基于改进A^*算法的无人机快速轨迹规划方法

针对旋翼无人机在三维障碍物环境中自主飞行时路径搜索速度慢、轨迹生成通常忽略无人机动力学特性的问题,发展一种基于改进A^*算法并同时考虑无人机动力学特性和运动学性能的快速轨迹规划方法。首先,在三维障碍物环境中运用改进A^*算法通过剔除部分网格节点降低A^*算法的节点计算量,提升算法的路径搜索速度;其次,以最小化飞行轨迹的四阶导数作为目标函数,以路径点处的位置、速度、加速度等各阶导数作为约束条件优化飞行轨迹;最后,在三维障碍物环境中对比A^*算法改进前后的路径搜索结果,并对优化的飞行轨迹进行仿真飞行测试。结果表明:改进A^*算法大幅降低了A^*算法的节点计算量,显著提升了路径搜索速度;且无人机能够始终以较小位置误差沿优化轨迹光滑连续飞行。

Rapid trajectory planning method of UAV based on improved A^*algorithm

Aiming at the problem that the path search speed is slow and the trajectory generation usually ignores the dynamic characteristics of the UAV when the UAV is flying autonomously in the three-dimensional environment with obstacles.A fast trajectory planning method based on improved A^*algorithm and considering both dynamic and kinematic characteristics of UAV is developed.Firstly,the improved A^*algorithm is used in the three-dimensional obstacle environment to reduce the node calculation amount of the A^*algorithm by eliminating some grid nodes,and the path search speed of the algorithm is improved.Secondly,the fourth derivative of the flight trajectory is minimized as the objective function,and the position,velocity and acceleration at the path points are used as constraints to optimize the flight trajectory.Finally,the path search results before and after the improvement of A^*algorithm are compared in three-dimensional obstacle environment and the optimized flight trajectory is simulated and tested.The results show that the improved A^*algorithm greatly reduces the amount of node calculation of A^*algorithm,which significantly improves the speed of path searching,and the UAV can fly smoothly and continuously along the optimized trajectory with a small position error.