考虑摩擦与测量噪声的液压缸泄漏诊断方法

Leakage Diagnosis Method of Hydraulic Cylinder Considering Friction and Measurement Noise

泄漏是液压缸的一种典型故障,及时诊断泄漏能够有效保障液压缸的效率性能并提高安全性。在阀控液压缸系统模型中引入Stribeck摩擦模型,建立接近实际情况的系统动力学方程;针对系统存在的非线性问题,采用状态反馈法进行系统状态空间建模;采用带有白色测量噪声的子空间辨识方法进行系统辨识,求解出系统的泄漏系数估计值以判别泄漏故障的存在、类型与泄漏程度,并通过MATLAB/Simulink平台进行验证。结果证明:状态反馈法能够建立线性的系统模型,使子空间辨识法可以对泄漏故障进行诊断;带有白色噪声的子空间辨识法能够消除噪声影响,精确地辨识出每一处泄漏系数估计值。

Leakage is a typical fault of hydraulic cylinder,the diagnosis of leakage can effectively guarantee its efficiency and improve the degree of safety.Stribeck friction model was introduced into the model of valve-controlled hydraulic cylinder system to establish the system dynamics equation which was close to the actual situation.Aimed at the non-linear problem of the system,the state space model of the system was established by the state feedback method.The subspace identification method with white measurement noise was used to identify the system,and the leakage coefficient of the system was estimated to identify the existence,the type and the degree of leakage fault.The diagnosis result was verified by MATLAB/Simulink platform.The result shows that the state feedback method can establish a linear system model,so that the subspace identification method can diagnose the leakage fault.The subspace identification method with white noise can eliminate the influence of noise,and accurately identify the estimated value of each leakage coefficient.