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FAULT DIAGNOSIS OF HYDRAULIC SERVO SYSTEM USING THE UNSCENTED K ALMAN FILTER
Author(s) -
Liu Hongmei,
Liu Dawei,
Lu Chen,
Wang Xuan
Publication year - 2014
Publication title -
asian journal of control
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.769
H-Index - 53
eISSN - 1934-6093
pISSN - 1561-8625
DOI - 10.1002/asjc.860
Subject(s) - control theory (sociology) , fault (geology) , hydraulic machinery , electrohydraulic servo valve , hydraulic cylinder , piston (optics) , discretization , servomechanism , kalman filter , servo , engineering , servo drive , state space representation , control engineering , computer science , mathematics , physics , mechanical engineering , algorithm , geology , artificial intelligence , optics , wavefront , mathematical analysis , control (management) , seismology
Fault occurrence can be embodied by the physical parameter variations of the hydraulic servo system. Faults can, therefore, be diagnosed according to the model coefficient variations of the hydraulic servo system. This paper proposes an approach for fault diagnosis based on the unscented K alman filter ( UKF ) with a mathematical model of the hydraulic servo system. The mathematical model is established using the dynamic equations of the hydraulic servo system. Based on the fault mechanism analysis results, several important system model parameters that can separately represent different faults in different components of the hydraulic servo system are chosen. Discrete state space equations are derived from the dynamic equations. The UKF algorithm is used to estimate the important system model parameters of the hydraulic servo system by utilizing the discretized state space model. According to the variations of these model parameters, the fault modes and locations of the hydraulic servo system can be diagnosed and isolated. Two types of faults, namely, abrupt fault in servovalve gain and slow wear fault in hydraulic cylinder piston, which cannot be directly detected from the system output, are introduced individually to the hydraulic servo system in this work. By comparing with the extended K alman F ilter, three different experimental cases are used to validate the effectiveness of the UKF for hydraulic servo system fault diagnosis.