ROBUST OUTPUT TRACKING OF A CLASS OF NONLINEAR TIME-VARYING UNCERTAIN SYSTEMS

摘要

A new method will be proposed to design a linear time-invariant(LTI) robust controller for a nonlinear time-varying plant which is unknown but belongs to a given set. By this method, a nominal controller is first designed to achieve the desiredcontrol properties for an artificial LTI nominal plant, then a robust compensator is designed to restrain the influence on the closed-loop properties of the real plant perturbations from the nominal one. It will be shown that for any plant in the setsatisfying some assumptions, the closed-loop control system with a LTI controller designed by the presented method is globally asymptotically stable and the output tracking error can be made as small as desired if the initial conditions are zeros.