| 摘要 |
<p>PURPOSE:To appropriately realize the posture control of a vibration-removing table, even if one position sensor is removed for the purpose of reducing a cost, by servo-controlling the height of a position for supporting the vibration- removing table supported by support legs on the basis of the vertical position or positional deviation in supporting parts by the support legs and of the output of an acceleration sensor. CONSTITUTION:In a feedback apparatus 17 with position signal restoration circuit, a position signal is restored when position signals Za, Zb, Zc in three feedback devices 15a, 15b, 15c for air spring-type support legs are used as inputs to the position signal restoration circuit 16. The output of this circuit is a position signal Zd equivalent to the vertical displacement of a supporting table 4d, and the signal Zd is guided to a comparison circuit 12d so that a positional deviation signal ed is obtained. Further, the positional deviation signal ed is guided to PI compensator 14d, and the output signal of this compensator and the output of a low-pass filter 9d are added to excite a voltage-current converter 10d.</p> |
