Development Of Robot Stable Trajectory Off-line Programming System For Automotive Die Casting Grinding

As an important technology in the robot machining industry,off-line programming solves the problems of teaching programming in the field of automotive engine die casting grinding,such as unsmooth machining path,high requirements for workers’ programming level,long production change time and so on.However,the existing off-line programming software can not meet the needs of high-efficiency and low impact grinding of automotive engine die castings.In this paper,the off-line programming system of grinding robot with high efficiency and low impact trajectory optimization function is researched and developed.For the high efficiency and low impact trajectory optimization problem,this paper adopts the high efficiency and low impact trajectory optimization method based on cubic non-uniform Bspline,and proposes a new method to transform the kinematic constraints into the upper and lower limits of the design variables of the optimization problem,which is verified by experiments.The research contents of this paper are as follows:（1）In order to solve the problem of realizing the off-line machining simulation platform of the grinding robot,the open cascade 3D display platform and MFC graphical interface basic class library are deeply studied,the functional requirements for low angle motion simulation of the robot manipulator,high-efficiency and low impact grinding trajectory planning and optimization are analyzed,the data structure and system framework of the grinding robot offline programming system are studied,and the robot off-line programming system is built with C++ language.（2）Aiming at the problem of robot simulation motion control,the rigid body kinematics,improved D-H modeling method and Pieper inverse kinematics solution method are studied.The attitude parameter model of FANUC R-2000 i C/165 F robot is built,and the low angle attitude parameterized solver of the manipulator of the smooth grinding robot is fully parameterized.The accuracy of the low angle attitude parameterized solver of the manipulator is verified by using MATLAB robotics toolbox.（3）In order to realize the function of defining,editing and planning the grinding path of automotive engine die castings,the discrete method of complex surface curve,linear interpolation,circular interpolation,quaternion spherical linear interpolation and low impact trajectory planning method based on cubic non-uniform B-spline are studied based on open cascade,and the trajectory planning algorithm library is developed.The trajectory interpolation experiment is carried out in this off-line programming system to verify the effectiveness of trajectory planning algorithm library and the stability of low impact trajectory based on cubic non-uniform B-spline.（4）Aiming at the problem of high efficiency and low impact trajectory optimization of grinding robot,four multi-objective optimization algorithms NSGA-II,MOEA/D-PBI,MOEA/D-TCH and MOEA/D-WS are studied.The time impact optimal trajectory optimization model is constructed based on cubic non-uniform B-spline,and a new upper and lower bound method for transforming kinematic constraints into optimization problem design variables is proposed.Trajectory optimization experiments are carried out on the four optimization algorithms.The experimental results show that the convergence and diversity of NSGA-II solution set are optimal;The solution sets meet the kinematic constraints of FANUC R-2000 i C/165 F robot,which proves that the kinematic constraint processing method proposed in this subject is effective;The compromise trajectory obtained by NSGA-II algorithm can reduce 87% joint impact and 70% running time.（5）Taking mworks as the simulation verification platform,the off-line programming system is used to carry out the simulation experiment of grinding the flash of the automobile engine cylinder block,the oil pan surface and the cylinder head burr.The results show that the off-line programming system can quickly and accurately define the grinding track of the automobile engine die castings,optimize the grinding track,shorten the running time of the track by 33% on average,reduce the joint impact by 95%,and effectively ensure the grinding efficiency and quality,Extend the service life of the robot and improve the economic benefits of the factory.