Nonlinear Output Feedback Control: Performance and Robustness

Michigan State University, East Lansing MI

Investigators

Abstract

It is proposed to conduct research on the design of output feedback control of nonlinear systems. The design procedure starts with the design of a state feedback control followed by the design of robust observer to recover performance achieved with a state feedback. The performance of such observers are usually hindered by difficulties due to measurement noise and excessively large transient response. The principal investigator has shown that the undesirable transient behavior can be eliminated by designing the feedback control to be globally bounded. The approach proved useful in achieving fundamental progress in semiglobal stabilization, sliding-mode control, servomechanisms, and adaptive control. While the earlier work has emphasized robustness, the goal of this proposal is to develop a comprehensive theory for the design of high-gain observer-based output feedback controllers for nonlinear systems that aims at achieving both robustness and good performance. The new element we bring in this proposal is the use of nonlinearities as a tool for improving performance. Research tasks include: improved performance of the universal integral regulator, performance issues in high-gain observer-based output feedback controllers, multivariable systems, experimental testbeds, and a pedagogic of the use of nonlinearities as a tool for improving performance. Nonlinear systems under consideration arise in many applications such as mechanical systems, aircraft control, and electric machines. Earlier results have been applied to the control of induction motors and a mechanical system known as the pendubot.