Research and Application of Force-position Mixed-control of Robotic Friction Stir Welding

The composition, PC system and data bus control system of force-position mixed-control of robotic friction stir welding were studied, and the principles and methods of down-force control, position control and force-position mix-control were introduced in detail. Based on the RSI interface of robot and C++ language, a host computer and control system for robotic friction stir welding was developed, the data communication of PC system, robotic system, PLC control system and seam tracking system was realized,and the second developed of robotic system and seam tracking system was realized. The force accuracy and the position accuracy of this force-position mixed-control were up to ± 10% and 0.5 mm/m respectively. The constant force control and position auto-correction of welding-process was realized, which solved the problem of poor weld quality caused by jitter and poor rigidity of the robot. The application results show that the developed PC system makes the programming easier, the equipment monitoring and data management more comprehensive, and the welding process with force-position mixed-control has the advantages of smooth down rolling, high control accuracy of down-pressure and good seam following.