Research On Path And Trajectory Planning Algorithm For Robot Off-line Programming

Robot programming method can be divided into the on-line teaching programming and the off-line programming,commonly used the on-line teaching programming method with low precision,teaching complex and other disadvantages.The off-line programming methods can overcome these disadvantages of the on-line teaching programming,thereby improving production efficiency and ensuring the machining accuracy.The off-line programming mainly uses the 3D CAD model of the workpiece to extract directly the trajectory of robot to complete the surface processing of the workpiece.This paper will deeply studies the trajectory planning,the key technology of the off-line programming system.The main research contents are as follows:1.Firstly,this paper have studied an algorithm that is based on balanced binary tree dynamic search,to generate the path from STL model.Since the STL format file contains the information of the surface to be processed,the STL model can be used as the source file to obtain the path.The STL model containing the surface to be machined is obtained by 3D CAD modeling,and then intersects the triangular patches of the STL model with multiple parallel tangent planes,and the data points of the path are obtained by the intersection of the slice plane and the triangular patches.The balanced binary tree dynamic search algorithm is used to optimize the sorting of the these disordered data points to form a complete rout line.2.Secondly,this paper uses the inverse algorithm of cubic NURBS curve to optimize the path for STL model.According to the STL model of the slice algorithm to achieve the path,the path is connected by the discrete points of irregular distribution.In order to the path more coherent,the cubic NURBS curve can be used to optimize the original path.An adaptive parameterization algorithm is proposed to determine the node vector.In the case of known path type points,the node vector and control points of cubic NURBS curves which can accurately describe the path.3.Then,the paper study the robot trajectory planning based on the chord intercept iteration method.Based on the expression of cubic NURBS curves which can be used to accurately describe the path,the node parameters at the interpolation point are predictedaccording to the bow height error,and the real node is obtained by iterating the predicted node parameters using the chord intercept iteration method,to ensure the ideal speed and the actual speed between the volatility in a certain range.4.Finally,the trajectory generation system is developed by MFC and OpenGL technology.According to the algorithm of path generation,path optimization and trajectory planning studied in this paper.The system structure,system interface and module function are proposed.The STL model of the monkey workpiece is introduced into the system to generate the trajectory of the robot and the actual processing is performed,and the verified by comparing with the trajectory obtained by the STL spline algorithm.