Using multiple UAVs to manipulate the full posture of an object is a promising capability in many industrial applications, such as autonomous building construction and heavy-load transportation. Among various methods, manipulation via cables excels in mechanical simplicity and ease of use, but is challenging from a control perspective. Existing centralized control methods either neglect the dynamic coupling between UAVs and the load or resort to a cascade structure, which limits the operational speed and cannot guarantee safety. In this work, we propose a centralized control method that uses nonlinear model predictive control. This control method takes into account the full nonlinear model of the load-UAV system, as well as the constraints of UAV thrust, collision avoidance, and ensuring all cables are taut. By taking into account the above factors, the proposed control algorithm can fully exploit the performance of UAVs and facilitate the speed of operation. We demonstrate our algorithm through 6-DoF simulations to achieve fast and safe manipulation of the pose of a rigid-body payload using multiple UAVs.

翻译：利用多架无人机操控物体的完整姿态，在许多工业应用中（例如自主建筑施工和重载运输）是一项具有前景的能力。在各种方法中，通过绳索进行操控在机械简单性和易用性方面表现出色，但从控制角度来看颇具挑战性。现有集中式控制方法要么忽略了无人机与负载之间的动态耦合，要么采用级联结构，这限制了操作速度且无法保证安全性。在本工作中，我们提出了一种基于非线性模型预测控制的集中式控制方法。该控制方法考虑了负载-无人机系统的完整非线性模型，以及无人机推力约束、避碰约束和确保所有绳索保持张紧的约束。通过考虑上述因素，所提出的控制算法能够充分利用无人机的性能并提升操作速度。我们通过六自由度仿真验证了该算法，实现了多架无人机对刚体负载位姿的快速且安全的操控。