基于速度障碍法和动态窗口法的无人水面艇动态避障

Dynamic obstacle avoidance for USV based on velocity obstacle and dynamic window method

速度障碍法是一种普遍应用在无人水面艇(unmanned surface vehicle,USV)上的动态避障方法,但传统的速度障碍法未考虑无人水面艇运动学性能与障碍物运动信息误差的影响,也未明确何时开始避障与结束避障.在速度障碍法的基础上,用椭圆表示无人水面艇与障碍物,给出一种求解椭圆切线的方法;将动态窗口法与速度障碍物法相结合,考虑无人水面艇的运动学性能,只使用无人水面艇在给定时间内能到达的速度和方向进行避障计算;通过比较碰撞时间与无人水面艇避开障碍物所需的时间来确定何时开始避障,并提出一种结束避障的判断方法;为了减小障碍物运动信息误差的影响,提出了一种虚拟障碍物方法.最后,通过仿真实验验证了该避障方法的可行性与有效性.

Velocity obstacle is a dynamic obstacle avoidance algorithm widely used on an unmanned surface vehicle （USV）. However, traditional velocity obstacle does not consider the effect of USV＇s kinematics and obstacle＇s motion information error, and does not know when to start and terminate avoidance. Based on velocity obstacle, USV and obstacle are represented by an ellipse. A method for solving ellipse tangent is proposed. Considering the kinematics performance of USV, a dynamic window method and velocity obstacle are combined. Only the speed and course that the USV can reach in a given time axe used in calculation. By comparing the collision time and the time required for the USV to finish avoidance to determine when to start avoidance, a method to terminate obstacle avoidance is proposed. A virtual obstacle method is then proposed to reduce influence of obstacle＇s motion information error. Feasibility and effectiveness of the method are verified by simulation.