SUMMARYThis paper addresses the problems of simultaneous actuator and sensor fault estimation for a class of descriptor linear parameter varying systems. By extending the sensor fault as an auxiliary state, the original system can be transformed into a descriptor one. Then, by the using of H 1 optimization technique, a reduced-order observer is developed with a new defining variable. The proposed approach is based on the parameterizations of the obtained algebraic constraints from the error equation. By using the designed reduced-order observer and super twisting algorithm, the actuator fault can be reconstructed via a polytopic algebraic method. Finally, a simulation example of electric network is given to illustrate the validation of the proposed method.