An online planning method for robot grinding trajectory in putty defect area of ​​rail car body

Abstract

The invention discloses an on-line planning method for a robot grinding trajectory of a putty defect area of ​​a rail car body. The steps are: collecting point clouds of car body surface data, obtaining the defect area according to the flatness requirements of the car body; The minimum polygonal convex hull is fitted with multiple splines to obtain the contour curve surrounding the defect area; the path distance a is calculated, and the contour curve of the defect area is biased inwards by a to obtain multiple circular trajectory curves; Each circular trajectory curve is discretized into path points, and all path points are projected onto the 3D model of the car body to obtain new path points on the circular trajectory; the new path points on each circular trajectory are connected in turn, and the adjacent trajectory is set. In the opposite direction, the robot grinding trajectory of the putty defect area is obtained. The invention solves the problems that the traditional off-line path planning method of the robot cannot be programmed for the defective area, cannot be ground and smoothed for the defective area, and the grinding lines are inconsistent.

Description

technical field [0001] The invention belongs to the technical field of industrial robot grinding, and in particular relates to a robot grinding technology for a putty defect area of ​​a rail car body. Background technique [0002] In the manufacturing process of the rail car body, in order to meet the requirements of the rail car's beauty and smoothness, its outer surface needs to be painted many times. At present, the car body coating polishing process is still mainly done manually, and the polishing process is labor-intensive. , low efficiency, and serious dust pollution, harmful to health and other problems. Compared with the manual method, the robot grinding system has the advantages of high efficiency, large operating space, and good consistency of processed products. [0003] At present, the robot grinding mainly adopts the offline programming method, which is to write the robot grinding trajectory according to the three-dimensional model of the workpiece to be polish...

AI Technical Summary

Problems solved by technology

[0004] The above-mentioned off-line programming method of the robot ignores the deviation between the actual car body and the theoretical design model, and can only remove the margin of the car body surface evenly. Since the program is compiled before grinding, it cannot generate a special grinding track for the defect area, so It is impossible to carry out targeted grinding on the putty defect area, and finally it is difficult to meet the flatness requirements of the car body surface

Since the surface curvature of the car body is small and almost flat, the grinding trajectory generated according to the UV direction is a Z-shaped trajectory formed by the connection of multiple straight line segments. There must be an obvious acceleration and deceleration process in the segment, and the moving speed of the robot directly affects the grinding removal amount. The greater the moving speed, the greater the removal amount. Therefore, the grinding removal amount in the connecting area is higher than that in the straight line segment. The amount of removal is inconsistent, and the defect area cannot be ground smooth in the end

In addition, the acceleration and deceleration of the robot will produce inconsistent grinding lines, which will also affect the surface quality of the car body putty

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