Effects of Desired Transmissibility Functions on the Performance and Design of Control Systems for Microgravity Isolation Systems

1995 ◽  
Author(s):  
N.-C. Tsai ◽  
A. Sinha
Keyword(s):  
Control System ◽  
Transfer Function ◽  
Control Systems ◽  
Closed Loop ◽  
Relative Displacement ◽  
Absolute Acceleration ◽  
Active Isolation ◽  
Space Experiments ◽  
Acceleration Feedback ◽  
Isolation Systems

Abstract This paper examines the performance of active isolation systems for micrograviry space experiments as a function of desired transmissibilities which are chosen to be either much below or close to what can be tolerated. The control system utilizes two feedback signals: absolute acceleration and relative displacement of the mass. The controller transfer function for acceleration feedback is chosen to avoid marginally stable pole-zero cancellations. The controller transfer function for relative displacement feedback is determined to achieve the desired transmissibility function. The issue of stability and properness of this controller transfer function are addressed. The required input forces and “equivalent” closed-loop stiffness are examined for various examples of desired transmissibilities.

scholarly journals Active Controller Design for Microgravity Isolation Systems

2002 ◽  
Vol 9 (6) ◽  
pp. 307-317
Author(s):  
Nan-Chyuan Tsai
Keyword(s):  
Control System ◽  
Transfer Function ◽  
Closed Loop ◽  
Controller Design ◽  
Relative Displacement ◽  
Absolute Acceleration ◽  
Active Isolation ◽  
Space Experiments ◽  
Acceleration Feedback ◽  
Isolation Systems

This paper examines the performance of active isolation systems for microgravity space experiments as a function of desired transmissibilities that are chosen to be either much below or close to what can be tolerated. The control system utilizes two feedback signals: absolute acceleration and relative displacement of the controlled mass. The controller transfer function for acceleration feedback is chosen to avoid marginally stable pole-zero cancellations. The controller transfer function for relative displacement feedback is determined to achieve the desired transmissibility function. The issue of stability and properness of this controller transfer function are discussed. The required input forces and equivalent closed-loop stiffness are examined for various examples of desired transmissibilities.

Tangible Programming for Basic Control System New Frameworks to Engineering Education for Children

2014 ◽  
Vol 931-932 ◽  
pp. 1298-1302
Author(s):  
Thiang Meadthaisong ◽  
Siwaporn Meadthaisong ◽  
Sarawut Chaowaskoo
Keyword(s):  
Control System ◽  
Engineering Education ◽  
Control Systems ◽  
Primary Schools ◽  
Closed Loop ◽  
Open Loop ◽  
Closed Loop Control ◽  
College Level ◽  
Loop Control ◽  
Tangible Programming

Programming control in industrial design is by its nature expert upon an example being Programmable Logic Controller (PLC). Such programmes are unsuitable for children or novices as they cannot understand how to use the programme. This research seeks to present tangible programming for a basic control system in new frameworks in engineering education for children. Such programmes could be for use in kindergartens, primary schools or general teaching where knowledge about basic control is required. Normally open-loop and closed-loop control system programming is taught at university and college level. This may be late as far as acquiring knowledge of basic control systems is concerned. Using tangible programming without a computer but instructions and interface, relay and motor could result in children in kindergartens and primary schools being able to programme open-looped control systems which mix chemicals or closed-loop control systems which control conveyor belts. However, the children would not be able to undertake programming using programmable control in a similar scenario.

Transient Response of Repetitive Control Systems

1996 ◽  
Vol 118 (4) ◽  
pp. 795-797
Author(s):  
S. S. Garimella ◽  
K. Srinivasan
Keyword(s):  
Control System ◽  
Transfer Function ◽  
Decay Rate ◽  
Control Systems ◽  
Transient Response ◽  
Continuous Time ◽  
Relative Stability ◽  
Repetitive Control ◽  
Upper Bounds ◽  
Repetitive Controller

Upper bounds on transient response magnitudes for a SISO continuous-time repetitive control system are derived. Limiting the size of these transients is shown to be related to limiting the ∞-norm of a transfer function product of filters used in the repetitive controller. The decay rate of the transients is related to the peak of a function of frequency called the regeneration spectrum, which has previously been shown in the literature to be a measure of the relative stability of the system. Bounds derived here, although conservative, can be useful in the design of the repetitive controller, as illustrated by means of an example.

Model Based Simulation of the Active Damping of a Cantilever Plate and Redistribution of Stresses

2000 ◽  
Author(s):  
Sathya V. Hanagud ◽  
Patrick J. Roberts
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Closed Loop ◽  
Active Vibration Control ◽  
High Stress ◽  
Element Simulation ◽  
Control Scheme ◽  
Acceleration Feedback ◽  
Order Of Magnitude ◽  
Active Vibration

Abstract In most structures, fatigue critical areas are associated with regions of high stresses. Sometimes, passive stiffening of structures can displace these high stress regions. Thus, for most applications, active vibration control is preferred. However, the question of whether an active vibration control scheme involving a set of actuators will reduce stresses in the whole structure or create high stress areas in the vicinity of the actuators arises. In previous works, this question has been addressed for cantilever beams which showed that the stresses are reduced by approximately the same order of magnitude as the reduction in vibrations. However, many aerospace structures are constructed of thin walled components whose response to vibration reduction can be very different than that of beams. In this paper, the stresses induced by an active vibration control system, based on the use of an offset piezoceramic stack actuator with acceleration feedback control, are investigated in a plate structure. A 3-D finite element simulation of the closed loop active vibration control system is developed and both the closed loop stresses and vibration amplitude reductions are studied.

Kinematics, Dynamics, and Control of Tendon-Driven Mechanisms Using Signal Flow Graphs

1998 ◽  
Author(s):  
Meng-Sang Chew ◽  
Theeraphong Wongratanaphisan
Keyword(s):  
Control System ◽  
Transfer Function ◽  
Closed Loop ◽  
Transfer Functions ◽  
Signal Flow ◽  
Signal Flow Graphs ◽  
Loop Transfer Function ◽  
Dynamics And Control ◽  
Flow Graphs ◽  
And Control

Abstract This paper presents the analysis of the kinematics, dynamics and controls of tendon-driven mechanism under the framework of signal flow graphs. For decades, the signal flow graphs have been applied in many areas, particularly in controls, for determining the closed-loop transfer function of a control system. The tendon-driven mechanism considered here consists of several subsystems including actuator-controller dynamics, mechanism kinematics and mechanism dynamics. Each subsystem will be derived and represented by signal flow graphs. The representation of the whole system can be carried out by connecting the graphs of subsystems at the corresponding nodes. Transfer functions can then be obtained by using Mason’s rules. A 3-DOF robot finger utilizing tendon-driven mechanism is used as an illustrative example.

ACS-Lite Algorithmic Architecture: Applying Adaptive Control System Technology to Closed-Loop Traffic Signal Control Systems

2003 ◽  
Vol 1856 (1) ◽  
pp. 175-184 ◽  
Author(s):  
Felipe Luyanda ◽  
Douglas Gettman ◽  
Larry Head ◽  
Steven Shelby ◽  
Darcy Bullock ◽  
...  
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Control Systems ◽  
Closed Loop ◽  
Signal Control ◽  
Traffic Signal Control ◽  
Adaptive Control System ◽  
Traffic Conditions ◽  
Run Time ◽  
Traffic Signal Control Systems

ACS-Lite is being developed by FHWA to be a cost-effective solution for applying adaptive control system (ACS) technology to current, state-of-the-practice closed-loop traffic signal control systems. This effort is intended to make ACS technology accessible to many jurisdictions without the upgrade and maintenance costs required to implement ACS systems that provide optimized signal timings on a second-by-second basis. The ACS-Lite system includes three major algorithmic components: a time-of-day (TOD) tuner, a run-time refiner, and a transition manager. The TOD tuner maintains plan parameters (cycle, splits, and offsets) as the long-term traffic conditions change. The run-time refiner modifies the cycle, splits, and offsets of the plan that is currently running based on observation of traffic conditions that are outside the normal bounds of conditions this plan is designed to handle. The run-time refiner also determines the best time to transition from the current plan to the next plan in the schedule, or, like a traffic-responsive system, it might transition to a plan that is not scheduled next in the sequence. The transition manager selects from the transition methods built in to the local controllers to balance the time spent out of coordination with the delay and congestion that is potentially caused by getting back into step as quickly as possible. These components of the ACS-Lite algorithm architecture are described and the similarities and differences of ACS-Lite with state-of-the-art and state-of-the-practice adaptive control algorithms are discussed. Closed-loop control system characteristics are summarized to give the context in which ACS-Lite is intended to operate.

Analysis of Disturbance Signals in Steel Rolling Process

2012 ◽  
Vol 490-495 ◽  
pp. 3065-3069
Author(s):  
Wei Yan ◽  
Jie Zhang ◽  
Ying Sheng Zhou
Keyword(s):  
Transfer Function ◽  
Control Systems ◽  
Output Signal ◽  
Closed Loop ◽  
Rolling Process ◽  
Closed Loop System ◽  
Steel Rolling ◽  
Input Signals ◽  
Low Pass ◽  
System Transfer Function

Many control systems are subject to extraneous disturbance signals that cause the system to provide an inaccurate output. The extraneous disturbance signals in steel rolling process are analysis in this paper. If the frequency spectrums of the noise and input signals are of a different character, the output signal-noise ratio can be maximized, often by simply designing a closed-loop system transfer function that has a low-pass frequency response.

Active Damping by Acceleration Feedback Control and Redistribution of Stresses in the Structure

1999 ◽  
Author(s):  
Maxime P. Bayon de Noyer ◽  
Patrick J. Roberts ◽  
Sathya V. Hanagud
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Vibration Control ◽  
Closed Loop ◽  
Driving Forces ◽  
Active Vibration Control ◽  
High Stress ◽  
Low Frequency ◽  
Acceleration Feedback ◽  
Active Vibration

Abstract In most structures, fatigue critical areas are associated with regions of high stresses. Passive stiffening of structures usually displaces these high stress regions. Thus, for most applications, active vibration control is preferred. However, the question of whether an active vibration control scheme involving a set of actuators will reduce stresses in the whole structure or create high stress areas in the vicinity of the actuators arises. In this paper, the stresses induced by an active vibration control system based on the use of an offset piezoceramic stack actuator with acceleration feedback control are investigated. Using a modal analysis of the actuator acting on a cantilever beam, a low frequency approximation of the actuator is developed in the form of a spring and two driving forces. Based on this approximation, a 3-D finite element simulation of the closed loop active vibration control system is developed and the closed loop stresses are studied.

scholarly journals Fault diagnosis method for closed-loop satellite attitude control systems based on a fuzzy parity equation

2018 ◽  
Vol 14 (10) ◽  
pp. 155014771880593 ◽  
Author(s):  
Hua Song ◽  
Pengqian Han ◽  
Junxiang Zhang ◽  
Chunhua Zhang
Keyword(s):  
Control System ◽  
Fault Diagnosis ◽  
Control Systems ◽  
Attitude Control ◽  
Closed Loop ◽  
Fuzzy Model ◽  
Attitude Control System ◽  
Satellite Attitude ◽  
Satellite Attitude Control ◽  
Diagnosis Method

This article proposes a fault diagnosis method for closed-loop satellite attitude control systems based on a fuzzy model and parity equation. The fault in a closed-loop system is propagated with the feedback loop, increasing the difficulty of fault diagnosis and isolation. The study uses a Takagi-Sugeno (T-S) fuzzy model and parity equation to diagnose and isolate a fault in a closed-loop satellite attitude control system. A fully decoupled parity equation is designed for the closed-loop satellite attitude control system to generate a residual that is sensitive only to a specific actuator and sensor. A T-S fuzzy model is used to describe the nonlinear closed-loop satellite attitude control system. With the combination of the T-S fuzzy model and fully decoupled parity equation, the fuzzy parity equation (FPE) of the nonlinear system can be obtained. Then this article uses a parameter estimator based on a Kalman filter to identify deviations and scale factor changes from information contained in the residuals generated by the FPE. The actuator and sensor fault detection and isolation simulation of the three-axis stable satellite attitude control system is provided for illustration.

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