Control of Systems with Actuator Failures

A number of fatal aircraft accidents in recent years have been linked to component failures. With the predicted increase in air traffic these numbers are likely to increase. With reduction of fatal accidents as motivation, the proposal plans to investigate design of fault tolerant control system for aircrafts undergoing actuator failures. The feasible approach for such a control scheme is to predesign various controllers anticipating these failures and switching to appropriate controller when the failure occurs. It is found that use of nominal controller when actuators fail may lead to catastrophic accidents. Switching to an appropriate controller enabled by the available redundancy in actuation allows the system to perform adequately even when these failures occur. However, the predesign for actuator failures is not trivial as the position at which the actuators fail is not known a priori. For linear systems the problem has been solved in recent literature; however failures when they occur can cause excursions into nonlinear regimes. The primary thrust of this research would be to extend the results in nonlinear control theory to accommodate actuator failures in aircraft.