Fault Reconstruction for Continuous-Time Switched Affine Systems With Actuator Faults via an Integrated UIO Approach

This article investigates the fault reconstruction problem for a class of continuous-time switched affine systems (SASs) subject to unknown but bounded actuator faults. First, to relax the design constraints imposed by the classic coordinates transformation, a novel TNL interval observer is designed to provide information about the interval estimate of the system output. These estimates are then used to construct are used to construct an algebraic relation between the states and actuator faults. Subsequently, an unknown input observer (UIO) is proposed that combines a Luenberger-like observer with an algebraic fault reconstruction scheme, enabling asymptotic reconstruction of both states and actuator faults. The average dwell time (ADT) switching constraint is adopted to prevent chattering caused by high-frequency switching. Sufficient conditions for achieving satisfactory fault reconstruction are derived using multiple Lyapunov functions. Finally, the practicality and effectiveness of the proposed method are demonstrated through a case study of a buck converter.