| Unmanned Surface Vehicle(USV) as a self-propelled vehicle has the advantages of small volume, high speed and intelligently control. As equipped with radar, sonar, the camera, some small arms and some other equipment, USV can complete the collection and dissemination of information, monitoring ocean conditions, topographic survey, search and rescue, detection, navigation, combat and some other tasks. With the increase of function of USV, it has been widely applied in military and civilian fields. Studying the rapidity performance, seakeeping performance, maneuverability performance and overturning resistance performance of USV is very important for the boat type design and analysis of fluid dynamics performance. And the optimization design of the comprehensive performance for USV has an irreplaceable role in the design and research of USV, which has been attracting more and more attention from the countries home and abroad.A new type of high-speed unmanned Surface Vehicle has been set as the research object. Finally, the mathematical model of comprehensive optimization of performance for such new type of USV has been established considering rapidity performance, seakeeping performance, maneuverability performance and overturning resistance performance. Finally,a integrated optimization software has been designed based on different optimization algorithms for this kind of high-speed USV through combining the mathematical model with optimization algorithm. The specific research steps are summarized as follows:1.Select an planing boat equipped with splash proof strip and hydrofoil as a research object. Some geometric models have been created, according to the size of splash proof strip,the size of the hydrofoil, the position of hydrofoil and different parameter of planing boat,which are used for grid generation and drag calculation through a software of NUMECA to construct database of resistance of this boat. And the hydrodynamic performance of different hull parameters have been compared and analyzed. Researches show that the hydrofoil and splash proof strip both can increase the lift force of ship, which can made the ship into planing state faster. While the hydrofoil and splash proof strip can improve the resistance performance of ship.2.According to the data of CFD calculation, the fitting formulas of polynomial response surface of total resistance of hull, friction drag, lift force, static wet area and static displacement of this boat have been obtained by using polynomial response surface method,which provide the foundation for the establishment of optimization mathematical model.Some design variables have been selected, admiralty coefficient has been chose as evaluation function of rapidity, and some constraint conditions have been established to construct the optimization mathematical model of rapidity performance finally.3.Based on the program design ideas of system identification theory and many kinds of optimization algorithm, identification software has been designed and created which can identify rotational motion, Z motion and rolling motion, and combined with the experimental data obtained from the maneuverability experiments, some identifying computation have been carried out to get the objective function of maneuverability performance. Some design variables have been selected, three evaluation functions including linear stability criterion, minimum relative turning diameter and index of ship’s head variation have been chose as objective functions, and some constraint conditions have been established to construct the optimization mathematical model of maneuverability performance finally.4.Some rolling motion experiments of this boat have been carried out, and then experimental data have been identifying computed and analyzed through identification software, which got better rolling motion equation, and also verify the reliability of identification algorithm in the software. The fitting formulas of pitch values and heave values of ship have been obtained by using the response surface method to realize the forecast of pitch values and heave values of ship. Considering the effect of pitching, heaving and rolling, three evaluation functions including dimensionless attenuation coefficient, pitch values and heave values have been selected as the objective function of the seakeeping performance to construct the optimization mathematical model of seakeeping performance.The stability of the ship has been studied and the force situation has been analyzed after overthrowing. The initial metacentric height formulas have been estimated when the boat is upright and upturned, which have been selected as the objective functions of overturning resistance performance to construct the optimization mathematical model of overturning resistance performance.5.The comprehensive performance optimization objective function of this high-speed USV has been constructed based on the optimized mathematical models of the rapidity performance, seakeeping performance, maneuverability performance and overturning resistance performance. The punishment function has been designed according to the constraint conditions. Finally, the mathematical model of comprehensive optimization of performance for such new type of high-speed USV has been established. The characteristicsof various kinds of intelligent optimization algorithm have been analyzed, and using C#language to write genetic algorithm, chaos algorithm, particle swarm optimization algorithm and complex algorithm, and combined with the parallel and hierarchical strategy to improve the optimization performance of algorithm. Finally, the better design of algorithm has been obtained through different improvement strategy and a integrated optimization software has been constructed based on different optimization algorithms for this kind of USV. Through using the completed optimization software, some optimal computations have been carried out to study the superiority and inferiority of different algorithms according to different optimization designs. Research shows that genetic algorithm of growth mechanism is better than complex algorithm which is superior to particle swarm algorithm which is better than chaos algorithm. Genetic algorithm of growth mechanism is superior to the genetic algorithm of roulette mechanism. Layered strategy and parallel strategy can effectively improve the search performance of the algorithm. Finally, a better optimization result and the optimal optimization algorithm which is suitable for the optimization system have been obtained through amount of calculations. |
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