Investigation of Innovative High-Response Piezoelectric Actuator Used as Smart Actuator–Sensor System
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsIn this paper, the authors present an experimental study with three piezoelectric stack actuators to study their static and dynamic characteristics. This work's motivation is to develop a smart Industry 4.0 component that incorporates both actuator and sensor functions.
The manuscript is fairly written and needs a little improvement. I think the work has important experimental data, but the results need better communication. But overall, I think that the manuscript is interesting and can be accepted with improvements. I leave below my comments.
1) References of this manuscript should be larger since there is a lot of literature on this subject, especially for the theoretical part.
2) The authors should not mention in the abstract how the paper is structures. For example, the expression “The final section…" should not be used. This is usually done in the introduction.
3) The authors chose to reference the equations only, without connecting them to the text. I don’t think this is a good way of writing and the authors should consider revising this.
4) The authors use the term Fpzt for both the generated force of the piezoelectric stack actuator (Eq. (5)) and for the blocking force (Eq. (1)). Wouldn’t it be better to distinguish these two forces?
5) The theoretical background of Section 2 needs references since the authors don’t deduce the equations.
6) Figure 4: Divide the 3 figures into subfigures. Numbers in Fig. 4 (b) must be described.
7) Please provide more description in the legend of the figures. Moreover, Figure 1 should have the (a) and (b) description in the legend, not below the figure()
8) Section 4.1, line 200: the authors don’t need to bullet points. Just divide into (1) and (2) in a phrase.
9) Section 4.1, line 204: Saying “NI LabVIEW interface”, Python, Matlab, etc, is the same thing, it does not add information. Usually, companies provide example scripts for several languages, including LabVIEW. Are the authors using any of these scripts? Please provide more details on the open-loop or closed-loop position control.
10) Please define the acronyms PWM and PNM. What is PNM?
11) In the PWM method, what are the parameters used?
12) In Figure 9, please define the variables in the figure. Moreover, write the second-order differential equation.
13) The acronym (PE) is defined again in page 9, line 257.
14) Figure 11: put the description of each subfigure. Once again, use the legend to write, not the figure itself.
15) Figure 11: Why waste so much space in the graphs for t<0 ?
16) Pulse width modulation is defined too late on page 11, line 296
17) Why not increase the size of some figure in x-direction like in the case of Figure 12? That way, we can observe better the response near t= 0.
18) Figure 14: The authors used commas instead of full stops for the decimal points in the x and y-axis. Please correct. Once again, a lot of space is not being used and the legend of the figure could be at the side. And provide more description on the legend explaining the subfigures and tn.
19) Figure 15: More description in the legend.
20) When referring to this manuscript, please use “This paper”, not “The paper”.
21) There are two sections called “6”. Either way, the first one that appears with title “The concept of smart piezoelectric actuator system” should actually be a subsection of Section 5. It is merely a proposal, there is no data involved, and therefore there is no reason to do a single Section out of it.
22) I think the authors should revise the second Section 6. It should only be a conclusion section. Some of the discussion is repeated and the remaining could be added to Section 5 of the results (Results and Discussion). Moreover, some phrases should have references.
23) The acronym for piezo elements (PE) is not defined when the word first appears. Moreover, in the conclusions, it is defined again. And after defining, the authors alternate between using and not using. Be consistent with the usage.
24) “According”, page 9, line 270.
25) Figure 11: The variables on the x and y-labels (t and U) should be italic.
Comments on the Quality of English Language
In some parts, the english needs small improvements only.
Author Response
Dear reviewer, thank you for your valuable comments, suggestions and guidelines, which help us to improve this paper. Please find all the answers related to your comments in the seperate attached document "Response to Reviewer 1 Comments". The changes in the article were marked by red text.
Comment 1: References of this manuscript should be larger since there is a lot of literature on this subject, especially for the theoretical part.
Response 1: The literature is added to cover piezoelectric actuator usage, their benefits and theoretical background. New reference:
- Zhou, X., Wu, S., Wang, X. et al. Review on piezoelectric actuators: materials, classifications, applications, and recent trends. Front. Mech. Eng. 2024, 19, 6. [CrossRef]
Comment 2: The authors should not mention in the abstract how the paper is structures. For example, the expression “The final section…" should not be used. This is usually done in the introduction.
Response 2: Thank you for these guidelines. The Abstract is modified and corrected, lines from 18 to 21. The additional text is added at the end of the Introduction section to highlight the structure of the paper, lines 61 to 69.
Comment 3: The authors chose to reference the equations only, without connecting them to the text. I don’t think this is a good way of writing and the authors should consider revising this.
Response 3: Thank you for this suggestion. At the beginning of the paragraph we added one sentence explain which reference is the base for the theoretical part. “The fundamentals of piezo electric actuators and the mathematical formulation is described on the basis described in [13].” The text related to the fundamentals of the piezo electric actuators and piezo / inverse piezo effect is covered by reference 11, 12 and 13. Reference 11 and 13 were used for the fundamentals and equations.
Comment 4: The authors use the term Fpzt for both the generated force of the piezoelectric stack actuator (Eq. (5)) and for the blocking force (Eq. (1)). Wouldn’t it be better to distinguish these two forces?
Response 4: Thank you for this comment. We carefully check the text describing the generated and blocking force of piezo actuator. In the beginning of the paragraph explaining the equation (1) (from line 113 and 118) we talk about Fpzt, generated force of piezo actuator. The blocking force is here corrected to generated force. The statement including “load exceed the generated force” is corrected.
Comment 5: The theoretical background of Section 2 needs references since the authors don’t deduce the equations.
Response 5: Thank you for these instructions. The references [11 - 15] were added in the paragraphs describing the piezo electric fundamentals and support equations from (1) to (8).
Comment 6: Figure 4: Divide the 3 figures into subfigures. Numbers in Fig. 4 (b) must be described.
Response 6: Thank you for this suggestion. Figure 4 is divided into (a), (b) and (c) and mentioned, explained in the text. Since Figure 4b and Figure 4c represents the model (virtual replica) and the real manufactured actuator we use one paragraph for description.
Comment 7: Please provide more description in the legend of the figures. Moreover, Figure 1 should have the (a) and (b) description in the legend, not below the figure ()
Response 7: Thank you for your comment. We checked all figures to apply this if necessary. Figure 1 is divided in (a) and (b). The description of Figure 1 is corrected as well as the title. The same was done for Figure 8.
Comment 8: Section 4.1, line 200: the authors don’t need to bullet points. Just divide into (1) and (2) in a phrase.
Response 8: Thank you for good suggestion. The text is corrected and the two main parameters are listed within the text.
Comment 9: Section 4.1, line 204: Saying “NI LabVIEW interface”, Python, Matlab, etc, is the same thing, it does not add information. Usually, companies provide example scripts for several languages, including LabVIEW. Are the authors using any of these scripts? Please provide more details on the open-loop or closed-loop position control.
Response 9: Thank you for the question and comment. The explanation was corrected as “Personal computer with NI LabVIEW tool and graphical user interface is used to perform testing cycle, the open-loop or closed-loop position control, to monitor the measured variables and to save the measured results. Standard block diagrams and NI LabVIEW library are used to create all functional diagrams.” So, in this case we use standard elements from NI LabVIEW library and create functional blocks, so this is programming using the blocks and not specific code, script. More details and principles about closed-loop and open loop control is given in the corrected text.
Comment 10: Please define the acronyms PWM and PNM. What is PNM?
Response 10: Thank you for the comment. Both acronyms PNM and PWM were checked and explained, when appears in the text for the first time. PNM in line 239 and PWM in line 247.
Comment 11: In the PWM method, what are the parameters used?
Response 11: Thank you to rise this missing part. The details and the parameters set at low-voltage control electronics are included in the section where PWM method is described in more details. Section 4.1, line 250.
Comment 12: In Figure 9, please define the variables in the figure. Moreover, write the second-order differential equation.
Response 12: Thank you for the comments. Figure 9 was corrected, second-order differential equation was added and parameters explained. Line 297 and 309
Comment 13: The acronym (PE) is defined again in page 9, line 257.
Response 13: Thank you for comment. We checked the paper and corrected when necessary. The acronym PE is explained only at the beginning in Section “Theoretical background of piezoelectric actuators”. PE or PEs are used in other parts of the paper. Since the comment is also related to comment No. 23, the answer is given in both comments.
Comment 14: Figure 11: put the description of each subfigure. Once again, use the legend to write, not the figure itself.
Response 14: Description of each figure or set of figures is added. Figure 11 was revised and corrected. The legend for different curves was deleted from figures and added separately in the Legend section.
Comment 15: Figure 11: Why waste so much space in the graphs for t<0?
Response 15: Thank you for remark. The testing cycle begins 0.25 ms before the step appears. So, we include the entire recorded cycle and not delete the first part. This is the set number of recorded and saved points in LabVIEW program.
Comment 16: Pulse width modulation is defined too late on page 11, line 296
Response 16: PWM description and the closed-loop control is explained earlier in the section 4.1 “Test rig setup method”.
Comment 17: Why not increase the size of some figure in x-direction like in the case of Figure 12? That way, we can observe better the response near t= 0.
Response 17: Thank you for the comment and suggestion. Additional explanation of step response of activation of one piezo element is given in the section 5.2 with a Figure 14a and Figure 14b. Figure 14a shows the step response by using different PWM signals explained by Figure 12, while Figure 14b shows the step response of activating one PE with minimal possible PWM width signal to achieve minimal possible stroke of piezoelectric actuator system. The step response range is given for the given case.
Comment 18: Figure 14: The authors used commas instead of full stops for the decimal points in the x and y-axis. Please correct. Once again, a lot of space is not being used and the legend of the figure could be at the side. And provide more description on the legend explaining the subfigures and tn.
Response 18: Figure 14, in the corrected version of the paper Figure 15, is corrected in terms of x and y axis. Figure 13 and Figure 14, in the corrected version of the paper Figure 13 and Figure 15 are corrected in terms of the Legend placement to fill the empty space. Additional description of step response times tni as well as subfigures representing graphical presentation of active PE was added to the text.
Comment 19: Figure 15: More description in the legend.
Response 19: Figure 15, Figure 16 in new revised paper, is corrected, the title is more precise, the legend is added to explain abbreviations given in the figure.
Comment 20: When referring to this manuscript, please use “This paper”, not “The paper”.
Response 20: Thank you for this suggestion. The paper was checked and corrected as proposed.
Comment 21: There are two sections called “6”. Either way, the first one that appears with title “The concept of smart piezoelectric actuator system” should actually be a subsection of Section 5. It is merely a proposal, there is no data involved, and therefore there is no reason to do a single Section out of it.
Response 21: The old Section 6 was added under section 5 “5.3. The concept of smart piezoelectric actuator system”.
Comment 22: I think the authors should revise the second Section 6. It should only be a conclusion section. Some of the discussion is repeated and the remaining could be added to Section 5 of the results (Results and Discussion). Moreover, some phrases should have references.
Response 22: The title of the section 5 was corrected to “Results and discussion”, we include the findings also from section Conclusions when necessary. Additional references are added for particular phrases. The sections were revised in order to eliminated the duplicated text. Section 6 Conclusions is rewritten according to the instructions of other reviewers, short conclusion with quantitative values highlighted.
Comment 23: The acronym for piezo elements (PE) is not defined when the word first appears. Moreover, in the conclusions, it is defined again. And after defining, the authors alternate between using and not using. Be consistent with the usage.
Response 23: The PE acronym is defined in the beginning of the paper when the PE appears for the first time. Further on, PE or PEs is used later in the paper.
Comment 24: “According”, page 9, line 270.
Response 24: The grammar is checked and the word corrected.
Comment 25: Figure 11: The variables on the x and y-labels (t and U) should be italic.
Response 25: The graphs were corrected, x and y-labels (t and U) are italic.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
1.(line 45 on page 2) In the introduction , there is extensive discussion of application scenarios, but insufficient reporting on the related research of piezoelectric actuators, which makes it difficult to highlight the advantages of the actuator described in this paper.
2.（line 120 on page 4）, is the “spring-loaded piezoelectric stack” the same as “a single disc spring” mentioned in chapter 3 (line 171 on page 6)?
3.（line 172 on page 6） does the 122N, 228N, 325N, and 418N in Table 3 represent the maximum force values within that range?
4. (on page 7)In Figure 6, what is BNC-2120? What kind of device is it? What are its performance parameters, and are there any similar devices?
5.The parameters for tuning in the PID algorithm are not clearly specified in the paper.
6.The response speed and stroke of the piezoelectric actuator in this paper can be compared with those available on the market
Author Response
Dear reviewer, thank you for your valuable comments, suggestions and guidelines, which help us to improve this paper. Please find all the answers related to your comments in the seperate attached document "Response to Reviewer 2". The changes in the article were marked by red text.
Comment 1: (line 45 on page 2) In the introduction, there is extensive discussion of application scenarios, but insufficient reporting on the related research of piezoelectric actuators, which makes it difficult to highlight the advantages of the actuator described in this paper.
Response 1: The statements and the paragraph are supported by new reference related to piezo actuators, their usage, benefits and possible applications. The new reference [10]: Zhou, X., Wu, S., Wang, X. et al. Review on piezoelectric actuators: materials, classifications, applications, and recent trends. Front. Mech. Eng. 2024, 19, 6. [CrossRef]
Comment 2: (line 120 on page 4), is the “spring-loaded piezoelectric stack” the same as “a single disc spring” mentioned in chapter 3 (line 171 on page 6)?
Response 2: Yes in some way, if we focus on operating principles. Three single disc springs were used to form disk spring unit with proper stiffness needed for the actuator system (three single disk springs connected in series).
Comment 3: (line 172 on page 6) does the 122N, 228N, 325N, and 418N in Table 3 represent the maximum force values within that range?
Response 3: The forces represent the required and realistic forces to deflect the disc spring to a certain deflection. The characteristics is provided by manufacturer of disc springs and verified by our own experimental test (applying the force to disk spring and measure the deflection). Four characteristic points were used to characterised the stiffness of a single springe as well as the disk spring unit, serial connected springs. For this purpose (serial connection of three single disc springs) we perform test to simulate the real condition of installed spring unit into the piezoelectric actuator system. The results are presented in Table 3, so these are the measured and verified values.
Comment 4: (on page 7) In Figure 6, what is BNC-2120? What kind of device is it? What are its performance parameters, and are there any similar devices?
Response 4: The additional description of DAQ device is given at test rig description. The reference for National Instruments is added for NI LabVIEW and BNC-2120 DAQ device, technical specifications and User manual.
National Instruments: https://www.ni.com/en.html
BNC-2120: https://www.ni.com/sl-si/support/model.bnc-2120.html?srsltid=AfmBOooiAOH0o-K5XxsXSTHo-K-pfbotgjld85544TNmXUcmhjF8CiUc
Comment 5: The parameters for tuning in the PID algorithm are not clearly specified in the paper.
Response 5: The explanation of open-loop and closed-loop position control is given in Section “4.1. Test rig setup”. Also, Pulse number modulation PNM and pulse width modulation PWM methods are described.
Comment 6: The response speed and stroke of the piezoelectric actuator in this paper can be compared with those available on the market
Response 6: Some of the comparisons are added in the section “5.2. Dynamic performance of piezoelectric actuator system” line 389.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors conducted an experimental analysis of a piezoelectric actuator component of hydraulic digital fluid control units. They determined static and dynamic characteristics, aiming to develop a smart Industry 4.0 component incorporating both actuator and sensor function. They examined the main challenges, advantages, disadvantages, and working principles to define the main design parameters. The system comprised three piezoelectric stack actuators in series, Simultaneous actuation and sensing function is based on the applied electrical voltage at each piezo-element. The experimental setup and testing resulted to superior actuator stroke control, high stroke resolution, and high-dynamic step response with appropriate open-loop or closed-loop control. Finally, a smart actuator concept is proposed, based on an I4.0 actuator administration shell, integrated with 5G and RFID technology. This enables plug-and-play functionality and efficient communication between the valve and the piezoelectric actuator system.
The following issues should be addressed in a revised version of the manuscript:
In the context of Equation 1: Further discussion is necessary with regard to the dependence of k_pzt to the specific material and design of the piezoelectric stack. See for example the following works for material selection and design implications on macro-properties of piezoelectric sensors and actuators:
10.1515/ehs-2022-0087
10.1117/12.776396
Line 128: A section cannot end with a Figure. Please add discussion below Figure 3.
Table 2: C, electrical capacitance
Table 3: The disc springs characteristic is based on FEM modeling or supplied by the manufacturer? Is it a critical component that should obey strict quality criteria? What about the contact behavior? Please explain in more detail.
Figure 9: A section cannot end with a Figure. Please add discussion below Figure 9: What is the optimal response seeked for this type of system? Do you add external capacitance?
Line 291; How much is the tolerance measured around 80V?
Line 296: Please show a typical PWM signal producing one of the responses presented. (in the oscilloscope).
Line 331-332: Do you mean high accuracy of the piezoelectric actuator system response stroke. Also, in the case of multiple piezo-elements, please discuss the effect of interface details.
Line 422: Please add a separate Conclusions section, no larger than 10 lines, to summarize your findings. This Conclusions section should contain some important quantitative information.
English language will need further improvement.
Comments on the Quality of English LanguageModerate English langage improvements required.
Author Response
Dear reviewer, thank you for your valuable comments, suggestions and guidelines, which help us to improve this paper. Please find all the answers related to your comments in the seperate attached document "Response to Reviewer 3". The improvements are included in the article in particular sections and marked with red text.
Comment 1: In the context of Equation 1: Further discussion is necessary with regard to the dependence of k_pzt to the specific material and design of the piezoelectric stack. See for example the following works for material selection and design implications on macro-properties of piezoelectric sensors and actuators:
10.1515/ehs-2022-0087
10.1117/12.776396
Response 1: Thank you for this additional consideration. We have checked how the stiffness of piezo stacks influence the static and dynamic performance. The original mathematical formulation was given by Physic Instruments reference, where Piezoelectric stack actuators fundamentals rely on simplified mathematical expressions appropriate for the practical use. Reference [14] and [15] were added to support theory and to discuss effective stiffness of piezo actuators and working conditions.
Comment 2: Line 128: A section cannot end with a Figure. Please add discussion below Figure 3.
Response 2: The discussion is added after Figure 3. There are some rearrangements of text and equations.
Comment 3: Table 2: C, electrical capacitance
Response 3: Thank you for revision. Corrected in Table 2.
Comment 4: Table 3: The disc springs characteristic is based on FEM modeling or supplied by the manufacturer? Is it a critical component that should obey strict quality criteria? What about the contact behavior? Please explain in more detail.
Response 4: Table 3 is revised and one column is added to characterise the experimental results for disc spring unit. The corrected text “Table 3 shows theoretical characteristic of a single disc spring (Value 1) and measured characteristic of disc spring unit (Value 2) used in piezoelectric actuator system [17].” The disc spring characteristics is based on real experimental tests, applied force and measured deflection. The same was done for disc spring unit (three springs in series), where contact conditions were included during the tests. The installation procedure or the assembly procedure of three discs is explained to understand the initial conditions. Since we measure the characteristics for disc spring unit, we consider also the real contact behaviour.
Comment 5: Figure 9: A section cannot end with a Figure. Please add discussion below Figure 9: What is the optimal response seeked for this type of system? Do you add external capacitance?
Response 5: The text is reallocated after Figure 9. Explanation about desired step response of piezoelectric actuator system is added. The piezo electronics has external capacitors for each piezo stack. We have independed control circuit for each piezo stack.
Comment 6: Line 291; How much is the tolerance measured around 80V?
Response 6: The detail analysis of electrical voltage measured at each PE is explained in more details. All measured and discussed values have tolerances added.
Comment 7: Line 296: Please show a typical PWM signal producing one of the responses presented. (in the oscilloscope).
Response 7: Figure 12 is divided to (a) and (b). (a) shows different actuator strokes while (b) shows control signal of low-voltage electronics, 0.1 ms width that corresponds to actuator stroke of 20 microns. Based on controlling the width of signal we are affecting the charging period and thus piezo stack extension.
Comment 8: Line 331-332: Do you mean high accuracy of the piezoelectric actuator system response stroke. Also, in the case of multiple piezo-elements, please discuss the effect of interface details.
Response 8: Thank you for this comment. Yes, we meant high accuracy, which is also a result of high resolution, for example 1 micron. The word is changed to “accuracy”.
Comment 9: Line 422: Please add a separate Conclusions section, no larger than 10 lines, to summarize your findings. This Conclusions section should contain some important quantitative information.
Response 9: The discussion and findings were involved in the section “Results and discussion”. Section 6 consider only conclusions and highlight the main quantitative results. The conclusions were shortened to 12 lines in order to highlight important findings.
Comment 10: English language will need further improvement.
Response 10: English was checked and improved.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors addressed most of my concerns and questions but now there is still some issues with the manuscript. I leave bellow my comments.
Major comments:
1) Page 2, line 69: The authors say that “is utilized for the development of a smart concept”, but it wasn’t utilized yet, right? So the authors should not write this phrase like this.
2) In Fig. 1(b) there is still variables like “U”; “Delta I”, “h” and “P” which are not described.
3) The authors added new references for the theoretical part but I'm very surprise with their choices. Reference 13 is a Master thesis and Reference 15 is a proceeding. Aren't the authors able to find peer-reviewed articles with a solid theoretical background?
4) Figure 5: Why do some of the x-ticks of the x-axis don’t have numbers?
5) Moreover, where does Figure 5 come from?
6) Page 10, line 333: The authors say “According to the theory using the disc”. This type of statement should be used. The authors considered a theoretical model which, of course, has a limit of validity. The authors should mention which model they are referring to. This phrase is also used in page 6, line 210.
7) References should be placed within the text, not after a full stop. (e.g., page 4, line 146)
Comments on the Quality of English Language
Regarding English and formatting
1) In the abstract, line 19, the phase starting with “That will allow” should not start like that. The authors can, for instance, use a comma and use the word “which”.
2) Page 8, line 254: comma should not be used for the decimals.
3) Page 12, line 357 “related”.
4) Page 5 line 135: Figure 4(a)
I invite the authors to review, improve and correct anymore English phrases or typos.
Author Response
Dear reviewer, thank you for your valuable comments, suggestions and guidelines, which will help us to improve this paper. Please find all the answers related to your comments bellow in the section “Point-by-point response to Comments and Suggestions for Authors”. The improvements are included in the paper in particular sections and marked with new red text. The corrections from Round 1 are included as normal black text.
Point-by-point response to Comments and Suggestions for Authors
Major Comments
Comment 1: Page 2, line 69: The authors say that “is utilized for the development of a smart concept”, but it wasn’t utilized yet, right? So, the authors should not write this phrase like this.
Response 1: Thank you for this comment. Yes, it is true, we proposed a concept only, which will be developed as a real actuator unit or system in the future. Therefore, we corrected the statement in a way presented below.
“The main part of this paper presents the experimental characterization of the static and dynamic performances of the piezoelectric actuator system, which is used as a base for development of a smart concept of actuator system. The proposed concept of actuator administration shell will be used for future development of a real actuator system as well as switching valve and DFCU.”
Comment 2: In Fig. 1(b) there is still variables like “U”; “Delta I”, “h” and “P” which are not described.
Response 2: Thank you for printing this out. Figure 1b has additional explanation of variables. Line 92 – 97.
Comment 3: The authors added new references for the theoretical part but I'm very surprise with their choices. Reference 13 is a Master thesis and Reference 15 is a proceeding. Aren't the authors able to find peer-reviewed articles with a solid theoretical background?
Response 3: Additional references were found and added in the theoretical part as well as in the Methodology and some Results sections to support the chosen methods, ideas and discussion of the results. You can find new references:
- X. Gao, J. Yang, J. Wu, X. Xin, Z. Li, X. Yuan, X. Shen, S. Dong, Piezoelectric Actuators and Motors: Materials, Designs, and Applications. Adv. Mater. Technol. 2020, 5, 1900716. [CrossRef]
Included in the line 82.
- Peidong, L.; Jie, F.; Yuan, W.; Zhiwei, X. and Miao, Y. Dynamic model and parameters identification of piezoelectric stack actuators. The 26th Chinese Control and Decision Conference (2014 CCDC), Changsha, China, 2014, pp. 1918-1923. [CrossRef]
Included in the lines 112, 117, 121, 137, 141.
- Stamatellou, Antiopi-Malvina. PZT and PVDF piezoelectric transducers’ design implications on their efficiency and energy harvesting potential. Energy Harvesting and Systems. 2023, vol. 10, no. 2, pp. 157-167. [CrossRef]
Included in the line 126.
- Sherrit, S.; M. Jones, J.; B. Aldrich, J.; Blodget, C.; Bao, X.; Badescu, M.; and Bar-Cohen, Y. Multilayer piezoelectric stack actuator characterization. Proc. SPIE 6929, Behavior and Mechanics of Multifunctional and Composite Materials. 2008, 692909. [CrossRef]
Included in the line 128.
- Jialin, Y.; Yongjian, M.; Bingbing Q. X. Y.; Mao, Y.; Bangzhao, Z. and Yonggang, L. Dynamic responses of normal and partially failed piezoelectric stack actuators under sinusoidal voltages with DC biasing. Smart Materials and Structures. 2024, 33, 9. [CrossRef]
Included in the line 164
- Kanchan, M.; Santhya, M.; Bhat, R.; Naik, N. Application of Modeling and Control Approaches of Piezoelectric Actuators: A Review. Technologies 2023, 11, 155. https://doi.org/10.3390/technologies11060155. [CrossRef]
Included in the line 272, 314.
- Zhao, J.H.; Wang, M.L.; Wang, Z.J.; Grekhov, L.; Qiu, T.; Ma, X.Z. Different Boost Voltage Effects on the Dynamic Response and Energy Losses of High-speed Solenoid Valves. Appl. Therm. Eng. 2017, 123, 1494–1503. [CrossRef]
Included in the line
- Gao, Q.; Wang, J.; Zhu, Y.; Wang, J.; Wang, J. Research Status and Prospects of Control Strategies for High Speed On/Off Valves. Processes 2023, 11, 160. [CrossRef]
Included in the line 434.
- CEDRAT TECHNOLOGIES. Parallel Pre-stressed Actuator. Available online: https://cedrat-technologies.com/categorie-produit/piezo-actuators/amplified-piezo-and-parallel-pre-stressed/parallel-pre-stressed-actuator-piezo-actuators/ (16.09.2024).
Included in the line 441.
Comment 4: Figure 5: Why do some of the x-ticks of the x-axis don’t have numbers?
Response 4: Thank you for this comment. Figure 5 was corrected and all x-ticks of the x-axis have numbers. There was not particular reason to hide the numbers, only to include the axis and the numbers relevant to the particular use case. Since the maximal free displacement of piezoelectric stack actuator unit is up to 138 microns (3x46 microns), we show the x-axis up to 145 microns. The same can be said for disc spring unit deflection by taking into account the initial pretension and initial deflection.
Comment 5: Moreover, where does Figure 5 come from?
Response 5: Figure 5 is constructed by us to show graphically the initial state of actuator system and the functional state (during the piezo stack operation for the given use case). It helps to understand the operational point of the actuator system.
Comment 6: Page 10, line 333: The authors say “According to the theory using the disc”. This type of statement should be used. The authors considered a theoretical model which, of course, has a limit of validity. The authors should mention which model they are referring to. This phrase is also used in page 6, line 210.
Response 6: Thank you for this comment. We are aware that we consider simplified model, which was highlighted in the text. Both statements were corrected. The first description is given in line 227 – 230 and the second is given in line 356 – 358.
Comment 7: References should be placed within the text, not after a full stop. (e.g., page 4, line 146)
Response 7: Thank you for pointing this out. References were corrected and placed within the text.
Regarding English and formatting
Comment 1: In the abstract, line 19, the phase starting with “That will allow” should not start like that. The authors can, for instance, use a comma and use the word “which”.
Response 1: Thank you for this suggestion. The sentence was corrected as “This paper proposes a concept of smart piezo actuator system focused on I4.0 and actuator ad-ministration shell, integrated with 5G and RFID technology, which will allow automatic plug-and-play functionality and efficient interconnection, communication and data transfer be-tween hydraulic valve and the piezoelectric actuator system.”
Comment 2: Page 8, line 254: comma should not be used for the decimals.
Response 2: Thank you for checking this. The paper was checked for similar mistakes and corrected.
Line 275: …set to 0.1 millisecond …
Comment 3: Page 12, line 357 “related”.
Response 3: The grammar and typos were checked with a native speaker.
Comment 4: Page 5 line 135: Figure 4(a)
Response 4: The paper was checked; the citations of Figures were corrected according to the given example. Figure 4a (before) – Figure 4(a) (new corrected version).
Additional clarifications
The text, figures, and tables have been arranged to fit the paper's pages and to comply with the journal’s guidelines, ensuring that descriptions are placed near the corresponding figure or table.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe author's editing of the manuscript effectively resolved my doubts.
Author Response
Dear Reviewer,
Thank you sincerely for taking the time to review our manuscript and for providing valuable comments and suggestions. Your feedback has been instrumental in enhancing the quality of the article, and we believe it has strengthened the work, making it more impactful and accessible to researchers and other readers.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe revised version is acceptable for publication.
Comments on the Quality of English LanguageMinor editing required
Author Response
Dear Reviewer,
Thank you sincerely for taking the time to review our manuscript and for providing valuable comments and suggestions. Your feedback has been instrumental in enhancing the quality of the article, and we believe it has strengthened the work, making it more impactful and accessible to researchers and other readers.
Point-by-point response to Comments and Suggestions for Authors
Comment 1: Does the introduction provide sufficient background and include all relevant references? Can be improved.
Response 1: The introduction was additionally improved, also according to the other reviewers’ comments.
Comment 2: English quality: Minor editing required.
Response 2: The English of the article was checked by native speaker and corrected.
Author Response File: Author Response.pdf
