A Four-Dimensional Space-Time Automatic Obstacle Avoidance Trajectory Planning Method for Multi-UAV Cooperative Formation Flight

Round 1

Reviewer 1 Report

The manuscript entitled " A Four-Dimensional Space-time Automatic Obstacle Avoidance Trajectory Planning Method for Multi-UAV Cooperative Formation Flight" makes a novel contribution to UAVs’ path planning. The Hungarian algorithm is tested by the comparison with Auction algorithms and random task assignment. The result is impressive. Moreover, engineering applications and flight tests demonstrate the effectiveness and feasibility of algorithms. However, there are some minor revisions to be done by the authors:

1. The paper uses some acronyms without definitions.

2. Figures’ format would be uniform, but this paper isn’t. 

Author Response

Dear Reviewers:

Thank you very much for your suggestions and the comments you gave me. Aimed at each comment which reviewers provided, I have revised my manuscript(drones-1826783). It mainly involves the following three aspects of revision:

(1) English writing;

(2) acronyms supplement;

(3) Figure Format modification.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript " A Four-Dimensional Space-time Automatic Obstacle Avoidance Trajectory Planning Method for Multi-UAV Cooperative Formation Flight" is clear, relevant to the field, and presented in a well-structured manner. The manuscript is scientifically reasonable, and the experimental design is suitable for testing hypotheses. According to the details given in the method section, the results of the manuscript are reproducible. Throughout the manuscript, the data were appropriately and consistently interpreted. The conclusion is consistent with the evidence and arguments presented. There are some issues which should be addressed by the authors.

1. In the simulation test, the author did not introduce how the UAVs follow the planned trajectory. Has the model of the multi-UAV been established for test the effect of the trajectory following?

2. In Section 5, the author did not summarize the highlights and innovation of this paper, as well as the value of this research, so this part should be revised.

Author Response

Dear Reviewers:

Thank you very much for your suggestions and the comments you gave me. Aimed at each comment which reviewers provided, I have revised my manuscript(drones-1826783). It mainly involves the following three aspects of revision:

(1) English writing;

(2) acronyms supplement;

(3) Figure Format modification.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript entitled " A Four-Dimensional Space-time Automatic Obstacle Avoidance Trajectory Planning Method for Multi-UAV Cooperative Formation Flight" has proposed an innovative trajectory planning method in four-dimensional space-time, which is very well written, and boasts quite significant value in engineering applications. However, there exist some problems, which must be solved before it is considered for publication.

1. Figure 1 should be revised, with some of the text and formulae extending beyond the boundaries of the flow box, and the case of the text initials should be kept consistent. Besides, the formulae and text in Figure 4 are partially overlapping, the line color should keep consistent, and the detail of the arrows in Figures 3 and 5 merit attention. In addition, figures 6-8 and 10-12 should be annotated and coordinates added for ease of understanding. Units should be added to Tables 1-2 and 7.

2. The quantitative results of the main contributions of this paper need to be put more specifically in the introduction and conclusion sections in order to make them accessible to researchers outside your particular research area.

Author Response

Dear Reviewers:

Thank you very much for your suggestions and the comments you gave me. Aimed at each comment which reviewers provided, I have revised my manuscript(drones-1826783). It mainly involves the following three aspects of revision:

(1) English writing;

(2) acronyms supplement;

(3) Figure Format modification.

Author Response File: Author Response.docx

Reviewer 4 Report

The manuscript entitled " A Four-Dimensional Space-time Automatic Obstacle Avoidance Trajectory Planning Method for Multi-UAV Cooperative Formation Flight" has been investigated in detail. A trajectory planning method in four-dimensional space-time was proposed to achieve cooperative trajectory planning and automatic obstacle avoidance in advance for multiple UAVs. The topic is potentially interesting and the manuscript contains some practical meanings in engineering application. however, there are some issues that should be addressed by the authors.
1. Some of the symbols used in the paper are missing from the nomenclature list；
2. Line sizes are small in Fig.6, 7, 8, 10,11, and 12. It is not easy to be seen by the naked eye. And coordinate axes are not marked with meaning.

Author Response

Dear Reviewers:

Thank you very much for your suggestions and the comments you gave me. Aimed at each comment which reviewers provided, I have revised my manuscript(drones-1826783). It mainly involves the following three aspects of revision:

(1) English writing;

(2) acronyms supplement;

(3) Figure Format modification.

Author Response File: Author Response.docx

Reviewer 5 Report

Good day dear authors,

The topic you are addressing is highly relevant.

Please do specify which is the project which results you are presenting here. What are the contents and goals of this project?

This study might have been performed only for the purposes to publish this paper at this journal. Where is the novel element, the innovative core of what you are willing to say? If such - please specify.

Please revise well the language, you quite much are using past tense, which I think is not optimal.

Please consider well the purpose of your paper - what it shall inform the readers about. Just explaining an existing method and saying it is suitable for the purpose is less than enough.

I would be very happy if you improve these parts and resubmit your paper! I'm definitely supporting each novel approach, after it is clearly described and its benefit is clear.

Thanks!

Author Response

Dear Reviewers:

Thank you very much for your suggestions and the comments you gave me. Aimed at each comment which reviewers provided, I have revised my manuscript(drones-1826783). It mainly involves the following three aspects of revision:

(1) English writing;

(2) acronyms supplement;

(3) Figure Format modification.

Author Response File: Author Response.docx

Round 2

Reviewer 5 Report

English language to be slightly improved - tense, use of THE etc.

Please do mention in your abstract what project does this paper result from, to prove the practical evidence.

Author Response

Dear Reviewers:

Thank you very much for your suggestions and the comments you gave me. Aimed at each comment which reviewers provided, I have revised my manuscript(drones-1826783). It mainly involves the following three aspects of revision:

(1) English writing;

(2) Modification of the abstract section;

Author Response File: Author Response.docx