| 摘要 |
PROBLEM TO BE SOLVED: To determine an adequate phase exchanging position with high accuracy by simultaneously and respectively applying currents that generate driving forces which are of the same level and have opposite directions to each other to both of coils that exchange phases of a motor in the vicinity of the exchanging position, then measuring the position of a stage that stops its movement under the above condition. SOLUTION: A table 1 is driven so that a light shading plate 8 passes through an origin photo switch 9 and a counter unit 10 is initialized, than the table 1 is conveyed to a position in the vicinity of a phase exchanging position. Currents having the same level are simultaneously applied to coils 2, 3 so that generated driving forces are opposite to each other. When continuing the applying of the currents, the table 1 stops at a position wherein the generated driving forces are balanced. The above stopping position which may be an optimum exchanging position that does not generate difference in level of the driving force is measured by means of a position detector 7. This measuring operation is executed at all of the exchanging positions in a movable range of the table 1 and the results are sequentially stored in a RAM 17. Thereby, it is possible to execute the accurate position determination without generating speed variation during the moving at a constant speed. |
