Research And Development Of Mechanical System Of Tank Wall Grinding Robot

At present,large pressure spherical tanks are widely used in aerodynamics research,petroleum,chemical industry and other fields.The large pressure spherical tank is mostly in the open environment,which is affected by the corrosion of natural environment and the positive and negative pressure load for a long time,so that the spherical tank is easy to appear cracks,pits,holes and other defects in the weld joint.If not handled in time,it will lead to the leakage of the material inside the spherical tank,which will cause fire,explosion and other dangers to petrochemical enterprises.It is necessary to use phased array ultrasonic equipment for periodic inspection of spherical tank welds.In order to facilitate detection,the three layers of epoxy paint in the weld area outside the spherical tank need to be polished and exposed to metallic luster.At present,manual work is commonly used for welding seam grinding,and there are few wall-climbing grinding robots,but most of them have low efficiency and poor effect of paint removal.Based on this situation,this paper developed a robot for grinding tank wall surface to achieve efficient and high-quality grinding of three layers of epoxy paint on the weld of spherical tank.The main work of this paper is as follows:1.Design of robot mechanical system for grinding tank wall surface.The application scenario and functional requirements of the tank wall grinding robot were analyzed,and the operation mode and adsorption mode of the robot chassis system were compared and analyzed to determine the structure of the robot chassis system.Then the statics analysis was carried out to determine the minimum adsorption force of a single permanent magnet and the minimum torque of the robot chassis system motor.An adaptive grinding system based on current feedback is designed.Based on the fact that the metal wires are evenly distributed but independently used,several kinds of metal wire polishing rollers are designed,and the design of the impeller polishing roller is inspired by this.The metal wires and impeller pieces can realize the efficient grinding of the three layers of epoxy paint on the surface of the spherical tank,and the effective grinding of the weld joint,and their toughness makes them less consumed in the work.Check the strength of the key parts of the robot to ensure that the strength meets the design requirements.2.Simulation analysis of robot mechanical system of tank wall grinding.The relationship between permanent magnet arrangement,permanent magnet shape and adsorption force of robot chassis system was simulated and analyzed to meet the requirements of adsorption force design in this paper while using as few permanent magnets as possible.At the same time,virtual prototype technology is used to simulate and analyze the operation of the robot chassis system and the damping effect of the grinding system to verify the rationality of the design and further optimize.3.Experimental test of the prototype of the wall-climbing grinding robot.Experimental tests were carried out on the tank wall grinding robot developed and manufactured in this paper to verify the rationality of the design and the load capacity,obstacle surmounting ability and operation stability of the robot chassis system,as well as the paint removal effect and efficiency of the adaptive grinding system on the surface of the spherical tank with three layers of epoxy paint.The successful development of this robot improves the adsorption stability compared with the traditional robot and also improves the obstacle crossing ability of the robot.The adaptive grinding system combined with the self-designed grinding roller realizes the high quality and high efficiency grinding of three layers of epoxy paint,which increases the efficiency by 3-10 times compared with the traditional artificial grinding,and can reduce the residual height of the weld.This study proposed a new grinding tool for high strength epoxy paint grinding on the surface of spherical cans,which ensured the grinding quality and improved the grinding efficiency.