1. Department of Mechanical Engineering, University of Ulsan, 93 Daehak-ro, Nam-gu, Ulsan 44610, Republic of Korea
2. Department of Unmanned and Autonomous Engineering, Kyungwoon University, Gumi-si, Gyeongbuk-do 39160 Republic of Korea
3. Unmanned Vehicle Advanced Research Center, Korea Aerospace Research Institute Yuseong-gu, Daejeon 34133, Republic of Korea