Switching control and its application to induction motors

Practical plants always contain some uncertainties, which require robust controllers to deal with. One such controller is the so called sliding mode controller, which has received a great deal of interest in theory and application. However, fast response of the sliding mode control systems is hard to reach without high cost control devices, due to their fixed switching surfaces which normally make the system state to reach the steady state with an exponential rate.

We propose a new switching control design method which uses the self -tuning switching surface to achieve the fast convergence property. Both the single -input single-output and the multi-input multi-output systems are dealt with. The switching surfaces are obtained using the well known Linear Quadratic Regulator design. The stability and the existence conditions of sliding modes are obtained and the fast convergence properties of the control strategies are analysed in detail. Simulations are conducted to show the effectiveness of the control design.