Design of Fault Detection and Isolation Filter for Switched Control Systems Under Asynchronous Switching

The problem of fault detection (FD) and isolation, in the presence of disturbances and noise, for continuous-time linear switched control systems is addressed in this paper. The residual generator is proposed, which is based on asynchronously switching filters, where asynchronous means that there is a lag between switching of filters and subsystems. To address the issue, the FD filter problem is formulated as a mixed H-/H-infinity filtering problem. In the proposed H-/H-infinity technique, residual is generated such that it is sensitive to faults and robust against process disturbances and measurement noise. In addition, the proposed filter has prominence of granting fault isolation capability along with FD. To deal with the major issue of asynchronous switching, during matched and unmatched time of switched systems, a piecewise Lyapunov function along with average dwell time scheme is employed, and sufficient conditions are derived in terms of linear matrix inequalities. To simplify the application procedure, an algorithm is also presented in the light of the proposed framework. Then, a solution is designed for two different case studies of highly maneuverable aircraft technology and boost-buck power converter. Finally, the designed filter parameters are simulated to illustrate the efficacy of the proposed framework.