基于Sigmoid函数的四旋翼无人机轨迹规划算法

A Trajectory Planning Algorithm for Quadrotor UAVs Based on Sigmoid Function

针对小型四旋翼无人机自主巡航的轨迹规划问题,提出一种基于Sigmoid函数的轨迹规划算法。在给出了一组由无人机必须飞经的路径点所定义的巡航任务的前提下,该算法采用圆滑可导的Sigmoid函数作为位置函数,规划出任意2个路径点之间的状态轨迹。该方法同时保证了光滑可导的速度轨迹函数。基于飞行器的最大速度约束,在相邻的2个路径点的距离小于一定值时还可保证可导的加速度轨迹函数。算法极为简单,可在计算能力有限的微小型无人机驾驶仪上得以实现。在对算法和其有关的性质做出介绍之后,文章还给出了采用典型的小型四旋翼无人机动态模型和控制算法对该算法制定的飞行轨迹进行跟踪飞行的仿真结果,证实了该算法的可行性、有效性和实时性。

For the autonomous navigation of quadrotor UAVs, this paper proposes a sigmoid function-based trajectory planning algorithm. Given a mission task specified by a set of predefined middle-way points the UAV has to fly pass, this approach applies the smooth and derivable Sigmoid function as the position function, and therefore determines the state trajectories between those midway points. The approach guarantees the smoothness and derivability of velocity functions. In the case where the distance between two midway points is smaller than a critical value, it also guarantees the derivability of the acceleration function. The algorithm is very simple and hence can be easily implemented on the autopilot of the small quadrotor UAV which usually has limited computing power. After giving a systemic introduction of the algorithm and its properties, the simulation results obtained by means of applying the dynamic model and tracking control scheme of a quadrotor UAV are presented, showing the effectiveness, feasibility and real-time feature of the algorithm.