Joint Trajectory Planning for Multiple UAVs Target Tracking and Obstacle Avoidance in a Complicated Environment

In scenarios where multiple UAVs need to collaborate in ground target tracking tasks within obstacle-dense environments, the obstacle avoidance ability may be insufficient. To address this challenge, we propose a joint trajectory planning algorithm for multiple UAVs, enabling them to simultaneously track targets and avoid obstacles using the null-space method. First, Lyapunov guidance vector field is used to obtain the target tracking velocity command for UAVs when they perform standoff tracking to the ground target coordinately. Obstacle model and artificial potential field function for obstacle avoidance are established, and the obstacle avoidance velocity command for UAVs is obtained by using artificial potential field method. Second, based on the null-space method, the obstacle avoidance task is set as a high-priority task, and the integrated UAV velocity command is obtained through the joint trajectory planning method, which projects the target tracking velocity command into the null-space of the obstacle avoidance task and then adds it to the obstacle avoidance velocity command. Through simulation analysis, the effectiveness of the proposed method is verified. Simulated results show that the proposed joint trajectory planning method can plan effective trajectories for multiple UAVs in real time in complex environments with dense obstacles, and ensure that UAVs avoid dense obstacles and maintain target tracking with good coordination between UAVs. © 2023 China Ordnance Society. All rights reserved.