Human-robot interaction will play an essential role in various industries and daily tasks, enabling robots to effectively collaborate with humans and reduce their physical workload. Most of the existing approaches for physical human-robot interaction focus on collaboration between a human and a single ground robot. In recent years, very little progress has been made in this research area when considering aerial robots, which offer increased versatility and mobility compared to their grounded counterparts. This paper proposes a novel approach for safe human-robot collaborative transportation and manipulation of a cable-suspended payload with multiple aerial robots. We leverage the proposed method to enable smooth and intuitive interaction between the transported objects and a human worker while considering safety constraints during operations by exploiting the redundancy of the internal transportation system. The key elements of our system are (a) a distributed payload external wrench estimator that does not rely on any force sensor; (b) a 6D admittance controller for human-aerial-robot collaborative transportation and manipulation; (c) a safety-aware controller that exploits the internal system redundancy to guarantee the execution of additional tasks devoted to preserving the human or robot safety without affecting the payload trajectory tracking or quality of interaction. We validate the approach through extensive simulation and real-world experiments. These include as well the robot team assisting the human in transporting and manipulating a load or the human helping the robot team navigate the environment. To the best of our knowledge, this work is the first to create an interactive and safety-aware approach for quadrotor teams that physically collaborate with a human operator during transportation and manipulation tasks.

翻译：人机交互将在各行各业及日常任务中发挥重要作用，使机器人能够有效与人协作并减轻其体力劳动负担。现有物理人机交互方法大多聚焦于人与单个地面机器人之间的协作。近年来，针对具有更高灵活性和机动性的空中机器人的相关研究进展甚微。本文提出一种新型安全人机协作方法，用于多空中机器人系统对缆绳悬挂负载的搬运与操作。我们利用所提方法实现被搬运物体与人类工人之间流畅直观的交互，同时通过利用内部运输系统的冗余性保证操作过程中的安全约束。该系统核心要素包括：(a) 无需任何力传感器的分布式负载外力矩估计器；(b) 用于人-空中机器人协作搬运与操作的六维导纳控制器；(c) 利用内部系统冗余的安全感知控制器，在保证负载轨迹跟踪与交互质量不受影响的前提下，确保执行守护人类或机器人安全的附加任务。我们通过大量仿真和真实世界实验验证该方法，实验场景包括机器人团队协助人类搬运操作负载，以及人类帮助机器人团队导航环境。据我们所知，本工作首次为与人类操作员在搬运和操作任务中进行物理协作的四旋翼机队创建了具有交互性与安全感知的方法。