Sliding mode and PID based tracking control of magnetic levitation plant and hil tests

Abstract

Magnetic levitation systems are convenient to provide frictionless, reliable, fast and economical operations in wide-range applications. The effectiveness and applicability of these systems require precise feedback control designs. The position control problem of the magnetic levitation plant can be solved with a cascade control method. In this thesis, sliding mode and PID based cascade controllers are designed to render high position control performance and robustness to the magnetic levitation. Sliding mode control (SMC) based cascade controller is proposed for controlling magnetic levitation. The SMC based controllers for the inner current loop are designed to eliminate the effects of the inductance related uncertainties of the electromagnetic coil of the plant. For the outer position loop, the integral SMC is designed to eliminate disturbances around operating point resulting from the linearization of the mechanical part. Finally, numerical simulation and experimental results for various cascaded controllers are provided and compared in order to validate the efficacy of the approaches.