抄録
An active anti-vibration apparatus is widely used in the field of precision measurement and precision positioning. In these fields, the realization of apparatus with low natural frequency is expected because the transmissibility from floor vibration to isolated table is especially improved in the high frequency region. In order to lower its frequency furthermore, it is necessary to change the mechanical impedance by means of mechanical or control ways. In the latter case, the following fact, namely, the characteristics of air spring roughly behaves as an integrator, is used for feedback control. However, since the break point frequency actually exists in very low frequency region of air spring, the conversion of mechanical impedance is restricted.
Then, in order to freely manipulate the mechanical impedance, this paper proposes to implement the pressure feedback for air spring. At this time, the complete integrator appears to optimize the whole control system. Using this integrator in place of pseudo-integrator of air spring itself, the conversion of the mechanical impedance can be easily manipulated. Finally, experimental results show that the natural frequency is lower than that of the conventional control using air spring characteristics.
