Fault detection of mechanical systems with inherent backlash

This paper proposes a scheme of fault detection for mechanical transmission system described by so-called sandwich models with backlash. In this scheme, the state variables of the system are estimated by a non-smooth observer due to the effect of backlash inherent in the transmission system can not be neglected. The fault detection is based on the estimated residual between the output of the observer and the measured data. The detection of faults happened in actuator, i.e. gearbox in the system is presented. The analysis of the effect of backlash on the fault detection is also illustrated in this paper.