Integrated fault-detection and fault-tolerant control of process systems

This work considers the problem of fault-tolerant control of nonlinear processes with input constraints subject to control system/actuator failures, and presents and demonstrates an approach to fault-tolerant control predicated upon the idea of integrating fault-detection, feedback and supervisory control. Specifically, a nonlinear observer is initially designed to generate estimates of the states that are used to implement Lyapunov-based state feedback controllers and a fault-detection filter. The fault-detection filter uses the state estimates to compute the expected closed{loop behavior in the absence of faults, and detects the occurrence of faults by comparing the expected behavior of the process variables with the estimates. A switching policy is then derived to orchestrate the activation/deactivation of the constituent control configurations to achieve fault-tolerant control in the event that a failure is detected. Finally, simulation studies are presented to demonstrate the implementation and evaluate the effectiveness of the proposed fault-tolerant control scheme. Copyright © 2005 IFAC.