Design of an Active Fault Tolerant Control and Polytopic Unknown Input Observer for Systems described by a Multi-Model Representation

Abstract — In this paper, an active Fault Tolerant Control (FTC) strategy is developed to systems described by multiple linear models to prevent the system deterioration by the synthesis of adapted controllers. First, a Polytopic Unknown Input Observer is synthesized for providing actuator fault estimation. The actuator fault estimation is used in a FTC scheme which schedules some predefined state feedback gains. These gains are performed through LMI both in fault-free and faulty cases in order to preserve the system performances over a wide operating range. For each separate actuator, a pole placement is designed by pole clustering. The effectiveness and performances of the method have been illustrated in simulation considering a hydraulic system: a three-tank system