Autonomous Sailboat Track Following Control

The research for unmanned autonomous sailing control has been developed for a period of time. At the end of the 20 th century, fuzzy logic control theory began to be applied on sailboat automatic control. Over the past 20 years, fuzzy logic has made considerable progress both in theory and technology. It has become one of the very fruitful branches in field of automatic control. But among the research articles which applied fuzzy logic theory to sailboat control, few articles including scientific and systematic model ship experimental verification can be found. Fuzzy logic automatic sailing control is still in the early stage and has not become maturational yet. The researchers still need to devote a lot of work.The research target of this paper is to realize the automatic control of sailboat and make the sailing yacht have the ability to follow a designated route. That is, the aim of the thesis is to develop an unmanned sailing control system for track following. The research results of this paper have several aspects of application significance. First of all, the track following control system can be applied to unmanned sailing boat which can do the task of ocean surface data acquisition. The unmanned sailboat may work in dangerous environment without any crew. And the autonomous sailboat use wind as its main energy, which is clean and good to environmental protection. Using wind energy makes the navigation time not restricted from onboard power capacity, which can extend the time of sailing. Second, automatic sailing control system can be applied to private sailing yacht as the auxiliary driving equipment of the crew, which can relieve the fatigue feeling of the sailors in a long voyage. In addition, it can also be applied to the indoor sailing training simulation station.In this paper, a track following controller for autonomous sailboat is developed on the basis of existing literature. The control system in the thesis has much innovative points. It includes three sub modules, namely, local path strategy module, rudder automatic control module and sail automatic control module. Local path strategy control module calculates the turning point and the time to execute rudder. At the same time, it also decides whether to change the sailing path when the sailboat is in the forbidden area against the current wind. Rudder control bases on fuzzy logic theory. The rudder automatic control module use speed heading error, yaw rate and the laterally vertical distance deviation as three input variables. And it includes 245 fuzzy logic rules which are based on the steering experience of sailors. This control module adds an integral control to eliminate steady error. Sail control module uses the relationship between sail angle and apparent wind to build the controller.This thesis establishes a 4-DOF mathematical motion model of sailing yacht in order to do simulation experiment and correct the controller to achieve better effect. In addition, this paper also carries out ship model experiments to validate the feasibility of the track following control system. The 1.5 meters long sailing yacht model used in this ship model experiment is designed by the author independently. Both simulation test and ship model experiment get good results finally that proves the validity of the control program. Data of simulation test and ship model experiment are recorded in this paper for analysis. The thesis puts forward the future study direction and possible methods.