| 摘要 |
PURPOSE:To obtain a fine displacement/angle setting device with a high resolution by controlling the feed pressure of stationary pressure bearing pads so as to apply a slight displacement or rotation to a table and by detecting and feedbacking the displacement quantity to correct the difference with a command signal. CONSTITUTION:Displacement detectors 14, 15 detecting the relative displacement between a pivot member 3 and a table 1 are fitted on the pivot member 3 against the moving direction of the table 1. The output signals H1, H2 of the displacement detectors 14, 15 are subtracted from the movement command signals Hc1, Hc2 given by a controller 22 and the differences are amplified by differential amplifiers 16, 17. These amplified error signals pass through compensation circuits 18, 19 and are guided to servo valves 10, 11 through servo amplifiers 20, 21. The servo valves 10, 11 apply differential pressures to upper and lower stationary pressure pads 5, 4 and 7, 6 respectively in accordance with control signals I1, I2 to move the table 1 and equilibrate the pressure of the upper and lower stationary pressure pads 5, 4 and 7, 6 when the table 1 has moved by a commanded value. |
