Research on Active Avoidance Control of Intelligent Vehicles Based on Layered Control Method

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper proposes a layered control method aimed at addressing the active avoidance problem of intelligent vehicles. Overall, the manuscript is well-organized, and the experimental results support the proposed method effectively. However, I have several suggestions and questions for improvement:

1. What are the specific advantages of the path planning and trajectory tracking hierarchical control proposed in this paper? It would be helpful to expand on the advantages of hierarchical control in the literature review section to provide a clearer context for the approach.
2. I recommend that the main contributions and innovations of the paper be explicitly outlined in the introduction section. This will help readers understand the significance of the work early on.
3. Please address the formatting inconsistencies throughout the manuscript, particularly with the font in Figure 2.2 and Figure 3.2. Ensuring consistency in font style and size will improve the overall readability of the document.
4. There are some discrepancies between the text and the figures. Please ensure that the variables in the formulas correspond correctly to the symbols used in the figures and that the text aligns with the content of the drawings.
5. A brief introduction to the tire model section is necessary to help readers understand the model’s relevance and how it integrates into the control framework.
6. The model shown in Figure 2.1 does not appear to be a 3-DoF monorail vehicle model. Please modify the kinetic model graphic to accurately represent the intended model.
7. There are some formatting issues in the reference section. For example, "Nie Xiaobo" should be formatted as "Xiaobo Nie" to conform to standard citation styles. Please ensure that all author names in the reference list are correctly formatted.
8. Please include the full name of any technical acronyms or abbreviations when first mentioned in the manuscript, such as LTV-MPC, to ensure clarity for readers who may not be familiar with the terms.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This paper proposes a method to plan and execute collision avoidance maneuvers with intelligent vehicles.
Please consider the following comments to improve the quality and clarity of the paper, and to better highlight the novelty of the proposed method.

Comments:
- The title is not very informative: it is too generic and does not highlight the novelty of the paper. Also, "Research on" is not a good way to start a title. 
- Since most of the title capitalizes the first letters, it would be better to capitalize the first letter of each word, apart from "of" and "on".
- "Monorail vehicle dynamics" --> "single-track vehicle model" is a more common term in the literature.
- When discussing polynomial- or curve-based approaches for vehicle motion planning and obstacle avoidance, the authors should mention other related techniques that used clothoid curves, for example in "Real-time approximation of clothoids with bounded error for path planning applications", and the neural-based polynomial motion primitives of "Computationally Efficient Minimum-Time Motion Primitives for Vehicle Trajectory Planning".
- At the end of the literature reviews for path planning and tracking, please briefly summarize the key limitations of the existing methods that this paper aims to address.
- The novel paper's contributions need to be better stated, in the form of a list at the end of the introduction or after the related work.
- What are the computational times of the MPC method for path tracking? What is the number of points / length of the MPC prediction horizon? What kind of optimal control solver and hardware were used?

Comments on the Quality of English Language

The paper needs many improvements in the English language. Please use some online tools to help you with this.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This study proposes a new approach to vehicle control for intelligent vehicles capable of avoiding collisions with other vehicles. The proposed controller plans the timing and method of lane changes, employing a specialized algorithm to ensure smooth transitions. In addition, a collision avoidance algorithm is proposed to assist the controller in determining when to make lane changes to avoid hitting other vehicles. Genetic algorithms are suggested for finding the optimal parameters of this algorithm, aiming to provide double quintic polynomial path planning.  The main strength of this article is the original method called the Magic Formula Tire Model. During vehicle movement, the tire is the only part that touches the ground and has strong nonlinear dynamics. Most of the forces that affect the vehicle's performance come from the tires. To ensure the accuracy of the algorithm, this paper uses the Magic Formula tire model, which has higher accuracy. The second advantage of this study is the use of genetic algorithms (GA). GA is designed to optimize the parameters of the system. Avoidance path planning is the basis for the vehicle to complete active avoidance. The vehicle uses its own sensors and V2X communication to collect information about the position, speed, acceleration, and relative distance of the vehicle and other traffic vehicles. It calculates the time required for lane change using double quintic polynomials for avoidance path planning. The GA uses two parameters of the avoidance path to find the optimal one, ensuring that the planned path meets the requirements for avoiding other traffic.  The main contribution of this article is to propose a new approach for improving the maneuverability of vehicles. However, there are some drawbacks in the paper. The main drawback of this article is the lack of readability. The text contains a lot of long and complex sentences, which make it difficult to understand the context. The author could improve the English to more clearly express their research. In general, the abstract and the use of keywords could be enhanced. In the abstract, the authors could benefit from a clearer statement of the main findings of their research and an answer to the question of how and why the upper controller with parameters calculated using genetic algorithms compares favorably to other approaches. What benefits, for instance, might arise from increasing traffic flow speed, reducing accident rates, or other improvements? The keywords should accurately represent the primary focus of the research and include terms such as improved maneuverability, genetic algorithms, road safety, and traffic simulation. The literature review also needs some improvements. Therefore, the following specific recommendations are provided.

1. The paper needs some text improvement. The text contains a lot of long and complex sentences, which make it difficult to understand the context. The author could improve the English to more clearly express their research.

2. In the abstract, the authors could benefit from a clearer statement of the main findings of their research and an answer to the question of how and why the upper controller with parameters calculated using genetic algorithms compares favorably to other approaches. What benefits, for instance, might arise from increasing traffic flow speed, reducing accident rates, or other improvements? The keywords should accurately represent the primary focus of the research and include terms such as improved maneuverability, genetic algorithms, road safety, and traffic simulation.

3. The literature review could be improved. As this study is directly related to improving vehicle maneuverability using genetic algorithms, it would be helpful to mention and cite some important works in this area:

[1] A. S. Akopov, L. A. Beklaryan and M. Thakur, "Improvement of Maneuverability Within a Multiagent Fuzzy Transportation System With the Use of Parallel Biobjective Real-Coded Genetic Algorithm," in IEEE Transactions on Intelligent Transportation Systems, vol. 23, no. 8, pp. 12648-12664, Aug. 2022, DOI: 10.1109/TITS.2021.3115827.

[2] Yan, Z., Dong, L., and Peng, Q., "Fuzzy Control Model of Intelligent Lane-Changing Decision Based on Genetic Algorithm Optimization," SAE Technical Paper 2021-01-5017, 2021, DOI: 10.4271/2021-01-5017.

4.  Section 3, "Double quintic polynomial path planning incorporating genetic algorithms", could be improved. It would be helpful to provide a formal statement of the optimization problem in terms of the objective function, decision variables, and constraints. For example:

Problem A: The need to minimize the objective function (17) (e.g., the probability of collision between two interacting vehicles) over the set of control parameters { ... }:

min F (...)            (17)

s.t. (subject to):

......

where ....

Thus, the problem statement should be provided before the flow chart for the avoidance trajectory (Figure 3.2).

Comments on the Quality of English Language

The paper needs some text improvement. The text contains a lot of long and complex sentences, which make it difficult to understand the context. The author could improve the English to more clearly express their research.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

A layered control method is proposed to aim at the active avoidance problem of intelligent vehicles.

Contributions compared to papers in Section I are not clear.

You mention that you use genetic algorithm for real-time optimization of the parameters of the quintic polynomials. However, as the number of particles in the genetic algorithm increases, real-time performance cannot be assured.  Genetic algorithms are computationally heavy. Genetic algorithms need to be explained in detail.

The effects of various aspects, such as weather, curved lanes or road slope, are not considered in the simulation section. 

 

Computation load of your method needs to be analyzed in detail.

Is it possible to run your method in real time?

Comparisons with the state of the arts controllers  are missing in this paper. 

 

Comments on the Quality of English Language

Ok

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The reviews made by the authors are appreciated, and the paper may be ready for publication. Still, I would recommend mentioning another couple of papers related to this topic, as the literature in this area is quite vast and discussing only 26 papers is not that much for a journal paper.

Author Response

Thank you very much for your suggestion. Your suggestion has been of great help to my article. I have added relevant references to the article to enrich its content.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have made improvements to their article, following the recommendations of the reviewers. However, despite these changes, the literature review remained almost unchanged. The authors are strongly encouraged to significantly expand the literature review by mentioning and quoting the most significant works in the field of intelligent transport systems and evolutionary optimization. There is a huge amount of research in this field on improving vehicle maneuverability, predictive control modeling (MPC), and genetic algorithms. It would be useful to at least briefly mention the most recent works in the introduction. It is also recommended to increase the list of references to at least 40-45 sources. The second problem is that during the formal description of the model in section 2.1 of the "Three-degree-of-freedom vehicle dynamics model", not all designations were introduced. For example, there is no description of the directional angle delta_f after Eq. (4), and the parameters b_0, b_1,..., b_10 in Eq. (7) and a_0, a_1,..., a_12 in Eq. (9) remain without explanation.. Authors are strongly advised to carefully check all formulas and descriptions of variables that are used in them. 

Author Response

Thank you very much for your suggestion, it has been very helpful for my article.

1. The article has added relevant references to 41, enriching the content of the article.
2. Recheck all variables and provide explanations. The article has already explained that delta_f is the front wheel steering angle. You may be referring to the lack of description for delta_r, which has been added to the article.
3. The article has added explanations for relevant parameters, such as selecting tire model 225/60 R18, where a0-a13, b0-b10, and c0-c17 are the parameters required for factor calculations.
4. I have rechecked and modified some of the formulas to ensure they are correct. Thank you again for your proposal.

Reviewer 4 Report

Comments and Suggestions for Authors

I am satisfied with revision 

Author Response

Thank you for your reply. Once again, thank you for taking the time to review my article amidst your busy schedule.

Round 3

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have made improvements to the article in response to the reviewers' comments. The paper is now suitable for publication.