Sliding mode fault tolerant control of uncertain systems with time varying delay: Application to AFR control

This paper considers fault tolerant control for systems with polytopic uncertainties and unknown interval time varying delay. Sliding mode technique is used for both controller and observer design. For the controller embedding the observer states the sliding surface is always bounded by the error dynamics. The accuracy of fault reconstruction depends not only on disturbance but the plant and observer states, as well as the error dynamics, which is used to reconstruct the fault. The proposed method tries to reduce the ultimate bound of the overall system to improve both control and fault reconstruction performance. The method is applied to AFR control of a gasoline engine. A nonlinear simulation of the model is used to verify the its effectiveness.