FAULT-DIAGNOSIS FOR A HYDRAULIC DRIVE SYSTEM USING A PARAMETER-ESTIMATION METHOD

Fault diagnosis using a parameter-estimation method is investigated in this paper. A digital state variable filter is employed to obtain der ivatives of the variables, and an interpolation technique is used to a pproximate the values of the variables between samples. The method is applied to a hydraulic test rig based on real data, and the simulated faults - changes in the physical parameters - are diagnosed. The simul ation results demonstrate that faults having the same direction in the state space of the system model can be isolated using this technique, which is impossible using any observer-based method or any parity equ ation method. Fault size can also be approximately identified. Copyrig ht (C) 1997 Elsevier Science Ltd.