Signal Processing Inc., Rockville, MD 20850, USA.
Sensors (Basel). 2019 Jan 9;19(2):227. doi: 10.3390/s19020227.
Preflight contingency planning that utilizes wind forecast in path planning can be highly beneficial to unmanned aerial vehicles (UAV) operators in preventing a possible mishap of the UAV. This especially becomes more important if the UAV has an engine failure resulting in the loss of all its thrust. Wind becomes a significant factor in determining reachability of the emergency landing site in a contingency like this. The preflight contingency plans can guide the UAV operators about how to glide the aircraft to the designated emergency landing site to make a safe landing. The need for a preflight or in-flight contingency plan is even more obvious in the case of a communication loss between the UAV operator and UAV since the UAV will then need to make the forced landing autonomously without the operator. In this paper, we introduce a preflight contingency planning approach that automates the forced landing path generation process for UAVs with engine failure. The contingency path generation aims true reachability to the emergency landing site by including the final approach part of the path in forecast wind conditions. In the contingency path generation, no-fly zones that could be in the area are accounted for and the contingency flight paths do not pass through them. If no plans can be found that fulfill reachability in the presence of no-fly zones, only then, as a last resort, the no-fly zone avoidance rule is relaxed. The contingency path generation utilizes hourly forecast wind data from National Oceanic and Atmospheric Administration for the geographical area of interest and time of the flight. Different from past works, we use trochoidal paths instead of Dubins curves and incorporate wind as a parameter in the contingency path design.
在路径规划中利用风预测进行预先应急规划，对无人机（UAV）操作人员来说可以极大地防止无人机可能发生的事故。如果无人机发动机故障导致所有推力损失，这一点就变得尤为重要。在这种应急情况下，风成为确定紧急着陆点可达性的重要因素。预先应急计划可以指导无人机操作人员如何滑翔飞机到指定的紧急着陆点，以安全着陆。在无人机操作人员与无人机之间的通信丢失的情况下，预先或飞行中应急计划的需求更加明显，因为无人机将需要在没有操作人员的情况下自主进行强制着陆。在本文中，我们介绍了一种预先应急规划方法，该方法为发动机故障的无人机自动生成强制着陆路径。应急路径生成的目的是通过在预测风条件下包含路径的最后进近部分，实现真正到达紧急着陆点。在应急路径生成中，考虑到可能在该区域的禁飞区，并且应急飞行路径不会穿过它们。如果在存在禁飞区的情况下找不到满足可达性的计划，则作为最后手段，才放宽禁飞区回避规则。应急路径生成利用美国国家海洋和大气管理局提供的每小时预测风数据，针对飞行的地理区域和时间。与过去的工作不同，我们使用摆线轨迹而不是杜宾斯曲线，并将风作为应急路径设计的参数。
