Inputs estimator for actuator faults detection

This paper proposes a fault detection method for a particular class of nonlinear flat system using a dynamic higher order sliding mode. The key idea consists to design an inputs estimator based on analytical redundancy relations by solving a constraint satisfaction problem. Indeed, the analytical redundancy relations require knowledge of the successive derivatives of the measured system outputs. For this aim, a sliding mode differentiator with dynamic gains is applied in order to take account a measurement noise. The performances of the proposed approach are illustrated through some simulation tests on three-tank system to detect an actuator fault.