Isolation and Handling of Sensor Faults in Nonlinear Systems

This work considers the problem of sensor fault detection and isolation (FDI) and fault-tolerant control for nonlinear systems subject to input constraints. The key idea of the proposed method is to exploit model-based sensor redundancy through state observer design. To this end, an output feedback control design using high-gain observers is first presented. An FDI scheme that utilizes the enhanced applicability of the observer design is then proposed, which is composed of a bank of high-gain observers. Upon FDI, the state estimate generated using measurements from the healthy sensors is used to preserve practical stability of the closed-loop system. The implementation of the FDI and fault-handling framework is illustrated using a chemical reactor example.