负载口独立控制系统非线性滤波振动抑制方法

A Nonlinear Filtering Method of Vibration Suppression for the Independent Metering Control System

针对负载口独立控制系统在作业过程中时常因控制信号突变而造成执行器速度振荡及液压缸两腔压力波动,从而导致操作舒适性和机器可靠性降低甚至引发安全事故的问题,首先,分析了负载口独立控制系统压力流量复合控制策略以及传统阻尼补偿方法抑振的局限性,阐明了引发速度振荡与压力波动的原因;然后,基于该控制系统,提出了采用非线性滤波器修改突变控制信号的抑振方法,并给出了非线性滤波器的边界选取原则;最后,设计了负载口独立控制系统的进出口阀控制器,通过修改参考流量信号,降低了不同突变信号对执行器速度带来的影响。基于20 t挖掘机负载口独立控制系统开展数值仿真,结果表明:相较于传统阻尼补偿方法,采用所提方法能够有效降低阶跃、斜坡信号引起的执行器速度振荡与压力波动,且在动臂液压缸全伸、全缩典型工况下压力波动较小,并使速度振荡降低了32.5%~64.7%,从而有效改善了系统的动态特性。

The independent metering control system often triggers oscillations between the actuator speed and the pressure in the two chambers of the hydraulic cylinder due to abrupt changes in the control signal during operation,thus leading to the reduction of operating comfort and machine reliability and even causing safety accidents.To address this problem,initially,the limitations of the pressure-flow composite control strategy of the independent metering control system as well as the vibration suppression of the traditional damping compensation method are analyzed,and the causes of velocity oscillations and pressure fluctuations are elucidated.Subsequently,based on this system,a vibration suppression method using the nonlinear filter for mutation control signal modification is proposed,and the boundary selection principle of the nonlinear filter is given.Ultimately,the inlet and outlet valve controllers of the independent metering control system are designed,and the effects of different mutation signals on the actuator speed are reduced through the reference flow signal modification.Numerical simulation is carried out based on the independent metering control system of a 20-ton excavator.The results indicate that compared with the traditional damping compensation method,the proposed method can effectively reduce the actuator speed oscillation and pressure fluctuation caused by step and ramp signals;the pressure fluctuation is small under typical working conditions featuring the full extension and full retraction of the movable arm’s hydraulic cylinder;and the speed oscillation is reduced by 32.5%to 64.7%.Under such circumstances,the dynamic characteristics of the system are effectively improved.