Design And Analysis Of Special Manipulators For Underwater Cleaning

The development of world economy has brought rapid development of ocean transportation industry. Both the hull below the waterline and the propeller grow sea creatures, leading to low speed and increased fuel consumption cost. It takes quite a lot time, manpower and money for maintenance. The development of underwater ship hull cleaning robot is the urgent problem to enhance the level of automation and economic benefits of shipyard. Manipulators for underwater propeller cleaning have rarely been designed and analyzed, and it has wide value. The prototype of manipulators for underwater propeller cleaning is put forward. It can be assembled to ROV as a skid to paw and clean propellers, the full surfaces of propeller’s blades can be cleaned underwater automatically. It’s composed of two paw manipulators of symmetric structure and a cleaning manipulator.First, study and analyze comprehensively about the underwater cleaning and underwater manipulators domestic and overseas. Propose feasible scheme of manipulator combining with the functional requirement, and determines the technique requirements and mechanism. And use the three-dimensional design software SolidWorks to do the modeling, then the body structure scheme is put forward. Due to the complexity of the operation workspace, manipulators for underwater cleaning depend on the strict parameters of link, range of joints and performance index of the hydraulic component parts. The elbow joint of paw manipulators, up-down expansion joint of cleaning manipulator, and rotary joint for grinding are representative, and the detailed mechanical design of these key joints is done. Then, to solve the problem of how to quickly obtain the structure parameters of manipulators without experience of similar manipulators, given only the propeller parameters, use graphical method, group-combining method, and subsection procession of propeller surface, then get link parameters and range of joints. And ensure that the manipulators can reach the complex workspace required. And then, use numerical method to get the kinematics solution. With Monte Carlo Method, the paw and cleaning manipulators’ workspace is analyzed in the MATLAB software environment, to verify the workspace obtained by graphical method and the rationality of link parameters and range of joints. Finally, analyze the stress and deformation of both the hydraulic cylinder of elbow joint and the paw manipulators using the finite element analysis software ANSYS to verify the design to meet the strength requirements. The research work results show that for underwater propeller cleaning, multi-manipulators collaboration can get efficient results and avoid inflicting physical harm. Using graphical method, group-combining method and subsection procession of propeller surface, link parameters and range of joints could be obtained quickly, and it could guarantee manipulators’ workspace meet the requirements. Manipulators have no bland of area coverage, the full surfaces of the four bladed propeller’s blades can be cleaned effectively, and the front or back surface’s cleaning of each blade requires just five times. The research work provides a solid basis of follow-up manufacturing of the prototype, and also for the manipulator design aiming at underwater propeller cleaning.