直驱泵控电液伺服泄露补偿保压方法研究
A Leakage Compensation Pressure Retaining Method of DDVC Electro-hydraulic Servo System

为解决传统阀控或变量泵保压系统在工程应用中因温升高、结构复杂而带来的对油液污染敏感、保压精度差、效率低等问题，在分析永磁同步交流伺服电机调速性能和效率的基础上，结合齿轮泵结构简单、可靠性高的特点，提出了一种直驱泵控电液伺服泄漏补偿保压方法。系统保压时，根据流量连续性方程，使齿轮泵输出流量仅补偿回转液压缸泄漏量。该系统较传统保压系统结构简单、可靠性高且实现了节能。通过齿轮泵实际流量实验以及回转液压缸泄漏实验得到齿轮泵转速和系统保压压力之间的数学关系，建立系统保压数学模型，通过系统阶跃响应实验分析了该系统的动态性能。实验结果表明，该系统的输出能很好地跟随输入，满足系统保压性能要求。
In order to solve the engineering application problem of the traditional pressure system driven by control valve or asynchronous motor associated with the rising temperature and complex structure which may result in the sensitiveness of oil pollution, poor pressure retaining accuracy and low efficiency, a novel leakage compensation pressure retaining method for a direct drive volume control electro-hydraulic servo system is proposed and implemented based on analysis of the speed regulation performance and efficiency of a permanent magnet synchronous AC servo motor that integrates the simple structure and high reliability of a gear pump. While retaining the pressure of the servo system, according to the flow continuity equation, the output flow of the gear pump only needs to compensate for the leakage of a rotary hydraulic cylinder. Compared with the traditional pressure retaining system, this servo system has the advantage of simple structure, high reliability and energy saving. Through the experiments on the actual flow of the gear pump and the leakage of the rotary hydraulic cylinder, the mathematical relationship between gear pump speed and servo system pressure is obtained, and the pressure retaining mathematical model is established. Meanwhile, the experiments on the step response of the servo system demonstrate its dynamic performance. The experimental results show that the output of the servo system is in good agreement with its input. The servo system satisfies requirements for pressure retaining