瞬变载荷下巨型水压机液压操作控制策略

Control Strategy of Hydraulic Operation Control System under the Transient Load in Giant Hydraulic Press

通过对巨型水压机液压操作控制系统的负载分析得知,其负载即分配阀心开启力在控制过程中出现瞬变,且变化幅度很大,影响控制系统的鲁棒性和控制精度。针对该载荷特点,提出PID-H_∞串级闭环控制策略,将液压操作控制系统的瞬变载荷当成控制系统的干扰信号,设计控制器,建立数学模型。将该控制策略应用于300 MN模锻水压机液压操作控制系统,对单一PID控制和PID-H_∞复合控制进行仿真比较。仿真结果和工业应用表明,采用PID-H_∞串级闭环控制较单一PID控制能更好地抑制瞬变载荷的干扰作用,提高系统的鲁棒性和控制精度。

The load of hydraulic operation control system in giant hydraulic press is analyzed. The conclusion is that the load is the transient change of the opening force of distribution valve spool occurring in the control process, and the change range is great, thereby affecting the robustness and control accuracy of the control system. Based on the characteristic of the load, a PID-H∞ closed-loop cascade control strategy is put forward. The transient load is regarded as disturbing signal of the control system. T he controller is designed and the mathematic model is established. The control strategy is applied in 300 MN die forging hydraulic press. Simulation and comparison of single PID control and PID-H∞ compound control are carded out, The simulation results and practical applications show that the PID-H∞closed-loop cascade control is better than the single PID control in suppressing the disturbance effect of transient load and in improving the robustness and control accuracy of the system.