采用滑模控制的电动静液压作动器位置跟踪的研究

Research on position tracking of electro-hydrostatic actuator based on sliding mode control

为了解决外界干扰力等因素引起的电动静液压作动器位置跟踪出错的问题,提出了一种采用滑模控制的电动静液压作动器位置跟踪的研究。首先,分析了电动静液压作动器的组成及其工作原理,计算了电机转动引起定量泵上产生的力矩大小,求取了定量泵产生角速度的传递函数,通过计算液压缸内的流量方程,获取了活塞杆上的动力学模型,从而推导出了电动静液压作动器的系统模型。然后,以目标压力差以及目标位移为依据,建立了滑模面方程,通过粒子群算法对目标压力差计算过程中的变量因子进行优化,以求取滑模控制过程中所需的控制率,进而实现控制电动静液压作动器对目标位置进行准确的跟踪。最后,利用所提方法与干扰观测器方法对不同目标位置轨迹进行了跟踪测试。测试结果显示:在对规则和不规则目标位置轨迹进行跟踪时,所提方法比干扰观测器方法的跟踪准确率分别提高了30.77%和27.76%。说明所提方法的控制性能优良,可以控制电动静液压作动器对目标位置进行准确的跟踪。

In order to solve the problem of position tracking error of electro-hydrostatic actuator caused by external interference,this paper presents a study of position tracking of electro-hydrostatic actuator using sliding mode control.Firstly,the composition and working principle of the electro-hydrostatic actuator are analyzed.The torque produced by motor rotation is calculated,and the transfer function of angular velocity produced by the pump is obtained.By calculating the flow equation in the hydraulic cylinder,the dynamic model on the piston rod is obtained,and the system model of the electro-hydrostatic actuator is derived.Then,based on the target pressure difference and target displacement,the sliding surface equation is established.Particle swarm optimization is used to optimize the variable factors in the calculation of the target pressure difference,so as to obtain the control rate needed in the sliding mode control process,and then to realize the accurate tracking of the target position by controlling the electro-hydrostatic actuator.Finally,the proposed method and the disturbance observer method are used to track different target position tracks.The test results show that the tracking accuracy of the proposed method is 30.77%and 27.76%higher than that of the disturbance observer method when tracking regular and irregular target position tracks.It shows that the control performance of the proposed method is excellent,and it can control the electro-hydrostatic actuator to track the target position accurately.