小球式旋转直驱压力伺服阀动态特性分析优化

Dynamic analysis and optimization of ball-type rotary direct drive pressure servo valve

针对在研的小球式旋转直驱压力伺服阀(Ball-type Rotary Direct Drive Pressure Servo Valve,BRDDPSV)阶跃响应超调量大、调整时间长等不稳定现象,建立了数学模型,分析了结构参数和电控方法对整阀动态特性的影响。理论分析表明:结构参数方面,减小阀芯直径、减小滑阀负遮盖量或将小球-柱形孔运动副改为小过盈配合均可提高整阀响应的稳定性;控制方法方面,在原有PI控制的基础上,采用积分分离可有效抑制控制压力动态响应的超调量,增加动压反馈校正可有效缩短控制压力动态响应的调整时间。优化选取结构参数和电控方法后,进行样机试验,整阀控制压力阶跃响应的超调量小于0.5 MPa(系统压力21 MPa),调整时间约30ms,能够满足飞机刹车压力伺服阀的使用需求。

To solve the problem of large overshoot and long adjustment time of dynamic pressure response of a new type Balltype Rotary Direct Dive Pressure Servo Valve（BRDDPSV）,a mathematical model is developed based on the classical control theory.The main structure parameters and electronic control method that affect the stability of BRDDPSV are analyzed.Theoretical analysis shows that the response stability of the BRDDPSV can be improved by properly adjusting the structural parameters,including reducing the spool diameter,and decreasing the negative cover of the valve port or changing the small ball and cylindrical hole into a slight interference fit.With respect to the control method,on the basis of the original PI control,large overshoot of dynamic response can be inhibited through integral separation,and the adjustment time of the dynamic response can be shortened through dynamic pressure feedback correction.Finally,semi-physical simulation experiments show that with proper structural parameters and electrical control methods,the pressure overshoot can be controlled to be less than 0.5 MPa（system pressure was 21 MPa）,and the response adjustment time can be controlled within 30 ms theoretically and experimentally.It can meet the requirements of aircraft brake pressure servo valve.