Research On Key Technology Of Hull Cleaning Robot Based On High Pressure Water Jet

Due to a lack of timely maintenance,a ship on a sea voyage or long anchored in a sea is likely to be subject to the massive accumulation of marine fouling like barnacles on the part of its hull that is below the waterline.The fouling makes the hull surface rough,thus increasing the resistance to the ship’s motion,lowering its speed and increasing its fuel consumption.A ship to which dense populations of marine organisms are attached is estimated to consume 2-3 times more fuel.Conventional hull cleaning methods have many disadvantages,such as requiring the use of a dock,high cost,high labor intensity,low efficiency,and poor working environment.In this study,a multi-legged hull cleaning robot based on high-pressure water jet is designed to replace divers in hull cleaning operations.This cleaning robot can move flexibly on hulls and perform automatic cleaning,thereby reducing the labor intensity and operational cost and increasing the efficiency of hull cleaning.The ways for the robot to adsorb on,move along,and clean the hull surface,the flow field of the high-pressure water jet,and the robot’s adsorption capacity and degree of freedom are analyzed based on underwater environment,hull surface conditions,technical requirements of hull cleaning,and forces acting on the robot during operation.The adsorbing device,driving system and other parts of the robot is studied.Then the overall scheme and structure and key components of the robot are designed.Next,a mathematical model based on the D-H theory is created for the robot and then used to investigate its kinematic performance.The positions and attitudes of the robot’s swing and support legs are analyzed based on the bend angles of the joints.Driving torques for the robot’s joints are determined by calculating dynamic parameters such as position,velocity,and acceleration.Later,virtual prototype of the robot is designed and used in a simulation study.Curves describing the relationships among the robot’s position,velocity,acceleration,moment,and joint rotation angle,as well as the modes of vibration and natural frequencies of joint parts,are derived by simulation.Based on the results obtained,the robot’s gait parameters and full traversal planning are analyzed and determined and the trajectory path of foot endpoint is planned.