Control of Nonlinear Systems With Unknown Actuator Nonlinearities

Abstract Control of nonlinear systems with unknown actuator nonlinearities is considered in this paper using disturbance observer based control (DOBC) approach. A nonlinear disturbance observer is presented to estimate the influence of unknown actuator nonlinearities and then is integrated with a conventional controller using disturbance observer based control techniques. The developed techniques is applied to a nonlinear mechanical system with unknown actuator nonlinearities where the unknown nonlinearities could be dead zone, backlash or both dead zone and backlash. Simulation shows that promising performance and good robustness against various actuator nonlinearities are achieved by the DOBC approach.