A Nonlinear Control Design for Cooperative Adaptive Cruise Control with Time-Varying Communication Delay

Round 1

Reviewer 1 Report

This paper deals with the design a of a Cooperative Adaptive Cruise Control under time-varying communication delay. The general development is well presented and the results are supported by simulations. I would appreciate if the authors could make the constributions more remarkable. The idea behind the use of a linear fisrt-order transfer function is not clear since they are dealing with a real commercial car. Even more, the design process for this methodology could be convenient to highlight the results. 

In general, the english used for writing this paper is good. There was not difficult to follows the main flow of the ideas. I only suggest to do a detailed review in order to make the reading a litle bit more fluent. 

Author Response

Hi,

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

In order to solve the problem that the communication delay in cooperative adaptive cruise control affects the control performance, the authors designed a nonlinear controller based on Lyapunov method and conducted stability analysis. Finally, the effectiveness of the research results is verified by numerical simulation. The paper is written with clear structure, but some technical details should be considered clearly, such as:

1)   In the problem statement section, it was not explained how the delay of the leader's input signal affects the error $e_i(t)$, The authors are requested to further elaborate based on Equation 4.

2)    In the absence of key theorems after the controller design, the authors are invited to summarize the work and propose theorems and prove them.

3)    In the verification section of the algorithm, the numerical simulation method is mainly used to verify the algorithm, which is lack of convincing. If the working conditions allow, it is suggested to increase the physical verification.

4)    Many existing works have studied the cooperative control problem of multi-agent systems in different scenarios, including communication delay, limited communication resources, such as: Flocking Dynamics for Cooperation-Antagonism Multi-Agent Networks Subject to Limited Communication Resources; Cucker-Smale flocking over cooperation-competition networks; Sub-super-stochastic matrix with applications to bipartite tracking control over signed networks. Compared to these works, the main innovation points of this article need to be further strengthened.

5)    The shortcomings of this article and future research plans need to be explained.

Language description needs further improvement.

Author Response

Hi,

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper focuses on addressing the challenge posed by time-varying delays in the communication channel on the performance, stability, and safety of Cooperative Adaptive Cruise Control (CACC) systems in Connected and Autonomous Vehicles (CAVs). It aims to mitigate the impact of such delays through a Lyapunov-based nonlinear controller to ensure secure and reliable vehicle following distances.

The research topic is highly relevant and original within the field of autonomous vehicle technology, addressing a critical gap concerning the impact of communication delays on CACC systems. This issue is pivotal for the real-world implementation of autonomous driving technologies, as it directly affects traffic safety, road capacity, and fuel consumption.

Compared with other published material, this study introduces a novel control strategy that is resilient to time-varying communication delays, external disturbances, and measurement noise. By utilizing Lyapunov-Krasovskii functionals for stability analysis, the paper advances the understanding and development of secure control designs for CACC systems, which have not been extensively explored in previous research, especially concerning time-varying delays.

But The authors should consider incorporating real-time adaptive mechanisms that dynamically adjust to varying degrees of communication delays, beyond the predefined bounds considered in the paper. 

Also there is no information on how reproducable are the results? and there is no comparison with previous works. Also they need to refer to some works that combines Ai and control such as:

- Modeling and nonlinear adaptive control for autonomous vehicle overtaking

- About an autonomous adaptive control methodology

- Development of a new control system for a rehabilitation robot using electrical impedance tomography and artificial intelligence

Author Response

Hi,

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

My problems have been resolved very well without any further comments.

My problems have been resolved very well without any further comments.