Method and apparatus for automatic position-finding assembling

Abstract

A control unit ( ) makes an end effector ( ) compliant with respect to an x-axis and a y-axis which are perpendicular to a z-axis parallel to a direction in which a shaft ( ) is moved for insertion and makes the end effector ( ) produce a pressing force acting in a direction parallel to the z-axis to press the shaft ( ) against an internally toothed disk ( ). The control unit ( ) moves the compliance center of the shaft ( ) along a predetermined groping route in a state where the pressing force acting in the direction parallel to the z-axis is produced by the end effector ( ). The shaft ( ) gripped by the end effector ( ) repeats radially outward movement from a position near the center of the center opening ( ) of the internally toothed disk ( ) in different phases in an xy plane defined by the x-axis and the y-axis to find a position where the splines ( ) of the shaft ( ) are able to engage the internal teeth ( ) of the outermost internally toothed disk ( ). If the shaft ( ) stays at the same z position for a predetermined time, the control unit ( ) instruct the end effector ( ) to reduce the pressing force for a predetermined time to separate the shaft ( ) temporarily from the internally toothed disk ( ) and to resume moving the shaft ( ) along the groping route.