Adaptive backstepping sliding mode control of MDF hot press hydraulic system based on fuzzy disturbance observer

In order to realize high-precision position tracking control for (Medium Density Fiberboard, MDF) continuous hot press hydraulic position servo system in the presence of interior parameter perturbations and external load disturbance, an adaptive backstepping sliding mode control strategy with fuzzy disturbance observer (FDO) is presented. Firstly, a modified FDO is designed to estimate and compensate the interior parameter perturbations and external load disturbance of the system. Secondly, the backstepping sliding mode controller is designed and adaptive algorithm is used to online estimate the uncertainty of the system. Thirdly, the convergence of tracking error and the asymptotic stability of system are strictly proved according to Lyapunov stability theory. The results of simulation experiments indicate that the controller has strong robustness against the interior parameter perturbations and external load disturbance. Moreover, the controller has good performance including fast response, high tracking accuracy and small steady-state error.