Routing and course control of an autonomous sailboat

In this paper, we present a layered control scheme for an autonomous sailboat. The high level control uses a custom cost function with a PRM-Dijkstra algorithm for the routing (global path planning) of autonomous sailboat. This algorithm exploits the sailboat kinematics and wind distribution on a map. For the low level control, we design a new nonlinear course (direction of the velocity vector) controller that exhibits superior performance compared to conventionally used heading controller. A smoothing function is also introduced in the design of the controller to switch easily from course control to heading control, especially when course measurements are noisy at low speed.