| With the rapid development of modern manufacturing, in order to meet the demands of social diversification and individuation, the mode of small-batch and diversification production has become the mainstream, and higher requirements for the efficiency and quality of robot are put forward. Especially in the field of welding processing, the mode of single teaching representation can’t meet the demand of the modern welding processing. Thus, off-line programming has gradually become the main mean in this field because of its flexibility and efficiency in programming. Today, most of the commercial off-line programming systems fail to provide effective technical support for welding processing. In the case of complex space curve welding seam, those systems can’t finish the work of information extraction of weld and welding planning successfully. And the method of CAD graphic navigation can make up for the above defects. Therefore, in this paper, a welding robot off-line programming system was developed by using the CAD software platform of 3D. The main research substances are as follows:First, a design scheme which focuses on developing a CAD navigation welding robot off-line programming system is put forward according to the demands of the modern welding robot off-line programming system. It has the functions of graphics environment modeling, welding path planning based on CAD navigation, offline teaching and robot processing code generation.Second, graphics environment modeling of the system includes robot modeling, deflection device modeling and welding tools modeling. And the robot modeling is based on the analysis of robot entity structure model and the kinematics analysis is based on D-H link coordinate system transformation theory. After that, the corresponding data model of the real robot is established. Thus a welding robot model environment is created in SolidWorks, and its accuracy is verified by using the function of MATLAB robot toolbox. Building a CAD graphics environment can provide a CAD navigation environment for the system which is similar to the physical teaching environment.Third, after analyzing the characteristics of welding pieces and path generation, the research of the calculation of weld process’s point position of CAD model is carried out and the weld path is planned by using the method of CAD navigation key point pose matrix. Then convert welding line to robots linear interpolation and circular interpolation model by the calculating operation, and extract space matrix of its critical path. Weld point coordinate is created on the CAD model according to the position and the type of weld. So coordinate system of the unit direction vector attitude matrix is established after calculating the information of data point. The establishment of the pose matrix provides the process planning data for robot processing code generation and modified gear adjustment for weld pose and welding-torch gesture.Based on the researches mentioned above, a welding robot off-line programming system based on CAD navigation is created by using VC++ and secondary development of SolidWorks. By comparing the lines of system’s programming test, motion simulation and the robot’s actual running, the results show that CAD navigation can effectively implement the off-line programming of welding robot. |
