旋转直接驱动电液压力伺服阀稳定性分析

Stability Analysis of Rotary Direct Drive Electrohydraulic Pressure Control Servo Valve

摘要:

针对最新研制的旋转直接驱动电液压力伺服阀（RDDPV）出现输出压力振荡问题；建立了其数学模型和简化框图，得到了RDDPV稳定性判据，并提出了解决方案。RDDPV取消了传统压力伺服阀的机械和液压反馈，采用马达转角内闭环和输出压力外闭环的电反馈伺服控制。研究表明，当阀芯处于进回油口中间位置附近，稳态液动力表现为阀芯位移的正反馈作用，导致整阀机械液压部分刚度为负，稳定性差；此时，马达转角内闭环电反馈刚度对整阀稳定性至关重要。数值模拟和试验表明，增加马达转角电反馈系数，增加了伺服阀电反馈刚度，提高了伺服阀的稳定性。

Abstract:

Aimed at the problem that the output pressure of newly developed rotary direct drive electrohydraulic pressure control servo valve (RDDPV) was oscillating, the mathematical model and block diagram of RDDPV were established, and the stability criteria was obtained. In RDDPV, the electrical feedback of motor rotational angle and output pressure are used instead of traditional mechanical or hydraulic feedback. When the spool valve near the middle position between inlet and outlet port, steady state flow forces provides the positive feedback on spool motion, leads to a negative stiffness of mechanical and hydraulic parts, and the stability of RDDPV is poor. In order to improve the stability of RDDPV, the electrical feedback stiffness of the servo valve was improved by increasing the electrical feedback coefficient of motor rotational angle. Numerical simulation and experiment results shown that the stability of RDDPV can be effectively improved by increasing the electrical feedback coefficient of motor rotational angle.