基于精确凸松弛的固定翼无人机实时轨迹规划

This paper investigates the trajectory planning issue for fixed-wing UAVs and proposes a real-time trajectory planning method based on exact convex relaxation. This method includes two steps,i. e. path planning and velocity optimization. In the first step, a flight path of UAV in the multi-obstacle environments is designed. In consideration of the dynamics and control constraints,an obstacle avoidance path planning method based on Dubins path is proposed to generate a flyable obstacle avoidance trajectory. In the second step, the velocity and control of a fixed-wing UAV flying along an obstacle avoidance path are calculated such that it can track the obstacle avoidance path. The nonlinearity retention and exact convex relaxation are used to convert the highly nonlinear velocity optimization problem into one single convex optimization problem, and the validity of the proposed method is theoretically proven. Since there is no iterative process of solving the convex optimization problems,the velocity optimization algorithm does not have convergence issues and has remarkable real-time performance. The simulated results demonstrate that the proposed method can realize obstacle avoidance trajectory planning reliably and rapidly in both multi-obstacle environment and unknown obstacle environment, and it significantly improves the computing efficiency compared with the nonlinear programming and successive convex optimization methods. The calculation time is only tens of milliseconds.