An Interval Approach for Robust Parameterization of Controllers for Electric Drives
Round 1
Reviewer 1 Report
The work is interesting and deals with an important practical aspect of tuning PID controller settings in drive systems.
The lack of experimental verification of the system's operation is the biggest disadvantage of this article.
The theoretical section is too extensive compared to the results of simulation studies (there are no examples of practical application). There are no numerical criteria for evaluating the operation of regulators. Could you please explain why friction is omitted from equation (3)?
Author Response
We thank the reviewer for the constructive comments, which we have taken into account in revising the paper. We address the individual comments in detail below:
Remark 1:
The lack of experimental verification of the system's operation is the biggest disadvantage of this article.
Response to Remark 1:
An experimental verification would only provide additional information about the quality of the model if a simulative verification has already been carried out. However, the modelling of an electric drive is not part of the paper, which is why detailed experimental studies were omitted in order to focus on the essential findings.
However, the comment prompted us to clarify this in the paper in line 785 to 789.
Remark 2:
The theoretical section is too extensive compared to the results of simulation studies (there are no examples of practical application). There are no numerical criteria for evaluating the operation of regulators.
Response to Remark 2:
The theory part is difficult to shorten due to its complexity. The simulation part is only intended to show that the theoretical calculation is correct. The numerical criteria are dealt with in detail in section 6 and form the basis of the results shown in Fig. 12, for example. In addition, in Fig. 13 in the lower row, in which a settling time is also taken into account, compliance with the maximum limit for this can be seen directly from the signal curves.
To clarify the value with regard to a practical application, we have added the lines 65 to 69.
Remark 3:
Could you please explain why friction is omitted from equation (3)?
Response to Remark 3:
The response to this comment is in a similar vein as that to remark 1. Since the focus is not on modeling but on the methodology for controller design, a simple yet common design model was used . We have added a footnote to clarify this in line 111.
Reviewer 2 Report
Abstract:
The introduction of the main finding is shady. It is recommended to add a concrete sentence about the finding of the study.
Introduction:
The literature review is basically good. It is recommended to extend it by some mor (5-10) studies to increase the scientific soundness of the study by making the background more sophisticated (more studies about what others found).
The goal of the study is clearly described. The contribution is detailed, it is acceptable. The structure of the paper is also clearly added.
Mathematical fundamentals:
The basic definitions connected to the stud are perfectly described. The list of definitions helps the understanding in a great extent.
Modeling:
The model is well-described, however there are some variables / parameters that should be named clearly in this section. e.g. Fi, i(s), s, etc.
Please name these right after the equations.
Performance criteria:
This section includes no error. Please be aware the naming of the parameters here too.
Controller parametrization / simulation:
The parametrization of the model is well-described. The simulation is reproducible, all the necessary information are available for that.
Discussion:
This section is recommended to be the part of the previous section. A separate section is recommended for the conclusions in which the authors summarize / list) the main findings in bullet points using concrete data. The point of such a summary is that the readers can find the findings in a concrete form without reading the whole paper.
Format:
The figures and tables are clear and well-edited. They help the understanding of the study.
Author Response
We thank the reviewer for the constructive comments, which we have taken into account in revising the paper. We address the individual comments in detail below:
Remark 1:
The introduction of the main finding is shady. It is recommended to add a concrete sentence about the finding of the study.
Response to Remark 1:
Lines 65 through 69 were added to further specify the main findings of the paper.
Remark 2:
The literature review is basically good. It is recommended to extend it by some mor (5-10) studies to increase the scientific soundness of the study by making the background more sophisticated (more studies about what others found).
Response to Remark 2:
We have considered this point and added other sources, especially those that have been published recently.
Remark 3:
The model is well-described, however there are some variables / parameters that should be named clearly in this section. e.g. Fi, i(s), s, etc. Please name these right after the equations.
Response to Remark 3:
Thank you very much for the remarks. We have added the missing variable descriptions in this chapter as well as in the chapter "Performance criteria".
Remark 4:
Discussion: This section is recommended to be the part of the previous section. A separate section is recommended for the conclusions in which the authors summarize / list) the main findings in bullet points using concrete data. The point of such a summary is that the readers can find the findings in a concrete form without reading the whole paper.
Response to Remark 4:
We have not combined the two chapters. The reason for this is that the previous chapter deals purely with the simulation and the discussion chapter spans the entire paper.
What we have changed, however, as suggested, is the structuring of the chapter. For this purpose, individual paragraphs were inserted, each of which explains a main finding.
Reviewer 3 Report
Comments:
The title looks interesting. “An Interval Approach for Robust Parameterization of Controllers for Electric Drives”. For improving the quality of the paper, the authors can address the following comments:
1. In the abstract, The reviewer would like to see one or two more sentences describing the methodology used to achieve this work. Also, show the importance or significance of the result.
2. In the introduction line 53, the authors talk about: “The aim of this publication is to close this gap” which is stated in lines 49 to line 52. In this regard, the authors need to review more on the research gap and highlight the limitations of the previous work on this topic.
3. The author might include a table in the introduction including previous work and their limitations.
4. The author/s highlight the future practical contribution in lines 61-63. Can the authors discuss in detail based on the results the vision of how it works in practice?
5. In figure 3, the authors can explain in detail what happened in each frequency region. Why only 103 ? because the authors claim the model accuracy is good?
6. Reference can be improved and include the latest 3 years of research on the topic.
Author Response
We thank the reviewer for the constructive comments, which we have taken into account in revising the paper. We address the individual comments in detail below:
Remark 1:
In the abstract, the reviewer would like to see one or two more sentences describing the methodology used to achieve this work. Also, show the importance or significance of the result.
Response to Remark 1:
To further elaborate the methodology, we have added lines 7 to 9 in the abstract. Furthermore, the importance in lines 65 to 69 has been highlighted in more detail.
Remark 2:
In the introduction line 53, the authors talk about: “The aim of this publication is to close this gap” which is stated in lines 49 to line 52. In this regard, the authors need to review more on the research gap and highlight the limitations of the previous work on this topic.
Response to Remark 2:
The only previous works with the objective pursued in this paper are those based on Rakotondrabe's approach. However, as has been explained, these are based on a methodological mistake that prevents practical applicability. To make this clearer, lines 55 to 59 have been reformulated and the term "gap" has been replaced with more precise wording.
Remark 3:
The author might include a table in the introduction including previous work and their limitations.
Response to Remark 3:
We have incorporated this point in the course of considering remark 2 in the lines referred to there.
Remark 4:
The author/s highlight the future practical contribution in lines 61-63. Can the authors discuss in detail based on the results the vision of how it works in practice?
Response to Remark 4:
Here our previous form was obviously unclear. This is not a future contribution, but the practical application is already shown in the paper within the simulation chapter and the associated controller design. We have modified the corresponding lines to clarify this for the reader.
Remark 5:
In figure 3, the authors can explain in detail what happened in each frequency region. Why only 103 ? because the authors claim the model accuracy is good?
Response to Remark 5:
The model could only be determined in this frequency range due to controller limitations regarding the excitation frequency. This limitation comes from the use of an industrial controller, which was not developed for these objectives, but represents a realistic setup in industry. To make this clear for the reader, a footnote has been added to line 122.
Remark 6:
Reference can be improved and include the latest 3 years of research on the topic.
Response to Remark 6:
We have addressed this point and added to the literature to that effect.
Round 2
Reviewer 3 Report
The authors addressed the raised concerns in round 1. Suggestion, the authors can show up more about the research contribution in the introduction part.
Author Response
We would to thank the reviewer for the additional suggestion for improvement.
To further clarify the research contribution, we added rows 58-60.
