基于时间约束的无人机避障研究

Study on collision avoidance for UAV based on the time constraint

对无人机避开障碍物这一热点问题展开了研究。在极坐标系下,基于无人机与障碍物之间的几何关系,建立了无人机与障碍物之间的运动学方程。通过设计滑模变结构有限时间收敛制导律,使连接无人机与避障点的视线角速率快速收敛到零,相对速度方向收敛到期望的避障方向,保证了无人机能够顺利避开运动障碍物。通过有限时间收敛分析,得到了相对速度收敛到期望的避障方向时间与制导律参数的表达式。通过选择合适的参数,可使收敛时间小于到达避障点的时间,保证了避障的完成,也确定了制导律参数的取值范围。最后对设计的避障算法进行了仿真,仿真结果验证了算法的有效性。

This paper studies the hot issue of the UAV to avoid obstacles. Based on the geometric relationship between the UAV and the obstacle,we obtain the kinematics equations between the UAV and the obstacle in the polar coordinate. Under the sliding-mode variable structure finite-time convergence guidance law,the angular rate of the sight line that connects the UAV with the collision avoidance point converge to zero,meanwhile the angle of the relative velocity converges to the required angle of the collision avoidance vector,so the UAV can avoid the obstacles successfully. By analyzing the convergence time,we get the equation of the convergence time with the guidance law parameters. So we can chose the appropriate parameters to make the convergence time be shorter than the time that the UAV reaches the obstacle,and also obtain the range of the parameters. Finally,we make the simulation of the algorithm,and the results show the effectiveness of the algorithm.