| 摘要 |
PROBLEM TO BE SOLVED: To provide a table positioning apparatus used in a semiconductor aligner, etc., wherein it has a high reliability and the wrong effect of its driving portion on its respective attachment portions can be eliminated by decelerating smoothly its driving portion of its driving device when its driving system is made uncontrollable. SOLUTION: In the polyphase type linear motor of a table positioning apparatus for driving a table 8 linearly to position it by changing over selectively the current-applications to respective coils 17C correspondingly to the position of the table 8, coil driving switches 36 are provided respectively in the current- application circuits to the respective coils 17C. When sensing an abnormality in the drive control of the table 8, both the terminals of the respective coils 17C are shorted successively to close them electrically, by controlling via a controller 35 the changeovers of the coil driving switches 36, thereby decelerating the table 8 continuing its movement smoothly by the actions of the induced electromotive forces of the coils 17C to stop it. |
