The autonomous quadrotor's flying speed has kept increasing in the past 5 years, especially in the field of autonomous drone racing. However, the majority of the research mainly focuses on the aggressive flight of a single quadrotor. In this letter, we propose a novel method called Pairwise Model Predictive Control (PMPC) that can guide two quadrotors online to fly through the waypoints with minimum time without collisions. The flight task is first modeled as a nonlinear optimization problem and then an efficient two-step mass point velocity search method is used to provide initial values and references to improve the solving efficiency so that the method can run online with a frequency of 50 Hz and can handle dynamic waypoints. The simulation and real-world experiments validate the feasibility of the proposed method and in the real-world experiments, the two quadrotors can achieve a top speed of 8.1m/s in a 6-waypoint racing track in a compact flying arena of 6m*4m*2m.

翻译：过去五年中，自主四旋翼飞行器的飞行速度持续提升，尤其在自主无人机竞速领域。然而，现有研究主要聚焦于单架四旋翼飞行器的激进飞行。本文提出一种名为成对模型预测控制（PMPC）的新方法，可在线引导两架四旋翼飞行器在无碰撞前提下以最短时间穿越航点。首先将飞行任务建模为非线性优化问题，进而采用高效的两步质点速度搜索方法提供初始值与参考量以提升求解效率，从而该方法能以50Hz频率在线运行并可处理动态航点。仿真与实际实验验证了所提方法的可行性，在实际实验中，两架四旋翼飞行器在6米×4米×2米的紧凑飞行场地内沿6航点竞速赛道可实现最高8.1米/秒的飞行速度。