Online Trajectory Planning for Multiple Quadrotors in Dynamic Environments Using Relative Safe Flight Corridor

This letter presents a new distributed multi-agent trajectory planning algorithm that generates safe, dynamically feasible trajectories considering the uncertainty of obstacles in dynamic environments. We extend the relative safe flight corridor (RSFC) presented in previous work to replace time-variant, non-convex collision avoidance constraints to convex ones, and we adopt a relaxation method based on reciprocal collision avoidance (RCA) to reduce the total flight time and distance without loss of success rate. The proposed algorithm can compute the trajectories for 50 agents on average 49.7 ms per agent with Intel i7 desktop and can generate safe trajectories for 16 agents with a success rate of more than 93% in simulation environments with four dynamic obstacles when the velocity of dynamic obstacles is below the maximum velocity of quadrotors. We validate the robustness of the proposed algorithm through a real flight test with four quadrotors and one moving human.