Discrete time sliding mode control with application to magnetic levitation system

This paper presents an interesting application of magnetic levitation system using discrete sliding mode control. There is a limited literature available for sliding mode control as applied to magnetic levitation system. In this work a model of linearized magnetic levitation system having small magnetic disc and cylinder with light weight is considered. As a part of review PD control and full state feedback with pole placement and Kalman estimator are presented. A discrete sliding mode control with multi-rate output feedback is then investigated for the present application. To mitigate chattering, discrete time power rate reaching based algorithm is applied. Numerical result for nonlinear system is also shown. In all the cases, inherently unstable system is shown to exhibit stability and stable initial condition response compared to the uncompensated system.