Evolving Systems: Adaptive Key Component Control With Persistent Disturbance Rejection

2011 ◽  
Author(s):  
Mark J. Balas ◽  
Susan A. Frost
Keyword(s):  
Disturbance Rejection ◽  
Evolution Process ◽  
Successful Operation ◽  
Specific Component ◽  
Aerospace Structures ◽  
Evolving Systems ◽  
Additional Control ◽  
Persistent Disturbances ◽  
Higher Purpose ◽  
Theoretical Results

This paper presents an introduction to Evolving Systems, which are autonomously controlled subsystems which self-assemble into a new Evolved System with a higher purpose. Evolving Systems of aerospace structures often require additional control when assembling to maintain stability during the entire evolution process. This is the concept of Adaptive Key Component Control which operates through one specific component to maintain stability during the evolution. In addition this control must overcome persistent disturbances that occur while the evolution is in progress. We present theoretical results for the successful operation of Adaptive Key Component control in the presence of such disturbances and an illustrative example.

Adaptive Key Component Control for Nonlinear Evolving Systems

2008 ◽  
Author(s):  
Mark J. Balas ◽  
Susan A. Frost
Keyword(s):  
Adaptive Controller ◽  
Evolution Process ◽  
Aerospace Structures ◽  
Evolving Systems ◽  
Additional Control ◽  
Evolving System ◽  
Higher Purpose ◽  
Area Of Study

The inheritance of subsystem traits in Evolving Systems is an important area of study. Evolving Systems are autonomously controlled subsystems which self-assemble into a new Evolved System with a higher purpose. Evolving Systems of aerospace structures often require additional control when assembling to maintain stability during the entire evolution process. If certain passivity traits of the subsystem components are inherited in the Evolving System, then it is possible to use an adaptive controller to restore stability in the Evolving System. This paper develops the theory for Nonlinear Evolving Systems and illustrates it with a simple example.

Suppression of Persistent Rotor Vibrations Using Adaptive Techniques

2006 ◽  
Vol 128 (6) ◽  
pp. 682-689 ◽  
Author(s):  
Alex L. Matras ◽  
George T. Flowers ◽  
Robert Fuentes ◽  
Mark Balas ◽  
Jerry Fausz
Keyword(s):  
Disturbance Rejection ◽  
Large Scale ◽  
Vibration Suppression ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Structural Systems ◽  
Running Speed ◽  
Rotor Systems ◽  
Adaptive Techniques ◽  
Persistent Disturbances

Recent work in the area of adaptive control has seen the development of techniques for the adaptive rejection of persistent disturbances for structural systems. They have been implemented and tested for large-scale structural systems, with promising results, but have not been widely applied to smaller-scale systems and devices. Rotor systems are subject to a variety of persistent disturbances (for example, due to mass imbalance, blade-pass effects) that occur at the rotor running speed or multiples of the running speed. The frequencies of such disturbance forces are generally known, but their magnitudes tend to vary over time. Adaptive techniques to counter the effects of such disturbances would appear to be a promising strategy in this regard. In order to assess the effectiveness of adaptive disturbance rejection for rotor applications and identify issues associated with implementation, an adaptive disturbance rejection control is developed, implemented, and tested for a magnetic-bearing-supported rotor system. Some conclusions and insights concerning the application of this method to rotor system vibration suppression are presented and discussed.

Attitude manoeuvre control and asymptotic disturbance rejection of flexible spacecraft

2017 ◽  
Vol 233 (2) ◽  
pp. 426-437
Author(s):  
Zhen Yu ◽  
Yu Guo ◽  
Chenxing Zhong ◽  
Yifei Wu ◽  
Jian Guo
Keyword(s):  
Attitude Control ◽  
Disturbance Rejection ◽  
Coupling Effect ◽  
Flexible Spacecraft ◽  
Control Performance ◽  
Novel Approach ◽  
Attitude Controller ◽  
The Stability ◽  
Persistent Disturbances ◽  
Lyapunov Technique

This paper presents a novel approach to tackle the issues of attitude manoeuvre control and asymptotic disturbance rejection for a flexible spacecraft. The resulting attitude controller employs an internal model-based compensator to reject a class of persistent disturbances and a modal estimator for dynamic compensation of the rigid-flex coupling effect. The convergence of the modal variables can be guaranteed without the measures of them. The stability of the system is proved via the Lyapunov technique rigorously. Numerical results illustrate that improved attitude control performance and asymptotic disturbance rejection can both be achieved.

Augmented Adaptive Control of Flexible Structures Using Residual Mode Filters

2010 ◽  
Author(s):  
Mark Balas ◽  
Susan A. Frost
Keyword(s):  
Adaptive Control ◽  
Flexible Structures ◽  
Adaptive Controller ◽  
Operating Conditions ◽  
Control Approach ◽  
Control Techniques ◽  
Direct Adaptive Control ◽  
Positive Realness ◽  
Persistent Disturbances ◽  
Theoretical Results

Flexible structures containing a large number of modes can benefit from adaptive control techniques which are well suited to applications that have unknown modeling parameters and poorly known operating conditions. In this paper, we focus on a direct adaptive control approach that has been extended to adaptively reject persistent disturbances. This theory will be extended to accommodate troublesome modal subsystems of a plant that might inhibit the adaptive controller. In some cases the plant in does not satisfy the adaptive controller requirements of Almost Strict Positive Realness. Instead, there maybe be a modal subsystem that inhibits this property. In this paper we will modify the adaptive controller with a Residual Mode Filter (RMF) to compensate for the troublesome modal subsystem, or the Q modes. This paper addresses leakage, or propagation, of the disturbances into the Q modes. We will apply the above theoretical results to a flexible structure example to illustrate the behavior with and without the residual mode filter.

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