Tilt Active Vibration Isolation Using Vertical Pendulum and Piezoelectric Transducer with Parallel Controller
Round 1
Reviewer 1 Report
The paper is interesting. The considered range of vibration frequencies is also harmful to people and propagates over long distances and is poorly damped by matter. Unfortunately, this was not indicated in the paper. Some notes in the file are attached. It is imperative to correct the conclusions.
Comments for author File: 
Comments.pdf
Author Response
Point 1: The considered range of vibration frequencies is also harmful to people and propagates over long distances and is poorly damped by matter. Unfortunately, this was not indicated in the paper.
Response 1: The device developed in this paper is used for ground tilt vibration isolation of gravitational wave detection, laser frequency stabilization and various types of microscopes. The amplitude of ground vibration is very small, generally the level of mrad, so it will not harm people and can not spread far. Such a statement has been added to the revision of manuscript on page 1.
Point 2: On page 1, vibro-isolators are selected taking into account the natural frequency of the isolated object and the frequency of excitations.
Response 2: In the revision of manuscript, the sentence “... from ?Hz to several Hz ...” has been revised as “Various types of microscopes, laser frequency stabilization and gravitational wave detection usually works in relatively quiet experimental environment, and these devices will be exciting by low-frequency ground vibration from ?Hz to several Hz. Therefore, vibration isolation at these low frequencies is of importance to improve the precision of measurement experiments”.
Point 3: One page 3, what is the form of external extortion?
Response 3: The external extortion is tilt vibration of ground. For example, the ground tilt to the right causes the frame to tilt to the right, and the feedback control circuit drives the PZT to tilt the frame to the left to balance the tilt to the right, so that the frame returns to the horizontal state.
Point 4: One page 3, In fig. 1, indicate the direction of the external force.
Response 4: In the revision of manuscript, the direction of the external force has been added to fig.1.
Point 5: One page 7, Fig. 7?
Response 5: It is Fig.7, and sorry for the clerical error. In the revision of manuscript, the sentence “Figure 6 ...” is revised as “Figure 8 ...” because another figure is added.
Point 6: On page 7 and 8, It is difficult to observe this value in Fig. 7.
Response 6: In the revision of manuscript, the Fig.8 has been enlarged.
Point 7: On page 8, conclusions for complete reflection and necessary improvement. As they stand today, most of these are not conclusions.
Response 7: In the revision of manuscript, the conclusion has been added, deleted and modified.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This paper is to develop tilt vibration isolation by PZT transducer with hysteresis control.
This looks good and solid, but needs to describe in detail experimental results and the effectiveness of tilt vibration isolator suggested in this study.
- In Fig 3, the hysteresis of PZT is a function of operating frequency. Pls refer to the operating frequeny.
- In Figs 6 and 7, the vibration isolation could not be seen to work effectively. More detailed explanation is needed.
- As the hysteresis of PZT varied with frequency, the mathematical model of hysteresis should be defined to frequency range in which to work effectively.
Author Response
Point 1: In Fig 3, the hysteresis of PZT is a function of operating frequency. Pls refer to the operating frequeny.
Response 1: The resonant frequency of PZT with type of NAC 2023 is 486 kHz, and the signal applied to PZT in testing hysteresis curves is DC voltage with zero frequency.
Point 2: In Figs 6 and 7, the vibration isolation could not be seen to work effectively. More detailed explanation is needed.
Response 2: In the revised manuscript, the data with feedback is added, and the effectiveness of the device is illustrated by comparing the output data of the device before and after vibration isolation.
Point 3: As the hysteresis of PZT varied with frequency, the mathematical model of hysteresis should be defined to frequency range in which to work effectively.
Response 3: The direct current driving voltages are used to test the hysteresis curves of PZT, so the mathematical model of PZT hysteresis presented in this manuscript is effective for quasi-static working voltage below several hertz.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
I accept the answers and find them satisfactory.Reviewer 2 Report
This paper was revised well according to the review's comments. So, it can be recommended to publish in Applied science.
