Adaptive fault diagnosis observer design for linear system with separated faults and disturbance

In this paper, we propose a fault detection observer (FDO) and an adaptive fault diagnosis observer (AFDO) for linear system with separated faults and disturbance. First, the FDO, which is designed by using the characteristic of output error, determines that the actuator and/or sensor faults have occurred when the output error is more larger than the given error boundary. Second, the AFDO which estimates that the actuator and/or sensor faults when the FDO alerts faulty situation, is designed by using both the Lyapunov analysis and LMI methods. Using Lyapunov stability analysis, we also prove the uniformly boundedness of the state, output and fault errors for the constant and time-varying faults. Finally, we illustrate the effectiveness of the proposed diagnosis method thorough simulation.