基于扩张状态观测器的泵控电液伺服系统滑模控制

以泵控电液伺服系统为研究对象，提出了一种基于扩张状态观测器的滑模位置跟踪控制策略。首先，利用奇异扰动理论对泵控电液伺服系统的数学模型进行降阶处理，得到降阶泵控电液位置伺服系统数学模型。其次，针对泵控电液伺服系统工况的复杂性及外负载干扰问题，设计了扩张状态观测器对系统干扰在线观测，同时该观测器还可以对活塞杆的位置和速度信号进行估计。然后，利用观测到的干扰信号及速度信号，基于滑模控制理论设计了滑模变结构控制算法，对所提出的控制策略的稳定性进行了理论分析。最后，利用MATLAB/Simulink和AMESim仿真平台，搭建了泵控电液伺服系统的联合仿真模型，对算法的可行性及有效性进行了仿真验证。仿真结果表明，所设计的扩张状态观测器能对干扰进行精确估计，基于扩张状态观测器的滑模控制策略的位置跟踪性能显著优于PID控制器和传统滑模控制器，且对外部干扰力具有较强的鲁棒性，提高了泵控电液伺服系统的控制性能。 

Extended-state-observer based sliding mode control for pump-controlled electro-hydraulic servo system

A sliding mode position tracking control strategy based on extended state observer is proposed for pump-controlled electro-hydraulic servo system. The mathematical model of the system is processed by reducing order using singular perturbation theory, and the mathematical model of reduced-order pump-controlled electro-hydraulic position servo system is obtained. Aimed at the complexity of pump-controlled electro-hydraulic servo system and the disturbance of random external load, an extended state observer is designed to estimate the disturbance on-line. Besides providing the estimations of disturbances, the observer can also estimate the position and velocity of piston rod. Based on the sliding mode control theory, a sliding mode variable structure control algorithm is designed using the estimations of disturbance and speed. The stability of the proposed control strategy is analyzed. Co-simulation model of pump-controlled electro-hydraulic servo system was conducted using MATLAB/Simulink and AMESim. The feasibility and effectiveness of the algorithm are verified by co-simulation. The simulation results show that the extended state observer can accurately estimate the disturbance. The position tracking performance of the proposed extended-state-observer based sliding mode control strategy is significantly better than that of PID controller and traditional sliding mode controller, and it has strong robustness to external disturbance, which improves the control performance of the pump-controlled electro-hydraulic servo system.