| 摘要 |
PURPOSE:To obtain a table feed controller in which a yawing is controlled securely if it is generated while the table is fed by installing a yawing correction device to magnetize at least one electromagnet coil according to the yawing direction and amount which is detected by a yawing detector. CONSTITUTION:A feed controller 17 finds the location of each of plane mirrors 11 and 12 of a table 10 based on the location detection signals output from location detectors 14 and 15, finding out the yawing direction and amount of the table 10 on a basis of a difference in location of the plane mirrors. Then, finding an electromagnet coil 16-k to correspond to the location of the plane mirror 12 detected by the location detector 15, the feed controller 17 magnetizes the electromagnet 16-k by applying to it a current in proportion to the yawing amount in the direction according to the yawing direction, in other words, a current required for vanishing a difference in location of the plane mirrors 11 and 12. In this case, the table slopes in the direction shown by an arrow (). So, a current of such a current value as in proportion to the inclination of the yawing is applied to the electromagnet 16-k in the flow direction against a permanent magnet 13. By this method, the yawing of the table 10 is controlled. |
