Research On Off-line Automatic Programming Of Robotic Shape-repairing For Large Castings And Forgings

With the rapid development of industrial robots under the trend of Industry 4.0,they are widely used in various fields such as production and processing,intelligent logistics,intelligent home,etc.,greatly improve the efficiency of production and processing and the quality of People's daily life.In this paper,the programming problem faced by robot in the process of mold modification of large casting and forging is discussed.At present,the robot still has some defects,such as long programming cycle,low efficiency of teaching and high requirement of user specialization,when it is faced with various processing sites and irregular processing objects.Therefore,the off-line automatic programming of industrial robots is favored by scholars at home and abroad because of its short programming cycle,wide application range,high programming accuracy and task-oriented programming mode.Based on the comparison of several off-line automatic programming methods,a method of generating robot program based on NC machining program data and instructions is presented in this paper,this paper designs an off-line automatic programming system for large-scale casting and forging machining by robot.The connection between NC program generated by Mastercam software and the control instruction of robot is studied,and a program which can realize data extraction and processing conversion between the two is designed,and through Matlab simulation process prediction and path trajectory optimization.The main research contents are as follows:(1)the scheme design of robot automatic programming system is to make off-line programming software have better applicability,the main functions of the off-line programming system and other auxiliary functions needed in the automatic programming process are analyzed,and the functional modules are designed.The main function modules include robot NC program code acquisition,data extraction and interpolation,workpiece coordinate system definition,kinematics forward and inverse solution,velocity and acceleration calculation module,task space optimization,error prediction and compensation module.In the realization of the program conversion function,but also reserved for its functional expansion of the interface.(2)taking the Motoman UP50 industrial robot of Yaskawa as an example,the kinematics equations between the position and posture of the robot's end effector and the joints of the robot are established,and the relations between the end velocity of the robot and the joints velocity and acceleration are analyzed.Through the analysis of the Anchuan robot language and the programming of the Algorithm,the research foundation of the off-line automatic programming system is established.(3)the foundation of off-line programming system for industrial robot is discussed.The three-dimensional model of the part is established,and the NC machining program is obtained by Master Cam.Making full use of the parameters of the instructions in the NC program,writing a data extraction program in Python language,extracting the data of the robot's machining path and transforming it to meet the instructions of the robot's programming system,finally,the task planning is carried out,and the parts processing program is generated.The relationship between workpiece coordinate system and robot world coordinate system is defined,and the coordinate information in NC program is expressed in robot coordinate system by means of kinematics equation.Then through the corresponding arc interpolation and linear interpolation transformation of the extracted trajectory data,the trajectory simulation in Matlab makes it appear in the three-dimensional simulation space,it is convenient for the user to control the robot's path and end-position in the process of machining with a more intuitive view.(4)the processing of circular interpolation instruction.In view of the difference between the expression of arc in numerical control program and that of arc in robot program,this paper designs an algorithm to find the third point on arc by the two points on arc and the coordinates of the center of ARC.In order to ensure the accuracy of the robot in the process of shaping,this paper studies the influence of the end-tool of the industrial robot on the error of the robot in the process of shaping,and carries out two kinds of compensation for the error,design Error Compensation Module.