Active Fault-Tolerant Control of Thrust Reallocation for DEP-AAV

The multiple motors in a distributed electric propulsion (DEP) system improve the aerodynamic performance of autonomous aerial vehicles (AAVs) and introduce additional redundancy, enabling fault-tolerant operation. This paper proposes an active fault-tolerant control (AFTC) method for DEP-AAVs that reallocates thrust among the distributed motors after partial propulsion motor failures. The proposed method helps to alleviate limitations of existing fault-tolerant control (FTC) approaches for DEP-AAVs, where centralized algorithms suffer from high computational complexity and the task-level formulation after faults is often incomplete, lacking an explicit integration of flight tasks and motor thrust safety constraints. The thrust reallocation problem is formulated as a convex optimization problem with consistency constraints, and the problem is solved in a distributed manner using the alternating direction method of multipliers (ADMM). Together with thrust-smoothing penalties, cruise speed regulation and yaw angle tracking are embedded in the optimization problem as control objectives, which enables parallel updates of local thrust commands while maintaining consistency through multiplier variables. The performance of the proposed method has been validated through hardware-in-the-loop (HIL) experiments on a DEP-AAV platform. HIL experimental results show that the proposed method achieves smaller post-fault airspeed deviations than the existing passive fault-tolerant control (PFTC) and AFTC methods, reducing the cruise-task airspeed excursion by about 30 % and more than 50 %, respectively, while maintaining a real-time average computation time of approximately 0.75 ms.