Research Of J-Groove Joint Robot Teaching Method Optimization

Advanced welding technology and welding automation must be used in the manufacturing of nuclear power equipment to achieve high-quality, high-efficiency welding process. Nuclear pressure vessel head is constituted by intersection structure of sphere and a given number of tubes. The welding groove is inside the vessel head, which is called J groove. In the automatic welding process of J-groove weld of the nuclear pressure vessel head, the general welding robot cannot meet the requirements due to the limited spatial range, and the special welding robots must be used.By establishing a mathematical model of tube-sphere intersection, the trajectory of J-groove joint robot could be generated by approximating the intersecting line with B-spline, the trajectory could be locally modified to fit the surface of the work piece. However, due to the influence of multi-pass welding, there is a big deviation between the intersecting line and the real welding trajectory, teaching procedure is relatively time-consuming. In this paper, By the s tudy of J- groove joint welding robot, the trajectory teaching optimization algorithm is discussed.In this paper, the next robot trajectory is generated by calculating the spatial offset spline of the former robot trajectory, the spatial offset spline could retain the modify features of the former trajectory, thus the offset spline could fit the surface of the work piece better, the optimization on the radial direction of robot trajectoryis achieved, so as to reduce the teaching time. In this paper, the projection of spatial curve is used to solve the deviation of the normal vectors, interpolation and approaching method are combined to fit the offset points, the combination could retain the modify features to a great extent, and remove most control points under a global error bound at the sa me time, so offset spline is applied in J- groove welding robot.The AVC system is utilized to adjust the height of the welding torch real-time, thereby the accuracy of the height direction during teaching is reduced. The AVC system of the J-groove joint robot is designed and established, the ADLINK MP-C152 motion control card and Yaskawa ?-V AC servo motor are used by this system. The AVC system includes adjust module, motion control module and arc voltage collection module. Results shows that the AVC system could reduce the accuracy requirement of the teaching process, thus reduce the teaching time.The remote teaching system of the J-groove robot is optimized, the communication data frame of the robot is redesigned, bit check and CRC check is included in the data frame; by using the EB8000 configuration software, the handheld box program is rewritten, thus it fits the requirement of the welding process better; the communication module of the IPC program is optimized at the same time, the window handle check features are added into the program, thus the crash of the program caused by misuse of the operator is avoided.