并联伺服阀的同步控制策略  

Synchronous control strategy for paralleled servo valves

作　　者：方锦辉[1] 魏建华[1] 孔晓武[1] 

机构地区：[1]浙江大学流体传动及控制国家重点实验室,浙江杭州310027

出　　处：《浙江大学学报（工学版）》2012年第6期1054-1059,1066,共7页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(50805127)

摘　　要：针对大型振动台和线性摩擦焊机等设备对液压伺服系统的大流量和高频响要求,以及现有伺服阀随着额定流量增加频响大幅降低的矛盾,提出多个伺服阀并联使用的方案.为克服伺服阀在通径、制造和电气等方面差异所导致的阀并联工作时阀芯过零位出现同步误差、造成流量降低和油路冲击等问题,通过监测伺服阀在不同频率、不同幅值正弦信号下和变幅值的类正弦信号下阀芯的位移,得出阀芯运动的若干非线性特征,并在此基础上采用移相和变幅相结合的同步控制策略,解决了阀芯运动的不同步问题.通过对相对滞后阀的指令信号进行超前移相,消除了大部分的同步误差;缩小相对滞后阀的指令信号幅值同时增大相对超前阀的信号幅值,进一步削减了阀并联运动的同步误差.实验结果表明,该同步控制策略效果良好,两阀阀芯穿越零位的相位差可控制在±2°.A new method which paralleled a number of servo valves was proposed,to meet the contradiction between the requirement of large flow and high frequency response in some industry areas,such as high-frequency vibration generators and linearity friction weld machines,and the decreasing frequency response of servo valves as the nominal flow increases.Because of the discrepancies of valves in sizes,manufacture,electrical,etc,the synchronous motion error of spools occurs when crossing the null position if they are paralleled and driven by the same signals,as well as the problem of flow decreasing and hydraulic shock.By analyzing the motion of spools under the drive of sinusoidal signal with different amplitudes and different frequencies,and of sine-like signal with varied amplitude,a number of nonlinear features of servo valves were obtained.Then,a control strategy through combination of phase-shifting and amplitude-varying was designed to achieve a synchronous motion objective.By shifting forward the phase of signal driving the valve which lagged behind others,the major synchronization error was eliminated.The rest of error was reduced by shrinking the amplitude of lagging valves and enlarging the amplitude of leading valves at the same time so that the total flow was the same.The experimental results show that the proposed strategy works well,and the phase error can be controlled within ± 2 °,when the spools cross the null position.

关 键 词：伺服阀 并联控制 同步控制 振动台 移相 变幅 

分 类 号：TH137[机械工程—机械制造及自动化]