Stability and Control Performance of Robust Model Reference Adaptive Control System: An Approach Based on Its Generalized Structure

摘要

This paper proposes a new analytical method for stability and control performance of a robust model reference adaptive control system (MRACS). In the past studies, the following analytical policy has been adopted, that is, deriving tight and quantitative conditions for a stable robust MRACS is not important since those conditions depend on unknown factors such as the transfer characteristic of the controlled object. As a result, the most important things about stability and control performance disappear in algebraic calculations based on many inequalities. Naturally, it is not easy to answer the following questions. How is the stabilization of a robust MRACS achieved? What can we prepare for design of a robust MRACS which has a sufficient stability margin and a better control performance? The motivation of this paper is to answer these questions. For the purpose, this paper defines a desired system for the model reference control, and uses an analytical model parameterized with the desired controller parameters. Especially in a main loop analysis, a certain equivalent feedback system is derived, and the stability of a robust MRACS is explained with an expanded notion of the L_(2) stability. According to this method, it is possible to understand stabilization of a robust MRACS. Furthermore, some useful findings for design of a robust MRACS can be obtained from the results of analysis and a numerical simulation.