Fault Accommodation of Multiple Faults for a Class of Nonlinear Uncertain Systems: A Dynamic Fault Isolation Information Framework

A new fault accommodation scheme is proposed for a class of nonlinear uncertain systems against multiple process faults. Different from the traditional fault detection information triggered static fault accommodation scheme for dealing with single batch of fault, a targeted and dynamic fault accommodation scheme is proposed based on the availability and quality of the fault information extracted by fault detection and isolation modules. A nominal controller is designed to maintain the essential tracking performance before a fault is detected, and it is reconfigured by the adaptive fault accommodation controller after fault detection. To deal with multiple process faults, the fault information acquisition based on fault detection and isolation modules is first formulated by fault isolation modes, including zero fault isolation, partial fault isolation, full fault isolation, missed fault isolation, and initialized fault isolation. With the established fault isolation modes, the dynamic fault accommodation scheme is proposed, where the adaptive fault accommodation controller updates synchronously with respect to the change of the available fault isolation modes. The performance of the closed-loop control system under different fault accommodation scenarios is rigorously analyzed. One example is used to show the effectiveness and properties of the proposed controllers.