Robust nonlinear actuator fault diagnosis for uncertain nonlinear systems subjected to state time-varying delays

An actuator fault diagnosis approach is presented in this paper for a class of time-delayed nonlinear systems via the use of adaptive updating rules. The considered system is represented by a time delayed dynamical state space model where the time delays are embedded in the state vector. The linear part of the system is subjected to dynamical model uncertainties. Fault diagnosis observer is established, where the Lyapunov stability theory is used to obtain the required adaptive tuning rules for the estimation of the nonlinear actuator faults. A simulated numerical example is included to demonstrate the use of the proposed approach and encouraging results have been obtained.