Robust adaptive estimation of arbitrary time-varying actuator faults

We design a robust fault estimation technique for arbitrary time-varying faults based on an adaptive observer with enhanced speed of adaptation. The construction of the observer is carried out through a transformation of the plant model into its special coordinate basis (SCB) form. This transformation allows a decoupling of the fault estimates from the disturbances. A key feature of the overall scheme is that the adaptive mechanism is viewed as a filtering process which allows easy parameter tuning to achieve faster and exact fault estimation in the presence of disturbances and plant-model uncertainties.