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

摘要:

针对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，影响工业生产的问题，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，通过对其平均值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系统测试验证了文章中诊断方法的有效性和实用性。

Abstract:

Aiming at the problem that the valve position cannot move according to the set signal due to the loose feedback rod of the pneumatic control valve positioner, which affects industrial production, an online fault diagnosis method based on wavelet analysis is proposed. The valve position response signal of the regulating valve in the industrial closed-loop control loop is selected as the target signal, and the DB3 wavelet base is used to decompose the target signal by 6 layers, and the detailed parameters of D6 characteristics are obtained, which can accurately detect the fault occurrence time. After that, the average value AV, variance VAR and rms are calculated in segments, and the normal state operation area and fault state operation area are divided by curve fitting of the mean value AV, variance VAR and rms to realize the online diagnosis of the loose fault of the feedback rod of the pneumatic control valve positioner. The effectiveness and practicability of the diagnostic method in this paper are verified by simulation and online closed-loop system testing.