The nonlinear speed control problem of a series dc motor was considered. Based on the nonlinear model built by a hybrid method, in which the local stability was proved by the Lyapunov’s first method to ensure the meaningfulness of the identification of the steady-state-about plant parameters, a sliding-mode control law, with a load torque Luenberger observer and an angular acceleration estimator, was derived theoretically, which effectiveness demonstrated by simulations and experiments. In order to reduce the steady-state error caused by the discrete implementation, a modified sliding-mode control with an auxiliary PI controller was proposed. The experiments show that the modified sliding-mode control law is superior to the PID regulator and the ordinary sliding-mode control law.
Enhancing sliding mode control with proportional feedback and feedforward: an experimental investigation on speed sensorless control of PM DC motor drives
