Development Of Offline Programming Software Based On OpenCASCADE Geometry Kernel

With the continuous development of our country's industry,the degree of automation of our country's industry continues to improve,and more and more factories use industrial robots for product processing.Industrial robots have the advantages of easy operation,high degree of automation,and high processing accuracy.The industrial robot generally generates the processing trajectory through manual teaching.After setting the tool TCP coordinate system and the workpiece coordinate system and calibrating,the processing can be performed according to the established trajectory.When encountering a more complex processing trajectory,manual teaching takes a long time,and the precision control is mostly based on the operator's experience and technical level.Due to the above shortcomings of manual teaching,people have developed offline programming software,which can pick up the points,lines,and surfaces of the workpiece in the software to directly generate the processing trajectory.Compared with manual teaching,the trajectory generation is faster and more accurate.The current excellent offline programming software is basically from abroad,such as Robot Master,Robot Studio,etc.,and the purchase cost is relatively expensive.Compared with foreign offline programming software,domestic offline programming software is not powerful enough,and there are certain problems in performance optimization.In view of this situation,this thesis will develop a full-featured offline programming software,which can realize the rapid generation of robot processing trajectory.The offline programming software of this thesis mainly includes the design of the following functions:(1)The functions of importing,displaying and interacting with the robot model are realized.The robot is the main carrier of production and processing.The geometry of the robot model in the offline programming software should be consistent with the real robot,and its appearance should be as realistic as possible.After the model is imported,the user should be able to freely control the movement of each axis of the robot to achieve free interaction.This paper uses the Open CASCADE open source geometric kernel for development.By calling the geometric modeling algorithm of the kernel,combined with the self-developed display module,and connecting the data bridge to build an independent kernel 3D display interaction module,the robot model can be modeled and displayed in the software.In order to enable the robot model to perform correct spatial motion in the offline programming software,the URDF file of the robot is generated by the Solid Works software,and the key information such as the position of the connecting rod and the joint of the robot can be obtained by parsing and reading the URDF file,which ensures that the robot can perform Correct spatial motion.(2)The function of off-line machining trajectory generation and trajectory planning is realized.By calling the relevant functions in the geometric kernel,the machining trajectory can be generated directly from the points,lines and surfaces of the workpiece,and the trajectory can be separated into several points,and the trajectory planning can be completed through the spatial trajectory correlation algorithm.After the machining trajectory is generated,some trajectory points may be unreachable due to the limitation of the robot's motion range or its own structure.By establishing the kinematics model of UR3 robot and solving the forward and inverse kinematics,the pose calculation problem of UR3 robot at each trajectory point is solved.(3)The process path information is generated into program code,and the code is verified by real robot.Different robot brands have different robot languages.After off-line trajectory is generated by off-line programming software,trajectory information needs to be converted into corresponding robot instructions,trajectory information is restructured according to corresponding syntax,and finally output into robot code files in corresponding formats.In this paper,trajectory information is converted into UR robot code by C++ language,and the obtained code file is imported into UR3 robot for off-line trajectory verification,which proves the reliability of software functions.