Actuator Fault diagnosis: H∞ framework with relative degree notion

A new actuator fault diagnosis and estimation approach is proposed for dynamical systems. The main contribution consists in enhancing the fault detection with a new observer that takes into account the relative degree of the output of the system with respect to the fault. The Single Input Single Fault (SIFO) case is considered to present the approach and an extension to systems with multiple outputs and multiple faults. The convergence of the proposed residual generator is analyzed using the Lyapunov theory which can be expressed straightforwardly in terms of Linear Matrix Inequalities (LMIs). Numerical examples are provided in order to illustrate the proposed approach.