Preserving Full 6-DOF Actuation Under Abrupt Total Rotor Failures: Passive Fault-Tolerant Flight Control Using a Biaxial-Tilt Hexacopter

Abstract:Abrupt total rotor failures can invalidate nominal allocation despite remaining wrench capability. This paper develops an allocator-layer passive fault-tolerant control (AL-PFTC) scheme for overactuated vector-thrust aerial vehicles. Analysis of convexified attainable force and torque spaces at horizontal hover compares biaxial- and uniaxial-tilt configurations and screens fault cases using prescribed reserve thresholds. Instantaneous wrench loss relative to these reserves characterizes the initial redistribution burden. AL-PFTC adapts the allocation matrix using a virtual error derived from filtered wrench commands and an onboard external wrench estimate, with adaptive parameter bounds constructed from right inverses. Joint analysis including estimator residuals and filter dynamics establishes local uniform ultimate boundedness for position and attitude regulation under the stated conditions. Controller-layer passive fault-tolerant control (CL-PFTC) provides a reference with nominal allocation and observer compensation. Both share a nominal tracking baseline and run at 600 Hz on an STM32H753 without explicit fault identification, fault-mode switching, or online optimization. Comparisons show that AL-PFTC satisfies the recovery criterion in more tested hovering cases than CL-PFTC. Additional experiments using only onboard sensing, including indoor tracking under wind disturbance, outdoor tracking under wind and low-temperature conditions, narrow-frame traversal, and contact-based aerial writing, further validate the robustness of AL-PFTC in complex operational environments.

Robotics (cs.RO)

arXiv:2606.05663 [cs.RO]

(or arXiv:2606.05663v2 [cs.RO] for this version)

https://doi.org/10.48550/arXiv.2606.05663 Focus to learn more arXiv-issued DOI via DataCite

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