An actuator fault isolation strategy for a class of nonlinear systems with time-delay using adaptive nonlinear unknown input observer

This paper investigates the actuator fault isolation problem for a class of disturbance driven time delay nonlinear systems. To accomplish fault isolation,we use a bank of observers for all possible faulty models. The paper considers constant actuator faults, that is, the output of some actuators are stuck at fixed undesirable constant values. The proposed fault isolation approach relies on a bank of adaptive nonlinear unknown input observers. Based on the designed observers, a bank of residuals are defined correspondingly. The actuator fault can be isolated if only one residual approaching zero while the others do not. The faulty model with residual approaching zero identifies the faulty actuator.