A Collision Avoidance System Based on COLREGs Rules for Autonomous Surface Vessels

Abstract

In this study, a proposed mathematical model consists of two parts, one is the maneuvering model, called MMG (Mathematical Model Group), and the other is a control algorithm based on traditional PD control system. The MMG model is used to compute the ship's maneuvering characteristics, and a ship can safely reach target coordinates with the help of a control algorithm if it encounters any obstacles along the way. Because of the suitable hydrodynamic coefficients of Esso Osaka, the proposed mathematical model is evaluated using trial test data from Esso Osaka. Firstly, the maneuvering characteristics of the ship were determined by performing the turning and zigzag tests for different velocity of the ship. By comparing the results obtained with the trial test results of the Esso Osaka, the suggested model was verified. Secondly, the ship's route was obtained for a determined target coordinate. Thirdly, a new route is automatically obtained by assuming that there is an obstacle between the starting point of the ship and the target coordinate determined for the previous simulation. As a result, this new route is created thanks to the virtual coordinates determined in accordance with the COLREGs rules. Since the maneuvering characteristic values of the ship are included in the written algorithm, it directly affects the determination of the virtual coordinates. Therefore, it is very important to find accurate maneuvering characteristics. Evaluating the simulation results obtained from the proposed mathematical model, it is concluded that a safe route has been created between the coordinates determined for the Esso Osaka ship. Moreover, the ship reaches the target coordinate without any collision.