論文（査読無） Keiji Kon, Yoshihiro Okumura, Yuji Dohi, Multi-UAV Observation for Tsunami Evacuation Drills, Proceedings of the 17th World Conference on Earthquake Engineering, 5f-0006，7p, 2020.
Evacuation drills are used to assess the behavioral characteristics of people to improve evacuation plans. Therefore, we used an unmanned aerial vehicle (UAV) to record visuals of all scenes of an evacuation drill. However, the requirement for changing batteries of the UAV every 15 min caused a lack of footage during this unrecordable time. Thus, in this research, we propose multi-UAV observations for tsunami evacuation drills to reduce unrecordable time.
UAVs used for shooting can be replaced in several manners. In this research, we use two UAVs, one in a waiting position right above the other, in a shooting position. The UAV at the shooting position leaves for a battery replacement such that it would again be available for shooting. After the UAV reaches far enough from the shooting position, the other UAV at the waiting position heads down to the shooting position.
Two rules for safety are strictly followed: First, an operator does not move their operating UAV without a declaration about the next operation; second, operators use determined declaration statements for all types of operations.
The unrecordable time, T, is divided into three categories: First, t1, the travel time from the shooting position to the safety position for the shooting UAV; second, t3, the travel time from the waiting position to the shooting position for the waiting UAV; and third, t2, the time taken for communication between the two operators. The unrecordable time, T, depends on the distance between the shooting position and the waiting position, and the distance is determined in consideration with safety and effect.
In this research, we established the relation between the unrecordable time and the distance between the shooting and waiting positions by conducting test observations for the distances of 30, 20, 10, and 5 m; the unrecordable time for these distances were found to be 19, 16, 11, and 8 s, respectively. This result is useful for an observer to determine the optimal distance for their observation. In tsunami evacuation drills conducted in Minamiawaji city, we could reduce the unrecordable time from 4 min 30 s with a single-UAV observation in 2017 to 13 s with a multi-UAV observation in 2018.
Keywords: Tsunami evacuation drill, UAV, Unrecordable time, Battery change