Sliding Mode Control of Servo System with Brushless DC Motor Based on Nominal Model

For brushless DC motor with parameter uncertainties and load disturbances in the practical servo system such as numerical control machine (NCM), a novel sliding mode control algorithm is proposed. This control algorithm consists of two controllers. One is the sliding mode controller for practical plant to ensure robustness against parameter uncertainties and load disturbances, the other is the backstepping controller for nominal model to compensate the position error for practical servo system. The Lyapunov approach is used to prove the convergence of the controllers.At last, The simulation results of nominal model-based sliding mode control algorithm show that it has high robustness and good position tracking performance with respect to parameter uncertainties and load disturbances.