Reconfigurable dynamic control allocation for aircraft with actuator failures

ABSTRACTIn this paper, the development of a fault-tolerant control system for an aircraft that exploits both the hardware and analytical redundancy in the system is considered. A control allocation approach is developed where the total control command is computed and distributed among the available control surfaces. The actuator’s position and rate limits are taken into account in the optimisation problem. Existing fault-tolerant control allocation techniques produce look-up tables of control gains based on certain faults in the model. In contrast, the developed reconfigurable approach presented here incorporates a new process that redistributes control efforts which is updated whenever a fault occurs. In order to correlate between control effort redistribution and the fault magnitude, a fuzzy logic scheme is implemented, which handles a wide range of fault magnitudes on-line. The approach is applied for the most severe type of fault, which is the “lock-in-place” (jam) fault. Results show that the developed approach successfully handles the faulty situations and enhances aircraft flying responses by utilising the available healthy controls.