Abstract: Electro‑hydraulic lifting system realized agricultural machinery equipment intelligentination and automation，through the combination of mechanical‑electro‑fluid and intelligent control technology.To improve the tractor reliability of farming and to reduce the energy of the electro‑hydraulic lifting system，this article analyzed the electro‑hydraulic lifting system.Load changing and the whole electro‑hydraulic lifting system could be simulated，by changing the variable throttling.This article designed a control strategy based on PSO—Fuzzy PID for the load sensitive variable pump，and used AMESim software to model and simulate it.The simulation results show that when the maximum opening signal of the variable throttling port is 0.6， 0.8 and 1，the maximum outlet flow of the load sensitive variable pump is 79.6 L/min， 106.4 L/min and 133.4 L/min，respectively. The load sensitive variable pump can achieve load feedback regulation.

Key words:  , tractor, electro?hydraulic lifting system, load sensitive variable pump, PSO—Fuzzy PID, variable 

摘要： 拖拉机电液提升系统将农机装备与机、电、液、智能控制技术相结合，实现农机装备的智能化和自动化。为提升拖拉机耕作可靠性、降低拖拉机电液提升系统的能耗，对电液提升阀控系统原理进行分析，通过改变负载敏感变量泵的可变节流阀阀口大小模拟负载变化，进而模拟整个电液提升阀控系统。设计一种基于PSO—模糊PID的控制策略，利用AMESim软件对负载敏感变量泵进行建模和仿真分析。由分析仿真结果可知，当负载敏感变量泵的可变节流口最大开口信号为0.6、0.8、1时，泵的出口最大流量分别为79.6 L/min、106.4 L/min、133.4 L/min，说明负载敏感变量泵能够实现负载反馈调节。

关键词: 拖拉机, 电液提升系统, 负载敏感变量泵, PSO—模糊PID, 可变节流口