Variable structure control of nonlinear systems.

Abstract

Variable Structure Control (VSC) with sliding mode is a special type of control technique that is capable of making a control system robust with respect to system parameter variations and external disturbances. The chattering of the VSC signal can be reduced by several methods. One way is to augment the system with an integrator to isolate the system from the VSC control signal which causes the chatter. In addition, the magnitude of the switching function can be reduced by estimation of the uncertainty. In this work, we designed a Variable Structure Controller for linearizable systems. The concept of augmented plant together with the identification of the uncertainty through an observer has been used to design a controller for uncertain nonlinear systems which do not necessarily meet the matching conditions. The scheme is also shown to reduce the chattering. The simulation and the comparison studies reported in this thesis suggest the usefulness of our scheme.