Finite-time Control for Nonlinear Magnetic Bearing System Based on Adaptive Second Order Sliding Mode Technique

A novel adaptive second order sliding mode control (ASOSMC) scheme with finite-time strategy is proposed for the control of a nonlinear thrust active magnetic bearing (TAMB) system with system uncertainty and disturbance. A Proportional + Integral + Derivative (PID) sliding surface is utilized for the sliding mode. We employ finite-time strategy to obtain the properties of fast response and high tracking-accuracy. To obtain a better disturbance rejection property, a adaptive control law is introduced to compensate the system uncertainty and external disturbance. The proposed ASOSMC algorithms ensure that the occurrence of the sliding motion in finite-time and the trajectory of tracking-error converge to the small neighborhood of equilibrium point. Finally, numerical simulations demonstrate the effectiveness of the proposed control scheme.