Preload Multi-Objective Optimization Method for Ultrasonic Motors Based on NSGA-II

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors proposed a novel multi-objective optimization method for preload, utilizing the Non-dominated Sorting Genetic Algorithm II (NSGA-II) to solve the problem of determining the optimal preload of ultrasonic motors. A few suggestions are as follows to improve the quality and readability of the manuscript.

1. The authors are advised to explain other multi-objective optimization methods like AHP, etc. in the introduction section.

2. How is NSGA-II more suitable to the current problem compared to NSGA-I or other multi-objective optimization methods?

3. Pg. 4 line 124 is not relevant to the manuscript. 

4. Include nomenclature in the manuscript where ever they are used for the first time.

5. In Table 3, AHP and NSGA-II methods were compared. Wether objective functions were the same for both the work? Also, output efficiency is less in the case of the NSGA-II method compared to AHP. Justify.

6. In the manuscript, the authors claimed the NSGA-II optimization method has low computational complexity. How?

Comments on the Quality of English Language

The authors are advised to check the entire manuscript through grammar checking to improve the quality of the English language.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This paper deals with an interesting study on preload optimization of ultrasonic motors using NSGA-II. However, improvements are needed in the research background, data analysis, statistical verification, and applicability of the conclusion. If these several parts are supplemented, the academic and practical value of the paper will be further enhanced.

 

1. This paper deals with preload optimization of ultrasonic motors and proposes a methodology to achieve multiple objectives using the NSGA-II algorithm. However, the background of the study is somewhat lacking in explaining why preload of ultrasonic motors is important and why existing methods have limitations. Therefore, it is recommended to describe more clearly the specific effects of preload on the performance of ultrasonic motors and how this study is innovative compared to existing studies. In particular, it would be good to emphasize the relevance to real industrial problems to further highlight the practical necessity of the study.

 

2. The research objective of this paper is understood to be to find the optimal preload through optimization of multiple performance indicators (no-load speed, stall torque, and power efficiency). However, this objective is not clearly described and the hypothesis is not stated. It would be good to present the research objectives in simple and clear sentences at the beginning to make it easier for readers to understand the research direction. For example, if the structure of establishing a hypothesis such as "there is a linear relationship between pre-pressure and performance indicators" and proving it with research results is strengthened, the author's intention will be clearly revealed.

 

3. The experimental device and methodology used in the paper are described, but information on specific conditions (temperature, environmental variables, sample size, etc.) is lacking. The experimental environment and control variables should be clearly described to increase research reproducibility. It is necessary to specify the precision and limitations of the data collection process and equipment.

In addition, although the data are presented in graphs and tables, there is a lack of in-depth analysis in interpreting the results. For example, the physical or mechanical explanation for why performance increases at a specific pre-pressure is somewhat insufficient. Therefore, it is recommended to explain the trends in the data shown in the graph and analyze the fundamental reasons for the performance improvement shown at the optimal pre-pressure value.

 

4. The operating principle of the NSGA-II algorithm is briefly explained, but it may be difficult for non-expert readers to understand it. We need to add more intuitive and visual explanations for the main concepts of NSGA-II (e.g., non-dominated sorting, crowding distance, elite strategy, etc.). It would be more persuasive if we could describe the reasons for choosing the algorithm and compare it with other optimization algorithms more clearly. And we did not evaluate the statistical significance of the experimental results. I think it would be more persuasive if we added statistical tests (e.g., calculating p-values, setting confidence intervals, etc.) to verify the significance of the experimental results.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have responded well to the suggestions for improvement.