Structure Design And Performance Analysis Of Composite Adsorption Based Underwater Robot For Hull Cleaning

With the increasing use of ships,attention to the issue of cleaning attached substances will grow.Manual cleaning of ship surfaces is inefficient,physically demanding,unsafe,and expensive.Therefore,cleaning work is rapidly shifting towards robotic operations.In this context,research on ship cleaning robots has become a current hot topic.This paper studies the cleaning,adsorption,and movement mechanisms of existing underwater ship cleaning robots,and analyzes their cleaning and adsorption performance.Finally,the mechanical design of the ship cleaning robot is completed.Through the following aspects:(1)The overall design of the underwater ship cleaning robot.This paper first summarizes the research status of ship cleaning robots at home and abroad,and analyzes and compares the three major mechanisms of cleaning,adsorption,and movement of ship cleaning robots.Secondly,combined with the actual working conditions that the ship cleaning robot needs to face,the overall design scheme of the robot is proposed,including ultrasonic cavitation cleaning mechanism,adsorption mechanism,movement mechanism,and shell,etc.The strength verification analysis of the robot’s shell and key connection components is also conducted.Finally,the prototype design was completed using SolidWorks.(2)The cleaning force of the cleaning mechanism was theoretically verified.Firstly,the barnacle(with an adhesion strength of 0.94 MPa)was identified as the most difficult fouling organism to clean from the hull,and was chosen as the removal target in this article.Secondly,an ideal model of a single cavitation bubble was established based on ultrasonic cavitation theory.The corresponding dynamic model was derived through force analysis and solved using the Simulink module in MATLAB,and the maximum impact pressure that a single cavitation bubble can generate during its collapse process was obtained.Finally,an idealized model of the barnacle was established.Using ANSYS simulation software and the impact pressure from cavitation collapse,the minimum cleaning stress on the barnacle’s attachment surface was found to be 1.049 MPa.This result confirmed that the cleaning force exceeded the barnacle’s adhesion strength.The design of the cleaning mechanism provides theoretical support.(3)The adsorption force of magnetic suction mechanism and thruster auxiliary adsorption mechanism is simulated.First,a static force analysis was performed on the robot to determine the minimum amount of force required by the magnetic suction mechanism for stable adhesion to the hull.This was followed by optimization of the permanent magnet size and distance from the adsorption surface in the magnetic suction mechanism,using ANSYS simulation software and magnetic field analysis.The flow field was also analyzed using ANSYS software to confirm that the propulsion-assisted adsorption mechanism generated enough thrust to meet the design requirements.Finally,the simulation is used to verify whether the magnetic adhesion mechanism still meets the adhesion requirements under different working conditions,based on the known adhesion force generated by the thruster.(4)Experimental verification of underwater hull cleaning robot.A prototype experiment platform was built,and the validity of the simulation data of the magnetic adsorption and cleaning mechanism of the robot was verified by experiments on adsorption,cleaning and air tightness of the robot.At the same time,the experiments show that the magnetic adsorption and cleaning performance of the robot meet the design requirements,and the robot has reliable air tightness when working in the underwater environment.