A Robust Electric Power-Steering-Angle Controller for Autonomous Vehicles with Disturbance Rejection
Round 1
Reviewer 1 Report
This paper discusses the adaptive sliding mode control for vehicle steering angle tracking. The comments are as follows:
- In Section 2, the system uncertainty of the EPS is not clearly discussed.
- In line 22, what is the value of n, w?
- Is there any reference to support (4)?
- In experiment, another comparison to conventional adaptive sliding mode controller is required.
- In Introduction, some new advances for active steering is missing, such as Active steering control for vehicle rollover risk reduction based on slip angle estimation.
- The observer as well as the controller is recommended to be organized in a Theorem and its corresponding proof.
- The main problem is that the design is simple which leads to limited contribution and improvement, compared to the similar research such as [10].
Author Response
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Reviewer 2 Report
The authors present a robust electric power steering angle controller for autonomous vehicles with disturbance rejection. Below are some of the main concerns.
- The contribution of this work is quite questionable to the reviewer. At the end, the EPS system is modeled as a quite simple 2nd order system, almost linear. It is quite hard to be convinced that there are some major challenges for the control design of such a system. The authors should provide some discussion in Section 2 and maybe a problem formulation would be welcome to highlight related potential challenges.
- There are some issues on the mathematical fonts in equations (4)-(6). Especially, the correction term s is not explicitly defined. And the remaining design technique is simply based on a standard LQR design.
- How is it possible to have the form (13) since the disturbance is UNKNOWN! This is a major issue because it is crucial to get the sliding mode variable s in (14).
- With the overall gain eta in (24), you need the time derivative of theta_p for the control law, which is not compatible with the observer part. Another major issue.
- Moreover, I don’t see yet any mechanism that allow to effectively reduce the chattering effect since S depends on the time derivative of theta_p, which can be very noisy.
- Some comparisons with existing methods should be necessary to show the interest of this work.
- I believe that there is a lack of focus on the motivation for the work in Section 1. The authors talked about many challenges such as backslash, etc. that is not addressed in the paper. Moreover, I would recommend the authors to enrich the literature review with various control techniques for vehicle/EPS control, and not essentially stay with SMC. I would invite the authors to discuss the following works and recent references therein.
https://www.sciencedirect.com/science/article/pii/S0888327021003265
https://journals.sagepub.com/doi/full/10.1177/1748302620931312
Author Response
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Reviewer 3 Report
This paper presents a robust electric power steering angle controller for autonomous vehicles. Some comments are listed as follows.
- Some symbols in equations are unclear, e.g., (4), (5), (6)…
- SMC has been widely used to address the control of steering, I cannot find the contribution of this paper.
- The comparative simulation between SMC and other control algorithm is suggested, e.g., robust control, MPC.
- The simulation scenario and software are not clear. The steering control should be considered with the whole vehicle’s motion control, yielding a closed-loop control.
Author Response
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Reviewer 4 Report
The paper is well structured and results are sound. Experimentation work is sufficient. A paper would benefit if comparison with alternative control approach is examined, to give a proper perspective.
Author Response
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Round 2
Reviewer 1 Report
Thanks for the authors' response. The paper has been improved a lot. However, the comment is still not fully answered. In comment 1, the authors should clarify the definitions of n and w IN THE PAPER to avoid any possible confusing. In comment 3, although some revision is made, it is not supported by any reference such as 10.1049/iet-csr.2019.0030
Author Response
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Reviewer 3 Report
Sorry, The response is not for my questions.
- Some symbols in equations are unclear, e.g., (4), (5), (6)…
- SMC has been widely used to address the control of steering, I cannot find the contribution of this paper.
- The comparative simulation between SMC and other control algorithm is suggested, e.g., robust control, MPC.
- The simulation scenario and software are not clear. The steering control should be considered with the whole vehicle’s motion control, yielding a closed-loop control.
Author Response
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Author Response File: Author Response.pdf
Round 3
Reviewer 3 Report
Thanks for the response.
Author Response
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Author Response File: Author Response.pdf