Research On Path Planning For Sailboat Racing Based On Fuzzy Logic And Evolutionary Algorithms

Like many sporting contests, sailboat racing carries with it a high degree of uncertainty. Since sailboats exploit the wind for their speed, a major source of uncertainty lies in the behavior of the wind. Besides, it has to compensate for stochastic disturbances acting upon it, such as wind, waves, and currents. Sailboat racing is a professional sport requiring the best velocity in giving voyage. So, path planning is an important link for the sailboat racing. To instruct the yachtsmen or yachtswomen selecting an optimal sailing route according to complex marine environments, it becomes an important research topic to develop an ancillary sailboat training system based on modern information technology and intelligent control methods. That system will not only improve the scientific training of sailing race as well as the athletes' scores but also enhance the research of perplexing intelligent system.With a view to optimal theory, optimum path planning for sailboat racing is an optimal question of a variable, nonlinear, and restricted system. It includes several interrelated research problems, such as mathematical models, sailing strategies, heading control, and heading decision of a training sailboat.Supported by the National Natural Science Foundation of China (NSFC), the research topic of this paper has been focused on the study of optimum path-planning algorithms for sailboat racing based on fuzzy logic and evolutionary. The main contributions of this paper include the following aspects:1. The theories of sailboat steering are recapitulated, the disturbance of sailboat steering is analyzed, and the mathematical models of the disturbance are established. All the work above is the basis of fuzzy adaptive controller design and path planning simulation.2. The optimal control strategies for sailboat navigation are proposed for trimming sail and select optimal heading by analyzing forces on the sailboat and movement status. Compare with wind, the applied forces acting upon sailboat of wavesand currents are small. A constrained nonlinear multivariable function on minimum navigation time during a certain sailing distance was put forward neglecting the disturbances caused by waves and currents. Given a different wind angle, the best heading angle and trimming angle of sails were found using optimal method, when the constrained nonlinear multivariable function get its minimum value. Several sailing strategies of optimal routing for sailboats to navigate are summarized, according to the optimal results. All the sailing strategies got of this part work are the essential necessary conditions for fuzzy adaptive controller design and path planning algorithms.3. A new fuzzy adaptive control method based on Sugeno fuzzy model is proposed for the nonlinear and time-variant navigation system of sailboats. It combines good merits of fuzzy logic and neural network. The controller uses Sugeno fuzzy model to divide the nonlinear control system into several local linear models, based on which several local linear controllers are constructed. The global control output can be obtained by combining all the local linear controllers' output. The system has high intelligent and adaptability by using linear neuron network to adjust coefficients of each Sugeno fuzzy model. Simulation results show that this method can efficiently implement autonomous navigation of sailboats. This autopilot of a sailboat will be used to simulate a helmsman in path planning simulation.4. Heading decision modeling for optimal path planning is proposed based on fuzzy logic and comprehensive evaluation concept. It uses dynamic programming method to set up the two-dimension moving information for sailing and puts forward a sailing membership function, describing its position and heading information, which relative to the end point. Moreover, it sets up a comprehensive evaluating function concerning the sailing velocity and the sailing membership function. Last, The optimum heading is obtained by finding the minimum of the comprehensive evaluating function with the limiting condition of sea-route width. The heading decision modeling is the basal theory for path planning.5. Path planning is an important link for the sailboat racing. An optimal path-planning algorithm is proposed for straightway sailing race based on evolutionary programming theory. First, an optimal path-planning algorithm based on dynamic programming is researched. Then, to solve the problem of the low convergence of dynamic programming algorithm, an optimal path-planning algorithm based on evolutionary programming theory is proposed. The evolution programming wasembedded in local search to improve the optimization performance and enhance the fast convergence of dynamic programming algorithm. The heading decision with the restriction of sea—route width is transformed into unconstrained nonlinear programming problem by using the penalty function. By compare the simulation results of two path planning algorithm. It indicated the effectiveness and the applicability of the evolutionary programming-based path-planning algorithm.6. From the engineering realization, a training monitoring system of sailboat racing is proposed. It uses GPS, GIS, wireless data transfer, and serial data transfer technologies to realize the real time detection and monitoring of practical sailing route. Therefore, with the using of this system, the path planning algorithms proposed in this thesis can be utilized to improve the scientific training of sailing race.The conclusions and directions for future research work are discussed in the last chapter of this paper.