Research On High-efficiency Motion Mode Of Underwater Snake-like Robot With Thruster

With the development of the country’s oceans,the demand for underwater robots is increasing.Among various underwater robots,underwater snake-like robots can be used on many occasions due to their unique structure and motion,such as military surveillance,water quality monitoring,underwater rescue,patrol,and maintenance of submarine equipment.Therefore,the development of underwater snake-like robots is of great significance.However,the traditional underwater snake-like robot moves at a slower speed and has a poor ability to pass through the narrow space.Therefore,this thesis proposes an underwater snake-like robot with thruster,which can improve the speed of movement and the ability of passing through a narrow space and investigates its high efficiency motion mode and installation position of the propeller.Firstly,this thesis introduces a prototype of underwater snake robot with thruster designed and developed by the research team,and introduces its structure,software,hardware system and external measuring devices.In this thesis,the iterative NewtonEulerian method is used to model the underwater snake-like robot.Secondly,this thesis studies how the underwater snake-like robot with thruster in the tail can effectively combine the movement of the lateral undulation gait and the advancement of the thruster.Through the NSGA-Ⅱ multi-objective optimization algorithm,the optimization simulation is carried out in the computer,and finally the optimal curve of speed and power is obtained,as well as the corresponding parameter solution set.According to the simulation results,an efficient transport mode of underwater snake-like robot with thruster is proposed for the first time: in the low-speed phase,the lateral undulation gait has the highest motion efficiency;in the middle-speed phase,the mixing motion combined with thruster propulsion and lateral undulation gait has the highest efficiency;in the high-speed phase,the thruster propulsion method has the highest efficiency.This kind of motion mode can improve not only the moving speed of the snake-like robot but also its movement efficiency in the middle-speed and high-speed sections.This mode was verified through an experiment carried out in a pool.Finally,this thesis studies the influence of the installation position of the thruster on the motion efficiency of the underwater snake-shaped robot.It is analyzed that the effects of the thruster on the movement efficiency of the snake-like robot when the thruster is installed on the head and tail in two typical gait states,lateral undulation gait and eel-like gait.As a result,it is found that in the lateral undulation gait state,the different installation positions of the thruster have a weak influence on the movement efficiency.Under the eel-like gait,the movement efficiency of the thruster mounted on the head is higher than that of the thruster installed at the tail.Finally,the motion efficiency of the lateral undulation gait and the eel-like gait when the propeller is installed on the head is analyzed.It is found that the eel-like gait can achieve higher motion efficiency when the thruster is installed on the head.These conclusions were also verified through an experiment carried out in a pool.