Simulations of Fault-Adaptive Control

Abstract

The objective of this work is to detect failures in a vibration control system and adapt the control system in order to maintain optimal performance. Fault detection and isolation (FDI) filters, which are a subset of state observers specifically designed to detect and identify known types of system failures, are used to detect sensor and actuator malfunctions. The output of such filters is used to reconfigure feedback compensators in order to maintain closed loop objectives. Such reconfiguration allows the system to continue operating optimally under certain system failures. Simulations have been performed for vibration control of a simply supported beam. The simulation is allowed to “fail” in certain pre-defined ways. FDI filters designed to detect these failures operate in parallel with the compensator. When a failure occurs the FDI filter output is used to switch to a new compensator that is appropriate for the new system condition. There are several challenges inherent in this effort but the most important is the management of compensator switching. Since switching involves system discontinuity, therefore stability of the system is very difficult to guarantee. Even if the plant and compensator are dissipative, stability cannot necessarily be proven. Simulation results will demonstrate some of these challenges and the effectiveness of this approach for maintaining suitable closed loop performance in the presence of system failures.