This article studies the collaborative transportation of a cable-suspended pipe by two quadrotors. A force-coordination control scheme is proposed, where a force-consensus term is introduced to average the load distribution between the quadrotors. Since thrust uncertainty and cable force are coupled together in the acceleration channel, disturbance observer can only obtain the lumped disturbance estimate. Under the quasi-static condition, a disturbance separation strategy is developed to remove the thrust uncertainty estimate for precise cable force estimation. The stability of the overall system is analyzed using Lyapunov theory. Both numerical simulations and indoor experiments using heterogeneous quadrotors validate the effectiveness of thrust uncertainty separation and force-consensus algorithm.

翻译：本文研究了两架四旋翼无人机协同运输吊索管道的问题。提出了一种力协调控制方案，其中引入力一致性项以平均四旋翼无人机之间的负载分布。由于推力不确定性与绳索力在加速度通道中耦合，扰动观测器仅能获得集总扰动估计。在准静态条件下，开发了一种扰动分离策略以消除推力不确定性估计，实现精确的绳索力估计。利用李雅普诺夫理论分析了整个系统的稳定性。通过数值仿真和使用异构四旋翼无人机的室内实验，验证了推力不确定性分离与力一致性算法的有效性。