Three-Dimensional Path Planning for Post-Disaster Rescue UAV by Integrating Improved Grey Wolf Optimizer and Artificial Potential Field Method

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Summary: In this work, the authors propose a fusion optimization algorithm called the Improved Grey Wolf Algorithm-Improved Artificial Potential Field (IGWO-IAPF) for UAV path planning. This algorithm builds upon the Grey Wolf Algorithm (GWO) and introduces several improvements. Firstly, a nonlinear adjustment strategy for control parameters is proposed to balance the global and local search capabilities of the algorithm. Secondly, an optimized individual position update strategy is employed to coordinate the algorithm's searchability and reduce the probability of falling into local optima. Additionally, a waypoint attraction force is incorporated into the traditional Artificial Potential Field (APF) algorithm based on the force field to fulfill the requirements of three-dimensional path planning and further reduce the probability of falling into local optima.  The IGWO algorithm is used to generate an initial path, where each point is assigned an attraction force, and then the IAPF algorithm is utilized for subsequent path planning. Simulation results demonstrate that the fused IGWO-IAPF algorithm exhibits stronger path planning capabilities compared to other traditional algorithms, characterized by shorter flight distances and higher levels of safety, thereby meeting the requirements of post-disaster rescue missions. I read the article, and this paper is concisely written and contributes somewhat to the body of literature. The contents of this paper can be useful for researchers working in this field (e.g., UAV path planning). Below, I provide some comments to improve this work further. I believe the following comments can further enhance this paper's quality.

1-      In the abstract, please mention the research gaps before presenting the solution. In its current form, the abstract is mainly about the authors' proposal. Please discuss with %age and number the proposed  IGWO brought in path length reduction and safety.  

2-      In the introduction, please highlight the experimental details. Please add the details of the experiment environment used in the test. The contributions are also not well written. For example, there is no description of the simulation environment. Please write the contribution with bullets.

3-      Please write this paper organization at the end of the introduction section.

4-      I suggest adding a comprehensive diagram with sample map data to show the working of the proposed approach. Please mention the main modules of the proposed approach in this figure.

5-      Many factors can affect the selection of trajectory curves. Therefore, It would be better to perform an ablation study to show the performance result of the proposed method in different environmental conditions given at the beginning of the abstract.

6-      What is the uniqueness and novelty of this paper compared to existing work? In my opinion,  many such methods have already been proposed with extensive evaluations. Please clarify the novelty of the revised work in the revised work.

7-      There is no related work section. I suggest adding such a section to provide the analysis of the state-of-the-art (SOTA) in this field.

8-      There is no description of SOTA methods with whom authors compared the results. Please add references to the baseline methods.

9-      Please add the limitation of the proposed work in the result section.

10-  Please add more descriptions of the graphs used in the result section and improve the visibility of the figures.

11-  Time complexity is also a very relevant factor in the context of the proposed method. If possible, please include time complexity results. Also, safety results should be included.

Author Response

Dear reviewer：          Thank you for your opinions, these comments are very helpful to improve the quality of the manuscript. We have carefully revised our manuscript, further clarify the logic of writing for improving the quality of the manuscript. Words in blue are the changes we have made in the manuscript. Now we response the reviewers’ comments with a point by point and highlight the changes in revised manuscript. Full detail responses of the comments are listed.   Yours Sincerely   QiZhou Yu

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper proposes an optimization algorithm, IGWO-IAPF, aiming to enhance the operational efficiency of post-disaster rescue UAVs in navigating complex three-dimensional obstacle environments. In comparison to the Grey Wolf Algorithm (GWO), IGWO-IAPF attempts to integrate a nonlinear adjustment strategy for control parameters and an optimized individual position update strategy to balance global and local search capabilities while mitigating the risk of falling into local optima. Furthermore, by incorporating a waypoint attraction force into the traditional Artificial Potential Field (APF) algorithm, the proposed approach tries to address the challenges of three-dimensional path planning. Simulation results claim better path planning capabilities of IGWO-IAPF compared to conventional methods. However, the following elements need to be addressed for the sake of improvement:

·         The introduction section clearly lacks an explicit presentation of the research contributions of this research study. All minor or major research contributions of this research study must be defined in clear and concise manner, preferably in bullet points for better readability.

·         The introduction section doesn’t address the need to explain the novelty of the proposed approach in explicit manner. There should be clear lines stating the novelty of this whole approach minding that research contribution and novelty are two different elements and they both need to be addressed.

·         Is there any computational complexity concern for the IGWO-IAPF algorithm when it needs to be applied to real-time path planning problems? The computational complexity should be discussed and highlighted in the paper.

· section 4.2 states that “various random task environments were designed for validation experiments”. Please give some details about these random environments for a better understanding of the readers.

• The Particle Swarm Optimization (PSO) algorithm seems to be the most efficient algorithm in terms of time consumption. What reasons do you assume behind this time difference with the IGWO-IAPF? And how do these reasons make this trade-off good enough?

 

 

Comments on the Quality of English Language

Minor corrections are required along with the proofreading.

Author Response

Dear reviewer：          Thank you for your opinions, these comments are very helpful to improve the quality of the manuscript. We have carefully revised our manuscript, further clarify the logic of writing for improving the quality of the manuscript. Words in blue are the changes we have made in the manuscript. Now we response the reviewers’ comments with a point by point and highlight the changes in revised manuscript. Full detail responses of the comments are listed.   Yours Sincerely   QiZhou Yu

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Abstract: 

1. The research problem and motivation are explicitly declared. Nevertheless, the gap needed to be presented. What is the specific issue that this manuscript intends to solve? Several fusion optimization algorithms have been applied to UAV path planning.
2. Introduction: 
   1. The same issues pointed out in the abstract should be included in the introduction. 
   2. The introduction claims to carry out experimental comparisons. Nevertheless, this manuscript only presents simulation results. No experimental data or results were presented. 
   3. Literature revision: It is recommended that research studies in the field of UAV rescue application and path planning be included. It could be helpful to point out the present research study's advances or contributions. Suggestions:
      1. Hayat, S., Yanmaz, E., Brown, T. X., & Bettstetter, C. (2017, May). Multi-objective UAV path planning for search and rescue. In 2017 IEEE international conference on robotics and automation (ICRA) (pp. 5569-5574). IEEE.
      2. San Juan, V., Santos, M., & Andújar, J. M. (2018). Intelligent UAV map generation and discrete path planning for search and rescue operations. Complexity, 2018.
      3. Zhang, C., Zhou, W., Qin, W., & Tang, W. (2023). A novel UAV path planning approach: Heuristic crossing search and rescue optimization algorithm. Expert Systems with Applications, 215, 119243.
      4. Ryan, A., & Hedrick, J. K. (2005, December). A mode-switching path planner for UAV-assisted search and rescue. In Proceedings of the 44th IEEE Conference on Decision and Control (pp. 1471-1476). IEEE.
3. Problem description: 
   1. What does a b c mean in Eq. (1)? Additional details or references should be added. 
   2. Figure 1 does not show the parameters of Eqs (1) and (2). It needs to be more evident to understand the environment definition based on the information presented in this section. 
4. "3. Ground collision risk": What is the relationship between ground collision risk "S" and the objective function of Eq. (6)?
5. In Eq. (11), b1+b2+b3=1? Why? 
6. In Eq(12), Does "t" refer to time? And x of Eq. 14?
7.  IGWO-IAPF algorithm description: The flowchart of Figure 9 should present how the proposed method was implemented based on the authors' equations. 
8. Results: 
   1. Simulation results are conveyed. However, additional comments should be added to indicate how the proposed method could be experimentally implemented into a real UAV path planning optimization. For example, experimental constraints such as sensor noise, uncertainties, and computational costs should be pointed out to indicate the potential drawbacks and limits of the proposed method.
      

 

Author Response

Dear reviewer：          Thank you for your opinions, these comments are very helpful to improve the quality of the manuscript. We have carefully revised our manuscript, further clarify the logic of writing for improving the quality of the manuscript. Words in blue are the changes we have made in the manuscript. Now we response the reviewers’ comments with a point by point and highlight the changes in revised manuscript. Full detail responses of the comments are listed.   Yours Sincerely   QiZhou Yu

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Summary: The authors have improved the work as evidenced by the response letter and modified draft. However, I feel that some comments (Parts of C2, C4, C6, C8, etc.) from the previous round are not properly understood and were addressed. I suggest making minor revisions by taking into account those comments and one new comment (Comment # 6). 

1-      Please write the contribution with bullets.

2-      I suggest adding a comprehensive diagram with sample map data to show the working of the proposed approach. Please mention the main modules of the proposed approach in this figure.

3-      What is the uniqueness and novelty of this paper compared to existing work? In my opinion,  many such methods have already been proposed with extensive evaluations. Please clarify the novelty of the revised work in the revised work.

4-      There is no description of the SOTA methods with whom the authors compared the results. Please add references to the baseline methods.

5-      Please add more descriptions of the graphs used in the result section and improve the visibility of the figures.

 

6-      Lastly, I suggest defining path constraints on line # 66.

Comments on the Quality of English Language

In some parts, there are language inconsistencies.

Author Response

Dear Reviewer:

Thank you for your comments, which were helpful in improving the quality of the manuscript. We have made a second careful revision of the manuscript to improve its quality. Words in red are the changes we have made in the manuscript. Now we response the reviewers’ comments with a point by point and highlight the changes in revised manuscript. Full detail responses of the comments are listed.

Yours Sincerely

QiZhou Yu

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The authors included all the corrections in this new version of the manuscript.

The size of Figure 12 should be increased.

Author Response

Dear Reviewer

Thank you for your comments, which were helpful in improving the quality of the manuscript. We have made a second careful revision of the manuscript to improve its quality. Words in red are the changes we have made in the manuscript. Now we response the reviewer’s comment with a point by point and highlight the changes in revised manuscript. Full detail response of the comment is listed.

Yours Sincerely

QiZhou Yu

Author Response File: Author Response.pdf