| 摘要 |
PURPOSE:To enable a high accurate, high rigid and high stable fine feed to be obtained, by supplying a differential pressure and controlling an attitude in a static pressure supporting part in a vertical and a horizontal direction with a static pressure guide surface in accordance with a detection signal in an angular change of the second table driven by a static pressure coupling. CONSTITUTION:A mechanism, converting by a detecting part 25, 26 a part of fluid from a fluid pressure source via a throttle 23b, 24b in a line 23a, 24a into an electric signal and comparing in a comparator circuit 30, 31 the electric signal with the input from a microcomputer system 34, relating to a position and an attitude of the second table 9 previously measured by a glass scale 27 and a displacement detector 23, 24, so as to align the both electric signal and input by subtraction, amplifies that signal by a servo-amplifier 32, 33 to be introduced to a servo valve 28, 29. A fluid output of the valve 28, 29, respectively passing through a line 28a, 28b and 29a, 29b, is introduced to a mutually opposed static pressure pad 4b through a throttle 4l, and the mechanism, equally differentially applying pressure to a pad 4g and displacing the table 9 to a fine distance in the vertical direction, enables an attitude in the pitching direction to be controlled in high accuracy and high rigidity. |
