连续对象具有未建模动态时的一种鲁棒混合自适应控制器

Robust Hybrid Adaptive Controller of Continuous Plant with Presence of Unmodeled Dynamics Considered

本文介绍了一种对象连续而控制参数进行离散式调整的鲁棒混合自适应控制器。在这种系统的对象中除了已建模部分之外,还具有相加和相乘未建模动态(Unmodeled Dynamics)。文中证明,如果这种未建模动态在低频范围内足够小,则这种混合自适应控制器可保证闭环中的所有信号有界,并且对任何有界初始条件,系统都具有较小的均值残余跟踪误差。

This paper presents a robust hybrid adaptive controller of continuous plant with presence of unmodeled dynamics considered. Since hybrid adaptive control system has the advantages of both continuous time system and discrete time system, it attracts increasingly the attention of researchers. Ref. [5] differs from Refs. [1]-[4] in the manner of presentation of the authors' viewpoints, but actually all five references did not consider the presence of unmodeled dynamics. In this paper we consider a class of unmodeled dynamics which consists of both additive and multiplicative plant perturbations. The additive plant perturbations are assumed to be small at all frequencies, but the multiplicative ones are required to be small only at the low frequency range. A hybrid adaptive law is proposed for the class of unmodeled dynamics. In this hybrid adaptive law we combine normalization with usual adaptive control algorithm to assure robust stability of the control system. It is shown that for this class of unmodeled dynamics the proposed algorithm guarantees boundedness for all signals in the closed loop and the residual tracking error between output of the closed loop plant and output of the desired model is small in the mean. This controller may be very useful for design of the control system of a wide variety of space structures.