| 摘要 |
PURPOSE:To virtually decrease almost to zero the displacement in a direction orthogonal with the feed direction of a slide table by detecting a load or a displacement amount in a direction orthogonal with the feed direction of the slide table and driving a piezoelectric element in accordance with this detected value. CONSTITUTION:When a slide table 20 is displaced in a direction crossing at a right angle with its feed direction, a load detector 48, provided between a bearing 40 rotatably supporting a feed thread 16 and a bed, detects a change amount of a load in the displaced direction, feeding a signal to a driving gear 50 of a piezoelectric element. A CPU52 calculates a correction amount of driving voltage of the piezoelectric elements 24, 26 in accordance with the change amount of the load in the displacement direction, and correcting the driving voltage by this correction amount, the piezoelectric elements 24, 26 are continuously displaced and driven through a piezoelectric element driving unit 58 in a manner wherein the change amount of the load decreases to zero. In this way, the slide table 20 is positioned feeding the bed so as to virtually eliminate the displacement in the direction orthogonal with the feed direction. |
