Straight-Line Path Tracking Control of Agricultural Tractor-Trailer Based on Fuzzy Sliding Mode Control
Round 1
Reviewer 1 Report
Please find the attachment file: Report-applsci-2099657
Comments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
This paper develops a sliding mode controller for straight-line path tracking of tractor-trailer vehicles using fast-reaching laws and fuzzy rules to achieve straight-line path tracking control with high robustness for the unmanned tractor-trailer. Overall, the paper was well-written and quite clear in its methodology. The authors presented adequate results and discussion for scientists in this matter, using it as a basis for future research and development. However, there are some comments to improve the quality of this manuscript listed below:
1. Introduction: Please include additional related research.
2. The article should add a literature review or additional references.
3. Please check for typographical and grammatical errors.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Strong aspects:
The authors devised a new path-tracking control method for agricultural tractor-trailers that combines sliding mode control (SMC) and fuzzy control.
The proposed method eliminates the existing SMC's chattering problem and improves the tracking performance of the target trajectory.
Furthermore, the stability of the proposed control method is theoretically guaranteed by Lyapunov stability analysis.
Demonstration tests using an actual tractor-trailer have shown that the proposed control method can improve the path-tracking speed and error compared to the conventional SMC.
Weak aspects:
Since the proposed method is compared only with a normal SMC, its superiority among other control methods is unclear. Comparison with other advanced techniques, such as adaptive PID and improved SMCs (high-order and integral SMCs) as mentioned by the authors in Section 1, should be performed.
Since the tractor-trailer was driven on uneven terrain, accurately reproducing the driving environment during the comparison verification would not be easy. To improve the reliability of the experimental results, it is necessary to determine statistical superiority through multiple tests.
What is the required performance of path tracking when assuming that an autonomous tractor-trailer will be operated on a farm? Have the improvements made in this paper reached the level of practical use, or are further improvements still needed?
Considering the actual operation of the autonomous tractor-trailer, it will be necessary to track straight and curved paths. It would be more convincing to readers if you could add whether the control method in this paper can be applied to curved paths or whether another approach will be necessary.
Others：
Typo on page 10, lines 297-298. Both are "tracking accuracy of the trailer", but one of them seems to be a mistake for "tracking accuracy of the tractor".
Author Response
Thanks for your advice, please see the attachment!
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
My comments have been well addressed. It can be accepted now.
