Research On Robot Polishing Path Planning Of Complex Curved Surface Based On STL Files

The polishing and grinding of complex curved surfaces of automobile molds has always been done manually by skilled workers.In another word,the quality of mold surface processing depends entirely on technical levels of the workers,which leads to many problems,such as low productivity and unstable process quality.Such a status is difficult to meet the industrial development requirements in the present day,like lowcost,short-cycle and high-quality manufacturing techniques.Therefore,the work of mold polishing urgently demands automation devices to replace labour.With the development of industrial robot technology,researches of robotic applications on automated polishing of complex curved surfaces have received more and more attention.However,the traditional method of robot teaching and reconstruction has great limitations.In most cases,manual teaching fail to satisfy the requirement of complex curved surface polishing,but offline path planning can directly generate the polishing path points needed by the robot using three-dimensional models,effectively avoiding the limitations of traditional methods.In view of the problems of complex robotic curved surface polishing,this paper probes into the robot’s polishing path planning based on STL files with specific research ideas as follows.In this paper,I design a functional floating robot end effector to meet the needs of robotic free-form surface polishing on a functional level,and then select a floating polishing product with similar functions on the market,according to the designed robot end effector,and verify if it conforms to processing requirements by testing.This paper is based on STL files to research a method for robot polishing path point generation.Firstly,the 3D CAD model of the polished workpiece is transformed into an STL model.Secondly,the topological reconstruction of the obtained STL file is performed by C++,and the redundant information in the STL file is removed to obtain the topological relationship of the vertices,edges and faces of the triangle mesh.At the same time of topological reconstruction,the normal vector of the vertex,the principal curvature,the side length of the edge,the area of the patch and the shape factor are calculated.Thirdly,the cross section method can be used directly to obtain desired polishing path points.I also use the basic idea of Douglas–Peucker algorithm to remove redundant path points.Then,according to the topological information of the polishing path point,the normal vector is calculated and its convexity is judged.The orientation information is calculated based on the normal vector,and the pose information of the polished path point is obtained next,i.e,x,y,z,a,b,c.Finally,the Qt application development framework is used to write the software and implement the above algorithm.The graphical user interface(GUI)can be used to read and display the STL model quickly and easily and then obtain the robot polishing path point information as required.Using the V-REP simulation software,the robot simulation environment is established to verify the validity of the polished path point information obtained from the software.