Design and Analysis of Variable-Stiffness Fast-Steering Mirror
, Wang Dai 1,2,3,4, Feixiang Yang 1,2,3,4, Luyao Zhang 3,5 and Li Miao 1,2,3,4,*
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper presents variable stiffness mechanism for the fast steering mirror's flexible hinge. Both theoretical and experimental works have been undertaken. The review comments are summarized as follows.
1. The motivation and final goal of this work are not clear. Why do you want to have the FSM? In addition, the fast motion should be clarified. Any direction or certain desired directional motion?
2. The word "Fast" should be defined in both qualitative and quantitative manners. Moreover, the application of the mirror should be mentioend to understand the physical meaning of the speed.
3. How to formulate the transfer function given by Eq.(18)? The mechanical model representing 1-DOF should be presented with some assumptions.
4. As shown in Figure 1, the variable stiffness mechanism consists of two springs. How to guarantee the durability of the spring stiffness for a long-term use? In experimental test, did you measure the dynamic stiffness? If yes, please explain it in detail.
5. Present the dynamic stiffness of the spring as a function of the frequency.
6. How to evaluate the "time" to judge the fast motion. The motion of the mirror depends on several parameters including the dynamic stiffness of the spring, damping proerty, boundary condition of the spring ends and so forth. Thes points need to be rectified. The higher stiffness does not bring the haster motion all the time. The phase angle, of course, is affected by several parameters.
7. The power of the servo-motor to change the natural frequency should be also presented. In fact, this is a real actuator and the spring stiffness depends on the power level.
8. This reviwer strongly suggests the authors to present the spring movement to change the stiffness and the corressponding mirror motion to show how fast it is.
9. To demonstrate some benefits and advantages of the proposed mechanism, a comparative work between the proposed method and one of previous methods (such as using piezoelectric materials actuators) will be very helpful.
Comments on the Quality of English LanguageEnglish should be improved a lot.
Author Response
Thank you for your valuable suggestion. The questions you summarized are very
valuable. In the revised manuscript, the authors elaborated on these issues in detail. The corresponding changes are highlighted in blue color in the revised manuscript. The detailed responses are given as below.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsFrom a technical point of view, the paper is interesting with sound theoretical discussions and experimental results. I have comments regarding the presentation which are given in the next section.
Comments on the Quality of English Language1. The first sentence of the abstract needs to rephrased, I am not sure what the authors are trying to say.
2. In lines 196 and 201 the authors may reconsider starting the sentence in a different way as using 'Where' makes it seem as if the sentence is a continuation from the previous line.
3. Is the start of line 274 supposed to be "Analysis of the sweep..."?
Author Response
Thank you very much for your recognition of our work. We sincerely appreciate the time you took to provide valuable suggestions. Your advice regarding paper writing has been tremendously helpful. We have carefully and thoroughly incorporated every piece of advice you provided. The corresponding changes are highlighted in blue color in the revised manuscript. The detailed responses are given as below.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe article discussed a variable stiffness mechanism, its mathematical formulation, and experimental validation for use in Fast Steering Mirror (FSM) flexible hinge. In general, the article will well written and covers both the theorical and experimental aspects. However, to improve the overall quality of the manuscript, the authors must address and incorporate the following comments to the revised manuscript.
1. In the introduction part, instead of consistently using Reference [abc], use a combination of XYZ at al. [abc], The research in [abc], the authors in [abc], which are the commonly employed style of referring to the published literature.
2. In section 2.2, the authors have shown in figure 2e the "negative stiffness" stiffness is a physical characteristic property which cannot be negative. The authors should explain the meaning and context of the negative stiffness.
3. For the experimental validation, the authors have employed a sweep frequency excitation in the range of 1Hz-400Hz, however, the measured response is showing a single peak for all the discussed cases. Explain this in the revised manuscript. In addition, also add the sweep signal in the time and frequency domains to give the reader a clearer idea of the dynamic testing and validation.
4. Add a table showing a comparison of the proposed work with similar works from the published literature.
Author Response
We are very glad to see this news and express our sincere thanks to you for the
recognition of our work. We would like to express our sincere gratitude to your
constructive comments on improving our paper. Thanks a lot for your very helpful comments and suggestion on the manuscript. As per your valuable advice and constructive comments, we seriously responded and revised the manuscript in detail. The corresponding changes are highlighted in blue color in the revised manuscript. The detailed responses are given as below.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper has been well revised based on the reviewers' comments.
It is now acceptable in its current form.
Comments on the Quality of English LanguageEnglish should be polished in terms of typos and grammatical errors.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors have addressed and incorporated all my comments to the revised manuscript which has improve the overall quality of the manuscript.
