Research on Control Strategy of a Magnetorheological Fluid Brake Based on an Enhanced Gray Wolf Optimization Algorithm
Round 1
Reviewer 1 Report
The authors modify the grey wolf optimization algorithm (GWOA) and use their modified grey wolf optimization scheme to tune the PID controller parameters, and in turn, demonstrate faster response and no overshoot when compared to conventional PID and GWOA. I believe the paper fails to address the limitations of their improved algorithm. I do not recommend the manuscript for publication in its current form and request the authors address the concerns raised.
Major:
Please add citation(s) for the claims made in lines 139-140 ("saturation magnetization intensity of No. 20 steel"), 141-142 ("working demand of MRB")
The authors should expand section 2.4 .
Lines 171-173 should state the equations or add relevant citations explaining what model/equations are used.
Line 181: "Finally, the best fit is 92.45 %, which is a good fitting degree. " It is not clear how or by whom has this standard been decided. Please add a citation.
There is a published paper titled "Improved Grey Wolf Optimization Algorithm and Application" (https://doi.org/10.3390%2Fs22103810), the authors are requested to use a different name instead of "Improved Grey wolf". Also, the authors should demonstrate the robustness of their scheme and its limitations.
The authors should clarify that the parameter 'a' is different in sections 3.1 and 3.2 by explicitly stating the equation. Also, the symbol N seems to be not defined.
The definition of fitness value and optimal accuracy is not clear in section 3.2.
Minor :
1. Improper use of Capitalization in between sentences.
2. Many passages are not clearly stated and there are grammar and spelling mistakes. The authors are requested to proofread the entire manuscript carefully for spelling and grammar.
I am just listing a few: Figure 6. The spelling of "Control" (Top block) is wrong.
Fig. 9 the axes labels are wrong
Line 171 "The MRB system with strong non-linear is difficult to establish a more accurate model."
Author Response
Modification declares:
Based on the editor and reviewers’ comments, the manuscript has been made extensive modification and the text of modified parts is marked in “red” color. Now, we would like to answer the questions raised by the reviewers as follows:
Response to Reviewer 1:
1. Please add citation(s) for the claims made in lines 139-140 ("saturation magnetization intensity of No. 20 steel"), 141-142 ("working demand of MRB").
Re: Thanks for your comments. References [25] and [26] have been added for the claims in the revised version.
2. The authors should expand section 2.4.
Lines 171-173 should state the equations or add relevant citations explaining what model/equations are used.
Re: Thanks for your comments. Explanations of the source formulas and models have been added in Section 2.4.
3. Line 181: "Finally, the best fit is 92.45 %, which is a good fitting degree. " It is not clear how or by whom has this standard been decided. Please add a citation.
Re: Thanks for your comments. According to experimental experience and literature comparison, the best fit of 92.45% can accurately describe equipment characteristics. Reference [22] has been added in revised version.
4. There is a published paper titled "Improved Grey Wolf Optimization Algorithm and Application" (https://doi.org/10.3390%2Fs22103810), the authors are requested to use a different name instead of "Improved Grey wolf". Also, the authors should demonstrate the robustness of their scheme and its limitations.
Re: Thanks for your comments. The title has been changed to “Research on Control Strategy of Magnetorheological Fluid Brake Based on Enhanced Gray Wolf Optimization Algorithm”. The robustness and limitations of the scheme have been emphasized in Section 5.
5. The authors should clarify that the parameter 'a' is different in sections 3.1 and 3.2 by explicitly stating the equation. Also, the symbol N seems to be not defined.
Re: Thanks for your comments. The parameter 'a' is different in sections 3.1 and 3.2, where the ‘a’ in section 3.1 has been replaced as ‘a1’, and the ‘a’ in section 3.2 has been replaced as ‘a2’. The symbol N has been defined in revised version.
6. The definition of fitness value and optimal accuracy is not clear in section 3.2.
Re: Thanks for your comments. In section 3.2, the standard test functions, known as the fitness function, was chosen with accuracy of 0.001, which has been explained in the revised version.
7. Improper use of Capitalization in between sentences.
Re: Thanks for your comments. The error has been corrected.
8. Many passages are not clearly stated and there are grammar and spelling mistakes. The authors are requested to proofread the entire manuscript carefully for spelling and grammar.
Re: The whole paper has been carefully checked and some grammatical and word errors have been corrected.
9. I am just listing a few: Figure 6. The spelling of "Control" (Top block) is wrong.
Re: Thanks for your comments. The error has been corrected.
10. Fig. 9 the axes labels are wrong
Re: Thanks for your comments. The error has been corrected to Fig 10 in revised version.
11. Line 171 "The MRB system with strong non-linear is difficult to establish a accurate model."
Re: Thanks for your comments. The sentence has been corrected, "The MRB system with strong non-linear is difficult to establish an accurate model."
Reviewer 2 Report
- In general, English grammar should be corrected by a native speaker.
- MR fluids are not a new technology. They have been commercialized over 20 years ago. (line 22)
- line 66: .. cannot meet (requirements)?
- section 3 - no data on the material properties used (B-H curves of steel and MRF, what alloys were used, etc.?)
- Fig. 4 and 5 - the captions should include operating conditions: current or magnetic field
- Section 2.2 should be complemented by steady-state calculations of the MR brake characteristics (torque vs current and velocity). If the characteristics were measured they should be included for comparison.
- Fig. 6 - please, add I/O signals to the diagram and improve the image quality
- line 155 - description of the data acquisition system should be more detailed.
- line 166 - the torque range is limited by viscous losses. Therefore, it cannot be 0 Nm.
- line 168 - which card and sensor were used? Manufacturers?
- line 170 - this is the least detailed part of the paper. On what grounds the authors assumed the MR brake is a 2nd order system? How was the identification experiment performed and what were the results obtained? The section does not included any experimental data which were surely used for the identification experiment. Simply writing down the transfer function is not sufficient.
- Fig. 8 is not clear - too small images, fuzzy characters and difficult to read
- Fig. 8 - grammar in the caption of the figure
- line 183 - the contens of sections 3.1 and 3.2 should be rewritten and perhaps combined. What is novel in these sections except for the fact that the authors simply compare the performance of these two algorithms using well-known test functions?
- Fig. 12 - low quality; should be improved
- In Fig. 13 what is unit of the response signal?
- Fig. 14 - low quality
- Section 4 (I consider it the most important part of the manuscript) is simply too short and lacks data. The authors simply demonstrate the performance of the tuned algorithm based on 2 discrete data sets (see Fig. 14 a,b) and on these grounds, they draw conclusions on the superiority of their algorithms. The information is simply not sufficient for this claim. In addition to the 2 step responses other control scenarios should be included. It would be very beneficial for the manuscript if the authors include Bode plots of the 2 close loop systems over a range of frequencies and input current and make a relevant comparison.
As a summary of the review:
The authors propose an interesting control strategy for MR brakes which seems original and with some significance, however, at the moment the paper lacks the scientific rigour and quality to be accepted for publication in the journal. The authors should rewrite the paper given the comments, improve the illustrations, add the requested or missing information and perhaps resubmit.
Author Response
Modification declares:
Based on the editor and reviewers’ comments, the manuscript has been made extensive modification and the text of modified parts is marked in “red” color. Now, we would like to answer the questions raised by the reviewers as follows:
1. In general, English grammar should be corrected by a native speaker.
Re: The whole paper has been carefully checked and some grammatical and word errors have been corrected.
2. MR fluids are not a new technology. They have been commercialized over 20 years ago. (line 22).
Re: Thanks for your comments. This inaccurate statement has been revised.
3. line 66: cannot meet (requirements)?
Re: Thanks for your comments. The sentence has been changed to “Firstly, the MRB still has some challenges in braking with large torque.”
section 3 - no data on the material properties used (B-H curves of steel and MRF, what alloys were used, etc.?)
Re: Thanks for your comments. The material properties have been added in Section 2.3. In order to obtain the best braking torque of MRB, the material is carefully selected. The 40# steel is chosen for magnetic circuit components, and 304 stainless steel is used for the non-magnetic parts. The adopted MRF is MRF-350, its rheological performance parameters are shown in Table 1, and B-H curve is shown in Fig. 5.
4. Fig. 4 and 5 - the captions should include operating conditions: current or magnetic field.
Re: Thanks for your comments. The working current is added to the captions.
5. Section 2.2 should be complemented by steady-state calculations of the MR brake characteristics (torque vs current and velocity). If the characteristics were measured they should be included for comparison.
Re: Thanks for your comments. In Section 2.2, the magnetic field analysis of the MRB has been modified, and in Section 2.3, the dynamic characteristics of magnetic torque and slip velocity has been added in revised version.
6. Fig. 6 - please, add I/O signals to the diagram and improve the image quality.
Re: Thanks for your comments. I/O signals is added to the revised Fig. 6, and the image quality is improved.
7. line 155 - description of the data acquisition system should be more detailed.
Re: Thanks for your comments. Description of the data acquisition system has been detailed in revised version.
8. The torque range is limited by viscous losses. Therefore, it cannot be 0 Nm.
Re: Thanks for your comments. The torque range is emended to “4~30 N·m” in Table 2.
9. Which card and sensor were used? Manufacturers?
Re: Thanks for your comments. Manufacturers are added in the Table 3 and 4.
10. line 170 - this is the least detailed part of the paper. On what grounds the authors assumed the MR brake is a 2nd order system? How was the identification experiment performed and what were the results obtained? The section does not included any experimental data which were surely used for the identification experiment. Simply writing down the transfer function is not sufficient.
Re: Thanks for your comments. Based on relevant literature [22] and experimental tests, 2nd order system of the device is assumed. Detailed data acquisition and model identification methods have been added in Chapter 2.4.
11. Fig. 8 is not clear - too small images, fuzzy characters and difficult to read.
Fig. 8 - grammar in the caption of the figure
Re: Thanks for your comments. Image quality of Fig. 8 has been changed, and the grammar of caption has been corrected.
12. line 183 - the contens of sections 3.1 and 3.2 should be rewritten and perhaps combined. What is novel in these sections except for the fact that the authors simply compare the performance of these two algorithms using well-known test functions?
Re: Thanks for your comments. Sections 3.1 and 3.2 have been revised. Section 3.2 mainly explains the improvement of the algorithm, that is, using the Logistic curve to optimize the update of parameter a1, and the optimization results are verified by the test functions.
13. Fig. 12 - low quality; should be improved
Re: Thanks for your comments. The quality of Fig. 12 is improved.
14. In Fig. 13 what is unit of the response signal?
Re: Thanks for your comments. The response signal from revised Fig. 14 has no unit, which is dimensionless quantities.
15. Fig. 14 - low quality.
Re: Thanks for your comments. The Fig. has been revised to Fig. 15.
16. Section 4 (I consider it the most important part of the manuscript) is simply too short and lacks data. The authors simply demonstrate the performance of the tuned algorithm based on 2 discrete data sets (see Fig. 14 a, b) and on these grounds, they draw conclusions on the superiority of their algorithms. The information is simply not sufficient for this claim. In addition to the 2 step responses other control scenarios should be included. It would be very beneficial for the manuscript if the authors include Bode plots of the 2 close loop systems over a range of frequencies and input current and make a relevant comparison.
Re: Thanks for your comments. The experimental part of Section 4 is indeed relatively short, but the effectiveness of the proposed method has been proved through sufficient data. This work mainly studies the output torque of the MRB in the working process, that is, the changing output torque with time. However, different input currents have little influence on the nonlinearity of the system, so there is less data in this aspect. Different control scenarios and test signals will be carried out in the future and this part has been added to the future works.
Reviewer 3 Report
The paper presents Control Strategy of Magnetorheological Fluid Brake Based on Improved Gray Wolf Optimization Algorithm. The research area of magnetorheological technology, especially in the application is very interesting and promising. The novelty of the paper looks middle or low. The paper also contains many inaccuracies. My selected comments (Q) and recommendation (R) can be seen below.
Q1: Page 1, Line 22
“Magnetorheological fluid (MRF) with rheological properties is considered as one of the most promising new intelligent materials.” Magnetorheological fluid is not new. Could you delete the word new, please?
R1: Page 1, Line 23
“… from a free fluid state to a solid-like state in milliseconds,…”. This publication can be interesting for you: DOI: 10.1038/s41598-022-14718-5. The change is usually under 1 ms.
R2: Page 1, Line 24
“ However, MRB has high nonlinearity, time delay and uncertainty as its working process, and affected by the interaction between current, magnetic field, magnetorheological fluid and 27 structure, which makes it difficult to accurately control its braking torque [6-7].” Very popular paper describing transient behaviour of MR clutch/ brake is: Maas J and Güth D 2011 Experimental investigation of the transient behavior of MR fluids, or new one: Wang H, Bi C, Zhang Y, Ji A and Qiu P 2021 Transient behavior of compressed magnetorheological brake excited by step currents.
Q2: Figure 1
Could you change the coil markings in the picture. The coil has its standard marking.
Q3: Page 3, line 100
“… shear yield stress of magnetorheological fluid.” I think this is not correct. This is shear stress in MR fluid not shear yield stress.
Q4: Page 4, line 112
“…and the simplified structure is shown in Fig. 3, where different colors represent different areas, and loop reluctance can be calculated by Ohm's law. “ This is not correct information. Magnetic reluctance cannot be calculated by Ohm's law. You are just using analogy to Ohm's law.
Q5: Page 5, line 124
“…μi is magnetic conductivity”. The term permeability is usually used.
Q6: Equation 8
Used the common version of this equation not that one. J = 4I / πd2
Q7: Line 139
“It can be seen from Fig. 4 that the magnetic induction intensity reaches its maximum value, about 2T, at the junction between the shell and the coil,...” This is not true. You have a numerical problem on the sharp edges. Remove this statement, please.
Q8: Line 139
“… magnetic induction intensity …”. This term is not usually used. Used magnetic flux density or magnetic induction.
Q9: Figure 4 and 5
Fig.4 a Fig.5 are really bad. Saying nothing. P resent the results in 2D form with the magnetic flux lines and magnetic flux density figures.
Author Response
Modification declares:
Based on the editor and reviewers’ comments, the manuscript has been made extensive modification and the text of modified parts is marked in “red” color. Now, we would like to answer the questions raised by the reviewers as follows:
1. “Magnetorheological fluid (MRF) with rheological properties is considered as one of the most promising new intelligent materials.” Magnetorheological fluid is not new. Could you delete the word new, please?
Re: Thanks for your comments. The word has been deleted.
2. “… from a free fluid state to a solid-like state in milliseconds,…”. This publication can be interesting for you: DOI: 10.1038/s41598-022-14718-5. The change is usually under 1 ms.
Re: Thanks for your comments. The reference has been added.
3. “However, MRB has high nonlinearity, time delay and uncertainty as its working process, and affected by the interaction between current, magnetic field, magnetorheological fluid and structure, which makes it difficult to accurately control its braking torque [6-7].” Very popular paper describing transient behavior of MR clutch/ brake is: Maas J and Güth D 2011 Experimental investigation of the transient behavior of MR fluids, or new one: Wang H, Bi C, Zhang Y, Ji A and Qiu P 2021 Transient behavior of compressed magnetorheological brake excited by step currents.
Re: Thanks for your comments. The references have been added.
4. Could you change the coil markings in the picture. The coil has its standard marking.
Re: Thanks for your comments. The Fig. 1 has been corrected in revised version.
5. “… shear yield stress of magnetorheological fluid.” I think this is not correct. This is shear stress in MR fluid not shear yield stress.
Re: Thanks for your comments. The statement has been corrected in the revised version.
6. and the simplified structure is shown in Fig. 3, where different colors represent different areas, and loop reluctance can be calculated by Ohm's law. “This is not correct information. Magnetic reluctance cannot be calculated by Ohm's law. You are just using analogy to Ohm's law.
Re: Thanks for your comments. The statement has been corrected in the revised version.
7. “…μi is magnetic conductivity”. The term permeability is usually used.
Re: Thanks for your comments. The magnetic conductivity has been represented by μ.
8. Used the common version of this equation not that one. J = 4I / πd2
Re: Thanks for your comments. It is corrected in the revised version.
9.“It can be seen from Fig. 4 that the magnetic induction intensity reaches its maximum value, about 2T, at the junction between the shell and the coil,...”This is not true. You have a numerical problem on the sharp edges. Remove this statement, please.
Re: Thanks for your comments. This statemen has been removed, where the magnetic induction intensity reaches its maximum range, about 1~1.2 T.
10. “… magnetic induction intensity …”. This term is not usually used. Used magnetic flux density or magnetic induction.
Re: Thanks for your comments. The term has been corrected in the revised version.
11. Fig. 4 and Fig.5 are really bad. Saying nothing. Present the results in 2D form with the magnetic flux lines and magnetic flux density figures.
Re: Thanks for your comments. The two Figs. have been replaced in revised version.
Reviewer 4 Report
The manuscript presents design, simulation, and control of a new MR brake. The proposed dynamic vibration absorber showed a reasonably well performance. A PID based algorithm was developed on the basis of an improved Grey Wolf Optimization Algorithm. The corresponding results are discussed.
General comment: There are many typos and grammatical errors throughout the manuscript. It is highly recommended to re-read and re-revise the manuscript in order to make it suitable for the readers. It cannot be followed with the current version. The abstract also needs a thorough revision.
There are also several major concerns remaining related to the technical perspectives that need to be addressed, such as:
1. The sentences and paragraphs in the introduction are properly connected.
2. The contribution of the present work has not been clearly reflected in the introduction.
3. It is recommended to add a reference for the Bingham Plastic model presented in Eq. 3.
4. All the parameters should be defined in the manuscript. For instance, the parameters presented in eq. 2 have not been defined.
5. In Eq. 4 the derivation should be added to the manuscript.
The parameters have not been selected properly. Miu is selected as shear strain rate, which should have been chosen as gama. In Eq. 7, miu is selected as magnetic conductivity. This should be magnetic permeability.
6. It is recommended to add references for the following arguments:
“When the coil of excitation has poor cooling performance, the current density Jr allowed to pass over a long period of time 127 shall not exceed 3~5 A/mm2. When the transmission device has good heating dissipation structure, although the current density can 128 be relaxed, but the value should not exceed 5~7 A/mm2.”
7. The B-H curves of the magnetic materials should be added to the manuscript.
8. It is recommended to mention why the response time and the weight of MRB has not been considered in the optimal design of magnetic circuit and MRB performance.
9. It is recommended to add the total weight of the designed MRB to the manuscript (Table 1).
10. The parameters used should be clearly revised:
“In the GWOA, ω wolves around the leadership gray wolves hunt prey, completing the determination of target location. The position information of three leadership has important role to optimization results of ω wolf, where the central position of the three 202 leadership wolves is more possible to get closer to the target position” omega should be changed.
11. The following is table or figure:
“The pseudocode of IGWO can be summarized as follows”
It is recommended to add the code at the end of manuscript as appendix. as appendix.
12. Turn or Tune! The manuscript requires a major revision.
13. The performance of the designed MRB should be compared with those recent work published in the literature.
Author Response
Modification declares:
Based on the editor and reviewers’ comments, the manuscript has been made extensive modification and the text of modified parts is marked in “red” color. Now, we would like to answer the questions raised by the reviewers as follows:
1. The sentences and paragraphs in the introduction are properly connected.
Re: Thanks for your comments. The introduction has been corrected in revised version.
2. The contribution of the present work has not been clearly reflected in the introduction.
Re: Thanks for your comments. The contribution of the present work has been emphasized in introduction of revised version.
3. It is recommended to add a reference for the Bingham Plastic model presented in Eq. 3.
Re: Thanks for your comments. The reference [10] has been added for the Bingham Plastic model.
4. All the parameters should be defined in the manuscript. For instance, the parameters presented in eq. 2 have not been defined.
Re: Thanks for your comments. All the parameters have been checked in revised version.
5. In Eq. 4 the derivation should be added to the manuscript.
Re: Thanks for your comments. Eq. 4 is derived by combining the Eq. 2 and 3, which has been explained in revised version.
The parameters have not been selected properly. Miu is selected as shear strain rate, which should have been chosen as gama. In Eq. 7, miu is selected as magnetic conductivity. This should be magnetic permeability.
Re: Thanks for your comments. The shear strain rate has been represented by γ, magnetic conductivity has been represented by μ in revised version.
6. It is recommended to add references for the following arguments: “When the coil of excitation has poor cooling performance, the current density Jr allowed to pass over a long period of time shall not exceed 3~5 A/mm2. When the transmission device has good heating dissipation structure, although the current density can be relaxed, but the value should not exceed 5~7 A/mm2.”
Re: Thanks for your comments. The description has been attached to the corresponding reference [24] in the revised version.
7. The B-H curves of the magnetic materials should be added to the manuscript.
Re: Thanks for your comments. The B-H curves of the MRF has been added as Fig. 5.
8. It is recommended to mention why the response time and the weight of MRB has not been considered in the optimal design of magnetic circuit and MRB performance.
Re: Thanks for your comments. Since the reaction speed of MRB is millisecond, the weight does not affect the design of magnetic circuit, so these two contents are ignored.
9. It is recommended to add the total weight of the designed MRB to the manuscript (Table 1).
Re: Thanks for your comments. The total weight of the designed MRB has been added in Table 1
10. The parameters used should be clearly revised: “In the GWOA, ω wolves around the leadership gray wolves hunt prey, completing the determination of target location. The position information of three leadership has important role to optimization results of ω wolf, where the central position of the three leadership wolves is more possible to get closer to the target position” omega should be changed.
Re: Thanks for your comments. The ω symbol is used by the traditional GWOA and has not been changed.
11. The following is table or figure: “The pseudocode of IGWO can be summarized as follows”. It is recommended to add the code at the end of manuscript as appendix. as appendix.
Re: Thanks for your comments. The sentence is not a title, but an introduction to pseudocode. Because the source code is complex and difficult to understand, adding this pseudo-code to the text helps reader understand the content.
12. Turn or Tune! The manuscript requires a major revision.
Re: Thanks for your comments. The whole paper has been carefully checked and some grammatical and errors have been corrected.
13. The performance of the designed MRB should be compared with those recent work published in the literature.
Re: Thanks for your comments. Due to the difference in the structure size of the devices, it cannot be compared with the published literature. However, using the MRB designed in this work, different control methods have been compared, which has been described in the experimental section.
Round 2
Reviewer 1 Report
The authors have addressed the comments, and I recommend the manuscript for publication.
Author Response
The authors have addressed the comments, and I recommend the manuscript for publication.
Re: Thank you for your comments.
Reviewer 2 Report
Mostly, the authors made corrections as required, however, I still have the following comments:
1. English grammar should be corrected.
2. The experimental results (section 4) should be presented in more detail. Simply, including 2 examples of the brake response is not sufficient. The claims made by the authors should be supported with more than 2 current levels and 2 velocities. Also, other excitations should be included as well, e.g. random command inputs, etc.
Author Response
1. English grammar should be corrected.Re: Thank you for your comments, The manuscript has been read carefully and the grammar has been revised.
2. The experimental results (section 4) should be presented in more detail. Simply, including 2 examples of the brake response is not sufficient. The claims made by the authors should be supported with more than 2 current levels and 2 velocities. Also, other excitations should be included as well, e.g. random command inputs, etc.
Re: Thank you for your comments. Four sets of experiments have been conducted in Fig. 15 and 16 of revised version. From Fig. 15, when the rotation speed n from 0 to 300, 400 and 500 r/min, the target torque T is controlled to 60, 100 and 110 N·m, respectively. The torque tracking control with three consecutive inputs has been added in Fig. 16 of revised version.
Reviewer 3 Report
Dear authors,
Thank you for your comments. I have just one more comment. Page 9: symbols T1, T2, and T2s have to be in subscripts.
Author Response
Thank you for your comments. I have just one more comment. Page 9: symbols T1, T2, and T2s have to be in subscripts.
Re: Thank you for your comments. These symbols have been corrected in revised version.
Reviewer 4 Report
The response to the all the comments should be provided in the manuscript. For instance, the response to the comment 8, has not been reflected in the manuscript. The weight, response time, inductance, operation time, and wire diameter are all related together.
Author Response
The response to the all the comments should be provided in the manuscript. For instance, the response to the comment 8, has not been reflected in the manuscript. The weight, response time, inductance, operation time, and wire diameter are all related together.
Re: Thanks for your comments. As requested in your first trial, we have reexamined and revised the manuscript. The weight of the MRB is 24 Kg, which has been presented in Table 2. Response time has been described through three different experiments, the results of which have been added in Table 7. The inductance and wire diameter of coil from MRB has been added in Table 2. The operation time is reflected by four experimental tests, namely the time-torque curves in Fig. 15 and Fig. 16 of revised version.
