

2011-11-01

This paper presents a novel nonlinear control strategy for a class of uncertain single-input and single-output discrete-time nonlinear systems with unstable zero-dynamics. The proposed method combines adaptive-network-based fuzzy inference system (ANFIS) with multiple models, where a linear robust controller, an ANFIS-based nonlinear controller and a switching mechanism are integrated using multiple models technique. It has been shown that the linear controller can ensure the boundedness of the input and output signals and the nonlinear controller can improve the dynamic performance of the closed loop system. Moreover, it has also been shown that the use of the switching mechanism can simultaneously guarantee the closed loop stability and improve its performance. As a result, the controller has the following three outstanding features compared with existing control strategies. First, this method relaxes the assumption of commonly-used uniform boundedness on the unmodeled dynamics and thus enhances its applicability. Second, since ANFIS is used to estimate and compensate the effect caused by the unmodeled dynamics, the convergence rate of neural network learning has been increased. Third, a "one-to-one mapping" technique is adapted to guarantee the universal approximation property of ANFIS. The proposed controller is applied to a numerical example and a pulverizing process of an alumina sintering system, respectively, where its effectiveness has been justified.

Asynchronous data change notification between database server and accelerator controls system

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

Fu, W.; Morris, J.; Nemesure, S.

2011-10-10

Database data change notification (DCN) is a commonly used feature. Not all database management systems (DBMS) provide an explicit DCN mechanism. Even for those DBMS's which support DCN (such as Oracle and MS SQL server), some server side and/or client side programming may be required to make the DCN system work. This makes the setup of DCN between database server and interested clients tedious and time consuming. In accelerator control systems, there are many well established software client/server architectures (such as CDEV, EPICS, and ADO) that can be used to implement data reflection servers that transfer data asynchronously to anymore » client using the standard SET/GET API. This paper describes a method for using such a data reflection server to set up asynchronous DCN (ADCN) between a DBMS and clients. This method works well for all DBMS systems which provide database trigger functionality. Asynchronous data change notification (ADCN) between database server and clients can be realized by combining the use of a database trigger mechanism, which is supported by major DBMS systems, with server processes that use client/server software architectures that are familiar in the accelerator controls community (such as EPICS, CDEV or ADO). This approach makes the ADCN system easy to set up and integrate into an accelerator controls system. Several ADCN systems have been set up and used in the RHIC-AGS controls system.« less

Accelerated Aging System for Prognostics of Power Semiconductor Devices

NASA Technical Reports Server (NTRS)

Celaya, Jose R.; Vashchenko, Vladislav; Wysocki, Philip; Saha, Sankalita

2010-01-01

Prognostics is an engineering discipline that focuses on estimation of the health state of a component and the prediction of its remaining useful life (RUL) before failure. Health state estimation is based on actual conditions and it is fundamental for the prediction of RUL under anticipated future usage. Failure of electronic devices is of great concern as future aircraft will see an increase of electronics to drive and control safety-critical equipment throughout the aircraft. Therefore, development of prognostics solutions for electronics is of key importance. This paper presents an accelerated aging system for gate-controlled power transistors. This system allows for the understanding of the effects of failure mechanisms, and the identification of leading indicators of failure which are essential in the development of physics-based degradation models and RUL prediction. In particular, this system isolates electrical overstress from thermal overstress. Also, this system allows for a precise control of internal temperatures, enabling the exploration of intrinsic failure mechanisms not related to the device packaging. By controlling the temperature within safe operation levels of the device, accelerated aging is induced by electrical overstress only, avoiding the generation of thermal cycles. The temperature is controlled by active thermal-electric units. Several electrical and thermal signals are measured in-situ and recorded for further analysis in the identification of leading indicators of failures. This system, therefore, provides a unique capability in the exploration of different failure mechanisms and the identification of precursors of failure that can be used to provide a health management solution for electronic devices.

Controlling Mechanical Properties of Bis-leucine Oxalyl Amide Gels

NASA Astrophysics Data System (ADS)

Chang, William; Carvajal, Daniel; Shull, Kenneth

2011-03-01

is-leucine oxalyl amide is a low molecular weight gelator capable of gelling polar and organic solvents. A fundamental understanding of self-assembled systems can lead to new methods in drug delivery and the design of new soft material systems. An important feature of self-assembled systems are the intermolecular forces between solvent and gelator molecule; by changing the environment the gel is in, the mechanical properties also change. In this project two variables were considered: the degree of neutralization present for the gelator molecule from neutral to completely ionized, and the concentration of the gelator molecule, from 1 weight percent to 8 weight percent in 1-butanol. Mechanical properties were studied using displacement controlled indentation techniques and temperature sweep rheometry. It has been found that properties such as the storage modulus, gelation temperature and maximum stress allowed increase with bis-leucine oxalyl amide concentration. The results from this study establish a 3-d contour map between the gelator concentration, the gelator degree of ionization and mechanical properties such as storage modulus and maximum stress allowed. The intermolecular forces between the bis-leucine low molecular weight gelator and 1-butanol govern the mechanical properties of the gel system, and understanding these interactions will be key to rationally designed self-assembled systems.

Structural model of control system for hydraulic stepper motor complex

NASA Astrophysics Data System (ADS)

Obukhov, A. D.; Dedov, D. L.; Kolodin, A. N.

2018-03-01

The article considers the problem of developing a structural model of the control system for a hydraulic stepper drive complex. A comparative analysis of stepper drives and assessment of the applicability of HSM for solving problems, requiring accurate displacement in space with subsequent positioning of the object, are carried out. The presented structural model of the automated control system of the multi-spindle complex of hydraulic stepper drives reflects the main components of the system, as well as the process of its control based on the control signals transfer to the solenoid valves by the controller. The models and methods described in the article can be used to formalize the control process in technical systems based on the application hydraulic stepper drives and allow switching from mechanical control to automated control.

Evaluation of the propulsion control system of a planetary rover and design of a mast for an elevation scanning laser/multi-detector system

NASA Technical Reports Server (NTRS)

Knaub, D.; Yerazunis, S. W.

1978-01-01

Vertical wheel loads, wheel speeds, and torque relationships are considered in the design of a propulsion system capable of responding to steering, slope climbing, and irregular local terrains. The system developed is applied to the RPI Mars roving vehicle. The mechanical system required to implement the elevation laser scanning/multidetector principle was the design and construction of a mechanical system for implementing the elevation scanning/multidetector principle is also discussed.

System identification of closed-loop cardiovascular control mechanisms: diabetic autonomic neuropathy

NASA Technical Reports Server (NTRS)

Mukkamala, R.; Mathias, J. M.; Mullen, T. J.; Cohen, R. J.; Freeman, R.

1999-01-01

We applied cardiovascular system identification (CSI) to characterize closed-loop cardiovascular regulation in patients with diabetic autonomic neuropathy (DAN). The CSI method quantitatively analyzes beat-to-beat fluctuations in noninvasively measured heart rate, arterial blood pressure (ABP), and instantaneous lung volume (ILV) to characterize four physiological coupling mechanisms, two of which are autonomically mediated (the heart rate baroreflex and the coupling of respiration, measured in terms of ILV, to heart rate) and two of which are mechanically mediated (the coupling of ventricular contraction to the generation of the ABP wavelet and the coupling of respiration to ABP). We studied 37 control and 60 diabetic subjects who were classified as having minimal, moderate, or severe DAN on the basis of standard autonomic tests. The autonomically mediated couplings progressively decreased with increasing severity of DAN, whereas the mechanically mediated couplings were essentially unchanged. CSI identified differences between the minimal DAN and control groups, which were indistinguishable based on the standard autonomic tests. CSI may provide a powerful tool for assessing DAN.

Regulation of gene expression in mammalian nervous system through alternative pre-mRNA splicing coupled with RNA quality control mechanisms.

PubMed

Yap, Karen; Makeyev, Eugene V

2013-09-01

Eukaryotic gene expression is orchestrated on a genome-wide scale through several post-transcriptional mechanisms. Of these, alternative pre-mRNA splicing expands the proteome diversity and modulates mRNA stability through downstream RNA quality control (QC) pathways including nonsense-mediated decay (NMD) of mRNAs containing premature termination codons and nuclear retention and elimination (NRE) of intron-containing transcripts. Although originally identified as mechanisms for eliminating aberrant transcripts, a growing body of evidence suggests that NMD and NRE coupled with deliberate changes in pre-mRNA splicing patterns are also used in a number of biological contexts for deterministic control of gene expression. Here we review recent studies elucidating molecular mechanisms and biological significance of these gene regulation strategies with a specific focus on their roles in nervous system development and physiology. This article is part of a Special Issue entitled 'RNA and splicing regulation in neurodegeneration'. Copyright © 2013 Elsevier Inc. All rights reserved.

Wave Phase-Sensitive Transformation of 3d-Straining of Mechanical Fields

NASA Astrophysics Data System (ADS)

Smirnov, I. N.; Speranskiy, A. A.

2015-11-01

It is the area of research of oscillatory processes in elastic mechanical systems. Technical result of innovation is creation of spectral set of multidimensional images which reflect time-correlated three-dimensional vector parameters of metrological, and\\or estimated, and\\or design parameters of oscillations in mechanical systems. Reconstructed images of different dimensionality integrated in various combinations depending on their objective function can be used as homeostatic profile or cybernetic image of oscillatory processes in mechanical systems for an objective estimation of current operational conditions in real time. The innovation can be widely used to enhance the efficiency of monitoring and research of oscillation processes in mechanical systems (objects) in construction, mechanical engineering, acoustics, etc. Concept method of vector vibrometry based on application of vector 3D phase- sensitive vibro-transducers permits unique evaluation of real stressed-strained states of power aggregates and loaded constructions and opens fundamental innovation opportunities: conduct of continuous (on-line regime) reliable monitoring of turboagregates of electrical machines, compressor installations, bases, supports, pipe-lines and other objects subjected to damaging effect of vibrations; control of operational safety of technical systems at all the stages of life cycle including design, test production, tuning, testing, operational use, repairs and resource enlargement; creation of vibro-diagnostic systems of authentic non-destructive control of anisotropic characteristics of materials resistance of power aggregates and loaded constructions under outer effects and operational flaws. The described technology is revolutionary, universal and common for all branches of engineering industry and construction building objects.

Spinal motor control system incorporates an internal model of limb dynamics.

PubMed

Shimansky, Y P

2000-10-01

The existence and utilization of an internal representation of the controlled object is one of the most important features of the functioning of neural motor control systems. This study demonstrates that this property already exists at the level of the spinal motor control system (SMCS), which is capable of generating motor patterns for reflex rhythmic movements, such as locomotion and scratching, without the aid of the peripheral afferent feedback, but substantially modifies the generated activity in response to peripheral afferent stimuli. The SMCS is presented as an optimal control system whose optimality requires that it incorporate an internal model (IM) of the controlled object's dynamics. A novel functional mechanism for the integration of peripheral sensory signals with the corresponding predictive output from the IM, the summation of information precision (SIP) is proposed. In contrast to other models in which the correction of the internal representation of the controlled object's state is based on the calculation of a mismatch between the internal and external information sources, the SIP mechanism merges the information from these sources in order to optimize the precision of the controlled object's state estimate. It is demonstrated, based on scratching in decerebrate cats as an example of the spinal control of goal-directed movements, that the results of computer modeling agree with the experimental observations related to the SMCS's reactions to phasic and tonic peripheral afferent stimuli. It is also shown that the functional requirements imposed by the mathematical model of the SMCS comply with the current knowledge about the related properties of spinal neuronal circuitry. The crucial role of the spinal presynaptic inhibition mechanism in the neuronal implementation of SIP is elucidated. Important differences between the IM and a state predictor employed for compensating for a neural reflex time delay are discussed.

Identification and Control of Non-Linear Time-Varying Dynamical Systems Using Artificial Neural Networks

DTIC Science & Technology

1992-09-01

finding an inverse plant such as was done by Bertrand [BD91] and by Levin, Gewirtzman and Inbar in a binary type inverse controller [LGI91], to self tuning...gain robust control. 2) Self oscillating adaptive controller. 3) Gain scheduling. 4) Self tuning. 5) Model-reference adaptive systems. Although the...of multidimensional systems (CS881 as well as aircraft [HG90]. The self oscillating method is also a feedback based mechanism, utilizing a relay in the

Development of High Fidelity Mobility Simulation of an Autonomous Vehicle in an Off-Road Scenario Using Integrated Sensor, Controller, and Multi-Body Dynamics

DTIC Science & Technology

2011-08-01

VEHICLE IN AN OFF-ROAD SCENARIO USING INTEGRATED SENSOR, CONTROLLER, AND MULTI-BODY DYNAMICS Paramsothy Jayakumar , PhD William Smith US Army...environment for a control system, mechanical system dynamics , and sensor simulation for an improved assessment of the vehicle system performance...improve vehicle dynamic performance; we must also evaluate and improve the sensor suite employed on the vehicle, and the controller used to operate

78 FR 32579 - Airworthiness Directives; Bombardier, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-31

... elevator control system. Investigation revealed that, the increase in the elevator breakout force induced by the introduction of a new elevator centering mechanism, in combination with the existing [[Page... behaviors of the elevator control system. This proposed AD would require repetitive replacement of the...

Modeling and controller design of a 6-DOF precision positioning system

NASA Astrophysics Data System (ADS)

Cai, Kunhai; Tian, Yanling; Liu, Xianping; Fatikow, Sergej; Wang, Fujun; Cui, Liangyu; Zhang, Dawei; Shirinzadeh, Bijan

2018-05-01

A key hurdle to meet the needs of micro/nano manipulation in some complex cases is the inadequate workspace and flexibility of the operation ends. This paper presents a 6-degree of freedom (DOF) serial-parallel precision positioning system, which consists of two compact type 3-DOF parallel mechanisms. Each parallel mechanism is driven by three piezoelectric actuators (PEAs), guided by three symmetric T-shape hinges and three elliptical flexible hinges, respectively. It can extend workspace and improve flexibility of the operation ends. The proposed system can be assembled easily, which will greatly reduce the assembly errors and improve the positioning accuracy. In addition, the kinematic and dynamic model of the 6-DOF system are established, respectively. Furthermore, in order to reduce the tracking error and improve the positioning accuracy, the Discrete-time Model Predictive Controller (DMPC) is applied as an effective control method. Meanwhile, the effectiveness of the DMCP control method is verified. Finally, the tracking experiment is performed to verify the tracking performances of the 6-DOF stage.

Thermionic switched self-actuating reactor shutdown system

DOEpatents

Barrus, Donald M.; Shires, Charles D.; Brummond, William A.

1989-01-01

A self-actuating reactor shutdown system incorporating a thermionic switched electromagnetic latch arrangement which is responsive to reactor neutron flux changes and to reactor coolant temperature changes. The system is self-actuating in that the sensing thermionic device acts directly to release (scram) the control rod (absorber) without reference or signal from the main reactor plant protective and control systems. To be responsive to both temperature and neutron flux effects, two detectors are used, one responsive to reactor coolant temperatures, and the other responsive to reactor neutron flux increase. The detectors are incorporated into a thermionic diode connected electrically with an electromagnetic mechanism which under normal reactor operating conditions holds the the control rod in its ready position (exterior of the reactor core). Upon reaching either a specified temperature or neutron flux, the thermionic diode functions to short-circuit the electromagnetic mechanism causing same to lose its holding power and release the control rod, which drops into the reactor core region under gravitational force.

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.

Pulse-density modulation control of chemical oscillation far from equilibrium in a droplet open-reactor system

PubMed Central

Sugiura, Haruka; Ito, Manami; Okuaki, Tomoya; Mori, Yoshihito; Kitahata, Hiroyuki; Takinoue, Masahiro

2016-01-01

The design, construction and control of artificial self-organized systems modelled on dynamical behaviours of living systems are important issues in biologically inspired engineering. Such systems are usually based on complex reaction dynamics far from equilibrium; therefore, the control of non-equilibrium conditions is required. Here we report a droplet open-reactor system, based on droplet fusion and fission, that achieves dynamical control over chemical fluxes into/out of the reactor for chemical reactions far from equilibrium. We mathematically reveal that the control mechanism is formulated as pulse-density modulation control of the fusion–fission timing. We produce the droplet open-reactor system using microfluidic technologies and then perform external control and autonomous feedback control over autocatalytic chemical oscillation reactions far from equilibrium. We believe that this system will be valuable for the dynamical control over self-organized phenomena far from equilibrium in chemical and biomedical studies. PMID:26786848

Pulse-density modulation control of chemical oscillation far from equilibrium in a droplet open-reactor system.

PubMed

Sugiura, Haruka; Ito, Manami; Okuaki, Tomoya; Mori, Yoshihito; Kitahata, Hiroyuki; Takinoue, Masahiro

2016-01-20

The design, construction and control of artificial self-organized systems modelled on dynamical behaviours of living systems are important issues in biologically inspired engineering. Such systems are usually based on complex reaction dynamics far from equilibrium; therefore, the control of non-equilibrium conditions is required. Here we report a droplet open-reactor system, based on droplet fusion and fission, that achieves dynamical control over chemical fluxes into/out of the reactor for chemical reactions far from equilibrium. We mathematically reveal that the control mechanism is formulated as pulse-density modulation control of the fusion-fission timing. We produce the droplet open-reactor system using microfluidic technologies and then perform external control and autonomous feedback control over autocatalytic chemical oscillation reactions far from equilibrium. We believe that this system will be valuable for the dynamical control over self-organized phenomena far from equilibrium in chemical and biomedical studies.

Combining metric episodes with semantic event concepts within the Symbolic and Sub-Symbolic Robotics Intelligence Control System (SS-RICS)

NASA Astrophysics Data System (ADS)

Kelley, Troy D.; McGhee, S.

2013-05-01

This paper describes the ongoing development of a robotic control architecture that inspired by computational cognitive architectures from the discipline of cognitive psychology. The Symbolic and Sub-Symbolic Robotics Intelligence Control System (SS-RICS) combines symbolic and sub-symbolic representations of knowledge into a unified control architecture. The new architecture leverages previous work in cognitive architectures, specifically the development of the Adaptive Character of Thought-Rational (ACT-R) and Soar. This paper details current work on learning from episodes or events. The use of episodic memory as a learning mechanism has, until recently, been largely ignored by computational cognitive architectures. This paper details work on metric level episodic memory streams and methods for translating episodes into abstract schemas. The presentation will include research on learning through novelty and self generated feedback mechanisms for autonomous systems.

Torsional vibration characteristic study of the grid-connected DFIG wind turbine

NASA Astrophysics Data System (ADS)

Yu, Songtao; Xie, Da; Wu, Wangping; Gu, Chenghong; Li, Furong

2017-01-01

This paper studies the torsional vibration characteristics of the grid-connected doubly-fed induction generator (DFIG) wind turbine by small signal analysis method. Firstly a detailed small-signal stability union model of the grid-connected DFIG wind turbine is developed, including the mechanical system and electrical system. To study the dynamic characteristic of the blade, gearbox, low speed and high speed shafts, a three mass shaft model for the mechanical system is adopted. At the same time, small signal models of DFIG, the voltage source converter (VSC) and the transmission line of the electrical system are developed respectively. Then, through calculating the eigenvalues of the state matrix A and the corresponding participation factors, the modal analysis is conducted in the shaft torsional vibration issues. And the impact of the system parameters including the series compensation capacitor, the flat-wave reactor, the PI parameters, especially the speed controller of generator rotor on shaft torsional vibration are discussed. The results show that the speed controller strengthens association between the mechanical system and the electrical system, and also produces a low-frequency oscillation mode.

Passive damping in EDS maglev systems.

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

Rote, D. M.

2002-05-03

There continues to be strong interest in the subjects of damping and drag forces associated with electrodynamic suspension (EDS) systems. While electromagnetic drag forces resist the forward motion of a vehicle and therefore consume energy, damping forces control, at least in part, the response of the vehicle to disturbances. Ideally, one would like to reduce the drag forces as much as possible while retaining adequate damping forces to insure dynamic stability and satisfactory ride quality. These two goals turn out to be difficult to achieve in practice. It is well known that maglev systems tend to be intrinsically under damped.more » Consequently it is often necessary in a practical system design to enhance the damping passively or actively. For reasons of cost and simplicity, it is desirable to rely as much as possible on passive damping mechanisms. In this paper, rough estimates are made of the passive damping and drag forces caused by various mechanisms in EDS systems. No attention will be given to active control systems or secondary suspension systems which are obvious ways to augment passive damping mechanisms if the latter prove to be inadequate.« less

Development of an in vivo visual robot system with a magnetic anchoring mechanism and a lens cleaning mechanism for laparoendoscopic single-site surgery (LESS).

PubMed

Feng, Haibo; Dong, Dinghui; Ma, Tengfei; Zhuang, Jinlei; Fu, Yili; Lv, Yi; Li, Liyi

2017-12-01

Surgical robot systems which can significantly improve surgical procedures have been widely used in laparoendoscopic single-site surgery (LESS). For a relative complex surgical procedure, the development of an in vivo visual robot system for LESS can effectively improve the visualization for surgical robot systems. In this work, an in vivo visual robot system with a new mechanism for LESS was investigated. A finite element method (FEM) analysis was carried out to ensure the safety of the in vivo visual robot during the movement, which was the most important concern for surgical purposes. A master-slave control strategy was adopted, in which the control model was established by off-line experiments. The in vivo visual robot system was verified by using a phantom box. The experiment results show that the robot system can successfully realize the expected functionalities and meet the demands of LESS. The experiment results indicate that the in vivo visual robot with high manipulability has great potential in clinical application. Copyright © 2017 John Wiley & Sons, Ltd.

External and Turbomachinery Flow Control Working Group

NASA Technical Reports Server (NTRS)

Ahmadi, G.; Alstrom, B.; Colonius, T.; Dannenhoffer, J.; Glauser, M.; Helenbrook, B.; Higuchi, H.; Hodson, H.; Jha, R.; Kabiri, P.;

Onboard Stability Control System for a Flapping Wing Nano Air Vehicle

DTIC Science & Technology

2009-04-24

15 Figure 14. Vehicle response to hover command with nitinol actuators and sensors...with nitinol actuators and sensors modeled. An extended Kalman filter has been implemented to estimate the functional roll rate from sensor...Actuators The wing control actuators subcomponent consists of nitinol wires connected to mechanisms that dictate the wing kinematics. These mechanisms

Caging Mechanism for a drag-free satellite position sensor

NASA Technical Reports Server (NTRS)

Hacker, R.; Mathiesen, J.; Debra, D. B.

1976-01-01

A disturbance compensation system for satellites based on the drag-free concept was mechanized and flown, using a spherical proof mass and a cam-guided caging mechanism. The caging mechanism controls the location of the proof mass for testing and constrains it during launch. Design requirements, design details, and hardware are described.

Quiet Clean Short-Haul Experimental Engine (QSCEE). Preliminary analyses and design report, volume 1

NASA Technical Reports Server (NTRS)

1974-01-01

The experimental propulsion systems to be built and tested in the 'quiet, clean, short-haul experimental engine' program are presented. The flight propulsion systems are also presented. The following areas are discussed: acoustic design; emissions control; engine cycle and performance; fan aerodynamic design; variable-pitch actuation systems; fan rotor mechanical design; fan frame mechanical design; and reduction gear design.

Computer aided analysis and optimization of mechanical system dynamics

NASA Technical Reports Server (NTRS)

Haug, E. J.

1984-01-01

The purpose is to outline a computational approach to spatial dynamics of mechanical systems that substantially enlarges the scope of consideration to include flexible bodies, feedback control, hydraulics, and related interdisciplinary effects. Design sensitivity analysis and optimization is the ultimate goal. The approach to computer generation and solution of the system dynamic equations and graphical methods for creating animations as output is outlined.

Reducing usage of the computational resources by event driven approach to model predictive control

NASA Astrophysics Data System (ADS)

Misik, Stefan; Bradac, Zdenek; Cela, Arben

2017-08-01

This paper deals with a real-time and optimal control of dynamic systems while also considers the constraints which these systems might be subject to. Main objective of this work is to propose a simple modification of the existing Model Predictive Control approach to better suit needs of computational resource-constrained real-time systems. An example using model of a mechanical system is presented and the performance of the proposed method is evaluated in a simulated environment.

Using Physical Models for Anomaly Detection in Control Systems

NASA Astrophysics Data System (ADS)

Svendsen, Nils; Wolthusen, Stephen

Supervisory control and data acquisition (SCADA) systems are increasingly used to operate critical infrastructure assets. However, the inclusion of advanced information technology and communications components and elaborate control strategies in SCADA systems increase the threat surface for external and subversion-type attacks. The problems are exacerbated by site-specific properties of SCADA environments that make subversion detection impractical; and by sensor noise and feedback characteristics that degrade conventional anomaly detection systems. Moreover, potential attack mechanisms are ill-defined and may include both physical and logical aspects.

Design and control of a macro-micro robot for precise force applications

NASA Technical Reports Server (NTRS)

Wang, Yulun; Mangaser, Amante; Laby, Keith; Jordan, Steve; Wilson, Jeff

1993-01-01

Creating a robot which can delicately interact with its environment has been the goal of much research. Primarily two difficulties have made this goal hard to attain. The execution of control strategies which enable precise force manipulations are difficult to implement in real time because such algorithms have been too computationally complex for available controllers. Also, a robot mechanism which can quickly and precisely execute a force command is difficult to design. Actuation joints must be sufficiently stiff, frictionless, and lightweight so that desired torques can be accurately applied. This paper describes a robotic system which is capable of delicate manipulations. A modular high-performance multiprocessor control system was designed to provide sufficient compute power for executing advanced control methods. An 8 degree of freedom macro-micro mechanism was constructed to enable accurate tip forces. Control algorithms based on the impedance control method were derived, coded, and load balanced for maximum execution speed on the multiprocessor system. Delicate force tasks such as polishing, finishing, cleaning, and deburring, are the target applications of the robot.

Control of hierarchical polymer mechanics with bioinspired metal-coordination dynamics

PubMed Central

Grindy, Scott C.; Learsch, Robert; Mozhdehi, Davoud; Cheng, Jing; Barrett, Devin G.; Guan, Zhibin; Messersmith, Phillip B.; Holten-Andersen, Niels

2015-01-01

In conventional polymer materials, mechanical performance is traditionally engineered via material structure, using motifs such as polymer molecular weight, polymer branching, or copolymer-block design1. Here, by means of a model system of 4-arm poly(ethylene glycol) hydrogels crosslinked with multiple, kinetically distinct dynamic metal-ligand coordinate complexes, we show that polymer materials with decoupled spatial structure and mechanical performance can be designed. By tuning the relative concentration of two types of metal-ligand crosslinks, we demonstrate control over the material’s mechanical hierarchy of energy-dissipating modes under dynamic mechanical loading, and therefore the ability to engineer a priori the viscoelastic properties of these materials by controlling the types of crosslinks rather than by modifying the polymer itself. This strategy to decouple material mechanics from structure may inform the design of soft materials for use in complex mechanical environments. PMID:26322715

Active control of bearing preload using piezoelectric translators

NASA Technical Reports Server (NTRS)

Nye, Ted W.

1990-01-01

In many spacecraft applications, mechanisms are required to perform precision pointing operations or to sometimes dither about or track a moving object. These mechanisms perform in a predictable and repeatable manner in benign temperature environments. Severe thermal gradients experienced in actual space applications however, cause assemblies to expand and contract around their bearings. This results in unpredictable changes in bearing preload, and hence bearing friction. This becomes a limitation for servos controlling pointing accuracy. Likewise, uncontrollable vibrations may couple into fixed preload (hence, fixed stiffness) mechanisms and limit pointing accuracy. Consequently, a complex problem faced today is how to design mechanisms that remain insensitive to changing thermal and vibrational spacecraft environments. Research presented involves the simplified modeling and test results of an actuator module that used piezoelectrically preload controlled bearings. The feasibility of actively controlling bearing preload was demonstrated. Because bearing friction is related to preload, a thermally active system designed with aluminum components and a 440 C bearing, was friction tested at temperatures ranging from 0 to 70 C (32 to 158 F). Effectiveness of the translators were demonstrated by mapping a controllable friction range throughout tested temperatures. It was learned that constant preload for this system could be maintained over an approximate 44 C (79 F) temperature span. From testing, it was also discovered that at the more deviate temperatures, expansions were so large that radial clearances were taken up and the duplex bearing became radially preloaded. Thus, active control of bearing preload is feasible but may be limited by inherent geometry constraints and materials used in the system.

Rotating Biological Contactors (RBC's). Student Manual. Biological Treatment Process Control.

ERIC Educational Resources Information Center

Zickefoose, Charles S.

This student manual provides the textual material for a unit on rotating biological contactors (RBC's). Topic areas considered include: (1) flow patterns of water through RBC installations; (2) basic concepts (shaft and stage); (3) characteristics of biomass; (4) mechanical features (bearings, mechanical drive systems, and air drive systems); (5)…

[Establishment and application of mechanical strain loading system of multi-channel cells].

PubMed

Li, Yongming; Wang, Hua; Zhang, Xiaodong; Tang, Lin

2012-02-01

Based on single-chip microcomputer, we have established a mechanical strain loading system with multi-channel to study the biological behavior of cultured cells in vitro under mechanical strain. We developed a multi-channel cell strain loading device controlled by single-chip microcomputer. We controlled the vacuum pump with vacuum chamber to make negative pressure changing periodically in the vacuum chamber. The tested cells were seeded on the surface of an elastic membrane mounted on the vacuum chamber, and could be strained or relaxed by cyclic pressure. Since the cells are attached to the surface of the membrane, they presumably experience the same deformation as that was applied to the membrane. The system was easy to carry and to operate, with deformation rate (1%-21%) and frequency (0-0. 5Hz) which could be adjusted correctly according to experimental requirement, and could compare different deformation rate of three channels at the same time. The system ran stably and completely achieved design aims, and provided a method to study the biological behavior of cultured cells attached to the surface of the elastic membrane under mechanical strain in vitro.

Central Neural Control of the Cardiovascular System: Current Perspectives

ERIC Educational Resources Information Center

Dampney, Roger A. L.

2016-01-01

This brief review, which is based on a lecture presented at the American Physiological Society Teaching Refresher Course on the Brain and Systems Control as part of the Experimental Biology meeting in 2015, aims to summarize current concepts of the principal mechanisms in the brain that regulate the autonomic outflow to the cardiovascular system.…

Thermogravimetric analysis for the determination of water release rate from microcrystalline cellulose dry powder and wet bead systems.

PubMed

Mayville, Francis C; Wigent, Rodney J; Schwartz, Joseph B

2006-01-01

The purpose of this work was to determine the total amount of water contained in dry powder and wet bead samples of microcrystalline cellulose, MCC, (Avicel PH-101), taken from various stages of the extrusion/marumerization process used to make beads and to determine the kinetic rates of water release from each sample. These samples were allowed to equilibrate in controlled humidity chambers at 25 degrees C. The total amount of water in each sample, after equilibration, was determined by thermogravimetric analysis (TGA) as a function of temperature. The rates of water release from these samples were determined by using isothermal gravimetric analysis (ITGA) as a function of time. Analysis of the results for these studies suggest that water was released from these systems by several different kinetic mechanisms. The water release mechanisms for these systems include: zero order, second order, and diffusion controlled kinetics. It is believed that all three kinetic mechanisms will occur at the same time, however; only one mechanism will be prominent. The prominent mechanism was based on the amount of water present in the sample.

Design of motion adjusting system for space camera based on ultrasonic motor

NASA Astrophysics Data System (ADS)

Xu, Kai; Jin, Guang; Gu, Song; Yan, Yong; Sun, Zhiyuan

2011-08-01

Drift angle is a transverse intersection angle of vector of image motion of the space camera. Adjusting the angle could reduce the influence on image quality. Ultrasonic motor (USM) is a new type of actuator using ultrasonic wave stimulated by piezoelectric ceramics. They have many advantages in comparison with conventional electromagnetic motors. In this paper, some improvement was designed for control system of drift adjusting mechanism. Based on ultrasonic motor T-60 was designed the drift adjusting system, which is composed of the drift adjusting mechanical frame, the ultrasonic motor, the driver of Ultrasonic Motor, the photoelectric encoder and the drift adjusting controller. The TMS320F28335 DSP was adopted as the calculation and control processor, photoelectric encoder was used as sensor of position closed loop system and the voltage driving circuit designed as generator of ultrasonic wave. It was built the mathematic model of drive circuit of the ultrasonic motor T-60 using matlab modules. In order to verify the validity of the drift adjusting system, was introduced the source of the disturbance, and made simulation analysis. It designed the control systems of motor drive for drift adjusting system with the improved PID control. The drift angle adjusting system has such advantages as the small space, simple configuration, high position control precision, fine repeatability, self locking property and low powers. It showed that the system could accomplish the mission of drift angle adjusting excellent.

Musclelike joint mechanism driven by dielectric elastomer actuator for robotic applications

NASA Astrophysics Data System (ADS)

Jung, Ho Sang; Cho, Kyeong Ho; Park, Jae Hyeong; Yang, Sang Yul; Kim, Youngeun; Kim, Kihyeon; Nguyen, Canh Toan; Phung, Hoa; Tien Hoang, Phi; Moon, Hyungpil; Koo, Ja Choon; Ryeol Choi, Hyouk

2018-07-01

The purpose of this study is to develop an artificial muscle actuator suitable for robotic applications, and to demonstrate the feasibility of applying this actuator to an arm mechanism, and controlling it delicately and smoothly like a human being. To accomplish this, we perform the procedures that integrate the soft actuator, called the single body dielectric elastomer actuator, which is very flexible and capable of high speed operation, and the displacement amplification mechanism called the sliding filament joint mechanism, which mimics the sliding filament model of human muscles. In this paper, we describe the characteristics and control method of the actuation system that consists of actuator, mechanism, and embedded controller, and show the experimental results of the closed-loop position and static stiffness control of the robotic arm application. Finally, based on the results, we evaluate the performance of this application.

Treatment of the control mechanisms of light airplanes in the flutter clearance process

NASA Technical Reports Server (NTRS)

Breitbach, E. J.

1979-01-01

It has become more and more evident that many difficulties encountered in the course of aircraft flutter analyses can be traced to strong localized nonlinearities in the control mechanisms. To cope with these problems, more reliable mathematical models paying special attention to control system nonlinearities were established by means of modified ground vibration test procedures in combination with suitably adapted modal synthesis approaches. Three different concepts are presented.

A Thermal Management System Using Ammonium Carbamate as an Endothermic Heat Sink (POSTPRINT)

DTIC Science & Technology

2017-04-01

Niedbalski and Soumya S. Patnaik Mechanical and Thermal Systems Branch Power and Control Division Douglas J. Johnson and Jamie S. Ervin University...failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE...and Control Division Air Force Research Laboratory, Aerospace Systems Directorate Wright-Patterson Air Force Base, OH 45433-7542 Air Force Materiel

Paver automation for road surfacing

NASA Astrophysics Data System (ADS)

Tihonov, A.; Velichkin, V.

2017-10-01

The paper discusses factors that bear on the quality of motor road pavement as access roads and highways are built and used. A block diagram is proposed to organize elements of the automatic control system to control the asphalt paver’s mechanisms; the system is based on a microprocessor onboard controller to maintain preset elevation of the finishing plate; description of its operation principle is offered. The paper names primary converters to control the finishing plate elevation. A new control method is described to control the machine’s straight-line movement with GLONASS Satellite Positioning System (SPS) during operation.

A pilot's opinion - VTOL control design requirements for the instrument approach task.

NASA Technical Reports Server (NTRS)

Patton, J. M., Jr.

1972-01-01

This paper presents pilot opinion supported by test data concerning flight control and display concepts and control system design requirements for VTOL aircraft in the instrument approach task. Material presented is drawn from research flights in the following aircraft: Dornier DO-31, Short SC-1, LTV XC-142A, and Boeing-Vertol CH-46. The control system concepts and mechanizations employed in the above aircraft are discussed, and the effect of control system augmentation is shown on performance. Operational procedures required in the instrument approach task are described, with comments on need for automation and combining of control functions.

Continuous performance measurement in flight systems. [sequential control model

NASA Technical Reports Server (NTRS)

Connelly, E. M.; Sloan, N. A.; Zeskind, R. M.

1975-01-01

The desired response of many man machine control systems can be formulated as a solution to an optimal control synthesis problem where the cost index is given and the resulting optimal trajectories correspond to the desired trajectories of the man machine system. Optimal control synthesis provides the reference criteria and the significance of error information required for performance measurement. The synthesis procedure described provides a continuous performance measure (CPM) which is independent of the mechanism generating the control action. Therefore, the technique provides a meaningful method for online evaluation of man's control capability in terms of total man machine performance.

New Terfenol-D actuator design with applications to multiple DOF active vibration control

NASA Astrophysics Data System (ADS)

Haynes, Leonard S.; Geng, Zheng J.; Teter, Joseph P.

1993-09-01

A linear actuator system for multi-dimensional structure control using the magnetostrictive material Terfenol-D has been designed, built, and tested by the Intelligent Automation, Inc. The actuator assembly incorporates an instrumented Terfenol-D rod, an excitation coil to provide the magnetic field, a permanent magnet assembly to provide a magnetic bias field, and a mechanical preload mechanism. The prototype of the actuator is 2.0 inches in diameter and 8 inches long, and provides a peak-to-peak stroke of 0.01 inches. A linear model was also established to characterize the behavior of the actuator for small motion. Based on the prototype of the actuator, we have performed a study of a six degree-of-freedom active vibration isolation system using a Stewart Platform in a new configuration. IAI's final system is intended for precision control of a wide range of space-based structures as well as earth- base systems.

ROMPS critical design review. Volume 1: Hardware

NASA Technical Reports Server (NTRS)

Dobbs, M. E.

1992-01-01

Topics concerning the Robot-Operated Material Processing in Space (ROMPS) Program are presented in viewgraph form and include the following: a systems overview; servocontrol and servomechanisms; testbed and simulation results; system V controller; robot module; furnace module; SCL experiment supervisor; SCL script sample processing control; SCL experiment supervisor fault handling; block diagrams; hitchhiker interfaces; battery systems; watchdog timers; mechanical/thermal systems; and fault conditions and recovery.

Oscillation control system for electric motor drive

DOEpatents

Slicker, James M.; Sereshteh, Ahmad

1988-01-01

A feedback system for controlling mechanical oscillations in the torsionally complaint drive train of an electric or other vehicle. Motor speed is converted in a processor to estimate state signals in which a plant model which are used to electronically modify thetorque commands applied to the motor.

Magnetic-field-mediated coupling and control in hybrid atomic-nanomechanical systems

NASA Astrophysics Data System (ADS)

Tretiakov, A.; LeBlanc, L. J.

2016-10-01

Magnetically coupled hybrid quantum systems enable robust quantum state control through Landau-Zener transitions. Here, we show that an ultracold atomic sample magnetically coupled to a nanomechanical resonator can be used to cool the resonator's mechanical motion, to measure the mechanical temperature, and to enable entanglement of more than one of these mesoscopic objects. We calculate the expected coupling for both permanent-magnet and current-conducting nanostring resonators and describe how this hybridization is attainable using recently developed fabrication techniques, including SiN nanostrings and atom chips.

Centrally activated pipe snubbing system

DOEpatents

Cawley, William E.

1985-01-01

An electromechanical pipe snubbing system and an electromechanical pipe snubber. In the system, each pipe snubber, in a set of pipe snubbers, has an electromechanical mechanism to lock and unlock the snubber. A sensor, such as a seismometer, measures a quantity related to making a snubber locking or unlocking decision. A control device makes an electrical connection between a power supply and each snubber's electromechanical mechanism to simultaneously lock each snubber when the sensor measurement indicates a snubber locking condition. The control device breaks the connection to simultaneously unlock each snubber when the sensor measurement indicates a snubber unlocking condition. In the snubber, one end of the shaft slides within a bore in one end of a housing. The other end of the shaft is rotatably attached to a pipe; the other end of the housing is rotatively attached to a wall. The snubber's electromechanical mechanism locks the slidable end of the shaft to the housing and unlocks that end from the housing. The electromechanical mechanism permits remote testing and lockup status indication for each snubber.

An integrated mathematical model of the human cardiopulmonary system: model development.

PubMed

Albanese, Antonio; Cheng, Limei; Ursino, Mauro; Chbat, Nicolas W

2016-04-01

Several cardiovascular and pulmonary models have been proposed in the last few decades. However, very few have addressed the interactions between these two systems. Our group has developed an integrated cardiopulmonary model (CP Model) that mathematically describes the interactions between the cardiovascular and respiratory systems, along with their main short-term control mechanisms. The model has been compared with human and animal data taken from published literature. Due to the volume of the work, the paper is divided in two parts. The present paper is on model development and normophysiology, whereas the second is on the model's validation on hypoxic and hypercapnic conditions. The CP Model incorporates cardiovascular circulation, respiratory mechanics, tissue and alveolar gas exchange, as well as short-term neural control mechanisms acting on both the cardiovascular and the respiratory functions. The model is able to simulate physiological variables typically observed in adult humans under normal and pathological conditions and to explain the underlying mechanisms and dynamics. Copyright © 2016 the American Physiological Society.

MD-11 PCA - Research flight team photo

NASA Technical Reports Server (NTRS)

1995-01-01

On Aug. 30, 1995, a the McDonnell Douglas MD-11 transport aircraft landed equipped with a computer-assisted engine control system that has the potential to increase flight safety. In landings at NASA Dryden Flight Research Center, Edwards, California, on August 29 and 30, the aircraft demonstrated software used in the aircraft's flight control computer that essentially landed the MD-11 without a need for the pilot to manipulate the flight controls significantly. In partnership with McDonnell Douglas Aerospace (MDA), with Pratt & Whitney and Honeywell helping to design the software, NASA developed this propulsion-controlled aircraft (PCA) system following a series of incidents in which hydraulic failures resulted in the loss of flight controls. This new system enables a pilot to operate and land the aircraft safely when its normal, hydraulically-activated control surfaces are disabled. This August 29, 1995, photo shows the MD-11 team. Back row, left to right: Tim Dingen, MDA pilot; John Miller, MD-11 Chief pilot (MDA); Wayne Anselmo, MD-11 Flight Test Engineer (MDA); Gordon Fullerton, PCA Project pilot; Bill Burcham, PCA Chief Engineer; Rudey Duran, PCA Controls Engineer (MDA); John Feather, PCA Controls Engineer (MDA); Daryl Townsend, Crew Chief; Henry Hernandez, aircraft mechanic; Bob Baron, PCA Project Manager; Don Hermann, aircraft mechanic; Jerry Cousins, aircraft mechanic; Eric Petersen, PCA Manager (Honeywell); Trindel Maine, PCA Data Engineer; Jeff Kahler, PCA Software Engineer (Honeywell); Steve Goldthorpe, PCA Controls Engineer (MDA). Front row, left to right: Teresa Hass, Senior Project Management Analyst; Hollie Allingham (Aguilera), Senior Project Management Analyst; Taher Zeglum, PCA Data Engineer (MDA); Drew Pappas, PCA Project Manager (MDA); John Burken, PCA Control Engineer.

Intermittent control with ankle, hip, and mixed strategies during quiet standing: a theoretical proposal based on a double inverted pendulum model.

PubMed

Suzuki, Yasuyuki; Nomura, Taishin; Casadio, Maura; Morasso, Pietro

2012-10-07

Human upright posture, as a mechanical system, is characterized by an instability of saddle type, involving both stable and unstable dynamic modes. The brain stabilizes such system by generating active joint torques, according to a time-delayed neural feedback control. What is still unsolved is a clear understanding of the control strategies and the control mechanisms that are used by the central nervous system in order to stabilize the unstable posture in a robust way while maintaining flexibility. Most studies in this direction have been limited to the single inverted pendulum model, which is useful for formalizing fundamental mechanical aspects but insufficient for addressing more general issues concerning neural control strategies. Here we consider a double inverted pendulum model in the sagittal plane with small passive viscoelasticity at the ankle and hip joints. Despite difficulties in stabilizing the double pendulum model in the presence of the large feedback delay, we show that robust and flexible stabilization of the upright posture can be established by an intermittent control mechanism that achieves the goal of stabilizing the body posture according to a "divide and conquer strategy", which switches among different controllers in different parts of the state space of the double inverted pendulum. Remarkably, it is shown that a global, robust stability is achieved even if the individual controllers are unstable and the information exploited for switching from one controller to another is severely delayed, as it happens in biological reality. Moreover, the intermittent controller can automatically resolve coordination among multiple active torques associated with the muscle synergy, leading to the emergence of distinct temporally coordinated active torque patterns, referred to as the intermittent ankle, hip, and mixed strategies during quiet standing, depending on the passive elasticity at the hip joint. Copyright © 2012 Elsevier Ltd. All rights reserved.

MIUS Integration and Subsystem Test (MIST) data system

NASA Technical Reports Server (NTRS)

Pringle, L. M.

1977-01-01

A data system for use in testing integrated subsystems of a modular integrated utility system (MIUS) is presented. The MIUS integration and subsystem test (MIST) data system is reviewed from its conception through its checkout and operation as the controlling portion of the MIST facility. The MIST data system provides a real time monitoring and control function that allows for complete evaluation of the performance of the mechanical and electrical subsystems, as well as controls the operation of the various components of the system. In addition to the aforementioned capabilities, the MIST data system provides computerized control of test operations such that minimum manpower is necessary to set up, operate, and shut down subsystems during test periods.

On-Orbit System Identification

NASA Technical Reports Server (NTRS)

Mettler, E.; Milman, M. H.; Bayard, D.; Eldred, D. B.

1987-01-01

Information derived from accelerometer readings benefits important engineering and control functions. Report discusses methodology for detection, identification, and analysis of motions within space station. Techniques of vibration and rotation analyses, control theory, statistics, filter theory, and transform methods integrated to form system for generating models and model parameters that characterize total motion of complicated space station, with respect to both control-induced and random mechanical disturbances.

Modeling and Simulation of Control Actuation System with Fuzzy-PID Logic Controlled Brushless Motor Drives for Missiles Glider Applications

PubMed Central

Muniraj, Murali; Arulmozhiyal, Ramaswamy

2015-01-01

A control actuation system has been used extensively in automotive, aerospace, and defense applications. The major challenges in modeling control actuation system are rise time, maximum peak to peak overshoot, and response to nonlinear system with percentage error. This paper addresses the challenges in modeling and real time implementation of control actuation system for missiles glider applications. As an alternative fuzzy-PID controller is proposed in BLDC motor drive followed by linkage mechanism to actuate fins in missiles and gliders. The proposed system will realize better rise time and less overshoot while operating in extreme nonlinear dynamic system conditions. A mathematical model of BLDC motor is derived in state space form. The complete control actuation system is modeled in MATLAB/Simulink environment and verified by performing simulation studies. A real time prototype of the control actuation is developed with dSPACE-1104 hardware controller and a detailed analysis is carried out to confirm the viability of the proposed system. PMID:26613102

Modeling and Simulation of Control Actuation System with Fuzzy-PID Logic Controlled Brushless Motor Drives for Missiles Glider Applications.

PubMed

Muniraj, Murali; Arulmozhiyal, Ramaswamy

2015-01-01

A control actuation system has been used extensively in automotive, aerospace, and defense applications. The major challenges in modeling control actuation system are rise time, maximum peak to peak overshoot, and response to nonlinear system with percentage error. This paper addresses the challenges in modeling and real time implementation of control actuation system for missiles glider applications. As an alternative fuzzy-PID controller is proposed in BLDC motor drive followed by linkage mechanism to actuate fins in missiles and gliders. The proposed system will realize better rise time and less overshoot while operating in extreme nonlinear dynamic system conditions. A mathematical model of BLDC motor is derived in state space form. The complete control actuation system is modeled in MATLAB/Simulink environment and verified by performing simulation studies. A real time prototype of the control actuation is developed with dSPACE-1104 hardware controller and a detailed analysis is carried out to confirm the viability of the proposed system.

Automotive Control Systems: For Engine, Driveline, and Vehicle

NASA Astrophysics Data System (ADS)

Kiencke, Uwe; Nielsen, Lars

Advances in automotive control systems continue to enhance safety and comfort and to reduce fuel consumption and emissions. Reflecting the trend to optimization through integrative approaches for engine, driveline, and vehicle control, this valuable book enables control engineers to understand engine and vehicle models necessary for controller design, and also introduces mechanical engineers to vehicle-specific signal processing and automatic control. The emphasis on measurement, comparisons between performance and modeling, and realistic examples derive from the authors' unique industrial experience

Integrating Software Modules For Robot Control

NASA Technical Reports Server (NTRS)

Volpe, Richard A.; Khosla, Pradeep; Stewart, David B.

1993-01-01

Reconfigurable, sensor-based control system uses state variables in systematic integration of reusable control modules. Designed for open-architecture hardware including many general-purpose microprocessors, each having own local memory plus access to global shared memory. Implemented in software as extension of Chimera II real-time operating system. Provides transparent computing mechanism for intertask communication between control modules and generic process-module architecture for multiprocessor realtime computation. Used to control robot arm. Proves useful in variety of other control and robotic applications.

Comparison of automatic control systems

NASA Technical Reports Server (NTRS)

Oppelt, W

1941-01-01

This report deals with a reciprocal comparison of an automatic pressure control, an automatic rpm control, an automatic temperature control, and an automatic directional control. It shows the difference between the "faultproof" regulator and the actual regulator which is subject to faults, and develops this difference as far as possible in a parallel manner with regard to the control systems under consideration. Such as analysis affords, particularly in its extension to the faults of the actual regulator, a deep insight into the mechanism of the regulator process.

Active porous transition towards spatiotemporal control of molecular flow in a crystal membrane

NASA Astrophysics Data System (ADS)

Takasaki, Yuichi; Takamizawa, Satoshi

2015-11-01

Fluidic control is an essential technology widely found in processes such as flood control in land irrigation and cell metabolism in biological tissues. In any fluidic control system, valve function is the key mechanism used to actively regulate flow and miniaturization of fluidic regulation with precise workability will be particularly vital in the development of microfluidic control. The concept of crystal engineering is alternative to processing technology in microstructure construction, as the ultimate microfluidic devices must provide molecular level control. Consequently, microporous crystals can instantly be converted to microfluidic devices if introduced in an active transformability of porous structure and geometry. Here we show that the introduction of a stress-induced martensitic transition mechanism converts a microporous molecular crystal into an active fluidic device with spatiotemporal molecular flow controllability through mechanical reorientation of subnanometre channels.

Applying Workspace Limitations in a Velocity-Controlled Robotic Mechanism

NASA Technical Reports Server (NTRS)

Abdallah, Muhammad E. (Inventor); Hargrave, Brian (Inventor); Platt, Robert J., Jr. (Inventor)

2014-01-01

A robotic system includes a robotic mechanism responsive to velocity control signals, and a permissible workspace defined by a convex-polygon boundary. A host machine determines a position of a reference point on the mechanism with respect to the boundary, and includes an algorithm for enforcing the boundary by automatically shaping the velocity control signals as a function of the position, thereby providing smooth and unperturbed operation of the mechanism along the edges and corners of the boundary. The algorithm is suited for application with higher speeds and/or external forces. A host machine includes an algorithm for enforcing the boundary by shaping the velocity control signals as a function of the reference point position, and a hardware module for executing the algorithm. A method for enforcing the convex-polygon boundary is also provided that shapes a velocity control signal via a host machine as a function of the reference point position.

X-ray pushing of a mechanical microswing.

PubMed

Siria, A; Rodrigues, M S; Dhez, O; Schwartz, W; Torricelli, G; Ledenmat, S; Rochat, N; Auvert, G; Bikondoa, O; Metzger, T H; Wermeille, D; Felici, R; Comin, F; Chevrier, J

2008-11-05

We report here for the first time the combination of x-ray synchrotron light and a micro-electro-mechanical system (MEMS). We show how it is possible to modulate in real time a MEMS mass distribution to induce a nanometric and tunable mechanical oscillation. The quantitative experimental demonstration we present here uses periodic thermal dilatation of a Ge microcrystal attached to a Si microlever, induced by controlled absorption of an intensity modulated x-ray microbeam. The mechanism proposed can be envisaged either for the detection of small heat flux or for the actuation of a mechanical system.

Feedback linearizing control of a MIMO power system

NASA Astrophysics Data System (ADS)

Ilyes, Laszlo

Prior research has demonstrated that either the mechanical or electrical subsystem of a synchronous electric generator may be controlled using single-input single-output (SISO) nonlinear feedback linearization. This research suggests a new approach which applies nonlinear feedback linearization to a multi-input multi-output (MIMO) model of the synchronous electric generator connected to an infinite bus load model. In this way, the electrical and mechanical subsystems may be linearized and simultaneously decoupled through the introduction of a pair of auxiliary inputs. This allows well known, linear, SISO control methods to be effectively applied to the resulting systems. The derivation of the feedback linearizing control law is presented in detail, including a discussion on the use of symbolic math processing as a development tool. The linearizing and decoupling properties of the control law are validated through simulation. And finally, the robustness of the control law is demonstrated.

SDRE control strategy applied to a nonlinear robotic including drive motor

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

Lima, Jeferson J. de, E-mail: jefersonjl82@gmail.com, E-mail: tusset@utfpr.edu.br, E-mail: fcjanzen@utfpr.edu.br, E-mail: piccirillo@utfpr.edu.br, E-mail: claudinor@utfpr.edu.br; Tusset, Angelo M., E-mail: jefersonjl82@gmail.com, E-mail: tusset@utfpr.edu.br, E-mail: fcjanzen@utfpr.edu.br, E-mail: piccirillo@utfpr.edu.br, E-mail: claudinor@utfpr.edu.br; Janzen, Frederic C., E-mail: jefersonjl82@gmail.com, E-mail: tusset@utfpr.edu.br, E-mail: fcjanzen@utfpr.edu.br, E-mail: piccirillo@utfpr.edu.br, E-mail: claudinor@utfpr.edu.br

A robotic control design considering all the inherent nonlinearities of the robot-engine configuration is developed. The interactions between the robot and joint motor drive mechanism are considered. The proposed control combines two strategies, one feedforward control in order to maintain the system in the desired coordinate, and feedback control system to take the system into a desired coordinate. The feedback control is obtained using State-Dependent Riccati Equation (SDRE). For link positioning two cases are considered. Case I: For control positioning, it is only used motor voltage; Case II: For control positioning, it is used both motor voltage and torque betweenmore » the links. Simulation results, including parametric uncertainties in control shows the feasibility of the proposed control for the considered system.« less

The EMIR experience in the use of software control simulators to speed up the time to telescope

NASA Astrophysics Data System (ADS)

Lopez Ramos, Pablo; López-Ruiz, J. C.; Moreno Arce, Heidy; Rosich, Josefina; Perez Menor, José Maria

2012-09-01

One of the main problems facing development teams working on instrument control systems consists on the need to access mechanisms which are not available until well into the integration phase. The need to work with real hardware creates additional problems like, among others: certain faults cannot be tested due to the possibility of hardware damage, taking the system to the limit may shorten its operational lifespan and the full system may not be available during some periods due to maintenance and/or testing of individual components. These problems can be treated with the use of simulators and by applying software/hardware standards. Since information on the construction and performance of electro-mechanical systems is available at relatively early stages of the project, simulators are developed in advance (before the existence of the mechanism) or, if conventions and standards have been correctly followed, a previously developed simulator might be used. This article describes our experience in building software simulators and the main advantages we have identified, which are: the control software can be developed even in the absence of real hardware, critical tests can be prepared using the simulated systems, test system behavior for hardware failure situations that represent a risk of the real system, and the speed up of in house integration of the entire instrument. The use of simulators allows us to reduce development, testing and integration time.

Microminiaturized minimally invasive intravascular micro-mechanical systems powered and controlled via fiber-optic cable

DOEpatents

Fitch, Joseph P.; Hagans, Karla; Clough, Robert; Matthews, Dennis L.; Lee, Abraham P.; Krulevitch, Peter A.; Benett, William J.; Da Silva, Luiz; Celliers, Peter M.

1998-01-01

A micro-mechanical system for medical procedures is constructed in the basic form of a catheter having a distal end for insertion into and manipulation within a body and a near end providing for a user to control the manipulation of the distal end within the body. A fiberoptic cable is disposed within the catheter and having a distal end proximate to the distal end of the catheter and a near end for external coupling of laser light energy. A microgripper is attached to the distal end of the catheter and providing for the gripping or releasing of an object within the body. A laser-light-to-mechanical-power converter is connected to receive laser light from the distal end of the fiberoptic cable and connected to mechanically actuate the microgripper.

Microminiaturized minimally invasive intravascular micro-mechanical systems powered and controlled via fiber-optic cable

DOEpatents

Fitch, J.P.; Hagans, K.; Clough, R.; Matthews, D.L.; Lee, A.P.; Krulevitch, P.A.; Benett, W.J.; Silva, L. Da; Celliers, P.M.

1998-03-03

A micro-mechanical system for medical procedures is constructed in the basic form of a catheter having a distal end for insertion into and manipulation within a body and a near end providing for a user to control the manipulation of the distal end within the body. A fiber-optic cable is disposed within the catheter and having a distal end proximate to the distal end of the catheter and a near end for external coupling of laser light energy. A microgripper is attached to the distal end of the catheter and providing for the gripping or releasing of an object within the body. A laser-light-to-mechanical-power converter is connected to receive laser light from the distal end of the fiber-optic cable and connected to mechanically actuate the microgripper. 22 figs.

Photochemical mechanisms of light-triggered release from nanocarriers

PubMed Central

Fomina, Nadezda; Sankaranarayanan, Jagadis; Almutairi, Adah

2012-01-01

Over the last three decades, a handful of photochemical mechanisms have been applied to a large number of nanoscale assemblies that encapsulate a payload to afford spatio-temporal and remote control over activity of the encapsulated payload. Many of these systems are designed with an eye towards biomedical applications, as spatio-temporal and remote control of bioactivity would advance research and clinical practice. This review covers five underlying photochemical mechanisms that govern the activity of the majority of photoresponsive nanocarriers: 1. photo driven isomerization and oxidation, 2. surface plasmon absorption and photothermal effects, 3. photo driven hydrophobicity changes, 4. photo driven polymer backbone fragmentation and 5. photo driven de-crosslinking. The ways in which these mechanisms have been incorporated into nanocarriers and how they affect release is detailed, as well as the advantages and disadvantages of each system. PMID:22386560

Control of constraint forces and trajectories in a rich sensory and actuation environment.

PubMed

Hemami, Hooshang; Dariush, Behzad

2010-12-01

A simple control strategy is proposed and applied to a class of non-linear systems that have abundant sensory and actuation channels as in living systems. The main objective is the independent control of constrained trajectories of motion, and control of the corresponding constraint forces. The peripheral controller is a proportional, derivative and integral (PID) controller. A central controller produces, via pattern generators, reference signals that are the desired constrained position and velocity trajectories, and the desired constraint forces. The basic tenet of the this hybrid control strategy is the use of two mechanisms: 1. linear state and force feedback, and 2. non-linear constraint velocity feedback - sliding mode feedback. The first mechanism can be envisioned as a high gain feedback systems. The high gain attribute imitates the agonist-antagonist co-activation in natural systems. The strategy is applied to the control of the force and trajectory of a two-segment thigh-leg planar biped leg with a mass-less foot cranking a pedal that is analogous to a bicycle pedal. Five computational experiments are presented to show the effectiveness of the strategy and the performance of the controller. The findings of this paper are applicable to the design of orthoses and prostheses to supplement functional electrical stimulation for support purposes in the spinally injured cases. Copyright © 2010 Elsevier Inc. All rights reserved.

Neural control and adaptive neural forward models for insect-like, energy-efficient, and adaptable locomotion of walking machines

PubMed Central

Manoonpong, Poramate; Parlitz, Ulrich; Wörgötter, Florentin

2013-01-01

Living creatures, like walking animals, have found fascinating solutions for the problem of locomotion control. Their movements show the impression of elegance including versatile, energy-efficient, and adaptable locomotion. During the last few decades, roboticists have tried to imitate such natural properties with artificial legged locomotion systems by using different approaches including machine learning algorithms, classical engineering control techniques, and biologically-inspired control mechanisms. However, their levels of performance are still far from the natural ones. By contrast, animal locomotion mechanisms seem to largely depend not only on central mechanisms (central pattern generators, CPGs) and sensory feedback (afferent-based control) but also on internal forward models (efference copies). They are used to a different degree in different animals. Generally, CPGs organize basic rhythmic motions which are shaped by sensory feedback while internal models are used for sensory prediction and state estimations. According to this concept, we present here adaptive neural locomotion control consisting of a CPG mechanism with neuromodulation and local leg control mechanisms based on sensory feedback and adaptive neural forward models with efference copies. This neural closed-loop controller enables a walking machine to perform a multitude of different walking patterns including insect-like leg movements and gaits as well as energy-efficient locomotion. In addition, the forward models allow the machine to autonomously adapt its locomotion to deal with a change of terrain, losing of ground contact during stance phase, stepping on or hitting an obstacle during swing phase, leg damage, and even to promote cockroach-like climbing behavior. Thus, the results presented here show that the employed embodied neural closed-loop system can be a powerful way for developing robust and adaptable machines. PMID:23408775

Closed-form solutions for linear regulator-design of mechanical systems including optimal weighting matrix selection

NASA Technical Reports Server (NTRS)

Hanks, Brantley R.; Skelton, Robert E.

1991-01-01

This paper addresses the restriction of Linear Quadratic Regulator (LQR) solutions to the algebraic Riccati Equation to design spaces which can be implemented as passive structural members and/or dampers. A general closed-form solution to the optimal free-decay control problem is presented which is tailored for structural-mechanical systems. The solution includes, as subsets, special cases such as the Rayleigh Dissipation Function and total energy. Weighting matrix selection is a constrained choice among several parameters to obtain desired physical relationships. The closed-form solution is also applicable to active control design for systems where perfect, collocated actuator-sensor pairs exist. Some examples of simple spring mass systems are shown to illustrate key points.

Concept for a Differential Lock and Traction Control Model in Automobiles

NASA Astrophysics Data System (ADS)

Shukul, A. K.; Hansra, S. K.

2014-01-01

The automobile is a complex integration of electronics and mechanical components. One of the major components is the differential which is limited due to its shortcomings. The paper proposes a concept of a cost effective differential lock and traction for passenger cars to sports utility vehicles alike, employing a parallel braking mechanism coming into action based on the relative speeds of the wheels driven by the differential. The paper highlights the employment of minimum number of components unlike the already existing systems. The system was designed numerically for the traction control and differential lock for the world's cheapest car. The paper manages to come up with all the system parameters and component costing making it a cost effective system.

The 10 MWe Solar Thermal Central Receiver Pilot Plant: Solar facilities design integration. Pilot-plant station manual (RADL Item 2-1). Volume 1: System description

NASA Astrophysics Data System (ADS)

1982-09-01

The complete Barstow Solar Pilot Plant is described. The plant requirements and general description are presented, the mechanical, electric power, and control and instrumentation systems as well as civil engineering and structural aspects and the station buildings are described. Included in the mechanical systems are the heliostats, receiver, thermal storage system, beam characterization system, steam, water, nitrogen, and compressed air systems, chemical feed system, fire protection system, drains, sumps and the waste disposal systems, and heating, ventilating, and air conditioning systems.

Cerebellar contribution to feedforward control of locomotion.

PubMed

Pisotta, Iolanda; Molinari, Marco

2014-01-01

The cerebellum is an important contributor to feedforward control mechanisms of the central nervous system, and sequencing-the process that allows spatial and temporal relationships between events to be recognized-has been implicated as the fundamental cerebellar mode of operation. By adopting such a mode and because cerebellar activity patterns are sensitive to a variety of sensorimotor-related tasks, the cerebellum is believed to support motor and cognitive functions that are encoded in the frontal and parietal lobes of the cerebral cortex. In this model, the cerebellum is hypothesized to make predictions about the consequences of a motor or cognitive command that originates from the cortex to prepare the entire system to cope with ongoing changes. In this framework, cerebellar predictive mechanisms for locomotion are addressed, focusing on sensorial and motoric sequencing. The hypothesis that sequence recognition is the mechanism by which the cerebellum functions in gait control is presented and discussed.

Cerebellar contribution to feedforward control of locomotion

PubMed Central

Pisotta, Iolanda; Molinari, Marco

2014-01-01

The cerebellum is an important contributor to feedforward control mechanisms of the central nervous system, and sequencing—the process that allows spatial and temporal relationships between events to be recognized—has been implicated as the fundamental cerebellar mode of operation. By adopting such a mode and because cerebellar activity patterns are sensitive to a variety of sensorimotor-related tasks, the cerebellum is believed to support motor and cognitive functions that are encoded in the frontal and parietal lobes of the cerebral cortex. In this model, the cerebellum is hypothesized to make predictions about the consequences of a motor or cognitive command that originates from the cortex to prepare the entire system to cope with ongoing changes. In this framework, cerebellar predictive mechanisms for locomotion are addressed, focusing on sensorial and motoric sequencing. The hypothesis that sequence recognition is the mechanism by which the cerebellum functions in gait control is presented and discussed. PMID:25009490

Generating giant and tunable nonlinearity in a macroscopic mechanical resonator from a single chemical bond

NASA Astrophysics Data System (ADS)

Huang, Pu; Zhou, Jingwei; Zhang, Liang; Hou, Dong; Lin, Shaochun; Deng, Wen; Meng, Chao; Duan, Changkui; Ju, Chenyong; Zheng, Xiao; Xue, Fei; Du, Jiangfeng

2016-05-01

Nonlinearity in macroscopic mechanical systems may lead to abundant phenomena for fundamental studies and potential applications. However, it is difficult to generate nonlinearity due to the fact that macroscopic mechanical systems follow Hooke's law and respond linearly to external force, unless strong drive is used. Here we propose and experimentally realize high cubic nonlinear response in a macroscopic mechanical system by exploring the anharmonicity in chemical bonding interactions. We demonstrate the high tunability of nonlinear response by precisely controlling the chemical bonding interaction, and realize, at the single-bond limit, a cubic elastic constant of 1 × 1020 N m-3. This enables us to observe the resonator's vibrational bi-states transitions driven by the weak Brownian thermal noise at 6 K. This method can be flexibly applied to a variety of mechanical systems to improve nonlinear responses, and can be used, with further improvements, to explore macroscopic quantum mechanics.

Controls on project proponents and environmental impact assessment effectiveness

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

Ortolano, L.

The degree of effectiveness of environmental impact assessment (EIA) for particular projects is associated with the existence of mechanisms of organizational control. Five dimensions of EIA effectiveness are considered: procedural compliance, completeness of EIA documents, methods to assess impacts, influence on project decisions, and weight given to environmental factors. Six mechanisms of control are introduced and illustrated by programs and projects in several countries. Experience in the Philippines under President Marcos demonstrates that procedural control in the form of EIA regulations, when used without other control mechanisms, will lead at most to token compliance. Judicial control, as practiced in themore » US, yields high procedural compliance. Evaluative control can yield effective EIA, but some systems based on this form of control treat only a small fraction of the major projects proposed. Both control exerted by development assistance organizations and control by professionals have great potential for yielding effective EIA, but that potential has not been fully realized. Control exerted directly by citizens or agencies not otherwise involved in EIA is uncommon, but cases from Taiwan demonstrate that those controls can be significant. An understanding of relationships between control mechanisms and EIA effectiveness is useful in designing EIA policies and programs.« less

49 CFR 174.67 - Tank car unloading.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (2) Monitored by a signaling system (e.g., video system, sensing equipment, or mechanical equipment... or at a remote location within the facility, such as a control room. The signaling system must— (i...

Attitude control system for a lightweight flapping wing MAV.

PubMed

Tijmons, Sjoerd; Karásek, Matěj; de Croon, G C H E

2018-03-14

Robust attitude control is an essential aspect of research on autonomous flight of flapping wing Micro Air Vehicles. The mechanical solutions by which the necessary control moments are realised come at the price of extra weight and possible loss of aerodynamic efficiency. Stable flight of these vehicles has been shown by several designs using a conventional tail, but also by tailless designs that use active control of the wings. In this study a control mechanism is proposed that provides active control over the wings. The mechanism improves vehicle stability and agility by generation of control moments for roll, pitch and yaw. Its effectiveness is demonstrated by static measurements around all the three axes. Flight test results confirm that the attitude of the test vehicle, including a tail, can be successfully controlled in slow forward flight conditions. Furthermore, the flight envelope is extended with robust hovering and the ability to reverse the flight direction using a small turn space. This capability is very important for autonomous flight capabilities such as obstacle avoidance. Finally, it is demonstrated that the proposed control mechanism allows for tailless hovering flight. © 2018 IOP Publishing Ltd.

Motor Controllers

NASA Technical Reports Server (NTRS)

1984-01-01

Kollmorgen Corporation's Mermaid II two person submersible is propeller-driven by a system of five DC brushless motors with new electronic controllers that originated in work performed in a NASA/DOE project managed by Lewis Research Center. A key feature of the system is electric commutation rather than mechanical commutation for converting AC current to DC.

Oscillation control system for electric motor drive

DOEpatents

Slicker, J.M.; Sereshteh, A.

1988-08-30

A feedback system for controlling mechanical oscillations in the torsionally complaint drive train of an electric or other vehicle. Motor speed is converted in a processor to estimate state signals in which a plant model which are used to electronically modify the torque commands applied to the motor. 5 figs.

46 CFR 58.25-70 - Steering-gear control systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Steering-gear control systems. 58.25-70 Section 58.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY... gear must be operable from the pilothouse by mechanical, hydraulic, electrical, or other means...

46 CFR 58.25-70 - Steering-gear control systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Steering-gear control systems. 58.25-70 Section 58.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY... gear must be operable from the pilothouse by mechanical, hydraulic, electrical, or other means...

46 CFR 58.25-70 - Steering-gear control systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Steering-gear control systems. 58.25-70 Section 58.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY... gear must be operable from the pilothouse by mechanical, hydraulic, electrical, or other means...

Damping torque analysis of VSC-based system utilizing power synchronization control

NASA Astrophysics Data System (ADS)

Fu, Q.; Du, W. J.; Zheng, K. Y.; Wang, H. F.

2017-05-01

Power synchronization control is a new control strategy of VSC-HVDC for connecting a weak power system. Different from the vector control method, this control method utilizes the internal synchronization mechanism in ac systems, in principle, similar to the operation of a synchronous machine. So that the parameters of controllers in power synchronization control will change the electromechanical oscillation modes and make an impact on the transient stability of power system. This paper present a mathematical model for small-signal stability analysis of VSC station used power synchronization control and analyse the impact of the dynamic interactions by calculating the contribution of the damping torque from the power synchronization control, besides, the parameters of controllers which correspond to damping torque and synchronous torque in the power synchronization control is defined respectively. At the end of the paper, an example power system is presented to demonstrate and validate the theoretical analysis and associated conclusions are made.

Development of a coupled expert system for the spacecraft attitude control problem

NASA Technical Reports Server (NTRS)

Kawamura, K.; Beale, G.; Schaffer, J.; Hsieh, B.-J.; Padalkar, S.; Rodriguezmoscoso, J.; Vinz, F.; Fernandez, K.

1987-01-01

A majority of the current expert systems focus on the symbolic-oriented logic and inference mechanisms of artificial intelligence (AI). Common rule-based systems employ empirical associations and are not well suited to deal with problems often arising in engineering. Described is a prototype expert system which combines both symbolic and numeric computing. The expert system's configuration is presented and its application to a spacecraft attitude control problem is discussed.

Investigation of longitudinal control system for a small hydrofoil boat

NASA Technical Reports Server (NTRS)

Phillips, W. H.; Shaughnessy, J. D.

1976-01-01

An analysis of a hydromechanical system for longitudinal control of a small hydrofoil boat is presented. The system incorporates height and acceleration sensors operating flaps on the foils through a mechanical linkage. Effects of some of the system parameters on the stability and response to waves are shown. The results indicate that the system is capable of providing adequate stability, but the response to stern waves at low frequencies is larger than desired.

Quiet Clean Short-haul Experimental Engine (QCSEE). Under-The-Wing (UTW) engine boilerplate nacelle test report. Volume 3: Mechanical performance

NASA Technical Reports Server (NTRS)

1977-01-01

Results of initial tests of the under the wing experimental engine and boilerplate nacelle are presented. The mechanical performance of the engine is reported with emphasis on the advanced technology components. Technology elements of the propulsion system covered include: system dynamics, composite fan blades, reduction gear, lube and accessory drive system, fan frame, inlet, core cowl cooling, fan exhaust nozzle, and digital control system.

Experience with synchronous and asynchronous digital control systems. [for flight

NASA Technical Reports Server (NTRS)

Regenie, Victoria A.; Chacon, Claude V.; Lock, Wilton P.

1986-01-01

Flight control systems have undergone a revolution since the days of simple mechanical linkages; presently the most advanced systems are full-authority, full-time digital systems controlling unstable aircraft. With the use of advanced control systems, the aerodynamic design can incorporate features that allow greater performance and fuel savings, as can be seen on the new Airbus design and advanced tactical fighter concepts. These advanced aircraft will be and are relying on the flight control system to provide the stability and handling qualities required for safe flight and to allow the pilot to control the aircraft. Various design philosophies have been proposed and followed to investigate system architectures for these advanced flight control systems. One major area of discussion is whether a multichannel digital control system should be synchronous or asynchronous. This paper addressed the flight experience at the Dryden Flight Research Facility of NASA's Ames Research Center with both synchronous and asynchronous digital flight control systems. Four different flight control systems are evaluated against criteria such as software reliability, cost increases, and schedule delays.

The (un)coupling between action execution and observation. Comment on "Grasping synergies: A motor-control approach to the mirror neuron mechanism" by D'Ausilio, Bartoli and Maffongelli

NASA Astrophysics Data System (ADS)

Cavallo, Andrea; Ansuini, Caterina; Becchio, Cristina

2015-03-01

When we observe actions performed by others, our motor system resonates along with that of the observed agent [1]. The exact features of this resonant motor response, however, are unclear. Do we mirror the goal of others' actions or rather the low-kinematic features of their movements? D'Ausilio et al. suggest that this is an ill-defined problem: the mirror system plausibly replicates the same computational mechanisms implicated by motor control. Accordingly, motor synergies may not only constitute a pervasive element of motor control, but also form the fundamental unit of action observation.

Incentive-Rewarding Mechanism for User-position Control in Mobile Services

NASA Astrophysics Data System (ADS)

Yoshino, Makoto; Sato, Kenichiro; Shinkuma, Ryoichi; Takahashi, Tatsuro

When the number of users in a service area increases in mobile multimedia services, no individual user can obtain satisfactory radio resources such as bandwidth and signal power because the resources are limited and shared. A solution for such a problem is user-position control. In the user-position control, the operator informs users of better communication areas (or spots) and navigates them to these positions. However, because of subjective costs caused by subjects moving from their original to a new position, they do not always attempt to move. To motivate users to contribute their resources in network services that require resource contributions for users, incentive-rewarding mechanisms have been proposed. However, there are no mechanisms that distribute rewards appropriately according to various subjective factors involving users. Furthermore, since the conventional mechanisms limit how rewards are paid, they are applicable only for the network service they targeted. In this paper, we propose a novel incentive-rewarding mechanism to solve these problems, using an external evaluator and interactive learning agents. We also investigated ways of appropriately controlling rewards based on user contributions and system service quality. We applied the proposed mechanism and reward control to the user-position control, and demonstrated its validity.

Servo-controlled pneumatic pressure oscillator for respiratory impedance measurements and high-frequency ventilation.

PubMed

Kaczka, David W; Lutchen, Kenneth R

2004-04-01

The ability to provide forced oscillatory excitation of the respiratory system can be useful in mechanical impedance measurements as well as high frequency ventilation (HFV). Experimental systems currently used for generating forced oscillations are limited in their ability to provide high amplitude flows or maintain the respiratory system at a constant mean pressure during excitation. This paper presents the design and implementation of a pneumatic pressure oscillator based on a proportional solenoid valve. The device is capable of providing forced oscillatory excitations to the respiratory system over a bandwidth suitable for mechanical impedance measurements and HVF. It delivers high amplitude flows (> 1.4 l/s) and utilizes a servo-control mechanism to maintain a load at a fixed mean pressure during simultaneous oscillation. Under open-loop conditions, the device exhibited a static hysteresis of approximately 7%, while its dynamic magnitude and phase responses were flat out to 10 Hz. Broad-band measurement of total harmonic distortion was approximately 19%. Under closed-loop conditions, the oscillator was able to maintain a mechanical test load at both positive and negative mean pressures during oscillatory excitations from 0.1 to 10.0 Hz. Impedance of the test load agreed closely with theoretical predictions. We conclude that this servo-controlled oscillator can be a useful tool for respiratory impedance measurements as well as HFV.

Active Control of Mixing and Combustion, from Mechanisms to Implementation

NASA Astrophysics Data System (ADS)

Ghoniem, Ahmed F.

2001-11-01

Implementation of active control in complex processes, of the type encountered in high Reynolds number mixing and combustion, is predicated upon the identification of the underlying mechanisms and the construction of reduced order models that capture their essential characteristics. The mechanisms of interest must be shown to be amenable to external actuations, allowing optimal control strategies to exploit the delicate interactions that lead to the desired outcome. Reduced order models are utilized in defining the form and requisite attributes of actuation, its relationship to the monitoring system and the relevant control algorithms embedded in a feedforward or a feedback loop. The talk will review recent work on active control of mixing in combustion devices in which strong shear zones concur with mixing, combustion stabilization and flame anchoring. The underlying mechanisms, e.g., stability of shear flows, formation/evolution of large vortical structures in separating and swirling flows, their mutual interactions with acoustic fields, flame fronts and chemical kinetics, etc., are discussed in light of their key roles in mixing, burning enhancement/suppression, and combustion instability. Subtle attributes of combustion mechanisms are used to suggest the requisite control strategies.

Shutter mechanism for spacecraft spectrophotometer

NASA Technical Reports Server (NTRS)

Weilbach, A.

1972-01-01

A shutter mechanism is described for the backscatter ultraviolet spectrophotometer experiment on the Nimbus D satellite. The purpose of the experiment is to determine spatial distribution of atmospheric ozone from measurements of ultraviolet radiation backscattered by the earth's atmosphere. The system consists of two independent, rotary cylinder shutters, controlled by a dual star Geneva mechanism, and driven by a single stepper motor. A single driver controls a combination of two independently driven Geneva stars. Design considerations involved the use of low friction, nonmetallic materials.

Fracture and failure: Analyses, mechanisms and applications; Proceedings of the Symposium, Los Angeles, CA, March 17-20, 1980

NASA Technical Reports Server (NTRS)

Tung, P. P. (Editor); Agrawal, S. P.; Kumar, A.; Katcher, M.

1981-01-01

Papers are presented on the application of fracture mechanics to spacecraft design, fracture control applications on the Space Shuttle reaction control thrusters, and an assessment of fatigue crack growth rate relationships for metallic airframe materials. Also considered are fracture mechanisms and microstructural relationships in Ni-base alloy systems, the use of surface deformation markings to determine crack propagation directions, case histories of metallurgical failures in the electronics industry, and a failure analysis of silica phenolic nozzle liners.

Design of mechanical arm for an automatic sorting system of recyclable cans

NASA Astrophysics Data System (ADS)

Resti, Y.; Mohruni, A. S.; Burlian, F.; Yani, I.; Amran, A.

2018-04-01

The use of a mechanical arm for an automatic sorting system of used cans should be designed carefully. The right design will result in a high precision sorting rate and a short sorting time. The design includes first; design manipulator,second; determine link and joint specifications, and third; build mechanical systems and control systems. This study aims to design the mechanical arm as a hardware system for automatic cans sorting system. The material used for the manipulator is the aluminum plate. The manipulator is designed using 6 links and 6 join where the 6th link is the end effectorand the 6th join is the gripper. As a driving motor used servo motor, while as a microcontroller used Arduino Uno which is connected with Matlab programming language. Based on testing, a mechanical arm designed for this recyclable canned recycling system has a precision sorting rate at 93%, where the average total time required for sorting is 10.82 seconds.

Bioregenerative system

NASA Technical Reports Server (NTRS)

1987-01-01

The design course is an eight semester credit multi-disciplinary engineering design course taught primarily to Engineering Science, Aerospace, Electrical and Mechanical Engineering seniors. This year the course project involved the design of the three interrelated loops: atmospheric, liquid nutrient and solid waste management, associated with growing higher plants to support man during long-term space missions. The project is complementary to the NASA Kennedy Space Center Controlled Environmental Life Support System (CELSS) project. The first semester the class worked on a preliminary design for a complete system. This effort included means for monitoring and control of composition, temperature, flow rate, etc., for the atmosphere and liquid nutrient solution; disease and contaminant monitoring and control; plant mechanical support, propagation and harvesting; solid and liquid waste recycling; and system maintenance and refurbishing. The project has significant biological, mechanical, electrical and Al/Robotics aspects. The second semester a small number of subsystems or components, identified as important and interesting during the first semester, were selected for detail design, fabrication, and testing. The class was supported by close cooperation with The Kennedy Space Center and by two teaching assistants. The availability of a dedicated, well equipped project room greatly enhanced the communication and team spirit of the class.

An In Vitro Perfusion System to Enhance Outflow Studies in Mouse Eyes

PubMed Central

Kizhatil, Krishnakumar; Chlebowski, Arthur; Tolman, Nicholas G.; Freeburg, Nelson F.; Ryan, Margaret M.; Shaw, Nicholas N.; Kokini, Alexander D. M.; Marchant, Jeffrey K.; John, Simon W. M.

2016-01-01

Purpose The molecular mechanisms controlling aqueous humor (AQH) outflow and IOP need much further definition. The mouse is a powerful system for characterizing the mechanistic basis of AQH outflow. To enhance outflow studies in mice, we developed a perfusion system that is based on human anterior chamber perfusion culture systems. Our mouse system permits previously impractical experiments. Methods We engineered a computer-controlled, pump-based perfusion system with a platform for mounting whole dissected mouse eyes (minus lens and iris, ∼45% of drainage tissue is perfused). We tested the system's ability to monitor outflow and tested the effects of the outflow-elevating drug, Y27632, a rho-associated protein kinase (ROCK) inhibitor. Finally, we tested the system's ability to detect genetically determined decreases in outflow by determining if deficiency of the candidate genes Nos3 and Cav1 alter outflow. Results Using our system, the outflow facility (C) of C57BL/6J mouse eyes was found to range between 7.7 and 10.4 nl/minutes/mm Hg (corrected for whole eye). Our system readily detected a 74.4% Y27632-induced increase in C. The NOS3 inhibitor L-NG-nitroarginine methyl ester (L-NAME) and a Nos3 null mutation reduced C by 28.3% and 35.8%, respectively. Similarly, in Cav1 null eyes C was reduced by 47.8%. Conclusions We engineered a unique perfusion system that can accurately measure changes in C. We then used the system to show that NOS3 and CAV1 are key components of mechanism(s) controlling outflow. PMID:27701632

Dynamic mechanical control of local vacancies in NiO thin films

NASA Astrophysics Data System (ADS)

Seol, Daehee; Yang, Sang Mo; Jesse, Stephen; Choi, Minseok; Hwang, Inrok; Choi, Taekjib; Park, Bae Ho; Kalinin, Sergei V.; Kim, Yunseok

2018-07-01

The manipulation of local ionic behavior via external stimuli in oxide systems is of great interest because it can help in directly tuning material properties. Among external stimuli, mechanical force has attracted intriguing attention as novel stimulus for ionic modulation. Even though effectiveness of mechanical force on local ionic modulation has been validated in terms of static effect, its real-time i.e., dynamic, behavior under an application of the force is barely investigated in spite of its crucial impact on device performance such as force or pressure sensors. In this study, we explore dynamic ionic behavior modulated by mechanical force in NiO thin films using electrochemical strain microscopy (ESM). Ionically mediated ESM hysteresis loops were significantly varied under an application of mechanical force. Based on these results, we were able to investigate relative relationship between the force and voltage effects on ionic motion and, further, control effectively ionic behavior through combination of mechanical and electrical stimuli. Our results can provide comprehensive information on the effect of mechanical forces on ionic dynamics in ionic systems.

Dynamic mechanical control of local vacancies in NiO thin films.

PubMed

Seol, Daehee; Yang, Sang Mo; Jesse, Stephen; Choi, Minseok; Hwang, Inrok; Choi, Taekjib; Park, Bae Ho; Kalinin, Sergei V; Kim, Yunseok

2018-07-06

The manipulation of local ionic behavior via external stimuli in oxide systems is of great interest because it can help in directly tuning material properties. Among external stimuli, mechanical force has attracted intriguing attention as novel stimulus for ionic modulation. Even though effectiveness of mechanical force on local ionic modulation has been validated in terms of static effect, its real-time i.e., dynamic, behavior under an application of the force is barely investigated in spite of its crucial impact on device performance such as force or pressure sensors. In this study, we explore dynamic ionic behavior modulated by mechanical force in NiO thin films using electrochemical strain microscopy (ESM). Ionically mediated ESM hysteresis loops were significantly varied under an application of mechanical force. Based on these results, we were able to investigate relative relationship between the force and voltage effects on ionic motion and, further, control effectively ionic behavior through combination of mechanical and electrical stimuli. Our results can provide comprehensive information on the effect of mechanical forces on ionic dynamics in ionic systems.

Probe Scanning Support System by a Parallel Mechanism for Robotic Echography

NASA Astrophysics Data System (ADS)

Aoki, Yusuke; Kaneko, Kenta; Oyamada, Masami; Takachi, Yuuki; Masuda, Kohji

We propose a probe scanning support system based on force/visual servoing control for robotic echography. First, we have designed and formulated its inverse kinematics the construction of mechanism. Next, we have developed a scanning method of the ultrasound probe on body surface to construct visual servo system based on acquired echogram by the standalone medical robot to move the ultrasound probe on patient abdomen in three-dimension. The visual servo system detects local change of brightness in time series echogram, which is stabilized the position of the probe by conventional force servo system in the robot, to compensate not only periodical respiration motion but also body motion. Then we integrated control method of the visual servo with the force servo as a hybrid control in both of position and force. To confirm the ability to apply for actual abdomen, we experimented the total system to follow the gallbladder as a moving target to keep its position in the echogram by minimizing variation of reaction force on abdomen. As the result, the system has a potential to be applied to automatic detection of human internal organ.

Math modeling and computer mechanization for real time simulation of rotary-wing aircraft

NASA Technical Reports Server (NTRS)

Howe, R. M.

1979-01-01

Mathematical modeling and computer mechanization for real time simulation of rotary wing aircraft is discussed. Error analysis in the digital simulation of dynamic systems, such as rotary wing aircraft is described. The method for digital simulation of nonlinearities with discontinuities, such as exist in typical flight control systems and rotor blade hinges, is discussed.

A composite controller for trajectory tracking applied to the Furuta pendulum.

PubMed

Aguilar-Avelar, Carlos; Moreno-Valenzuela, Javier

2015-07-01

In this paper, a new composite scheme is proposed, where the total control action is composed of the sum of a feedback-linearization-based controller and an energy-based compensation. This new proposition is applied to the rotary inverted pendulum or Furuta pendulum. The Furuta pendulum is a well-known underactuated mechanical system with two degrees of freedom. The control objective in this case is the tracking of a desired periodic trajectory in the actuated joint, while the unactuated link is regulated at the upward position. The closed-loop system is analyzed showing uniformly ultimately boundedness of the error trajectories. The design procedure is shown in a constructive form, such that it may be applied to other underactuated mechanical systems, with the proper definitions of the output function and the energy function. Numerical simulations and real-time experiments show the practical viability of the controller. Finally, the proposed algorithm is compared with a tracking controller previously reported in the literature. The new algorithm shows better performance in both arm trajectory tracking and pendulum regulation. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

On the applicability of the decentralized control mechanism extracted from the true slime mold: a robotic case study with a serpentine robot.

PubMed

Sato, Takahide; Kano, Takeshi; Ishiguro, Akio

2011-06-01

A systematic method for an autonomous decentralized control system is still lacking, despite its appealing concept. In order to alleviate this, we focused on the amoeboid locomotion of the true slime mold, and extracted a design scheme for the decentralized control mechanism that leads to adaptive behavior for the entire system, based on the so-called discrepancy function. In this paper, we intensively investigate the universality of this design scheme by applying it to a different type of locomotion based on a 'synthetic approach'. As a first step, we implement this design scheme to the control of a real physical two-dimensional serpentine robot that exhibits slithering locomotion. The experimental results show that the robot exhibits adaptive behavior and responds to the environmental changes; it is also robust against malfunctions of the body segments due to the local sensory feedback control that is based on the discrepancy function. We expect the results to shed new light on the methodology of autonomous decentralized control systems.

Multi-Objectives Optimization of Ventilation Controllers for Passive Cooling in Residential Buildings

PubMed Central

Grygierek, Krzysztof; Ferdyn-Grygierek, Joanna

2018-01-01

An inappropriate indoor climate, mostly indoor temperature, may cause occupants’ discomfort. There are a great number of air conditioning systems that make it possible to maintain the required thermal comfort. Their installation, however, involves high investment costs and high energy demand. The study analyses the possibilities of limiting too high a temperature in residential buildings using passive cooling by means of ventilation with ambient cool air. A fuzzy logic controller whose aim is to control mechanical ventilation has been proposed and optimized. In order to optimize the controller, the modified Multiobjective Evolutionary Algorithm, based on the Strength Pareto Evolutionary Algorithm, has been adopted. The optimization algorithm has been implemented in MATLAB®, which is coupled by MLE+ with EnergyPlus for performing dynamic co-simulation between the programs. The example of a single detached building shows that the occupants’ thermal comfort in a transitional climate may improve significantly owing to mechanical ventilation controlled by the suggested fuzzy logic controller. When the system is connected to the traditional cooling system, it may further bring about a decrease in cooling demand. PMID:29642525

Design of a powered elevator control system. [powered elevator system for modified C-8A aircraft for STOL operation

NASA Technical Reports Server (NTRS)

Glende, W. L. B.

1974-01-01

The design, fabrication and flight testing of a powered elevator system for the Augmentor Wing Jet STOL Research Aircraft (AWJSRA or Mod C-8A) are discussed. The system replaces a manual spring tab elevator control system that was unsatisfactory in the STOL flight regime. Pitch control in the AWJSRA is by means of a single elevator control surface. The elevator is used for both maneuver and trim control as the stabilizer is fixed. A fully powered, irreversible flight control system powered by dual hydraulic sources was designed. The existing control columns and single mechanical cable system of the AWJSRA have been retained as has been the basic elevator surface, except that the elevator spring tab is modified into a geared balance tab. The control surface is directly actuated by a dual tandem moving body actuator. Control signals are transmitted from the elevator aft quadrant to the actuator by a linkage system that includes a limited authority series servo actuator.

Research on equipment of micro-pressure measure and control in loading experiment of plant cell mechanics

NASA Astrophysics Data System (ADS)

Zhang, Lian; Yu, Chengbo; Tao, Hongyan; Chen, Xuejun; Zhai, Feng

2005-12-01

The equipment is developed to measure and control micro-pressure in loading experiment of plant cell mechanics. The motivation for the development of this equipment was to maintain a stationary micro-pressure on the agar of culturing cells to keep cytoactive in biology experiments. A singlechip controls the stepping motor of this equipment to drive loading equipment in the system, in order to load between 50mN and 250mN under a constant voltage. The accuracy is estimated to be +/-0.4 mN. The structure and control system of this equipment is introduced and described in detail. The experimental results show that the equipment is capable of maintaining a constant, stationary micropressure in cell culturing application and is worth of extending and applying.

Dynamic analysis and control PID path of a model type gantry crane

NASA Astrophysics Data System (ADS)

Ospina-Henao, P. A.; López-Suspes, Framsol

2017-06-01

This paper presents an alternate form for the dynamic modelling of a mechanical system that simulates in real life a gantry crane type, using Euler’s classical mechanics and Lagrange formalism, which allows find the equations of motion that our model describe. Moreover, it has a basic model design system using the SolidWorks software, based on the material and dimensions of the model provides some physical variables necessary for modelling. In order to verify the theoretical results obtained, a contrast was made between solutions obtained by simulation in SimMechanics-Matlab and Euler-Lagrange equations system, has been solved through Matlab libraries for solving equation’s systems of the type and order obtained. The force is determined, but not as exerted by the spring, as this will be the control variable. The objective is to bring the mass of the pendulum from one point to another with a specified distance without the oscillation from it, so that, the answer is overdamped. This article includes an analysis of PID control in which the equations of motion of Euler-Lagrange are rewritten in the state space, once there, they were implemented in Simulink to get the natural response of the system to a step input in F and then draw the desired trajectories.

Characterization of active hair-bundle motility by a mechanical-load clamp

NASA Astrophysics Data System (ADS)

Salvi, Joshua D.; Maoiléidigh, Dáibhid Ó.; Fabella, Brian A.; Tobin, Mélanie; Hudspeth, A. J.

2015-12-01

Active hair-bundle motility endows hair cells with several traits that augment auditory stimuli. The activity of a hair bundle might be controlled by adjusting its mechanical properties. Indeed, the mechanical properties of bundles vary between different organisms and along the tonotopic axis of a single auditory organ. Motivated by these biological differences and a dynamical model of hair-bundle motility, we explore how adjusting the mass, drag, stiffness, and offset force applied to a bundle control its dynamics and response to external perturbations. Utilizing a mechanical-load clamp, we systematically mapped the two-dimensional state diagram of a hair bundle. The clamp system used a real-time processor to tightly control each of the virtual mechanical elements. Increasing the stiffness of a hair bundle advances its operating point from a spontaneously oscillating regime into a quiescent regime. As predicted by a dynamical model of hair-bundle mechanics, this boundary constitutes a Hopf bifurcation.

Activity-dependent self-regulation of viscous length scales in biological systems

NASA Astrophysics Data System (ADS)

Nandi, Saroj Kumar

2018-05-01

The cellular cortex, which is a highly viscous thin cytoplasmic layer just below the cell membrane, controls the cell's mechanical properties, which can be characterized by a hydrodynamic length scale ℓ . Cells actively regulate ℓ via the activity of force-generating molecules, such as myosin II. Here we develop a general theory for such systems through a coarse-grained hydrodynamic approach including activity in the static description of the system providing an experimentally accessible parameter and elucidate the detailed mechanism of how a living system can actively self-regulate its hydrodynamic length scale, controlling the rigidity of the system. Remarkably, we find that ℓ , as a function of activity, behaves universally and roughly inversely proportional to the activity of the system. Our theory rationalizes a number of experimental findings on diverse systems, and comparison of our theory with existing experimental data shows good agreement.

Type-Based Access Control in Data-Centric Systems

NASA Astrophysics Data System (ADS)

Caires, Luís; Pérez, Jorge A.; Seco, João Costa; Vieira, Hugo Torres; Ferrão, Lúcio

Data-centric multi-user systems, such as web applications, require flexible yet fine-grained data security mechanisms. Such mechanisms are usually enforced by a specially crafted security layer, which adds extra complexity and often leads to error prone coding, easily causing severe security breaches. In this paper, we introduce a programming language approach for enforcing access control policies to data in data-centric programs by static typing. Our development is based on the general concept of refinement type, but extended so as to address realistic and challenging scenarios of permission-based data security, in which policies dynamically depend on the database state, and flexible combinations of column- and row-level protection of data are necessary. We state and prove soundness and safety of our type system, stating that well-typed programs never break the declared data access control policies.

An Active Micro Vibration Isolator with Zero-Power Controlled Magnetic Suspension Technology

NASA Astrophysics Data System (ADS)

Hoque, Md. Emdadul; Takasaki, Masaya; Ishino, Yuji; Suzuki, Hirohisa; Mizuno, Takeshi

In this paper, a three-degree-of-freedom vibration isolation system using active zero-power controlled magnetic suspension is presented in order to isolate vibrations transmitted from the ground and to attenuate the effect of direct disturbances on the table. The zero-compliance of the isolator for direct disturbances was realized by connecting a conventional mechanical spring in series with a negative spring produced by an active magnetic suspension mechanism. In this work, each degree-of-freedom-of-motion of the vibration isolator is treated analytically and it is shown that the developed system is capable to generate infinite stiffness in each mode. Experimental studies have been conducted as well to measure the effectiveness of the isolator under both types of disturbances. Further improvements for the developed system as well as the control techniques are also discussed.

Principle, design and validation of a power-generated magnetorheological energy absorber with velocity self-sensing capability

NASA Astrophysics Data System (ADS)

Bai, Xian-Xu; Zhong, Wei-Min; Zou, Qi; Zhu, An-Ding; Sun, Jun

2018-07-01

Based on the structural design concept of ‘functional integration’, this paper proposes the principle of a power-generated magnetorheological energy absorber with velocity self-sensing capability (PGMREA), which realizes the integration of controllable damping mechanism and mechanical energy-electrical energy conversion mechanism in structure profile and multiple functions in function profile, including controllable damping, power generation and velocity self-sensing. The controllable damping mechanism consists of an annular gap and a ball screw. The annular gap fulfilled with MR fluid that operates in pure shear mode under controllable electromagnetic field. The rotational damping torque generated from the controllable damping mechanism is translated to a linear damping force via the ball screw. The mechanical energy-electrical energy conversion mechanism is realized by the ball screw and a generator composed of a permanent magnet rotor and a generator stator. The ball screw based mechanical energy-electrical energy conversion mechanism converts the mechanical energy of excitations to electrical energy for storage or directly to power the controllable damping mechanism of the PGMREA. The velocity self-sensing capability of the PGMREA is achieved via signal processing using the mechanical energy-electrical energy conversion information. Based on the principle of the proposed PGMREA, the mathematical model of the PGMREA is established, including the damping force, generated power and self-sensing velocity. The electromagnetic circuit of the PGMREA is simulated and verified via a finite element analysis software ANSYS. The developed PGMREA prototype is experimentally tested on a servo-hydraulic testing system. The model-based predicted results and the experimental results are compared and analyzed.

Universal Controller for Spacecraft Mechanisms

NASA Technical Reports Server (NTRS)

Levanas, Greg; McCarthy, Thomas; Hunter, Don; Buchanan, Christine; Johnson, Michael; Cozy, Raymond; Morgan, Albert; Tran, Hung

2006-01-01

An electronic control unit has been fabricated and tested that can be replicated as a universal interface between the electronic infrastructure of a spacecraft and a brushless-motor (or other electromechanical actuator) driven mechanism that performs a specific mechanical function within the overall spacecraft system. The unit includes interfaces to a variety of spacecraft sensors, power outputs, and has selectable actuator control parameters making the assembly a mechanism controller. Several control topologies are selectable and reconfigurable at any time. This allows the same actuator to perform different functions during the mission life of the spacecraft. The unit includes complementary metal oxide/semiconductor electronic components on a circuit board of a type called rigid flex (signifying flexible printed wiring along with a rigid substrate). The rigid flex board is folded to make the unit fit into a housing on the back of a motor. The assembly has redundant critical interfaces, allowing the controller to perform time-critical operations when no human interface with the hardware is possible. The controller is designed to function over a wide temperature range without the need for thermal control, including withstanding significant thermal cycling, making it usable in nearly all environments that spacecraft or landers will endure. A prototype has withstood 1,500 thermal cycles between 120 and +85 C without significant deterioration of its packaging or electronic function. Because there is no need for thermal control and the unit is addressed through a serial bus interface, the cabling and other system hardware are substantially reduced in quantity and complexity, with corresponding reductions in overall spacecraft mass and cost.

Control theory for scanning probe microscopy revisited.

PubMed

Stirling, Julian

2014-01-01

We derive a theoretical model for studying SPM feedback in the context of control theory. Previous models presented in the literature that apply standard models for proportional-integral-derivative controllers predict a highly unstable feedback environment. This model uses features specific to the SPM implementation of the proportional-integral controller to give realistic feedback behaviour. As such the stability of SPM feedback for a wide range of feedback gains can be understood. Further consideration of mechanical responses of the SPM system gives insight into the causes of exciting mechanical resonances of the scanner during feedback operation.

Operation of passive membrane systems for drinking water treatment.

PubMed

Oka, P A; Khadem, N; Bérubé, P R

2017-05-15

The widespread adoption of submerged hollow fibre ultrafiltration (UF) for drinking water treatment is currently hindered by the complexity and cost of these membrane systems, especially in small/remote communities. Most of the complexity is associated with auxiliary fouling control measures, which include backwashing, air sparging and chemical cleaning. Recent studies have demonstrated that sustained operation without fouling control measures is possible, but little is known regarding the conditions under which extended operation can be sustained with minimal to no fouling control measures. The present study investigated the contribution of different auxiliary fouling control measures to the permeability that can be sustained, with the intent of minimizing the mechanical and operational complexity of submerged hollow fiber UF membrane systems while maximizing their throughput capacity. Sustained conditions could be achieved without backwashing, air sparging or chemical cleaning (i.e. passive operation), indicating that these fouling control measures can be eliminated, substantially simplifying the mechanical and operational complexity of submerged hollow fiber UF systems. The adoption of hydrostatic pressure (i.e. gravity) to provide the driving force for permeation further reduced the system complexity. Approximately 50% of the organic material in the raw water was removed during treatment. The sustained passive operation and effective removal of organic material was likely due to the microbial community that established itself on the membrane surface. The permeability that could be sustained was however only approximately 20% of that which can be maintained with fouling control measures. Retaining a small amount of air sparging (i.e. a few minutes daily) and incorporating a daily 1-h relaxation (i.e. permeate flux interruption) period prior to sparging more than doubled the permeability that could be sustained. Neither the approach used to interrupt the permeate flux nor that developed to draw air into the system for sparging using gravity add substantial mechanical or operational complexity to the system. The high throughput capacity that can be sustained by eliminating all but a couple of simple fouling control measures make passive membrane systems ideally suited to provide high quality water especially where access to financial resources, technical expertise and/or electrical power is limited. Copyright © 2017 Elsevier Ltd. All rights reserved.

Protein Quality Control and the Amyotrophic Lateral Sclerosis/Frontotemporal Dementia Continuum

PubMed Central

Shahheydari, Hamideh; Ragagnin, Audrey; Walker, Adam K.; Toth, Reka P.; Vidal, Marta; Jagaraj, Cyril J.; Perri, Emma R.; Konopka, Anna; Sultana, Jessica M.; Atkin, Julie D.

2017-01-01

Protein homeostasis, or proteostasis, has an important regulatory role in cellular function. Protein quality control mechanisms, including protein folding and protein degradation processes, have a crucial function in post-mitotic neurons. Cellular protein quality control relies on multiple strategies, including molecular chaperones, autophagy, the ubiquitin proteasome system, endoplasmic reticulum (ER)-associated degradation (ERAD) and the formation of stress granules (SGs), to regulate proteostasis. Neurodegenerative diseases are characterized by the presence of misfolded protein aggregates, implying that protein quality control mechanisms are dysfunctional in these conditions. Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative diseases that are now recognized to overlap clinically and pathologically, forming a continuous disease spectrum. In this review article, we detail the evidence for dysregulation of protein quality control mechanisms across the whole ALS-FTD continuum, by discussing the major proteins implicated in ALS and/or FTD. We also discuss possible ways in which protein quality mechanisms could be targeted therapeutically in these disorders and highlight promising protein quality control-based therapeutics for clinical trials. PMID:28539871

Printing Highly Controlled Suspended Carbon Nanotube Network on Micro-patterned Superhydrophobic Flexible Surface

PubMed Central

Li, Bo; Wang, Xin; Jung, Hyun Young; Kim, Young Lae; Robinson, Jeremy T.; Zalalutdinov, Maxim; Hong, Sanghyun; Hao, Ji; Ajayan, Pulickel M.; Wan, Kai-Tak; Jung, Yung Joon

2015-01-01

Suspended single-walled carbon nanotubes (SWCNTs) offer unique functionalities for electronic and electromechanical systems. Due to their outstanding flexible nature, suspended SWCNT architectures have great potential for integration into flexible electronic systems. However, current techniques for integrating SWCNT architectures with flexible substrates are largely absent, especially in a manner that is both scalable and well controlled. Here, we present a new nanostructured transfer paradigm to print scalable and well-defined suspended nano/microscale SWCNT networks on 3D patterned flexible substrates with micro- to nanoscale precision. The underlying printing/transfer mechanism, as well as the mechanical, electromechanical, and mechanical resonance properties of the suspended SWCNTs are characterized, including identifying metrics relevant for reliable and sensitive device structures. Our approach represents a fast, scalable and general method for building suspended nano/micro SWCNT architectures suitable for flexible sensing and actuation systems. PMID:26511284

Printing Highly Controlled Suspended Carbon Nanotube Network on Micro-patterned Superhydrophobic Flexible Surface.

PubMed

Li, Bo; Wang, Xin; Jung, Hyun Young; Kim, Young Lae; Robinson, Jeremy T; Zalalutdinov, Maxim; Hong, Sanghyun; Hao, Ji; Ajayan, Pulickel M; Wan, Kai-Tak; Jung, Yung Joon

2015-10-29

Suspended single-walled carbon nanotubes (SWCNTs) offer unique functionalities for electronic and electromechanical systems. Due to their outstanding flexible nature, suspended SWCNT architectures have great potential for integration into flexible electronic systems. However, current techniques for integrating SWCNT architectures with flexible substrates are largely absent, especially in a manner that is both scalable and well controlled. Here, we present a new nanostructured transfer paradigm to print scalable and well-defined suspended nano/microscale SWCNT networks on 3D patterned flexible substrates with micro- to nanoscale precision. The underlying printing/transfer mechanism, as well as the mechanical, electromechanical, and mechanical resonance properties of the suspended SWCNTs are characterized, including identifying metrics relevant for reliable and sensitive device structures. Our approach represents a fast, scalable and general method for building suspended nano/micro SWCNT architectures suitable for flexible sensing and actuation systems.

Modeling of Steer-by-Wire System Used in New Braking Handwheel Concept

NASA Astrophysics Data System (ADS)

Messaoudène, K.; Oufroukh, N. Ait; Mammar, S.

2008-06-01

The handwheel is one of the primary control mechanisms of automobile thus interaction between the handwheel and the driver is critical to safety. The driver applies forces that direct the vehicle while the handwheel communicates feedback information to the driver of the forces experience by the car within its environment. The handwheel also provides a predictable mechanical feel to the driver to allow smooth and safe control. Many researchers tried to reproduce this feeling by creating steer-by-wire systems. This paper explores this new concept of handwheel and it describes the modeling steps of the components including the restitution mechanism for force feedback and its various links with the vehicle lateral dynamics and the pneumatic contacts. The aim is to explore the possibility to combine a braking device within the steer-by-wire system in order to provide a more suitable and ergonomic device to the driver.

Partitioning in Avionics Architectures: Requirements, Mechanisms, and Assurance

NASA Technical Reports Server (NTRS)

Rushby, John

1999-01-01

Automated aircraft control has traditionally been divided into distinct "functions" that are implemented separately (e.g., autopilot, autothrottle, flight management); each function has its own fault-tolerant computer system, and dependencies among different functions are generally limited to the exchange of sensor and control data. A by-product of this "federated" architecture is that faults are strongly contained within the computer system of the function where they occur and cannot readily propagate to affect the operation of other functions. More modern avionics architectures contemplate supporting multiple functions on a single, shared, fault-tolerant computer system where natural fault containment boundaries are less sharply defined. Partitioning uses appropriate hardware and software mechanisms to restore strong fault containment to such integrated architectures. This report examines the requirements for partitioning, mechanisms for their realization, and issues in providing assurance for partitioning. Because partitioning shares some concerns with computer security, security models are reviewed and compared with the concerns of partitioning.

Military-civilian cooperative emergency response to infectious disease prevention and control in China.

PubMed

Ma, Hui; Dong, Ji-Ping; Zhou, Na; Pu, Wei

2016-01-01

In recent years, the incidence of severe infectious diseases has increased, and the number of emerging infectious diseases continues to increase. The Chinese government and military forces have paid a great deal of attention to infectious disease prevention and control, and using military-civilian cooperation, they have successfully prevented numerous severe epidemic situations, such as severe acute respiratory syndrome (SARS), influenza A (H1N1), avian influenza H5N1 and H7N9, and Ebola hemorrhagic fever, while actively maintained public health, economic development, and national construction. This paper focuses on the mechanisms of the military-cooperative emergency response to infectious diseases--the joint working mechanism, the information-sharing mechanism, the research collaboration mechanism, and the joint disposal mechanism--and presents a sorted summary of the practices and experiences of cooperative emergency responses to infectious diseases. In the future, the Chinese military and the civilian sector will further strengthen the cooperative joint command system and emergency rescue force and will reinforce their collaborative information-sharing platform and technical equipment system to further improve military-civilian collaborative emergency infectious diseases disposal, advance the level of infectious disease prevention and control, and maintain public health.

Apoptosis in the homeostasis of the immune system and in human immune mediated diseases.

PubMed

Giovannetti, A; Pierdominici, M; Di Iorio, A; Cianci, R; Murdaca, G; Puppo, F; Pandolfi, F; Paganelli, R

2008-01-01

The immune system has evolved sophisticated mechanisms controlling the development of responses to dangerous antigens while avoiding unnecessary attacks to innocuous, commensal or self antigens. The risk of autoimmunity is continuously checked and balanced against the risk of succumbing to exogenous infectious agents. It is therefore of paramount importance to understand the molecular events linking the breakdown of tolerance and the development of immunodeficiency. Apoptotic mechanisms are used to regulate the development of thymocytes, the shaping of T cell repertoire, its selection and the coordinate events leading to immune responses in the periphery. Moreover, they are at the heart of the homeostatic controls restoring T cell numbers and establishing T cell memory. T lymphocytes shift continuously from survival to death signals to ensure immune responsiveness without incurring in autoimmune damage. In this review we shall consider some key facts on the relationship of lymphopenia to autoreactivity, the mechanisms controlling positive and negative selection in the thymus, the role of apoptosis in selected primary immunodeficiency states and in systemic and organ-specific autoimmunity, with examples from human diseases and their animal models.

The effect of sudden server breakdown on the performance of a disassembly line

NASA Astrophysics Data System (ADS)

Udomsawat, Gun; Gupta, Surendra M.

2005-11-01

Product and material recovery relies on the disassembly process to separate target components or materials from the end-of-life (EOL) products. Disassembly line is especially effective when products in large quantity are disassembled. Unlike an assembly line, a disassembly line is more complex and is subjected to numerous uncertainties including stochastic and multi-level arrivals of component demands, stochastic arrival times for EOL products, and process interruption due to equipment failure. These factors seriously impair the control mechanism in the disassembly line. A common production control mechanism is the traditional push system (TPS). TPS responds to the aforementioned complications by carrying substantial amounts of inventories. An alternative control mechanism is a newly developed multi-kanban pull system (MKS) that relies on dynamic routing of kanbans, which tends to minimize the system's inventories while maintaining demand serviceability. In this paper we explore the impact of sudden breakdown of server on the performance of a disassembly line. We compare the overall performances of the TPS and MKS by considering two scenarios. We present the solution procedure and results for these cases.

Test Rig for Evaluating Active Turbine Blade Tip Clearance Control Concepts

NASA Technical Reports Server (NTRS)

Lattime, Scott B.; Steinetz, Bruce M.; Robbie, Malcolm G.; Erker, Arthur H.

2004-01-01

The objectives of the research presented in this viewgraph presentation are to 1) Design a mechanical ACC system for HPT tip seal clearance management; 2) Design a test rig to evaluate ACC system concepts. We have focused our efforts on designing mechanical ACC systems that articulate the seal shroud via mechanical linkages connected to actuators that reside outside the extreme environment of the HPT. We opted for this style of design due to a lack of high temperature/low profile actuators that are presently available. We have also selected multiple hydraulic actuators for this first generation ACC system. Fuel-draulic actuators are already a well established technology.

A unifying framework for systems modeling, control systems design, and system operation

NASA Technical Reports Server (NTRS)

Dvorak, Daniel L.; Indictor, Mark B.; Ingham, Michel D.; Rasmussen, Robert D.; Stringfellow, Margaret V.

2005-01-01

Current engineering practice in the analysis and design of large-scale multi-disciplinary control systems is typified by some form of decomposition- whether functional or physical or discipline-based-that enables multiple teams to work in parallel and in relative isolation. Too often, the resulting system after integration is an awkward marriage of different control and data mechanisms with poor end-to-end accountability. System of systems engineering, which faces this problem on a large scale, cries out for a unifying framework to guide analysis, design, and operation. This paper describes such a framework based on a state-, model-, and goal-based architecture for semi-autonomous control systems that guides analysis and modeling, shapes control system software design, and directly specifies operational intent. This paper illustrates the key concepts in the context of a large-scale, concurrent, globally distributed system of systems: NASA's proposed Array-based Deep Space Network.

Damage-Mitigating Control of Space Propulsion Systems for High Performance and Extended Life

NASA Technical Reports Server (NTRS)

Ray, Asok; Wu, Min-Kuang

1994-01-01

A major goal in the control of complex mechanical system such as spacecraft rocket engine's advanced aircraft, and power plants is to achieve high performance with increased reliability, component durability, and maintainability. The current practice of decision and control systems synthesis focuses on improving performance and diagnostic capabilities under constraints that often do not adequately represent the materials degradation. In view of the high performance requirements of the system and availability of improved materials, the lack of appropriate knowledge about the properties of these materials will lead to either less than achievable performance due to overly conservative design, or over-straining of the structure leading to unexpected failures and drastic reduction of the service life. The key idea in this report is that a significant improvement in service life could be achieved by a small reduction in the system dynamic performance. The major task is to characterize the damage generation process, and then utilize this information in a mathematical form to synthesize a control law that would meet the system requirements and simultaneously satisfy the constraints that are imposed by the material and structural properties of the critical components. The concept of damage mitigation is introduced for control of mechanical systems to achieve high performance with a prolonged life span. A model of fatigue damage dynamics is formulated in the continuous-time setting, instead of a cycle-based representation, for direct application to control systems synthesis. An optimal control policy is then formulated via nonlinear programming under specified constraints of the damage rate and accumulated damage. The results of simulation experiments for the transient upthrust of a bipropellant rocket engine are presented to demonstrate efficacy of the damage-mitigating control concept.

Test Platform for Advanced Digital Control of Brushless DC Motors (MSFC Center Director's Discretionary Fund)

NASA Technical Reports Server (NTRS)

Gwaltney, D. A.

2002-01-01

A FY 2001 Center Director's Discretionary Fund task to develop a test platform for the development, implementation. and evaluation of adaptive and other advanced control techniques for brushless DC (BLDC) motor-driven mechanisms is described. Important applications for BLDC motor-driven mechanisms are the translation of specimens in microgravity experiments and electromechanical actuation of nozzle and fuel valves in propulsion systems. Motor-driven aerocontrol surfaces are also being utilized in developmental X vehicles. The experimental test platform employs a linear translation stage that is mounted vertically and driven by a BLDC motor. Control approaches are implemented on a digital signal processor-based controller for real-time, closed-loop control of the stage carriage position. The goal of the effort is to explore the application of advanced control approaches that can enhance the performance of a motor-driven actuator over the performance obtained using linear control approaches with fixed gains. Adaptive controllers utilizing an exact model knowledge controller and a self-tuning controller are implemented and the control system performance is illustrated through the presentation of experimental results.