| 摘要 |
<p>PROBLEM TO BE SOLVED: To make a recovery to a noncontact state without any human intervention by inputting a vibratory waveform to a driving means and driving it when a guide surface and a support surface comes into contact with each other. SOLUTION: The vibratory waveform is inputted to drive the driving means and then the contact state of the guide surface and support surface is gradually reduced to put them back into a noncontact state. When the attitude of a hold board in the contact state of the guide surface and support surface is known, a vibratory waveform which has a larger amplitude in the direction of driving from the attitude in the contact state to the attitude in the noncontact state is inputted to make a recovery to the noncontact state more effectively. Namely, when the guide surface and support surface of a static pressure bearing are in the contact state, the vibratory waveform is inputted to the driving means to make the recovery to the noncontact state. As the vibratory waveform, a waveform which enables a more effective recovery to the noncontact state can be selected out of a sine wave, a rectangular wave, a triangular wave, a random noise, etc., according to the contact state and the structure of the positioning device.</p> |
