进气压力调节执行机构故障诊断方法研究

Fault Diagnosis Method of Intake Pressure Regulating Actuator

关键词:  进气压力调节系统  特种调节阀  电液伺服执行机构  自适应滑模观测器  故障诊断

Key words:  Intake pressure regulating system  Special regulating valve  Electro-hydraulic servo actuator  Adaptive sliding mode observer  Fault diagnosis

摘要:

面向高空台进气压力调节系统试验和维护需求，提出了一种基于滑模观测器的执行机构故障诊断方法。考虑特种调节阀的流量-压差气动特性对执行机构外负载作用机制，建立了电液伺服执行机构的非线性模型。由其识别出最佳估计数学模型，以获得自适应滑模观测器。分析确定不同故障对应伺服阀或液压缸的主导特征参数，据此选择可观测状态量且结合自适应阈值进行判断某部件是否发生故障，仿真验证该观测器对典型故障的诊断效果。结果表明，基于自适应滑模观测器的故障诊断方法可实现对进气压力调节系统中电液伺服执行机构典型液压、机械、电气故障的诊断和定位，诊断准确率达91%以上。

Abstract:

A fault diagnosis method of actuator based on sliding mode observer is proposed to meet the test and maintenance requirements of intake pressure regulating system of high altitude platform. Considering aerodynamic characteristics of flow-pressure difference across the special valve on external load mechanism of the actuator， the nonlinear model of the electro-hydraulic servo actuator is established. The best estimation model is identified based on the nonlinear model， so as to obtain an adaptive sliding mode observer. The dominant characteristic parameters of the servovalve or the hydraulic cylinder for different faults are analyzed and determined. Accordingly， the observable state parameters are selected to decide whether one component has a fault or not by comparing with the adaptive threshold. Simulation demonstrator verifies diagnostic effect on typical faults using this observer proposed in this paper. The results show that the fault diagnosis method based on adaptive sliding mode observer can realize the diagnosis and location of typical hydraulic， mechanical and electrical faults in electro-hydraulic servo actuator of the intake pressure regulating system of high altitude platform， and the diagnosis accuracy is no lower than 91%.