Control of nonlinear systems with unknown actuator nonldnearities

Control of nonlinear systems with unknown actuator nonlineari ties is considered in this paper using disturbance observer based control (DOBC) approach, A nonlinear disturbance observer is presented to estimate the inouence 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 nonlineari lies where the unknown non linearities could be dead zone, backlash or both dead zone and backlash. Simulation shows that promising performance and good robustness against various actuator nonlineari ties are achieved by the DOBC approach.