On the sea trial test for the validation of an autonomous collision avoidance system of unmanned surface vehicle, ARAGON

ARAGON is an unmanned surface vehicle (USV) for ocean observation and sea surveillance of Korea Research Institute of Ships and Ocean Engineering (KRISO). It has been constructed through the research and development project, which is entitled with "The development of intelligent unmanned surface vehicle for multipurpose mission of ocean observation and sea surveillance" under the financial support of Korea Ministry of Oceans and Fisheries since 2011. Now, it is the final eighth fiscal year of the project. The length of ARAGON is about 7.5 meter and its maximum speed is over 40 knots. ARAGON has 400-HP diesel engine with single water-jet. In order to make USV navigate safely according to the convention on the international regulations for preventing collisions at sea, 1972 (COLREGs) without human operation, autonomous navigation system is needed. A collision avoidance system is developed by using changeable action space searching. Action space can be flexibly changed according to the collision risk, which is estimated by using obstacle information on a basis of fuzzy inference. Navigational information of USN' such as position, speed, course and attitude are acquired by using real-time kinematic (RTK) GPS and Integrated Navigation System (INS). Obstacles can be detected and tracked by using multi-sensors fusion of automatic identification system (AIS), Pulse radar, light detection and ranging (Lidar) and EO/IR (Electro Optical/Infra-Red) camera. Optimal route for collision avoidance is estimated according to the cost functions related to collision risk in real-time. Autopilot and speed controller is actuated for the following to the optimal route. In order to evaluate the performance of autonomous navigation of ARAGON, field tests are carried out in actual sea area, Busan on the complicated colliding situations such as head-on, crossing and overtaking with multiple obstacles. Three physical powerboats are used as moving obstacles in the colliding situation of head-on, port-crossing and starboard-crossing. Two virtual boats are used as moving obstacles in the colliding situation of the 2nd head-on and overtaking. In this paper, the main features of ARAGON and main results of field test are described.