Integral Sliding Mode Control with Exponential Approximation Law for an AMB Rotor System Considering the Alford Force

In order to deal with the nonlinear problems associated with the Alford force and active bearing rotor system in fluid machinery, an integral sliding mode control with exponential reaching law is proposed in this paper. An integral term is incorporated into the switching function, and an exponential approaching law, along with a boundary layer saturation function that replaces the symbolic function, is adopted to suppress the chattering and tracking error of sliding mode control. Simulation and experimental results show that, under the magnetic bearing force and Alford force, the system exhibits improved anti-disturbance performance compared to a PID controller. Moreover, the rotor amplitude is reduced by 33% when using this controller. The proposed controller demonstrates good dynamic performance and strong robustness, even when the parameters of the entire system are perturbed.