Design And Implementation Of Off-Line Programming System For Welding Robot Workstation

Manual teaching and off-line programming are common programming methods for industrial robots.Compared with manual teaching,off-line programming allows users to operate the robot in the simulation environment,which can improve the programming efficiency and ensure the safety of operators.Therefore,based on the existing welding workstation,this paper develops a special off-line programming system with the functions of scene construction,virtual teaching,motion simulation,trajectory planning,code conversion and so on.The main work and research contents of this paper are as follows:(1)Firstly,this paper formulates the technical route of off-line programming system,which chooses QT and OpenSceneGraph(OSG)3D engine as development tools.Then,this paper designs the framework of the system,which divides the off-line programming software into scene management module,motion control module,trajectory simulation module and code conversion module.Besides,this paper describes the key functions and processes off-line programming system.(2)Aiming at the motion control of simulation equipment,this paper establishes the kinematics model of six-dof robot,positioner and rotating boom in the workstation based on D-H parameter method,which can ensure the consistency of movement about the model and the actual equipment.Then this paper correlates the kinematic models of each equipment to analyze the overall motion of the workstation.In addition,this paper establishes a coordinate system with reference to the actual workstation,which can express the position and attitude in a more intuitive way.(3)Aiming at the trajectory planning of simulation equipment,this paper studies the position interpolation algorithm of linear path and circular path of robot in Cartesian space and use Linear spherical interpolation algorithm to realize the robot attitude interpolation.At the same time,this paper also designs a simple trajectory interpolation algorithm in joint space.(4)This paper realizes the development of each module of offline programming system.Scene management module:Build a three-dimensional simulation environment using QT and OSG technology,and realize fast import and assembly of equipment model and workpiece model.Motion control module:Based on kinematics algorithm and model pose transformation algorithm in OSG,the simulation motion and manual control of the robot are realized.Trajectory simulation module:Based on the motion control function and trajectory planning algorithm,the functions of virtual teaching,trajectory interpolation and motion simulation of the robot along the interpolation trajectory are realized.In addition,this paper uses OSG drawing technology to realize the drawing and displaying of trajectory.Code conversion module:This paper analyzes the job file format and common instruction form of FANUC system,then realizes the transformation of virtual teaching path into robot executable file,which can drive the actual servo equipment to run according to the teaching results.(5)The off-line programming system was tested on the existing welding workstation.The functions of virtual teaching,model control,motion simulation and job generation of offline programming system are verified by configuration comparison test,single path welding test and comprehensive trajectory test.The test results show that the function of each module is normal,the off-line programming system meets the design expectations and has a certain usability.