Hydrodynamic Analysis And Calculation Of Wave Gliding Robot

Wave gliding robot is a new type of autonomous surface mobile robot,which consists of three parts: surface floating body,underwater glider and flexible cable.It does not need external kinetic energy.Wave energy can be converted into forward kinetic energy through the swing of hydrofoil.It has strong endurance and can realize long-term autonomous navigation in the ocean.It also has the advantages of low noise,low maintenance and manufacturing costs,long working cycle,high reliability and reusability.By carrying different types of sensors,it can realize resource detection and environmental monitoring.Military reconnaissance and other functions belong to innovative robots using ocean energy.They have very important research significance and use value in military and civil fields.The structure of wave glider is introduced,Based on theoretical analysis,the design requirements of surface floating body,underwater glider and cable are put forward,The working mechanism of wave gliding robot is analyzed.The nonlinear dynamic model of the cable is established,and the dynamic equation of the cable is obtained.The NACA0012 airfoil is used as the hydrofoil of underwater glider,The calculation method of hydrofoil thrust based on lift and drag coefficient is given.The influence of angle of attack on horizontal thrust of hydrofoil is analyzed.The numerical curve between horizontal thrust and angle of attack is obtained.The optimal angle of attack of hydrofoil is determined to be 14 degrees.The calculation method of optimal deflection angle of hydrofoil is proposed.The influence of hydrofoil spacing on hydrodynamic performance is analyzed.The results show that increasing hydrofoil spacing properly in a certain range can improve the horizontal thrust of underwater glider.The frequency domain and time domain analysis of the three-dimensional floating body with speed of wave glider is carried out,and the mathematical model of the three-dimensional floating body with speed in frequency domain and time domain is established.The diffraction and radiation problems of three-dimensional floating body with speed are solved by using AQWA software.The influence of speed and wave frequency on the maneuverability of the floating body is analyzed.The numerical curves of additional mass,damping coefficient anddiffraction force under different speed and wave frequency are obtained.Based on the three-dimensional potential flow theory and quasi-steady time-domain method,a time-domain method for calculating the motion response of a floating body with speed under the combined action of wind,wave and current is proposed,taking into account the influence of steady speed and adding the line integral term.The effects of different shape structures of surface buoys on the stability of swaying in deep-sea navigation are analyzed.The numerical curves of swaying displacement,swaying velocity,rolling angle,rolling angular velocity,pitching angle and pitching angular velocity of surface buoys under combined action of wind,wave and current are obtained.The results show that the variation trend of rolling angle,rolling angular velocity,pitching angle and pitching angular velocity of vertical head-water floating body is better.Therefore,the vertical head-water floating body is used as the surface floating body of the wave gliding robot.