Vision-based rotary part offset correction for weld toolpathing

A method for controlling an automated welding process, the method comprising:

• securing a workpiece to a rotatable fixture, the workpiece being rotatable in unison with the rotatable fixture about an axis of rotation (X-axis), the workpiece including first and second parts defining a gap therebetween;
• providing a laser above the rotatable fixture for welding the first part to the second part, the laser being operable to generate a laser beam according to a preprogrammed laser beam toolpath;
• providing a machine vision camera oriented toward the workpiece, the workpiece being secured to the rotatable fixture, the machine vision camera being fixed in relation to the laser;
• measuring a deviation between the laser beam toolpath and a gap centerpoint of the gap between the first and second parts of the workpiece that are being welded together, the gap centerpoint being separated from the axis of rotation (X-axis) by a first distance (R), the deviation including a horizontal (Y-axis) offset (AY) and a vertical (Z-axis) offset (AZ), wherein the Y-axis and the Z-axis are orthogonal to the axis of rotation (X-axis);
• calculating the deviation between the laser beam toolpath and the gap centerpoint, including the vertical (Z-axis) offset and the horizontal (Y-axis) offset, such that the deviation can be corrected in at least two dimensions;
• correcting the deviation by causing the fixture to rotate about the axis of rotation (X-axis) through an angle of rotation (Δθ) to bring the gap centerpoint into alignment with the laser beam toolpath, wherein the angle of rotation (Δθ) is determining according to sin−1 ((√(ΔY2+ΔZ2))/R);
• and
• after correcting the deviation, welding, using the laser, the first part of the workpiece to the second part of the workpiece.