基于模糊PI的电比例排量泵控制研究

针对正流量液压系统的挖掘机,使用电比例排量泵替代液控恒功率泵可以实现泵与发动机更加完美的功率匹配。但电比例排量泵的排量调节控制对算法的准确性、稳定性以及比例电磁阀的快速响应性能提出了很高要求。为满足以上条件,电比例排量泵的控制策略采用了基于BP神经网络的恒功率MAP图计算方法以及模糊逻辑整定PI参数的方法,使得电比例排量泵可以根据发动机转速和液压系统工作压力大小准确计算出变量泵排量并调度PI参数,消除液压系统时变特性与非线性对控制性能的不利影响。根据测试结果,采用模糊PI控制的挖掘机液压系统在控制准确性、稳定性方面都得到了提升。

Research on Fuzzy PI Control Strategy for Variable Displacement Pump

Thanks to the perfect torque matching between engine and pump, hydraulic constant-power pump is widely replaced by electric control pump in hydraulic excavator, especially those equied with positive flow system. However, the displacement modulation of electronic control pump requires good stability and short response time, which should be applied in the control method of electromag-netic valve. Fuzzy PI control strategy was proposed to make up the negative effect of the time-varying and non-linear character of exca-vator’ s hydraulic system, and BP neural network was used to calculate the pump’ s displacement. According to this method, PI param-eters were tuned when the engine speed and working pressure changed. The experimental results show that the fuzzy PI control system is much more stable and plays good performance in calculation accuracy of torque matching.