This paper deals with the robust fault detection problem in the finite frequency domain for a class of Lipschitz nonlinear systems with uncertain parameters. The design conditions ofH−/L∞fault detection observers are proposed. These conditions make the error estimation system stable, and the residual hasL∞disturbance attenuation performance for external disturbances and uncertain parameters. In addition, considering that fault occurs in the finite frequency domain, the residual also hasH−fault sensitivity performance. To ease of solution, the observer design conditions are further transformed into linear matrix inequalities. On this basis, a dynamic threshold design method based onL∞analysis is presented. Finally, simulation results demonstrate the superiority of the proposed method.
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