基于干扰观测器的非对称液压缸鲁棒运动控制

Disturbance observer based robust motion control for single rod hydraulic actuators

为实现对比例阀控制非对称液压缸系统的高性能位置伺服控制,提出了基于干扰观测器的新型鲁棒运动控制方法.在闭环控制中采用干扰观测器,对各种外部力扰动和系统参数变化进行估计并引入相应补偿,从而提高系统运动性能和鲁棒稳定性;对于比例阀中位死区,基于名义模型位置输出信息的新型补偿策略,保证在不牺牲系统动态品质的情况下,能有效地避免阀芯的频繁切换.对挖掘机器人关节液压缸系统进行计算机仿真的结果表明,该方法对外部力扰动和参数变化均具有很强的鲁棒性,且新型比例阀死区补偿环节能明显增强液压系统运动的平稳性.

A novel robust motion control method based on disturbance observer was presented. In order to achieve high performance control specifications for single rod hydraulic positioning servo systems using proportional valves. The disturbance observer was included in the proposed closed loop motion controller, which is used to estimate various external force disturbances and the changing of hydraulic parameters, and thus compensation was introduced to enhance the servo systems＇ motion performance and robust stability. In order to compensate for the dead zone nonlinearities of the proportional valve, a novel compensation term using the nominal model＇s output information was proposed, which was capable of avoiding the spool＇s frequently switching effectively and meanwhile have no impact on the servo system＇s dynamic performance. Computer simulations are developed for the excavator＇s hydraulic systems, and the results show that the proposed design have strong robustness to parameter uncertainty and external disturbance, and that applying the new dead area compensation term can obviously improve servo system＇ s output smoothness.