大型起竖装备液压系统及其鲁棒切换控制策略

Robust Switched Control Strategy of Large Erecting Equipment Hydraulic Systems

针对大型起竖装备液压系统供油压力与负载特性不匹配而导致能量损失严重的问题,通过对负载特性的分析,将其近似等效为"初始-中间-终了"三段式折线负载。在起竖初始阶段采用恒定高压,以提供足够驱动力;在中间阶段设定随起竖角度线性单调递减的线性压力,以降低系统能耗;在起竖终了阶段采用恒定低压,以保持起竖稳定,从而实现系统供油压力与起竖负载的近似匹配,降低系统能耗。针对供油压力切换可能导致起竖过程振动和不稳定的问题,通过建立液压系统数学模型,提出了鲁棒切换控制策略。仿真和实验结果均表明,起竖过程平稳,无振动和超调现象,油液温度比直接采用节流控制降低约40℃,表明该系统及其鲁棒切换控制策略能有效降低起竖过程的能量损失。

Aimed at high energy loss of large erecting equipment due to supply pressure unmatched with load characteristics, the load characteristics were analyzed, which was approximately equivalent to initial-middle-final three-segment broken line load. In initial stage of erection, constant high pressure was used to provide sufficient driving force;in middle stage, pressure decreases linearly and monotonously with the erection angle to reduce energy consumption of the system;in final stage, constant low pressure was used to maintain erection stability. The switching control strategy may match the oil supply pressure with approximate external loads and reduce energy consumption. Aiming at the problems that the switching of supply pressure might lead to vibration and instability in erection processes, a mathematical model of hydraulic system was built, and a robust control strategy was proposed. Experimental and simulation results show that the erecting processes are smooth, stable and not overshoot. The temperature of the oil is reduced about 40℃ compare with the throttle control, which shows the system and robust switched control strategy may save energy effectively.