Fault Tolerant Control of Tilt-rotor Aircraft Based on Adaptive Control Allocation

The growing deployment of unmanned aerial vehicles (UAVs) require robust fault-tolerant control (FTC) strategies to ensure stability under actuator failures. This paper proposes two passive adaptive control allocation (CA) methods for overactuated tilt-rotor aircraft to achieve 6-degree-of-freedom (DOF) trajectory tracking under actuator failures without explicit fault detection. A hierarchical framework integrates a backstepping controller for disturbance rejection with adaptive CA laws that dynamically update the allocation matrix solely through aerodynamic wrench estimation. Comparative simulations validate both methods, with the discrete CA method demonstrating superior robustness: When three thrust vectoring units completely fail, it confines transient errors to 11.37 cm in position and 3.83° in attitude. The strategy demonstrates portability to other overactuated systems and resilience to disturbances.