An Integrated Approach to Mode Tracking and Diagnosis of Hybrid Systems

In this paper, information from a hybrid bond graph (HBG) model and from discrete-event systems (DESs) is integrated into a fault diagnosis method for hybrid systems. In a pure-HBG framework, mode-change detection and isolation is handled by the mode-change signature and the mode-change signature matrix. In a DES approach, discrete states and faults are traced based on observable events (e.g., control signals) and diagnosers. Based on the two approaches, a new diagnoser that is driven by both observable events and consistency indicators generated by continuous residuals is presented. The proposed method allows not only to effectively trace the system mode but also to decide whether this mode is faulty or normal. The new method is presented and implemented on a testbed. The experimental results presented in this paper demonstrate the effectiveness of the method.