Work position detection method and hanger maintenance work necessity determination method

摘要

The stop position of a workpiece is detected by a position detection unit. A control unit calculates and records a difference between the detected stop position (actual stop position) and a reference stop position set in advance. After recording the difference multiple times, the control unit performs a statistical processing of the differences and calculates a compensation amount based on results of the statistical processing. In the next position detecting, the position detection unit is disposed at a compensated position which is obtained by adding the compensation amount to the reference stop position, and in this state, detects the position of a predetermined portion of the workpiece.