Practical stabilization of a class of uncertain composite control systems

A class of continuous controls, embedded in a multifunction, is presented which guarantees that the system can be practically stabilized, i.e. each control guarantees that a compact set, the `size´ of which depends on some design parameter(s), is globally uniformly asymptotically stable. By tuning the design parameter(s), the `size´ can be made as small as desired. Here, the underlying approach is based on the deterministic theory of feedback control for uncertain dynamical systems and Lyapunov-based techniques for the stability analysis of the closed-loop systems. The design of the feedback control law, follows closely that in which the nominal nonlinear system is more general, but the `residual´ uncertainty region considered is smaller in comparison