基于干扰观测器的电液位置伺服系统跟踪控制

Tracking Control for Electro-hydraulic Positioning Servo System Based on Disturbance Observer

针对电液位置伺服系统存在匹配和不匹配模型不确定性的问题,提出一种基于滑模的模型不确定性补偿控制策略。通过设计滑模观测器估计电液位置伺服系统的匹配和不匹配模型不确定性,以在控制器设计中将其补偿,有效地削减控制器不连续项增益。将观测器滑模面引入到控制器滑模面中构造新的控制器滑模面,消除不确定性的估计误差,以保证控制器良好的动态性能。此外,不使用系统加速度信息,以降低可测噪声对跟踪性能的恶化。通过Lyapunov稳定性理论验证了闭环系统的全局稳定性。仿真结果显示,与积分滑模控制策略相比,所提方法能够补偿电液位置伺服系统中存在的匹配和不匹配模型不确定性,同时削弱滑模控制的抖振,具有良好的跟踪性能和较强的鲁棒性。

A kind of modeling uncertainties compensation control strategy based on sliding mode is proposed for electro-hydraulic positioning servo system with matched and unmatched modeling uncertainties.A sliding mode observer is designed to estimate the matched and unmatched modeling uncertainties of electro-hydraulic positioning servo system and compensate the uncertainties during the design of the sliding mode controller,thus effectively weakening the discontinuous term gain. The sliding surface of observer is introduced to the sliding surface of controller to construct a new controller sliding surface and eliminate the estimation error of uncertainties so that the good dynamic performance of the controller can be ensured. Besides,the deterioration of tracking performance,which comes from the measured noise,can be reduced without system acceleration. Finally,the global stability of the closed-loop system is verified by the Lyapunov stability theory. Simulation results show that the matched and unmatched modeling uncertainties of the electro-hydraulic positioning servo system can be compensated by the proposed method compared with the integral sliding model control strategy. At the meantime,the chattering of sliding mode control is weakened,and the system possesses good tracking performance and strong robustness.