Fast finite-time feedback linearization sliding mode position tracking control of electro-hydraulic systems with terminal sliding mode disturbance observer

This paper focuses on the fast finite-time and high accuracy control issue of electro-hydraulic systems (EHS). A third-order mathematical dynamic model of EHS with parametric uncertainty and external load disturbance is provided at first. Then, a feedback linearization transversion via Lie derivative for EHS is manipulated to overcome the nonlinear part in the nonlinear EHS model, which reduce the difficulty of controller design process since the nonlinear part of the EHS system can be unconsidered. A kind of disturbance observer is constructed for linearized EHS model via sliding mode disturbance observer to compensate the lumped uncertainty unavoidable in the system, based on which a finite-time sliding mode position tracking control strategy is designed for EHS, which realize the fast finite-time tracking control purpose of EHS. The feasibility of the theoretical results in this paper are verified by simulation and experiment, which illustrate that the feedback linearization transversion via Lie derivative can effectively reduce the negative impact of the nonlinear part of the EHS model, the proposed disturbance observer can effectively estimate the lumped uncertainties and raised the control accuracy and the controller designed in this paper can accelerate the tracking performance of EHS.