Three-Dimensional Velocity Obstacle Method for UAV's Uncoordinated Avoidance Maneuver

This paper proposes a novel avoidance method called the Three-Dimensional Velocity Obstacle (3DVO) method. The method is designed for Unmanned Aerial Vehicle (UAV) applications, in particular to autonomously handle uncoordinated encounters in an integrated airspace, by exploiting the limited space in a three-dimensional manner. The method is a three-dimensional extension of the Velocity Obstacle method that can reactively generate an avoidance maneuver by changing the vehicle velocity vector based on the encounter geometry. Adverse maneuvers of the obstacle are anticipated by introducing the concept of a buffer velocity set, which ensures that the ownship will diverge before the collision. A three-dimensional resolution is generated by choosing the right plane for avoidance, in which the UAV conducts a pure turning maneuver. Implementation of the 3DVO method is tested in several simulations that demonstrate its capability to resolve various three-dimensional conflicts. A validation using Monte Carlo simulations is also conducted in stressful ’super-conflict’ scenarios, which results in zero collisions for the entire set of samples.