挖掘机电液流量匹配控制系统特性分析

Characteristic Analysis of Electro-hydraulic Flow Matching Control System in Hydraulic Excavator

电液流量匹配控制系统采用电比例阀和电比例泵同步控制的方式,基本消除传统负载敏感系统中存在的泵滞后阀控现象,同时由于该系统无须进行压力闭环反馈控制,不用预设泵出口与最高负载之间的压力裕度,因此系统的动态性能和节能水平有很大的提高。以2 t挖掘机试验样机为研究对象,试验对比分析负载敏感系统和电液流量匹配控制系统的动态特性及能耗特性,设计阀前压力补偿型电液流量匹配控制系统的抗流量饱和控制器。试验表明,与负载敏感系统相比,电液流量匹配控制系统不仅弥补了负载敏感系统流量饱和时不能按比例分配流量的不足,而且泵与最高负载之间的压力裕度降低0.6～0.7 MPa,节能8%～10%,在提高系统动态性和节能性的同时,稳定性也得到明显增强。

The electro-hydraulic flow matching control system with the electro-proportional valve and electro-proportional pump works in a synchronous control mode of the valve and pump. It eliminates the hysteresis between the pump and valve in the traditional load-sensing systems nearly. Closed-loop feedback control of pressure and preset pressure margin between pump and maximum load pressur are not needed. It reflects the combination of flexibility and efficiency of hydraulic systems, improving energy efficiency and control performance. The experimental prototype of 2-ton excavator with the electro-hydraulic flow control system is taken as the investigation subject. Energy consumption and dynamic characteristic are comparatively analyzed between the traditional load sensing hydraulic system and the elec^o-hydranlic flow matching hydraulic system. The controller with flow share capabilities is designed for electro-hydraulic flow matching control. Compared with the Iraditional load-sensing system, the electro-hydraulic flow matching hydraulic system has the same as with post compensation with anti saturation. The pressure margin is reduced by more than 0.6-0.7 MPa, and the energy consumption is decreased by 8%-10%. It can not only improve the dynamic characteristic and energy efficient, but also the system stability.