| 摘要 |
<p>Two optical methods are described, both of which rely on light reflected from the metal surfaces and not reflected from the gap between them. Diffuse light is played upon the welding area, and collected by a lens system. In the first method, the light reaches a set of three photoelastic cells, arrayed perpendicular to the welding direction. The signals from these cells are amplified, and used to control a motor which positions the welding head above the gap between the two pieces of material to be welded. In the second method, only one photoelectric cell is used, and reflected light from different positions across the welding direction is supplied to it by a revolving disc with holes cut in it in the appropriate places, the disc being located between the lens and the photoelectric cell.</p> |
