Design of adaptive sliding mode controller for a separately excited DC motor

In this paper, a nonlinear field weakening controller is proposed for speed tracking control of a separately excited DC motors (SEDCMs). The method is based on Lyapounov stability and variable structure control theorems. When the system is in the sliding mode, the adaptive gain in the designed of the sliding surface is used to tackle the mismatched and unknown load torque disturbance. The simulation result shows that the algorithm is robust and the speed tracking error can be achieved in stability asymptotically.