Aerial unperching of multirotors has received little attention as opposed to perching that has been investigated to elongate operation time. This study presents a new aerial robot capable of both perching and unperching autonomously on/from a ferromagnetic surface during flight, and a switching controller to avoid rotor saturation and mitigate overshoot during transition between free-flight and perching. To enable stable perching and unperching maneuvers on/from a vertical surface, a lightweight ($\approx$ $1$ \si{kg}), fully actuated tiltrotor that can hover at $90^\circ$ pitch angle is first developed. We design a perching/unperching module composed of a single servomotor and a magnet, which is then mounted on the tiltrotor. A switching controller including exclusive control modes for transitions between free-flight and perching is proposed. Lastly, we propose a simple yet effective strategy to ensure robust perching in the presence of measurement and control errors and avoid collisions with the perching site immediately after unperching. We validate the proposed framework in experiments where the tiltrotor successfully performs perching and unperching on/from a vertical surface during flight. We further show effectiveness of the proposed transition mode in the switching controller by ablation studies where large overshoot and even collision with a perching site occur. To the best of the authors' knowledge, this work presents the first autonomous aerial unperching framework using a fully actuated tiltrotor.

翻译：空中多旋翼的脱离相较于用于延长操作时间的栖停研究鲜少受到关注。本研究提出了一种新型空中机器人，能够在飞行过程中自主地在铁磁表面完成栖停与脱离，并设计了一种切换控制器以避免转子饱和并减轻自由飞行与栖停切换过程中的超调现象。为实现垂直表面上的稳定栖停与脱离操作，首先开发了一款重量约1千克、可全向驱动的倾转旋翼机，其能在90°俯仰角下悬停。我们设计了由单个伺服电机和磁铁组成的栖停/脱离模块，并安装于倾转旋翼机上。提出了一种包含自由飞行与栖停间过渡专用控制模式的切换控制器。最后，我们提出了一种简单而有效的策略，以确保在存在测量与控制误差时实现稳健栖停，并在脱离后立即避免与栖停点的碰撞。通过实验验证了所提框架，实验中倾转旋翼机在飞行过程中成功完成了垂直表面的栖停与脱离。进一步通过消融实验展示了切换控制器中过渡模式的有效性，在未使用该模式时出现了大幅超调甚至与栖停点的碰撞。据作者所知，本研究首次提出了基于全向倾转旋翼机的自主空中脱离框架。