Review Reports

Round 1

Reviewer 1 Report

1-       The manuscript is written very badly, full of grammar mistakes, revise again and correct them.

2-     In page 2 line 84, The obstacle avoidance function of MAS based on artificial potential field is also a 84 hot topic [5–7]. [5] …. correct the citation.

3-     At present, there are few research works on the optimization of MAS communication 97 topology using control theory. [9] explored the influence of channel fading on control 98 from the perspective of communication, and analyzed the classical control theory used 99 in traditional formation from the perspective of communication topology. However, this 100 paper did not consider the influence of delay on control. It's better to use the author, Algorithm name and instead of this you should use these 100 papers…

4-     At present, there are few research works on the optimization of MAS communication 97 topology using control theory. [9] explored the influence of channel fading on control 98 from the perspective of communication and analyzed the classical control theory used 99 in traditional formation from the perspective of communication topology. However, this 100 paper did not consider the influence of delay on control.( …97 topologies using…) revise it .

5-     In section 2, the author didn't cite any method or technique. Carefully recheck and mention all the method references and other terms you have used.

6-     Improve the visibility of all figures.

7-     Add more detail about figures caption that are self-explanatory for the reader (All figs).

8-     Even its not compulsory I suggest you upload your source code with revised manuscript.

9-     There are ambiguities and unclear meanings throughout the whole paper. Carefully revised all sections of this manuscript.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Paper Title:

Stability Analysis and Network Topology Optimization of Multi-agent Systems for Material Transport in Industrial Parks

 

Manuscript No. 2300288

 

The paper claims building a stability model of multi-agent system (MAS) under the background of swarm robots transporting materials in an industrial park, and propose a network topology optimization method for keeping stability analysis of MAS.

 

After carefully reviewing the paper, there are major concerns I would like to highlight:

Corrections:

1)      You need to amend the references to show some recent relevant works.

2)      Improve the visual appearance of the figures and  the tables and fix the captions. 

3)      Evaluation measurements done on the proposed model is not enough, and comparisons with other related models are needed. More measurements are needed to be conducted to effectively test the model success or failure.

4)      Using artificial intelligence is not apparent in this manuscript, although mentioning that in the abstract and introduction. I suggest to include AI in your future work.

5)      The structure of writing needed to be improved and corrected by proof reader.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

There should be a comprehensive literature review rather than some descriptions in the introduction. The literature review can help the readers to understand the state-of-art research in this domain and relevant comparisons. 

The system model is not formalized enough. A lot of description from 141 to 181 is more like a scenario design than a system model.

In section 2.1, many concepts are not well explained such as the "AGV with the strongest ability" in line 190. How do you define 'strongest ability'? How does every agent communicate and vote for the leader?

Between lines 192 to 194, what is the 'weighted graph' for? "E represents the edge", are you saying the corresponding edge node or what? What is the ‘A’ (adjacency matrix) designed for?

What is the Laplace matrix in line 194? It's not clear about the equation in line 201. Is it the probability of successful communication between two nodes? Where the equation comes from? 

In line 205, "The value ranges from 2 to 6", what is the value? 

All of the concepts and equations need to be well-defined and explained. If any equation is used based on common knowledge or from other sources, please properly cite them. For example, in line 219, "We use Shannon’s formula to calculate....", Shannon's formula should be properly cited. 

In line 230, what does it mean that "the controller inside the leader of each cluster is considered as the controller of all AGVs in this cluster"? Is the delay only from information transmission? Do you also consider the delay from processing or calculation?

Why Zigbee or Wifi is used for communication? They are very different protocols and usually should be used in different scenarios. 

Since the message is sent to several different decentralized devices, how do you guarantee their time clocks are synchronized? If their time clocks are not synchronized, how can the delay be accurately calculated? 

Most mathematical reasoning and simulations seem fine, however, the article needs to be better structured, explained, and written. Many parts make me confused. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

All the changes you have made to the manuscript I couldn't find in your main manuscript. (Highlighted Manuscript. Before submission, you must show your manuscript to your corresponding author. Add more detail for all figures in the figure caption. All changes you have made show in highlighted manuscript with color. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Point 1: You need to amend the references to show some recent relevant works.

Response 1: We would like to thank you for your comment. We've added some recent articles, some of which is as follows:

There are many researches on cooperative control of MASs [1–12].

Above researches do not consider adaptive coupled MAS. In practice, MAS with internal coupling and external adaptive coupling is more practical. There are also some studies considering adaptive topology. Finite-time and fixed-time protocols are proposed in [4] to solve the consensus problem in multi-agent systems with time-varying directed topologies. In [5], time-varying formation control of fractional-order MASs with general linear dynamics is studied under fixed and switched directed interaction topologies. A distributed control protocol based on observer is proposed to realize time varying formation control.

At present, there are few research works on the optimization of MAS communication topology using control theory. In [11], Hao explores the influence of channel fading on control from the perspective of communication, and analyzes the classical control theory used in traditional formation from the perspective of communication topology. However, this paper did not consider the influence of delay on control. In addition, a unified optimization framework is proposed in [12]. At the same time, the weight of the primary communication graph edge is reduced to optimize the network topology and ensure the consistency and adjustable convergence rate of the uncertain multi-agent system. However, these papers did not consider the influence of delay on control.

 [4]Iqdal.M.; Kolios.X.; Polycarpou.M.; et al. Finite- and Fixed-Time Consensus Protocols for Multi-Agent Systems With Time-Varying Topologies IEEE Control System Letters 2022, 6, 1568-1579.

[5]Gong.Y.; Wen.G.; Peng.Z.; et al. Observer-Based Time-Varying Formation Control of Fractional-Order Multi-Agent Systems With General Linear Dynamics. IEEE Transactions on Circults and Systems—II: Express Briefs 2020, 67, 82-86.

[12]Iqdal.M.; Kolios.X.; Polycarpou.M.; et al. A Unified Optimization-Based Framework to Adjust Consensus Convergence Rate and Optimize the Network Topology in Uncertain Multi-Agent Systems, IEEE/CAA Journal of Automatica Sinica 2021, 8, 1539-1548.

My Comments on (Response 1)

It is ok, recent references added to the manuscript.

 

 

Point 2: Improve the visual appearance of the figures and the tables and fix the captions.

Response 2: Thank you for your comment. We have rerun the program and updated a few images that are not clear.

My Comments on (Response 2)

Good, figures appearance enhancement is acceptable.

Redo figure 7 caption, not clear.

 

Point 3: Evaluation measurements done on the proposed model is not enough, and comparisons with other related models are needed. More measurements are needed to be conducted to effectively test the model success or failure.

Response 3: We would like to thank you for your comment. However, we designed a different scenario, and considered the transmission delay and obstacle avoidance. Therefore, it is more complicated to apply other algorithms to this scenario. But we compare the stability of the system under different channel conditions. And the optimization method is proposed. After verification, the system performance is improved significantly.

My Comments on (Response 3)

I accept the author justification.

 

Point 4: Using artificial intelligence is not apparent in this manuscript, although mentioning that in the abstract and introduction. I suggest to include AI in your future work.

Response 4: Thank you for your comment. Firstly, I want to explain to you the meaning of using an agent. Agent refers to the entity with the basic characteristics of autonomy, sociality and reactivity. It can be seen as a corresponding software program or an entity (such as people, vehicles, robots, etc.), which is embedded in the environment, senses the environment through sensors, acts autonomously on the environment through effectors and meets design requirements.

As mentioned in this paper, AGVs can be aware of their surroundings and adjust their position in real time. The goal of MAS is to enable several systems with simple intelligence but easy to manage and control to achieve complex intelligence through mutual cooperation, so as to reduce the complexity of system modeling while improving the robustness, reliability and flexibility of the system.

In addition, artificial potential field method is a classical path planning algorithm for robots. In this algorithm, the object and the obstacle are regarded as objects with attractive and repulsive forces on the robot respectively, and the robot moves along the resultant force of attractive and repulsive forces. Therefore, the artificial potential field method is not traditional artificial intelligence

We have also adopted your opinion and will try to use artificial intelligence method to study path planning in the future.

To sum up, this paper focuses on intelligent agents, and we also add the direction of future work in section 6.

Now we only consider the delay generated in the transmission process and ignore the computation and processing delay. In addition, we did not consider packet loss in transit. Therefore, a possible direction for future research is MAS stability analysis considering packet loss and more delay. In addition, using artificial intelligence method for path planning is another possible direction for future research.

My Comments on (Response 4)

I accept the argument and addition of these line regarding using artificial intelligence as a future direction.

 

Point 5: The structure of writing needed to be improved and corrected by proof reader.

Response 5: We would like to thank you for your comment. We have changed a lot of things, including fixing grammar problems, adding definitions to some nouns and theorems, etc.

My Comments on (Response 5)

I have noticed amendments on the manuscript, good, it is acceptable

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Although some questions are explained in the response letter, I couldn't find the changes in the submitted manuscript. The questions are not only about my concerns, but related to the quality of the paper. You should restructure and revise the paper based on the questions rather just answer in the reponse letter. Please highlight all the changes you've made in the submitted manuscript. 

The voting and leader selection is one of the core parts in MAS system. Even though it's not the focus, it at least should have a mechanism description such as where and when it happened? If you're not focus on this, you can also choose to assign the leader role to some AVGs rather than to do a voting process without any explanation. 

For some questions, if they're related to the core motivation/limitation of the paper, you should also mention them in the paper both in the Introduction and Limitation sections. For example, "At present, only the message transmission delay is considered in this paper." & "How to ensure clock synchronization is another issue, which is not the focus of this paper."

If you choose to use Wifi/Zigbee, it usually means you're doing experiments with these protocols with a reason. Please be aware that the difference between Wifi and Zigbee is not only about the range. Zigbee is ad hoc but wifi is not. They have fundamental differences in principles, which will change the way how they transmit messages and topologies. 

Please also don't mix the introduction with literature review. 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf