A robust controller for uncertain nonlinear systems and its application to a motor-driven system

This paper introduces a robust controller for a class of nonlinear systems in the presence of unmatched uncertainties. The requirement of the proposed control is that the uncertainties are bounded by some known functions. The uncertainties are divided into the matched parts and the unmatched parts, and then are compensated respectively by the specially constructed robust controller. The design of the robust controller includes a class of continuous function /spl phi/ (t), such that the robust controller can guarantee the asymptotic stability of the closed-loop control system. Then, the robust controller design is applied to the motor-driven electromechanical system of a certain two-axes, yaw-pitch motion test bed. The simulation results are given.