Simultaneous, Multiplicative Actuator and Sensor Fault Estimation using Fuzzy Observers

This paper considers the detection and diagnosis of simultaneous, multiplicative, or parametric, sensor and actuator faults in nonlinear systems. This is performed here using a fuzzy system model of the underlying nonlinear system to design a fuzzy system of linear observers. A method for fault detection and diagnosis from linear systems theory is then applied. It will show how asymptotic convergence of the fault estimates, under ideal conditions, is possible through the feasibility of constraints on the stability of the global model, the use of a dummy sensor fault free output and updating rules of the augmented error method seen in model reference adaptive control.