Robust unknown input observer design for simultaneous actuator and sensor faults

Abstract

The paper deals with the problem of simultaneous estimation of the state as well as the sensor and actuator faults. The proposed approach is developed in such a way that it allows decoupling the actuator faults from the state. In a similar fashion, the sensor fault is derived directly from the output. Moreover, the quadratic boundedness approach is utilised for guaranteeing the robust stability of the observer. It supposes that the uncertainty are limited within an ellipsoidal set. The final part of the paper shows the illustrative example with the implementation to the laboratory multi-tank system.