Abstract: Aiming at the flight path planning problem of emergency communication unmanned aerial vehicle (UAV) in complex mountainous environment, by  comprehensively considering the constraints such as obstacles, UAV load and UAV battery capacity, in order to reduce the flight time and extend the flight distance of UAV, based on the framework of Harris hawk algorithm, we designed a three-dimensional path planning method of UAV based on improved Harris hawk algorithm. Firstly, we  improved the initial position of Harris hawk population, position update equation and escape energy of prey. Secondly, the path was smoothed by using cubic spline curve interpolation method to ensure safe, reliable and smooth operation of the UAV during flight. Finally, the emergency UAV was tested in mountainous areas with different obstacles, and the results were compared with the standard Harris hawk, ant colony algorithm and artificial bee colony algorithm. The analysis results show that the path generated by the three-dimensional path planning method planned by this algorithm is shorter and can find the optimal path faster.

Key words: path planning, Harris hawk algorithm, unmanned aerial vehicle, optimal path