A new modeling reference direct adaptive sliding mode control for electromechanical actuator

A new model reference direct adaptive sliding mode control (MRDASMC) approach for electromechanical actuator (EMA) is presented. Uncertainties with parameter variation, external load disturbance, nonlinear structure and unmodelled dynamics in the system are treated as a lumped uncertainty. The lumped uncertainty is estimated without the bounds known in advance. A switching function is employed to compensate for the estimated error of the lumped uncertainty. While the issue of chattering in classical SMC is suppressed as the amplitude of the switching function is tuned with the tracking error by adaption law. The adaption law contains a fading factor which can prevent saturation of the control effort. The stability of the control system is guaranteed by Lyapunov approach. Simulation results show that the proposed controller can provide favorable performance and is robust to system uncertainties.