| At present,marine buoys play an irreplaceable role in collecting marine water quality hydrology and meteorological data,performing anti-submarine missions,collecting enemy intelligence,etc.,and have gradually become a hot spot in many countries.The research object of this paper is a motorized buoy,which is different from the traditional unpowered marine buoy.It is loaded with propulsion device itself,and can depend on its own power to keep itself near the measurement position when performing self-preservation measurement tasks.The power supply equipment for motorized buoys is a rechargeable lithium battery pack that provides limited energy.Therefore,designing effective control systems and control algorithms to reduce energy loss and improve navigation efficiency has practical engineering application significance.Wave added resistance is one of the important factors that increase the resistance of motorized buoys and affect the cruising ability of motorized buoys.In this paper,the problem of wave added resistance of motorized buoys sailing near the surface is studied.Firstly,the hydrodynamic model under the influence of the mobile buoy near the surface wave is established.Then the mechanism of wave added resistance is studied.Finally,the motorized buoy near-surface navigation path planning algorithm and motion controller are designed to improve the efficiency of maneuvering buoy self-preservation navigation.Firstly,based on the design of the structure of the motorized buoy and the characteristics of its working state,the mathematical model of the motorized buoy is established.By analyzing the motion state of the motorized buoy,the mathematical model is simplified,and a threedegree-of-freedom mathematical model of the horizontal plane is finally established to design the heading controller.In addition,a mathematical model of maneuvering buoy roll-heave-pitch motion is established to analyze real-time sea wave interference prediction of motorized buoys near water surface motion.Secondly,through the research on the wave added resistance calculation method of general surface ship,the calculation method of wave added resistance in accordance with the motorized buoy is summarized,combined with the shape structure of the motorized buoy.Using the MAXSURF software,a three-dimensional model of the motorized buoy was built and simulated under different sea conditions and encounter angles.Through the analysis of the simulation data,the relationship between the wave added resistance and the encounter angle is established.The least squares method is used to fit the relationship between the wave added resistance and the encounter angle and the function expression between the two is given.By studying the resistance of the motorized buoy in still water,combined with the increase of the resistance of the wave interference,the expression of the velocity loss of the motorized buoy under wave interference is given.Then,according to the established mathematical model of the motorized buoy roll-heavepitch motion,the time series and RAO data of the corresponding motion are obtained through MATLAB simulation.The MAR model method is used to obtain the cross spectrum of the corresponding motion.Combined with the cross spectrum and RAO data,the real-time ocean wave direction spectrum of the motorized buoy in two sea conditions is obtained.The accuracy of the obtained wave direction spectrum is verified by comparison with the actual wave power spectrum.Finally,a new path planning method is proposed for the problem of low-energy selfpreservation navigation of motorized buoys.By setting up virtual nodes,the A* algorithm is used to plan the path of motorized buoys with the least energy consumption from guarding navigation.The fuzzy PD heading controller is designed to verify the simulation under different sea conditions.By comparing and analyzing the simulation data before and after the path planning.The effectiveness of using A* algorithm to plan the optimal path of energy consumption is verified. |
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