We consider transporting a heavy payload that is attached to multiple quadrotors. The current state-of-the-art controllers either do not avoid inter-robot collision at all, leading to crashes when tasked with carrying payloads that are small in size compared to the cable lengths, or use computational demanding nonlinear optimization. We propose an extension to an existing efficient geometric payload transport controller to effectively avoid such collisions by designing an optimized cable force allocation method, and thus retaining the original stability properties. Our approach introduces a cascade of carefully designed quadratic programs that can be solved efficiently on highly constrained embedded flight controllers. We demonstrate our method on challenging scenarios with up to three small quadrotors with various payloads and cable lengths, with our controller running in real-time directly on the robots.

翻译：本文考虑由多架四旋翼协同运输重型载荷的问题。现有最先进控制器要么完全无法避免机器人间碰撞，导致在运输相对于缆绳长度尺寸较小的载荷时发生碰撞事故，要么采用计算量巨大的非线性优化方法。我们提出对现有高效几何载荷运输控制器的扩展方案，通过设计优化的缆绳力分配方法，在保持原有稳定性特性的同时有效避免此类碰撞。该方法引入级联精心设计的二次规划问题，可在高度受限的嵌入式飞行控制器上高效求解。我们通过最多三架小型四旋翼在不同载荷与缆绳长度下的挑战性场景验证该方法，控制器可在机器人本体上实时运行。