Abstract:

This paper presented the design of H∞ robust controller to improve the position control of a hydraulic system. First, the hydraulic system model was established by the analysis of the hydraulic and mechanical dynamics. The Dahl friction model was adopted. Then the H∞ robust controller was designed around the nominal parameter values based on mixed sensitivity. The weighting functions were chosen as optimized objectives. Finally, by simulation and experiments, it is proved this control method can effectively suppress the friction error's effects on the position tracking control, especially the effects of the friction model uncertainty in reversing of velocity. The tracking errors are reduced significantly. Both of the steady and transient performance of the robust controller is superior to the conventional PID controller. Therefore the method was validated.

Key words: robot, hydraulic system, friction, robust control

摘要：

基于H∞鲁棒控制器来改善机器人液压系统位置控制性能。首先经液压动力学和机械动力学分析，建立液压驱动系统的数学模型，摩擦力采用Dahl模型。然后按系统参数标称值设计基于混合灵敏度的H∞鲁棒控制器，对权值函数进行优化选择。最后经仿真和实验验证得出如下结论：该控制方法可以有效抑制摩擦力参数误差对位置跟踪控制的影响，尤其在速度换向时摩擦力模型的不确定性产生的影响，显著减小了位置跟踪误差，且该控制器稳态和过渡性能都优于传统PID控制器。

关键词: 机器人, 液压系统, 摩擦力, 鲁棒控制