Development of a Structural-Functional Approach for Heterogeneous Glider-Type Marine Robotic Complexes’ Group Interaction to Solve Environmental Monitoring and Patrolling Problems

Round 1

Reviewer 1 Report

The topic addressed in the paper is potentially interesting in both theory and practice, however, the submission should be carefully revised based on the following comments:

1/ The major concern is that this paper is pretty general and lack of details and rigorous discussion. This paper should have more theoretical contributions. The experimental contribution is minor since the manuscript does not present results from real trials.

2/ The paper uses a lot of abbreviations, symbols, and notations. Maybe a nomenclature section will help in enhancing the overall readability of the paper

3/ In the introduction, it is suggested that the novel index of this paper should be explained in detail. And the introduction should be added to do a better job of explaining the existing methods and why they are or are not valuable. The authors reviewed and summarized some existing methods relating to their work. What research gap did you find from previous researchers in your field (it is still partially described, but needs to be expanded and made clearer)?  Mention it in the Novelties section. It will improve the strength of the article.

4/ Write the organization of the paper.

5/ Benefit of the proposed method is not clear. This should be clarified. The objective/problem statement needs to be explained. What are the novelties of the proposed method? what the research challenges/motivations of the paper are?

6/ The motivation and background of wide practical use of the theoretic results presented should be clearly emphasized to facilitate the readers.

7/ Please highlight which section(s) discusses each of the contributions. This way there will be cohesiveness in the manuscript contents.

8/ A detailed explanation on the dynamics of an underwater glider is needed. All assumptions and physical constraints should be provided. A sub-section “Assumptions” should be added to make the problem clearer

9/ In this paper, it is recommended to give an intuitive representation (e.g., a flow chart) of the whole technical procedure of the detailed implementation information. The authors can add the steps of implementing the algorithms. The steps will be for the benefit of the readers, maybe they’ll help the readers to implement the proposed algorithm.

10/ Detailed implementation information should be provided (hardware, software, configuration, settings). A detailed discussion of hardware and software applied to the vehicle should be mentioned. Provide specifications of the hardware and software used for simulation of the approach. Because there is not enough data on this paper, the research results on the core idea of this paper seem unreliable.

11/ The authors have mentioned issues concerning visibility but the problem of acquiring good data needs to be discussed. In addition, it would have been appropriate to discuss how accuracy would be degraded in real-world scenarios.

12/ The practical implementation deserves greater discussion. Baseline separation is an issue both in terms of installation in the glider and its depth accuracy. In addition, the underwater environment is plagued by visibility, and illumination, especially at depth. Obviously, the performance of the glider system is affected by environmental disturbances such as wind, waves, and current. There is no result robustness under the disturbance. The author needs to give more detailed data references or results.

13/ There is a need to simulate time-varying and space-varying currents to understand energy consumption implications. That will add value to the current state of the art.

14/ In results part, more design parameters and comparisons with some existing results are recommended to prove the efficacy of the proposed method. The results look simple and analysis is insufficient. Also, the explanation in this section is really confusing. Please re-write and enrich the analysis of simulation results more.

15/ The presentation of the paper can be improved and the quality of some figures should be enhanced. My disappointment regards figures, to look at them I have to zoom in a lot exploiting their high definition. In my opinion, in a printed version it should be impossible to correctly read some of the figures. So please enlarge them, such as: Fig. 1b, Fig. 5, Fig.6, and Figs. 8 and 12. Please check the entire figures in the paper.

16/ What are the differences between Figure 5 and Figure 6, the reviewer thinks that Figure 5b and Figure 6b are the same. Please clarify it!

17/ In lines 184-185 Page 7, the authors mentioned that “ Sea trials confirmed… 10-15 percent” What are the seal trial results? The reviewer did not see that in the paper.

18/ The conclusion section has less information. However, it should be included more information about new methods, concepts, results and conclusions on the novelty of the method.

19/ The manuscript writing can be further polished with professional English. The manuscript can be thoroughly revised for grammar check.

 

 

 

 

 

Author Response

Dear Sir or Madam,

Thank you for your review and respone

Regarding to your comments:

1. Theoretical contributions were added into the updated manuscript.
2. The nomenclature section was not presented in the MDPI template, for this reason we did not create it. In any case, all nomenclatures are explained in the main text.
3. Description of existing projects and novelties in the proposed work are added in the new version of the article
4. Organization of the paper is added at the end of the introduction
5. Updated
6. Updated
7. Updated
8. Various mathematical models of an underwater glider dynamics have been published to the date in a large number of papers. As a basic model of the dynamics of an underwater glider we used the already existing mathematical models considered in other articles, in the article the corresponding references are given to them.
9. Since the article considers both description of the design features of underwater gliders and algorithms for interaction and planning of group movement, drawing up a single block diagram is a problematic task. The organization scheme of the developed planning system is presented in Figure 10.
10. The description of the developed software has been added to the latest version of the article. No more information can be provided due to commercial confidentiality reasons.
11. In the section of the article where the system of the general field of view is considered, a theoretical algorithm is presented, which is currently being implemented by the authors on full-scale models of robotic complexes. We agree that the application of this algorithm in real environments is an issue that requires additional consideration and discussion. Therefore we plan to conduct full-scale tests in the near future.
12. A more detailed description of the conducted experiment added
13. An analysis of energy consumption of the glider in missions will be provided in future work
14. The conclusion updated
15. Pictures updated
16. Fixed
17. Trial results added
18. The conclusion updated
19. Reviewed

Author Response File: Author Response.pdf

Reviewer 2 Report

It is suggested to add the contributions in the introduction section.

The average speed of steady currents in the straits ranges from 0.5 to 2 knots. For instance, an underwater glider will deviate from its target trajectory by about 900 m in the direction of the disturbing current at a current speed of 0.5 knots during 1-hour mission. How do the authors estimate the value (900 m)?

phi – pitch angle of the glider; gamma – heading angle of the glider; theta – roll angle of the glide; These definitions are different from the Figure 3.

The results are shown in the Figure 6. As seen above, the introduced design and hardware modification have significantly increased the underwater glider’s maneuverability by reducing the turning radius R = 21m. This description didn't seem to tally with what we saw in the Figure 6.

It is suggested to improve the quality of Figures 5,6,7,8,11,12.

Author Response

Dear Sir or Madam,

Thank you for your review

Regarding to your comments

1. With minimum direct lateral impact 0.5 knots on a vehicle moving at a longitudinal velocity 0.8 knots, its lateral deviation from the target trajectory in direction of resulting velocity vector will be about $\backsim 1.3$ km per 1 hour of movement - This sentece was added to the manuscript also
2. The text was updated according to your comments, pictures were also updated

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The quality of the paper has been improved by properly addressing my previous comments. I do not have further comments