• Liang An Department of Mechanical and Manufacturing Engineering, The University of Manitoba, Winnipeg, MB, Canada R3T 5V6
  • Nariman Sepehri Department of Mechanical and Manufacturing Engineering, The University of Manitoba, Winnipeg, MB, Canada R3T 5V6


fault detection and isolation, extended Kalman filter, leakage, hydraulic actuators


This paper presents the application of extended Kalman filter (EKF) in order to identify leakage faults in hydraulically powered actuators. A hydraulic actuator can suffer from two types of leakages: internal or cross-port leakage at the piston seal and, external leakage at the shaft seal or the connecting pipes. An EKF-based estimator is constructed that includes complete nonlinear models of hydraulic functions as well as inevitable stick-slip friction in the actuator. It is shown that, firstly, under normal (no-fault) operating condition, the developed estimator closely predicts the states of the system, using only a few basic measurements. Secondly, in the presence of leakage faults, the level of residual errors between the estimated and the measured line pressures, increase significantly indicating the occurrence of faults. Thirdly, different leakage types can be identified by mapping the residual errors changes. Experiments are performed on a laboratory-based hydraulic actuator circuit. The results demonstrate the efficacy of the proposed


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Author Biographies

Liang An, Department of Mechanical and Manufacturing Engineering, The University of Manitoba, Winnipeg, MB, Canada R3T 5V6

Liang An received B. Sc. in Automation Engineering from the Zhengzhou Institute of Technology in 1993, and an M. Sc. in Control Engineering from the Beijing University of Chemical Technology in 1999. His research interests include robotics, system estimation, and control engineering. His is currently a Ph.D. candidate at the University of Manitoba.

Nariman Sepehri, Department of Mechanical and Manufacturing Engineering, The University of Manitoba, Winnipeg, MB, Canada R3T 5V6

Nariman Sepehri is a professor with the Department of Mechanical and Manufacturing Engineering, at the University of Manitoba. He received M.Sc. and Ph.D. both from the University of British Columbia. His areas of interest include telerobotics applied to heavy-duty hydraulic machines and fluid power control and diagnosis systems.


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