Welding motion synchronization of tank with variable curvature section based on discrete planning method of welding torch posture

Welding path planning and motion synchronization of complex tanks are important research areas in the intelligentization of welding equipment. In the present work, the welding of tank with variable curvature section was taken as the study object, an innovative method to automatically generate the posture of welding torch at the welding spots of variable curvature section was proposed. The method involves establishing a homogeneous transformation matrix for the torch posture and combining it with the angle planning equation of the positioner to form an equation for welding motion synchronization based on the torch posture planning method. Then, a set of welding torch posture and positioner's rotation angles along the welding path of variable curvature section was created in Matlab, and the combination code of the welding torch movement and positioner rotation were obtained to accurately control the welding speed, wire feed rate and the posture of welding torch. An aluminum alloy tank composed of eight arcs was chosen to verify the proposed technique. The results show that the difference of welding position at the same positioner's rotation angle ranged from -0.7976 mm to 0.7616 mm, the repeatability accuracy of the automatic welding system's posture was less than 0.1 mm, and the weld qualification rate of the aluminum alloy tank exceeds 98% with limited weld defects. That is, the tanks with variable curvature sections can be automatically and accurately welded by the proposed method.