Study On Unmanned Aerial Vehicle Path Planning

With the increasing use of unmanned aerial vehicle(UAV) in military and civilian fields, UAV flight path planning attracts the attention of scientific researchers from all countries. With the development of computer technology and aerospace technology, UAV path planning system plays an important role in the process of UAV combat mission.UAV path planning, the key component of UAV mission planning system, is to plan the flight path under some constraints. This paper mainly studies some key issues, including off-line path planning, on-line path re-planning with unexpected situations, and cooperative path planning for UAVs.Firstly, in terms of off-line path planning, the original RRT algorithm is improved using heuristic direction enhancement, which makes random trees easy to extend in the direction of target, and makes the search range smaller and the path shorter and better. Then in terms of the timeliness requirements of on-line path planning we introduce threat probability method to simulate threatened areas, which makes the random tree extend in the direction of the lower threat probability. It ensures that the UAV can be able to react immediately and avoid threat area in case of emergency. The UAV can also pass through the threatened area according to mission requirements when necessary. In the end,two-stage planning method is used to solve the problem of cooperative path planning for multiple unmanned aerial vehicles. By analyzing limitations of existing methods, we put forward an improved method, which greatly retained optimal paths without establishing alternative path set at the same time, thus being able to re-plan timely when faced with emergency.Simulation experiments were carried out in MATLAB, the results of which show that the proposed methods in this paper are practical.