| In actual industrial production,intersecting forms of the circular tube-circular tube are widely applied.The intersecting line of circular pipe has complex structure,which is a complex three-dimensional space curve.At present,there are few special welding robots for this kind of structure,and most of the intersecting pipe fittings are welded manually.In order to complete the automatic welding of the intersecting seam of two circular pipes,improve the quality and production efficiency of the automatic welding,reduce the workload of labor,and process the weld seam of the intersecting line of the circular pipe which meets the requirement of welding precision,It is necessary to design a robot and its control system for welding the intersecting seam of circular pipe.On the basis of analyzing the welding robot of the intersecting line of the circular pipe at home and abroad,the characteristics of the intersecting weld of the two circular pipes are analyzed,and the mathematical model of the weld seam of the intersecting line of the pipe is deduced and established by the transformation of coordinates.The correctness of the mathematical model of the curve is verified by using the GUI module of the MATLAB programming software.According to the welding process parameters and the auxiliary coordinate system,the mathematical model of the position and attitude of the weld seam in the intersecting line of two circular pipes and the attitude of the welding torch are established,and the relative geometric relationship between them is established.The types of the coordinates of the robot are analyzed.By analyzing the type of the robot coordinate and the motion freedom of the weld line of the intersecting line,the overall structure of the robot is determined,and the whole structure of the welding robot is designed,and the 3D solid model of the intersecting welding robot is drawn by the SolidWorks software.The A direction of rotating motion,the direction of moving X,the direction of Z and the direction of B and C controlled by wrist are designed.The direction of each movement can be carried out independently.The circular welding of the branch pipe is completed through the rotating motion mechanism.The control of the different half diameter of the branch pipe is completed through the lateral feed mechanism and the lifting machine is carried out through the lifting motion machine.The adjustment of the location of the solder joint on the weld is completed,and the linkage between three motion mechanisms is completed together to track the weld line of intersecting line.Meanwhile,wrist movement mechanism constantly adjusts the posture of welding torch to ensure the quality of weld.Through the analysis of the mathematical model of intersecting line weld,this paper studies the intersecting line motion control algorithm,designs two control algorithms,one kind of interpolation algorithm of equal rotation angle,the other kind of control algorithm of constantly changing rotation angle.The coordinate values of each axis are calculated by the angle change,and the two algorithms are simulated by MATLAB,which meet the requirements of welding parameters and errors,and ensure the accuracy and stability of welding.The motion control system of intersecting line welding robot is designed in software and hardware.The hardware adopts the control mode of PC solid-height motion controller.After setting up the hardware structure of the control system,the communication relationship between PC and motion controller is established and debugged.The software structure of the motion control system is designed in the visual programming software VB6.0 environment.The friendly man-machine interface is designed,including parameter setting module,trajectory calculation module,motion control module,state detection module.Fault diagnosis module and other functional modules,operating interface is practical and intuitive.The motion structure of intersecting line welding robot can be controlled by hardware and software. |
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