Research On Underwater Ship Hull Cleaning Robot & Interrelated Technologies

As a special type of working robot, wall-climbing robot has been used in many areas, such as nuclear industry, petrifaction enterprise, building industry, fire fighting and ship building etc. It has been provoking high attention world widely ever since it was born in 1960's. The underwater ship hull cleaning robot researched in this paper belongs to the wall-climbing robot, and is supported by The Heilongjiang Homecoming Scholar Fund. It has wide application value.The author systematically overviews the developing situation of underwater cleaning technology and the wall-climbing robot, and successfully develops the principle prototype of underwater robot for cleaning ship hull. According to the particular condition of underwater robot work, the paper studies the related key technology, including body structure, magnetic structure, control system, cleaning work set etc.At first, the dissertation describes the classification and characteristic of the wall-climbing robot, and summarizes the state-of-the-art of underwater cleaning work and wall-climbing robot, and puts forward the structure scheme which adopts double crawler movement and permanent magnetic adsorption for the robot.The paper studies and designs adsorption mechanism, driving mechanism, transmission mechanism and anti-topple mechanism which the body of robot is made up of. Considering the underwater work environment, the author analyses the robot movement on the ship hull with wave action, and establishes mechanics model of the robot in stationary and moving state. By using model simulation, some parameters are chosen, for instance irummum magnetic adsorption force for a piece of magnet and the driving torque of motor.The design of magnetic structure is the key technology of ensuring reliable adsorption of the robot on the ship hull. On the basis of the magnetic adsorptive force, it chooses Nd-Fe-B permanent magnet material with high coercive force and magnetic circuit type. It analyses the relationship between the clearance ofthe dynamic magnetic circuit and the magnetic adsorptive force. The magnetic circuit, which has been packaged with vulcanization rubber, overcomes the crispness disadvantage of permanent magnet material, and strengthens the resistance to sea water corrosion, and ensures the safe and reliable work for the robot.The paper analyses the motion path of the robot on the ship hull and develops kinematics model of the robot. By choosing the high accuracy electric inclinometer, it realizes high precision pose control of the robot. Due to the nonlinearity of the robot system, position controller uses the parameter self-adjusting fuzzy control strategy, which assures good pose regulating power. The simulation and test results show that designed controller meets the demand of the robot control precision.It devises underwater cleaning set for the robot, which is made up of capacitor start asynchronous motor, belt transmission and steel wire brush. By rotating brush, it can clean the ship hull. It has made an analysis of relationships between radius of brush, rotating speed of brush and sea viscous resisting moment, friction resisting moment, inertia moment, then establishes mechanics model of brush basing on underwater rotating.At last, performance experiments for the robot are made. Test results indicate that the developed ship hull cleaning robot has the characteristic of strong holding load, smooth and steady movement, adjustable speed, strong anti-topple capability and good deviation-rectifying. Performance index of robot is in accordance with the design specifications.In conclusions, the successful development of the underwater ship hull cleaning robot opens up a new domain for the application of the wall-climbing robot.