被动式电液负载模拟器的变增益滑模控制研究

Variable gain sliding mode control of passive electro-hydraulic load simulator

针对被动式电液负载模拟器的加载精度和响应速度问题,对电液负载模拟器中非线性环节和舵机位置系统的扰动进行了研究,其中非线性环节包括非线性摩擦以及液压缸的容腔效应。对于非线性环节问题,建立了包含光滑摩擦模型以及液压缸容腔效应的系统非线性数学模型;对于舵机位置系统的扰动问题,基于Lyapunov稳定性理论,讨论了滑模面s中增益的参数选取问题;提出了一种基于双幂次趋近律,能使控制器具备光滑输出的变增益滑模控制器;通过Matlab/Simulink进行了系统数值仿真。研究结果表明:引入该变增益滑模控制器后,提高了系统的加载精度和响应速度,舵机位置系统对负载模拟器的不确定性影响具有较好的鲁棒性,使其输出的超调量不超过5%,静、动态的最大误差不超过5%。

Aiming at the problem of loading accuracy and response speed of passive electro-hydraulic load simulator,non-linear factors which including non-linear friction and chamber s effect of the actuator and the disturbance of position system in electro-hydraulic load simulator were studied.For non-linear factors,a system nonlinear mathematical model including smooth friction model and chamber s effect of the actuator were established.For the disturbance of position system,based on Lyapunov stability theory the selection of gain in the sliding surface s was discussed.Then a variable gain sliding mode controller with smooth output was designed by employing the double power reaching law.The numerical simulation of the system was carried out by using Matlab/Simulink.The results indicate that the loading accuracy,response speed and the robustness of the load simulator are improved by the variable gain sliding mode controller.The overshoot of system output is not more than 5%,and the maximum static and dynamic errors are not more than 5%.