A Raycast Approach to Collision Avoidance in Sailing Robots

This paper presents a simple mechanism for an autonomous sailing robot to detect when it is within close proximity to fixed obstacles and a reactive mechanism to avoid those obstacles. This is achieved by using a raster based map of the local area and raycasting from the boat's current position in order to determine the distance and heading to the nearest coastline. Once this is determined a new target heading which does not result in any immediate danger is computed. Simulations have shown that it is possible for a robot to sailing between a set of waypoints while avoiding obstacles placed between those waypoints. This method has been shown to be capable of selecting a sensible course and avoiding collisions in most cases, however when the robot becomes trapped in small inlets or between groups of tightly packed islands it can fail to find a suitable course.