In view of the criticisms of the reviewer(s) found at the bottom of this letter, your manuscript has not been recommended for publication. Unfortunately, we will not accept resubmissions of this article.

Thank you for considering -----------for the publication of your research.

Sincerely,

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Reviewer: 1

Recommendation: Reject

Comments:
A model-based real-time robust controller design problem for a small-size helicopter is studied. This reviewer has the following comments:
-The new features are not clear, especially in comparisons with the recent relevant ones. Robust control of helicopter is a quite traditional problem. Comparisons should be made in both the theoretical and experimental aspects.
-The theoretical contributions seem weak as there is no theorem in this paper.
-Experiment videos or links for the experiment video should be provided.
-The presentation can be further improved. There are too many typos.



Additional Questions:
Does the paper contribute to the body of knowledge?: y

Is the paper technically sound?: n

Is the subject matter presented in a comprehensive manner?: n

Are the references provided applicable and sufficient?: y


Reviewer: 2

Recommendation: Reject

Comments:
The airticle addresses the tracking problem of small-sized helicopter, the controller includes two parts, the part of inner-loop based on H¡Þ technique and the part of outer-loop which adopts PPC method.The idea is interesting and it presents a unique approach to design outer-loop controller.But there are some limitations and key problems.
1.There is no specific comparison of the method with previously known research result, so it is hard to judge whether the algorithm is an improvement on previous work. Some simulation or experiment results of comparison should be added.
2.The configuration design of controller is sound, but stability of the whole system should be considered or explained. The study did not show enough about these problems. Some some trajectory tracking results are needed as a practical and unambiguous evidence.
3.the subject is presented synthetically and the analysis about helicopter modeling is described attentively. The description of the design process of the controller is methodical. But, here are some irregular and oversized formulas which can be reformat.
4.In my opinion, the references about the research on PPC in recent years should be added. The length of introduction about H¡Þ technique can be shorter.

Additional Questions:
Does the paper contribute to the body of knowledge?: Yes

Is the paper technically sound?: Yes

Is the subject matter presented in a comprehensive manner?: It's not bad

Are the references provided applicable and sufficient?: Need to improve ·µ»ØСľ³æ²é¿´¸ü¶à