Online speed optimization with feedforward of unmanned sailboat via extremum seeking without steady-state oscillation.

Concentrated on the problem of steady-state oscillation of the traditional extremum seeking algorithm (ESA) that it is not beneficial to the speed optimization of unmanned sailboat, a novel speed optimization scheme with feedforward of unmanned sailboat via extremum seeking without steady-state oscillation (ESWSO) is proposed. This scheme consists of feedforward and feedback control: the feedforward part firstly presets the initial sail angle of attack according to an approximate piecewise constant function of the sailing speed polar diagram, its main function is avoid the large deviation of the longitudinal speed from the optimal value. Subsequently, the feedback part fine-tunes the speed to reach the optimal value through the extremum seeking (ES) control. In the process of continuously optimizing longitudinal speed, a functional relationship between the excitation signal amplitude and the extremum estimation error is constructed to eliminate the steady-state oscillation. Besides, the rigorous stability Proof of the scheme is given. Finally, taking a 12-m class unmanned sailboat as the simulation object, the results show that the optimization scheme can effectively eliminate steady-state oscillation and enable the sailing speed to reach the ideal optimal value, as well as has a high control accuracy and strong robustness. • A novel speed optimization scheme of unmanned sailboat via extremum seeking is proposed. • This scheme effectively overcomes the problem of steady-state oscillation. • This scheme is strong robustness with external perturbation. • This speed optimizer has higher control accuracy. • The unmanned sailboat accurately reaches the ideal optimal speed value. [ABSTRACT FROM AUTHOR]