伺服阀动压反馈网络流体建模与辨识分析

Fluid Modeling and Identification Analysis of Servo Valve Dynamic Pressure Feedback Network

动压反馈网络是抑制液压伺服系统阻尼比的最关键装置之一。目前其时间常数τ基本按湍流模型进行设计,实际机理并不清楚,造成动压反馈式伺服阀的试验结果与理论结果偏差较大。为了提高时间常数τ的设计精度,提出了一种新的建模方法。在低频段,建立基于层流模型参数τ的设计方法;在高频段,通过黑箱辨识方法建立时间参数τ的线性模型。仿真与试验结果对比表明,该设计方法能够大大提高伺服阀建模的准确性,从而为伺服阀动压反馈网络设计奠定理论基础。

Dynamic pressure feedback network is one of the most critical devices for suppressing damping ratio of hydraulic servo system.At present,its time constant is designed basically based on turbulence model,and the test results of dynamic pressure feedback servo valve is deviated from the theoretical result greatly because the actual mechanism is not clear.A new modeling method is proposed for improve design accuracy of time constant.In low frequency band,a design method of time constant is established based on a laminar flow model.In high frequency band,a linear model of time constant is established by the black box identification method.The comparison results of simulation and experimental indicate that the design method can improve the accuracy of servo valve modeling greatly.Therefore,the new modeling of time constant lays a theoretical foundation for servo valve dynamic pressure feedback network design.