Research On Grinding Process Of Large Pressure Vessels And Design Of Wall-Climbing And Polishing Robot

Magnetic particle testing is one of the primary means of large surface nondestructive testing of pressure vessels. Magnetic non-destructive testing requirements for welds and heat affected area need to remove grease, rust, scale or other material handling adhesion of magnetic powder. Nowadays,manual work is the primarily ways of polishing pressure vessel wall through building scaffold and handling grinder. There is a highly risk, time-consuming,low efficiency in manual operation. Therefore, development of a wall-climbing and grinding robot has a strong practical significance.Starting from the grinding process research, the article developed, according to the needs,the structure and control of robot design, and finally completed the prototype manufacturing and testing. The main work and achievements are as follows:(1) Surface grinding process of large pressure vessels was investigated through experiments. Robot would get reactive force from wall surface during grinding process.Influence factors of grinding apparatus type and influence factors of grinding process would be get by analyzing. Based on the universal platform of tension and compression testing machine, we determined the grinding head speed, positive pressure, feeding rate and other parameters by experiment.(2) We completed wall-climbing and polishing robot structure and programs design in this article. Through analysis of wall-climbing robots polished basic requirements, functional requirements, performance requirements, we established the model for the different needs of sub-function principle, and combined function of different principles for the overall structure scheme The article proposes mechanism for a two degrees of freedom of movement within the same plane; presents a polished head lifting damping mechanism; proposes a new magnetic wheel adsorption topology unit which is based on the Halbach array theory.(3) We simulated Halbach permanent magnet wheel structure and did experiment for verifying the accuracy of the theoretical analysis the thickness of the magnetic yoke round,the number of poles, the proportion of unit on the axial and circumferential magnetization on the adsorption force by the finite element simulation are studied. Two control experiments are designed to study the circumferential magnetic wheel impact on magnetic wheel adsorption force, effect of the air gap. After verifying the accuracy of the results, structure of magneticwheels global optimization parameters were analyzed through a multi-island genetic algorithm.(4) A prototype of wall-climbing and grinding robot and performance testing were carried out The control system of wall-climbing and polishing robot is based on AT89S52 MCU. the manufacture robots and test equipments are completed in the last part. We tested crawling carrying capacity, the ability to go straight and polished performance of the robot which meets the functional and performance design.Researching on this subject is in conjunction with pressure vessel inspection. We originally designed two degrees of freedom movement structure in a plane, grinding head movements damping structure. The article presents a special magnetic adsorption wheel structure was carried out by finite element optimization. We integrated of robot structure and control systems, created a prototype, and did the performance test. The robot system greatly improves the large pressure vessel wall grinding efficiency, enriching special robot types. The research results have a high value in engineering to improve the efficiency of the pressure vessel inspection and safety.