Evaluation of seismic absolute displacement sensors based on sensitivity calibration and control tests of an anti-vibration apparatus

In the field of vibration control of aero space structures, Direct Velocity and Displacement FeedBack (DVDFB) is well-known as an effective control scheme in terms of robustness. However, according to the skyhook control theory, Direct Acceleration, Velocity, and Displacement FeedBack (DAVDFB) is preferable as to manipulate seismic parameters of controlled objects. To contribute for implementation of the DAVDFB, we have proposed a seismic displacement sensor, which can simultaneously detect absolute acceleration, velocity and displacement signals. Prototype sensors have been applied as feedback or feedforward sensors in vibration control of antivibration apparatuses. However, due to low detection sensitivity and narrow bandwidth, control performance is not enough for practical use in industrial scenes. Thus, the detection sensitivity is mechanically improved by increasing the number of coil turns, and this effect is evaluated by sensitivity calibration. Moreover, to confirm the effect on practical applications, we carry out control tests of an anti-vibration apparatus with one degree-of-freedom by using the improved displacement sensor.