Method for performing automatic alignment-adjustment of laser robot and

Abstract

Automatic alignment correction of the setting angles of mirrors in a laser robot is achieved by mirrors 2c,2d, and 2e being linearly displaced a predetermined distance in a sequence from one closer to a laser oscillator 1 to another. At the same time, a locus of displacement of a spot S on a position sensor during movement of a particular mirror is detected by the position sensor 9 disposed in front of a laser output nozzle 4. An error in the setting angle of a mirror preceding to the particular mirror having been moved is computed on the basis of the detected value, so as to perform angular correction relative to the particular mirror by motors 11a and 11b. In one embodiment, mirror 2e is rotated about the C-axis. When the incident position of the laser beam is offset from the center of rotation of the mirror 2e, the spot S obtained in the position sensor 9 will move in a circular path. The center of the circle is determined and the setting angle of the mirror 2c is adjusted so that the spot S comes to the center. Because of this modification in the setting angle of mirror 2c, the optical axis between mirrors 2d and 2e is again out of parallel to the Z-axis. This operation is then repeated to minimize the size of the spot S. By this sequence, the laser beam incident to the mirror 2e is accurately directed to the center of the mirror 2e in parallel with the C-axis.