Intermittent Sensor Fault Detection for a Class of Nonlinear Systems via Predefined-Time Observer

This article is concerned with the problem of intermittent fault detection for a class of nonlinear systems through observer-based methods. Different from the permanent fault detection, this article devotes to detecting both the appearance and disappearance of intermittent faults, which has strict requirements on the convergence property of the observation error. A predefined-time observer is designed for sector-bounded nonlinear systems to guarantee that the observation error reaches stability within a preset time. Using the implicit Lyapunov function method and the homogeneity theory, some linear matrix equations and inequalities are derived to solve the observer gain such that the observation error system is input-to-state stable. Then, the residual is generated and evaluated to detect the fault. Finally, the feasibility and effectiveness of the proposed approach are verified by an experiment on the prototype of rotary steerable drilling tool system.