scholarly journals Robust H∞ Control for the Spacecraft with Flexible Appendages

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Aiping Pang ◽  
Hui Zhu ◽  
Junjie Zhou ◽  
Zhen He ◽  
Jing Yang
Keyword(s):  
Controller Design ◽  
Flexible Structures ◽  
Solar Array ◽  
Attitude Stability ◽  
Performance Requirements ◽  
Performance Matrix ◽  
Oscillation Suppression ◽  
Comprehensive Performance ◽  
Pointing Accuracy ◽  
Flexible Appendages

Aiming at the oscillation suppression of spacecraft with large flexible appendages, we propose a control strategy using H∞ control. The weighting functions are designed for the specific flexible modes of the spacecraft and the frequency of harmonic interference in its operating environment. Taking into account the structural uncertainty of systematic modeling and the comprehensive performance requirements of system bandwidth constraint and attitude stability, the H∞ comprehensive performance matrix is constructed. A space telescope with a large flexible solar array is presented as an illustrative example, and a control design that meets the requirement for pointing accuracy is proposed. The simulation results show that the designed controller satisfies the requirements of attitude stability and high pointing accuracy and has effectively suppressed the disturbance of endemic frequency. The design scheme and selection method of the weight function shown in this paper can be a reference for the controller design for oscillation suppression of this type of spacecraft with flexible structures.

scholarly journals Structured H∞ Control for Spacecraft with Flexible Appendages

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 930
Author(s):  
Yuntian Zhang ◽  
Aiping Pang ◽  
Hui Zhu ◽  
Huan Feng
Keyword(s):  
Low Frequency ◽  
Low Complexity ◽  
Performance Criteria ◽  
Solar Array ◽  
Engineering Practice ◽  
Multiple Control ◽  
H Infinity ◽  
Performance Requirements ◽  
Comprehensive Performance ◽  
Flexible Appendages

Spacecraft with large flexible appendages are characterized by multiple system modes. They suffer from inherent low-frequency disturbances in the operating environment that consequently result in considerable interference in the operational performance of the system. It is required that the control design ensures the system’s high pointing precision, and it is also necessary to suppress low-frequency resonant interference as well as take into account multiple performance criteria such as attitude stability and bandwidth constraints. Aiming at the comprehensive control problem of this kind of flexible spacecraft, we propose a control strategy using a structured H-infinity controller with low complexity that was designed to meet the multiple performance requirements, so as to reduce the project cost and implementation difficulty. According to the specific resonant mode of the system, the design strategy of adding an internal mode controller, a trap filter, and a series PID controller to the structured controller is proposed, so as to achieve the comprehensive control goals through cooperative control of multiple control modules. A spacecraft with flexible appendages (solar array) is presented as an illustrative example in which a weighted function was designed for each performance requirement of the system (namely robustness, stability, bandwidth limit, etc.), and a structured comprehensive performance matrix with multiple performance weights and decoupled outputs was constructed. A structured H-infinity controller meeting the comprehensive performance requirements is given, which provides a structured integrated control method with low complexity for large flexible systems that is convenient for engineering practice, and provides a theoretical basis and reference examples for structured H-infinity control. The simulation results show that the proposed controller gives better control performance compared with the traditional H-infinity one, and can successfully suppress the vibration of large flexible appendages at 0.12 Hz and 0.66 Hz.

Solving Vibration Control Problems Using Reduced Order Models for Flexible Structures: A Genetic Algorithm Approach

1997 ◽  
Author(s):  
Sourav Kundu ◽  
Kentaro Kamagata ◽  
Shigeru Sugino ◽  
Takeshi Minowa ◽  
Kazuto Seto
Keyword(s):  
Genetic Algorithm ◽  
Vibration Control ◽  
Controller Design ◽  
Fitness Function ◽  
Flexible Structures ◽  
Design Solution ◽  
Reduced Order Models ◽  
Reduced Order ◽  
Fitness Value ◽  
Genetic Algorithm Approach

Abstract A Genetic Algorithm (GA) based approach for solution of optimal control design of flexible structures is presented in this paper. The method for modeling flexible structures with distributed parameters as reduced-order models with lumped parameters, which has been developed previously, is employed. Due to some restrictions on controller design it is necessary to make a reduced-order model of the structure. Once the model is established the design of flexible structures is considered as a feedback search procedure where a new solution is assigned some fitness value for the GA and the algorithm iterates till some satisfactory design solution is achieved. We propose a pole assignment method to determine the evaluation (fitness) function to be used by the GA to find optimal damping ratios in passive elements. This paper demonstrates the first results of a genetic algorithm approach to solution of the vibration control problem for practical control applications to flexible tower-like structures.

Robust vibration control of flexible panel: modeling and simulation

2017 ◽  
Vol 14 (5) ◽  
pp. 433-442
Author(s):  
Aalya Banu ◽  
Asan G.A. Muthalif
Keyword(s):  
Robust Control ◽  
Vibration Control ◽  
Controller Design ◽  
Control Strategies ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Parametric Uncertainty ◽  
Design Algorithm ◽  
Content Type ◽  
And Performance

Purpose This paper aims to develop a robust controller to control vibration of a thin plate attached with two piezoelectric patches in the presence of uncertainties in the mass of the plate. The main goal of this study is to tackle dynamic perturbation that could lead to modelling error in flexible structures. The controller is designed to suppress first and second modal vibrations. Design/methodology/approach Out of various robust control strategies, μ-synthesis controller design algorithm has been used for active vibration control of a simply supported thin place excited and actuated using two piezoelectric patches. Parametric uncertainty in the system is taken into account so that the robust system will be achieved by maximizing the complex stability radius of the closed-loop system. Effectiveness of the designed controller is validated through robust stability and performance analysis. Findings Results obtained from numerical simulation indicate that implementation of the designed controller can effectively suppress the vibration of the system at the first and second modal frequencies by 98.5 and 88.4 per cent, respectively, despite the presence of structural uncertainties. The designed controller has also shown satisfactory results in terms of robustness and performance. Originality/value Although vibration control in designing any structural system has been an active topic for decades, Ordinary fixed controllers designed based on nominal parameters do not take into account the uncertainties present in and around the system and hence lose their effectiveness when subjected to uncertainties. This paper fulfills an identified need to design a robust control system that accommodates uncertainties.

scholarly journals Nonlinear Controller Design for a Flexible Spacecraft

2020 ◽  
Vol 67 (4) ◽  
pp. 1500-1520
Author(s):  
Jose Luis Redondo Gutiérrez ◽  
Ansgar Heidecker
Keyword(s):  
Controller Design ◽  
Flexible Structures ◽  
Rigid Motion ◽  
Nonlinear Controller ◽  
Assumed Mode Method ◽  
Control Approach ◽  
Mode Method ◽  
Study Case ◽  
Nonlinear Controller Design ◽  
Assumed Mode

AbstractThis paper combines the nonlinear Udwadia-Kalaba control approach with the Assumed Mode Method to model flexible structures and derives an attitude controller for a spacecraft. The study case of this paper is a satellite with four flexible cantilever beams attached to a rigid central hub. Two main topics are covered in this paper. The first one is the formulation of the equation of motion and the second one is the nonlinear controller design. The combination of these two techniques is able to provide a controller that damps the vibration of a flexible structure while achieving the desired rigid-motion state.

Control of Two-Link Flexible Structures

Volume 1 ◽  
2004 ◽  
Author(s):  
Clarice Wagner-Nachshoni ◽  
Yoram Halevi
Keyword(s):  
Transfer Function ◽  
Time Delays ◽  
Wave Motion ◽  
Controller Design ◽  
Flexible Structures ◽  
Infinite Dimensional ◽  
Second Stage ◽  
Finite Dimensional ◽  
Control Scheme ◽  
Two Stages

A method of noncollocated controller design for non-uniform flexible structures, governed by the wave equation, is proposed. An exact, infinite dimensional, transfer function, relating the actuation and measurement points, with general boundary conditions, is derived for the multi-link case. Three modeling methods are presented and discussed. A key element of the model is the existence of time delays, due to the wave motion, which play a major role in the controller design. The design consists of two stages. First an inner rate loop is closed in order to improve the system dynamic behavior. It leads to a finite dimensional plus delay inner closed loop, which is the equivalent plant for the outer loop. In the second stage an outer noncollocated position loop is closed. It has the structure of an observer–predictor control scheme to compensate for the response delay. The resulting overall transfer function is second order, with arbitrarily assigned dynamics, plus delay.

Optimization of Controllers for Gas Turbine Based on Probabilistic Robustness

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Chuanfeng Wang ◽  
Donghai Li ◽  
Zheng Li ◽  
Xuezhi Jiang
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Controller Design ◽  
Dynamic Performance ◽  
Optimization Method ◽  
Monte Carlo Experiment ◽  
Performance Requirements ◽  
System Robustness ◽  
Manufacturing Tolerances ◽  
Probabilistic Robustness

An optimization method for controller parameters of a gas turbine based on probabilistic robustness was described in this paper. As is well known, gas turbines, like many other plants, are stochastic. The parameters of a plant model are often of some uncertainties because of errors in measurements, manufacturing tolerances and so on. According to model uncertainties, the probability of satisfaction for dynamic performance requirements was computed as the objective function of a genetic algorithm, which was used to optimize the parameters of controllers. A Monte Carlo experiment was applied to test the control system robustness. The advantage of the method is that the entire uncertainty parameter space can be considered for the controller design; the systems could satisfy the design requirements in maximal probability. Simulation results showed the effectiveness of the presented method in improving the robustness of the control systems for gas turbines.

Modeling and Simulation of Solar Array Drive Assembly Disturbance Driving a Flexible Load

2014 ◽  
Vol 565 ◽  
pp. 67-73 ◽  
Author(s):  
Jiang Pan Chen ◽  
Wei Cheng ◽  
Yun Feng Wang
Keyword(s):  
Modeling And Simulation ◽  
Natural Frequencies ◽  
Pulse Signal ◽  
Solar Array ◽  
Input Frequency ◽  
Electromagnetic Model ◽  
Pointing Accuracy ◽  
Flexible Load ◽  
Disturbance Model ◽  
Three Degree Of Freedom

SADA (Solar Array Drive Assembly) is used to drive solar array rotating in spacecraft in order to get the most solar energy. The disturbance generated by SADA driving its load will influence the imaging quality and pointing accuracy of spacecraft. This research focuses on the disturbance properties of SADA driving a flexible load. Firstly, the disturbance model of SADA driving no load is obtained by deducing and simplifying the electromagnetic model of SADA. Secondly, the disturbance model of SADA driving a flexible load (a three-degree of freedom inertia-spring-damping system) is achieved based on the disturbance model of SADA driving no load. Finally, the disturbance model of SADA driving a flexible load is simulated by using Matlab/Simulink toolbox. The simulation result shows that: the disturbance frequencies of SADA driving a flexible load are consisting of all the natural frequencies of the coupled mechanical system and the input frequency of the electrical pulse signal and its harmonic frequencies.

Sign in / Sign up

Export Citation Format

Share Document