Quaternion-Based Non-Singular Terminal Sliding Mode Control of Quadrotor with a Two-Degree-of-Freedom Deformable Arm for Narrow Environments
, Zhong Yang 1,*, Xu Chen 1, Haoze Zhuo 1,2, Hongyu Xu 3, Nuo Xu 1,4 and Danguo Cheng 1
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper highlights a Quaternion-based Non-singular Terminal Sliding Mode Control of Quadrotor with 2DOF Deformable Arm for Narrow Environment. A novel vehicle with the capability of traversing narrow environments in space named QTDA is proposed and its overall scheme is modeled and analyzed for traversing horizontally and vertically narrow environments. Due to the interference of internal parameter perturbations, channel coupling, and external perturbations during the deformation process of QTDA, the position control method based on non-singular terminal sliding modes and the attitude control method based on quaternionic non-singular terminal sliding modes are investigated. The paper also suffers from the following problems:
1. The innovation of this paper is not found from the introduction. The innovation of this paper needs to be accounted for and pointed out at the end of the introduction.
2. The introduction part spends a lot of space to introduce the current research status of the deformable quadrotor, while the research of this thesis is about the flight control of the deformable quadrotor. The authors need to give an account of the current state of research in flight control of deformable quadrotors and the shortcomings in the introduction, and then point out the innovation of this article.
3. Try not to use the same line type for each curve in the picture, and don't just use solid lines. You can use curves such as triangles and diamonds.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsIn this paper, a novel two-degree-of-freedom arm deformable quadrotor QTDA is proposed and a non-singular terminal sliding mode control is designed. Moreover, it seems that the desired effect is realized from the simulation results. However, there are still some language and formatting problems in the paper. Thus, a major revision is required, and the final decision cannot be made until the following problems are solved.
The following are the comments.
1）The titles of Chapters 3 and 4 are too brief and do not adequately summarize the core content of the section. It is recommended that the authors optimize the titles of these two chapters to make them more specific and clear so that readers can quickly understand the theme and main content of each chapter.
2）There are some problems with the language presentation in this paper, which may affect the reader's accurate understanding of the content. It is suggested that the author should make further modifications to the language of the whole paper to ensure that the sentence structure is clear and the expression is concise and fluent.
3）Some of the equations in this paper are not beautiful enough, affecting the reading of the problem, such as Equation 27 and Equation 32. It is recommended that the authors of the full paper of the equation to re-format, to ensure that the equation format is uniform, clear, and improve the overall layout of the beauty and readability.
4）The explanation of the symbols in this paper is concentrated in the second paragraph, but this does not meet the specification. It is recommended that the authors provide a clear explanation of the symbols in each equation as they appear to ensure that the reader understands the meaning of the symbols in the first place.
5）There is an error in the reference to figure in the first sentence of section 4.1.2.
6）The conclusion section should succinctly summarize and summarize the work throughout the paper. It is recommended that the authors rework the conclusion section so that it focuses on summarizing the research findings, methods and conclusions. In addition, the innovations should be placed in the introductory part of the article rather than in the conclusion section, which will help to improve the logical structure of the paper and the reader's understanding.
Comments on the Quality of English LanguageIn this paper, a novel two-degree-of-freedom arm deformable quadrotor QTDA is proposed and a non-singular terminal sliding mode control is designed. Moreover, it seems that the desired effect is realized from the simulation results. However, there are still some language and formatting problems in the paper. Thus, a major revision is required, and the final decision cannot be made until the following problems are solved.
The following are the comments.
1）The titles of Chapters 3 and 4 are too brief and do not adequately summarize the core content of the section. It is recommended that the authors optimize the titles of these two chapters to make them more specific and clear so that readers can quickly understand the theme and main content of each chapter.
2）There are some problems with the language presentation in this paper, which may affect the reader's accurate understanding of the content. It is suggested that the author should make further modifications to the language of the whole paper to ensure that the sentence structure is clear and the expression is concise and fluent.
3）Some of the equations in this paper are not beautiful enough, affecting the reading of the problem, such as Equation 27 and Equation 32. It is recommended that the authors of the full paper of the equation to re-format, to ensure that the equation format is uniform, clear, and improve the overall layout of the beauty and readability.
4）The explanation of the symbols in this paper is concentrated in the second paragraph, but this does not meet the specification. It is recommended that the authors provide a clear explanation of the symbols in each equation as they appear to ensure that the reader understands the meaning of the symbols in the first place.
5）There is an error in the reference to figure in the first sentence of section 4.1.2.
6）The conclusion section should succinctly summarize and summarize the work throughout the paper. It is recommended that the authors rework the conclusion section so that it focuses on summarizing the research findings, methods and conclusions. In addition, the innovations should be placed in the introductory part of the article rather than in the conclusion section, which will help to improve the logical structure of the paper and the reader's understanding.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsI read the manuscript with great enthusiasm, which grew up as the next chapters were read. In other words, I haven't read something so well written for a long time.
The paper addresses the problem of universal, flexible in space movement, in all directions, drone control systems. Without doubts the presentation is full of novelty. Thus, the authors very well justified the selection of the quaterions method. The presented model is complete enough, taking into account, among others, disturbing forces. Hence, the article presents a solid theoretical model and conducts detailed simulations based on it.
In general, the topic is very important for scientific community and relevant to be investigated and the authors presentation is extremely clearly provided the presented equations, for example, are deeply explained, described and derived from the perspective of multidimensional control of drones.
The provided discussion about universal, flexible control of drones is full, and the conclusions are in-depth and have a bright structure.
The manuscript should published in the actual form – it’s logical structure warrants wide dissemination of results among scientists and engineers. The list of references is appropriate.
Comments on the Quality of English Language
Something is wrong with grammar in line 168 – there are some typos, like lack of commas for example, which should be checked by editors. In line 217 – the short sentence can’t begin with And. Line 290 – lack of the fig. number – 5b?.
However, the overall English is good.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsAgree to publish in the current form.
Reviewer 2 Report
Comments and Suggestions for AuthorsI have no further comment. This paper can be accepted.
Comments on the Quality of English LanguageI have no further comment. This paper can be accepted.
