Optimal sail angle computation for an autonomous sailboat robot

A method to compute the optimal sail angle for an autonomous sailboat is proposed, which allows for maximizing the longitudinal velocity while maintaining safe sailing conditions by limiting the roll angle. A simplified 4-DOF dynamic model of the sailboat is used to obtain the roll dynamics and longitudinal sail force. From these expressions, we derive a cost function which depends on the thrust force. The cost needs to be minimized under stability constraint in roll motion while the system is subject to a bound on the roll angle. Numerical simulations, using a full nonlinear dynamic model of the sailboat, show the improved performance of the proposed method, compared to traditional solutions that can be found in the literature.