An Efficient RRT Algorithm for Motion Planning of Live-Line Maintenance Robots

Round 1

Reviewer 1 Report

Appl. Sci. 1403836

Comments to the authors

 

The reviewer understood that the paper claimed a practical method to give a plan for a manipulator in a specific task.

 

Yet he was interested in the experimental verifications, he had the following concerns for publication.

 

(1) Copyright issues

Obviously, the manuscript represented a part of the article [a] published by the same authors through IEEE Access. He believes the authors MUST refer to the article and HAVE TO state the positioning of this manuscript clearly.

 

He was also worry that some of figures are almost the same as the ones appeared in [a], yet he didn’t know the agreement of copyright transfer among the authors and IEEE.

 

[a] Jiao Feng and Weijun Zhang (2021) Autonomous Live-Line Maintenance Robot for a 10 kV Overhead Line. IEEE Access 9, 61819-61831. DOI: 10.1109/ACCESS.2021.3074677

 

(2) Problem statement

He needed to know clear problem statement(s) for the algorithm. Since there are so many variations of RRT, he needed to know theoretical background of the proposed algorithm. He also questioned whether the algorithm was designed for a specific task or generic uses. If it was for a specific task, the authors must state conditions and constraints clearly related to the task. If it was for generic use, the authors should avoid notations about the machine and introduce common benchmarks to evaluate the performance of the proposed algorithm.

 

(3) Verifications

He couldn’t clearly see the contribution of the proposed algorithm in the tasks of the experiments. Please clearly describe what the authors did in the experiments and show the value of the proposed algorithm.

 

(End of comments)

 

Author Response

Thank you for reviewing our article. Your opinions are very helpful to improve the book review of this article. Regarding your concerns, our response is as follows：

Response 1: 

Thank you for your suggestions. As you mentioned, this article is closely related to article a. This article is the follow-up research content of thesis a. Based on the original research, a new path planning method is proposed. This article is the follow-up research content. On the basis of the original research, a new path planning method is proposed. Following your suggestion, we quote [a] in the article and explain the relationship between the two articles.

Line68-70: “In the previous research\cite{ref28}, the entire robot system was introduced, including path planning algorithms. The focus of this article is a new motion planning method suitable for task scenarios.”

Thanks for your reminding about the figure copyright. We asked IEEE about copyright issues and learned that these figures can be used. Of course, the source of the picture must be noted..The copyright transfer of [a] is CC BY-NC-ND 4.0.

 

Response 2: 

Thank you for your suggestions. The algorithm in this article is designed for a specific task. The improvement of the algorithm is also based on the particularity of the task. We have added a summary of the particularity of the scene in the article as follows:

Line155-160:

“In conclusion, the path planning in the Live-line working scene has the following particularities:

1) There are a lot of obstacles in the environment, and some of the obstacles are mobile;

2) The end posture of the robot is restricted during the movement of the robot;}

3) Based on safety factors, the robot Stay away from charged objects as much as possible during the movement. ”

 

Of course, this method can also be applied to some similar scenarios, such as some flexible production processes. We are trying to apply this method in industry 4.0 scenarios.

 

Response 3:  

In the process of using robots to perform tasks, a large part of the work is to control the robot to move to the target position. The traditional method is remote control, which is inefficient, high labor intensity, and requires high personnel. The path planning algorithm eliminates the need for personnel to spend energy on moving the manipulators.

In the simulation experiment, we adjust the position of the platform and the work object, change the environmental obstacles, and test the algorithm to evaluate the reliability, stability and optimality of result (line386-401). During the test, there is no difference from the actual working condition except that the wire is not charged.

By introducing path planning algorithms, the automation level of robots can be improved, the labor intensity of operators can be reduced, and safety can be improved.

Author Response File: Author Response.docx

Reviewer 2 Report

After reading I would conclude; well, very practical paper, however I have some doubts related to scientific soundness, namely: there is a tool, there is testing method and measured results, but what is the underlying effects, mechanisms which result in such presentation, seen for example in Fig. 8?

Other issues are related to editorial quality; for example in Fig. 9, size of characters is unacceptable. Also, starting, for example, from Tab. 1, there are "hundreds" of unexplained acronyms in the text body - all these should be expanded.

Thus, I suggest major revision.

Author Response

Thank you for reviewing our article. Your opinions are very helpful to improve the book review of this article. Regarding your concerns, our response is as follows：

Response 1: 

Thank you for your suggestion.  It is very important to clarify the mechanism of the algorithm. The RRT method expands the tree by random sampling, so by changing the uniformity and randomness of the sampling, the tree can be controlled to grow in a desired manner. According to your suggestion, we have added the following content to the article:

Line183-186: “The RRT method expands the tree through random sampling. Therefore, by changing the uniformity and randomness of sampling, the tree can be controlled to grow according to the constraint conditions. Representative RRT improved algorithms based on this principle include RRT-informed and RRT-connect.”

Response 2: 

Thank you for your patient review. This is a serious omission. According to your suggestions, we have adjusted the fonts of related pictures, including Fig.8, Fig.9, Fig.11, Fig.13, Fig.15, Fig.16, Fig.18, Fig.20, Fig.21 and Fig.24.

In addition, we explained the abbreviations in Table 1. (Page16)

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Appl. Sci. 1403836 v2

Comments to the authors

 

• Reference to the previous publication

The reviewer welcomed authors’ referring to their previous work. However, the manuscript still has some issues to be revised. The reviewer believes that the authors re-write the manuscript with considerations of the previous publication. For example, they can omit details of the whole system and make problem statement(s) of this manuscript clearer.

 

• Problem statement

He still needed to know clear problem statement(s) for the algorithm. Since there are so many variations of RRT, he needed to know the state conditions and constraints clearly related to the task. He thought the authors must refine the organization of the manuscript.

 

• Verifications

He couldn’t clearly see the contribution of the proposed algorithm in the tasks of the experiments. Especially, he didn’t figure out what the field test said about the proposed algorithm.

 

(end of comments)

 

Author Response

Thank you for participating in the review of the article. I'm sorry that you didn't understand your intentions well in the last round of review. In response to your suggestions, we revised the manuscript. Since there are figure and formulas in the revised content, we submitted a word document for explanation. Of course, you can also view the manuscript, and the revised part has been marked in blue. 

Finally, your suggestions are very helpful to this manuscript. Thank you from the bottom of my heart!

Best regards

Author Response File: Author Response.doc

Reviewer 2 Report

After the next round I have no extra remarks

Author Response

Thank you for participating in the review of the article. Your valuable suggestions are very helpful to the improvement of the article.

Round 3

Reviewer 1 Report

The reviewer confirmed the revisions by the authors.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

applsci-1310563

Comments to the authors

 

The reviewer didn’t think that the manuscript was suitable for publication. His concerns included the following three major concerns.

 

• Original contributions by the authors were vague

He couldn’t find any technical or theoretical contributions by the authors. The methods introduced in the manuscript seemed quite common ones. The authors must indicate their original contributions clearly.

 

• Mismatch among the target task and the proposed method.

He didn’t agree that the planning algorithm was designed for the target task, which the authors indicated in the first and second section. The planning algorithm was just a general one without any specific considerations of the target task. They must formulate the problem more exactly.

 

• Insufficient results

Yet the authors claimed that they carried out a field test, the reviewer couldn’t find any solid results that proofed effectiveness of the proposed planning algorithm. The authors must state clearly how they evaluate the results before experiments. He needed to see comparisons with other algorithms, because he expected the problem could be solved by other deterministic algorithms.

 

(End of Comments)

Reviewer 2 Report

Throughout the article, I feel difficulty to understand the originality and benefit of the presented research. There are two reasons of this, (1) Explanation of how the entire robot system is formed and achieves a given task is lacked. Although the system should be composed of hardware, sensor system, measurement and motion control algorithm, detailed explanation is completely lacked. Secondly, the explanation of the motion planning algorithm is too long and redundant, which makes the understanding of user's original work difficult.

(1)  Each of figures in Fig.3 (a)-(d) is not enough informative since it cannot be understood from the figure that how each task is accomplished and how a corresponding tool works.
(2) What does  "URs" mean (in line 126)?
(3) In the itemization of the operation situation, it is said that "(1) Most obstacles in the robot motion environment remain unchanged", but it is also also said that "(2) The positions of obstacles are changed during each operation." These two phrases seem to be conflicting each other.
(4) Regarding the wire stripping task, is is said that "Since the cable passes through the inside of the tool, ...., the difficulty of motion planning is greatly increased." What the reason which makes the motion planning difficult is? From the explanation, the task looks like just a conventional line-tracking. Is there any difference from that? [line 141-142]
(5) In line 146, there is a sentence that "The position of the cable is uncertain", but use of "uncertain" may not be correct because it is measured by vision sensors. Instead of "uncertain", "non-constant" or "variable" may be more suitable.
(6) The explanation of motion planning seems to be redundant. Through the explanation written in the pages 6 to 14, it is hard to understand that which part is the explanation of generally known algorithm called RRT* and which part is that of authors' original work.