Sliding mode control of nonlinear systems using time varying surface and applications

In this study, sliding mode control method with linear time varying surfaces isproposed for the control of a class of nonlinear systems.The idea presented in this thesis is based on the ?freezing technique? and SMCdesign for linear time invariant (LTI) systems. The nonlinear system is frozen ateach time step and system matrices are evaluated at these operating points. Thisprocess results in LTI systems and the Standard SMC design procedure isapplied at each time step. Thus, sliding surface design is achieved by changingthe slope of the linear sliding surface at each operating point yielding timevarying surfaces. In this thesis, two different methods are used to determine theslope of the linear sliding surfaces which are pole placement and optimumsliding surfaces. After designing the sliding surface, the controller which forcesthe system to the sliding surface and maintain it on the sliding surface isdesigned.The success of the proposed methods are shown by applying the methods to aninverted pendulum mechanism and a missile model. Sliding mode control withlinear time varying surfaces is used to stabilize the inverted pendulummechanism and to track a normal acceleration command for the missile model.