Super twisting control of linear induction motor considering end effects with unknown load torque

This paper proposes a super twisting sliding mode control technique for linear induction motors (LIMs) with unknown load torque, taking into consideration the dynamic end effects. First, LIM's dynamic end effects are presented by Ducan's T-model, then following this model is controlled by a designed super twisting controller (STC) for flux tracking and speed tracking purpose. Simultaneously, an open loop flux observer and a reduced order load torque observer are designed based on Lyapunov's analysis. Finally, simulation results show that the designed observer-based super twisting controller has great tracking performance and the system is robust with disturbances and uncertainties, and flux observer and reduced torque observer show good estimate performance with nominal system and input-to-state stability (ISS) property with uncertainty system.