A Research On The Key Technologies Of Weld Grinding Robot For Aluminum Alloy Train Body

High carrying capacity, low operating costs, short transition period are advantages of railway transportation. In less than a decade, China’s railway transportation has entered a golden age, China has the most complete technologies, strongest integration capabilities, the longest operating mileage, and the best price. The railway constructed by China is gradually being recognized abroad, a large number of railway construction orders continue to sign with china. And it has already become a symbol of China.In order to speedup train velocity, aluminum alloy has become the most famous material to construct the vehicle’s body. Welding process is the key technology in the railway vehicle produce, a lot of parts of the train body are all linked together by the large-scale structure. When the train running fast on the tracks, the vehicle will be subject to a variety of alternating loads, under this circumstance, connection parts of the body are prone to fatigue failure, and it will also reduce the life of the vehicle body. Improve the welding quality can effectively extend the fatigue life of the vehicle. Grinding the welds surplus height or polishing the weld toes to be arc transition not only can eliminate stress concentration, reducing the probability of fatigue cracks, but also provide a good surface flatness and surface quality for painting process.It’s labor-intensive, low efficiency, and hard to guarantee the quality when polishing the weld beam by hand. In order to overcome these difficulties, this project aim to bring up an robot system which can detect the weld shape, navigate along the weld beam, and grinding the weld surplus height automatically. The following stuffs are discussed on my research, leak of sucker, sucker interference, air pipe entanglement, pressure fluctuation of the vacuum system, robot yaw, etc.The main research items are illustrated as following,Structure design of the robot. Design the sucker lift mechanism, which could avoid the interference between suckers and work surface when robot crawl on the work surface. Simulate the kinematics of the sucker lift module under Adams. Calculate and analyze the ultimate stress of bearing shaft under harsh environment. Improve the reliability of key parts.To prevent the entanglement of air pipes, the pneumatic rotary distribution mechanism had been researched.Discuss the pressure fluctuations of the vacuum system form both theoretical and experimental. Normally closed 2-position 2-way mechanical valve had been designed to mount on every suction cups. Dynamic response curves of pressure before and after sucker structural optimization were measured through a pressure sensor, so that the robot can move smoothly and continuously upon the work surface.Experiment had been implement to measure the straightness of the robot movement along X direction. In order to measure the positioning accuracy of grinding tool, we use the image processing method. The success of these experiments validate the structural design of the robot, and the experimental data will provide strong theoretical support and experimental basis for the structural optimization and grinding process planning in the future.