Robust fault diagnosis algorithm for a class of Lipschitz system with unknown exogenous disturbances

A robust fault diagnosis scheme for nonlinear system is designed and a novel algorithm for a robust fault diagnosis observer is proposed in this paper. The robustness performance index is defined to ensure the robustness of the observer designed. The norm of most unknown input disturbances are assumed bounded at present. However, some systems are proved unstable under traditional assumptions. In the proposed algorithm, the external disturbances constraint condition that satisfies the system stability is derived based on Gronwall Lemma. The design procedure of the observer proposed is implemented by pole assignment. Adaptive threshold is generated using the designed observer. Simulations are performed on continuous stirred tank reactor (CSTR) and the results show the effectiveness and superiority of the proposed algorithm.