基于小波分析的气动调节阀反馈杆松动故障在线诊断研究

Research on On-line Diagnosis of Pneumatic Control Valve Feedback Rod Loosening Fault Based on Wavelet Analysis

气动调节阀定位器反馈杆松动导致阀位无法按照设定信号运动,影响工业生产;针对上述问题,提出了一种基于小波分析的在线故障诊断方法;选取工业闭环控制回路中调节阀阀位响应信号作为目标信号,采用Db3小波基对目标信号进行6层分解,得到d6特征细节参数,可以实现对故障发生时间点的准确检测;之后,分段计算其平均值AV、方差VAR、均方根值RMS,对其平均值AV、方差VAR、均方根值RMS进行曲线拟合,划分正常状态运行区与故障状态运行区,实现气动调节阀定位器反馈杆松动故障的在线诊断;通过仿真和在线闭环测试,验证了诊断方法的有效性和实用性。

Due to the loose feedback rod of pneumatic control valve positioner,the valve position cannot be moved by the set signal,which affects industrial production.Aimed at above problem,an online fault diagnosis method based on wavelet analysis is proposed.The adjustment valve position response signal ofindustrial closed-loop control loop is selected as target signal,and DB3 wavelet base is used to decompose the target signal by 6 layers and obtain the detailed parameters of D6 characteristics,which realizes the accurate detection of the fault occurrence time.After that,average value(AV),variance(VAR)and root mean square(RMS)are calculated in segments,and the normal state operation area and fault state operation area are divided by the curve fitting of the AV,VAR and RMS,which realizes the online diagnosis on the loose fault with the feedback rod of the pneumatic control valve positioner.The effectiveness and practicability of the diagnostic method are verified by the simulation and online closed-loop testing.