An Improved Nonlinear Speed Controller for Series DC Motors

The issue of speed tracking control for series DC motors is addressed. Based on the classic backstepping design technique, an improved recursive nonlinear controller is proposed to improve the transient response. In the design, two additional class K functions as design functions are adopted to achieve desirable varying decay rate. Application of this strategy substantially improves the transient response and convergence rate without remarkably increasing the controller “gains”. Series DC motors with jumping load torques are also studied. The dynamics of such a motor with jumping load torques are modeled as a switched system. A switching controller based on the improved nonlinear design method is presented. Simulation results demonstrate the effectiveness of the proposed method.