Control Methods Comparison for the Real Quadrotor on an Innovative Test Stand

Round 1

Reviewer 1 Report

The paper entitled “Control methods comparison for the real quadrotor on an innovative test stand” studies the verification of already designed control techniques on a real platform.

 

However, I have some concerns as follows:

 

Technical aspect:

 

• There is a lack of explanation of the rationale used in the study.

 

• Each part is independent of each other and no relationship can be found.

 

• The literature review section at the beginning is superficial and does not represent the state-of-the-art considering different methods for controlling a Quadrotor. For example, some recent related articles are as follows. The first reference (a) is well-known in UAVs, reference (b-c) are recent review articles about the multi-rotor aerial vehicles, and the rest (d-j) are just few examples of the learning based and backstepping trajectory tracking methods.

 

• Valavanis, K.P. and Vachtsevanos, G.J. eds., 2015. Handbook of unmanned aerial vehicles (pp. 2993-3009). Dordrecht, The Netherlands:: Springer.

 

• Nascimento, T.P. and Saska, M., 2019. Position and attitude control of multi-rotor aerial vehicles: A survey. Annual Reviews in Control.

 

• Tahir, A., Böling, J., Haghbayan, M.H., Toivonen, H.T. and Plosila, J., 2019. Swarms of Unmanned Aerial Vehicles–A Survey. Journal of Industrial Information Integration, p.100106.

 

• Carrillo, L.R.G. and Vamvoudakis, K.G., 2019. Deep-Learning Tracking for Autonomous Flying Systems Under Adversarial Inputs. IEEE Transactions on Aerospace and Electronic Systems.

 

• Jafari, M., Xu, H. and Garcia Carrillo, L.R., 2019. A neurobiologically-inspired intelligent trajectory tracking control for unmanned aircraft systems with uncertain system dynamics and disturbance. Transactions of the Institute of Measurement and Control, 41(2), pp.417-432.

 

• Jafari, M. and Xu, H., 2018. Intelligent control for unmanned aerial systems with system uncertainties and disturbances using artificial neural network. Drones, 2(3), p.30.

 

• Madani, T. and Benallegue, A., 2006, October. Backstepping control for a quadrotor helicopter. In 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems (pp. 3255-3260). IEEE.

 

• Shao, X., Liu, J., Cao, H., Shen, C. and Wang, H., 2018. Robust dynamic surface trajectory tracking control for a quadrotor UAV via extended state observer. International Journal of Robust and Nonlinear Control, 28(7), pp.2700-2719.

 

• Wang, N., Su, S.F., Han, M. and Chen, W.H., 2018. Backpropagating constraints-based trajectory tracking control of a quadrotor with constrained actuator dynamics and complex unknowns. IEEE Transactions on Systems, Man, and Cybernetics: Systems, 49(7), pp.1322-1337.

 

• Liu, H., Zhao, W., Hong, S., Lewis, F.L. and Yu, Y., 2019. Robust backstepping-based trajectory tracking control for quadrotors with time delays. IET Control Theory & Applications, 13(12), pp.1945-1954.

 

• The study on each part is not deep and just a simple illustration is shown. All part seems just like a framework without concrete content.

 

• Abstract and Introduction Sections need to be rewritten and reconstructed.

 

• What are the main contributions of this paper in comparison to the related articles?

 

• The Conclusion Section needs to be revised to improve the quality of the paper.

 

• Some elements in the paper sound not clear/complete/rigorous, and sometimes vague.

 

• I would recommend the respected authors to spend more time in presenting and also in highlighting the contributions of their paper.

 

• It is recommended that the respected authors add the outline of their paper: “The rest of this study is organized as follows: ….. presented in Section 2. In Section 3, the ….. are investigated and discussed and finally Summary and conclusions are presented in Sections 4”.

 

Presentation aspect:

 

• The paper needs significant improvement in presentation. For example, the English adopted in the paper is not enough for such a scientific publication. There are too many typos, sometimes English is not formal, and it seems that the authors did not review the paper themselves before submitting it.

 

• The paper is not well written and is difficult to follow.

 

• Linguistics, readability of the paper should be improved, and the authors should restructure the paper in order to have a smooth transition among the sections.

 

• Avoid long sentences. Lengthy and convoluted sentences make the text hard to read.

 

• There are many parts of the paper in which the results and their considerations are merely thrown at the reader without a further and detailed description. It is not the reader that needs to analyze, but it is the authors who need to discuss and explain.

 

• There is inconsistency in the format of the references in this paper.

 

• Replace all figures with the new one with good quality.

 

Author Response

First of all we want to thank the reviewer for all the comments. We believe that they have helped us to significantly improve the quality of our article.

All the changes the text are indicated with yellow background. As you can see, there are many of changes.

1. We focused on highlighting the main contributions of the article. This is reflected especially in abstract, introduction and conclusion. Let us have one more comment to this - As far as we know, in the literature does not exist such complex comparison of various control techniques of the quadrotor. This is supported by the fact that our previous work [35] has this record: Times Cited: 28 (from Web of Science Core Collection) and 35 citations in SCOPUS. This new article documents logical next step of our work.
   
2. We tried to improve the relationship between the individual sections of the article, especially in the introduction of each section. We always explain why this section is in the article. The structure of the article was structured as follows: Introduction (VTOL->quadrotor->control techniques->justification of our work), Test stands (used for evaluation of the control techniques, justification of the need for a new stand that has been designed by us), Experimental setup and results (this section has been divided into several logical subsections including overall comparison of the controllers), Conclusion.
3. Almost all recommended articles were studied and the references were added into our article. However, as we also highlight in the new version of our article, so complex comparison of various control techniques does not exist in the literature. Yes, basic overview is provided in many of them, but the researchers just improve one technique by its own modification. Therefore, there is no objective comparison between the various control techniques of the quadrotor.
4. We tried to improve the overall text of the article so that there should not be long or incomprehensible sentences.
5. Many sections have been improved so we believe that the reader gets a better overview of the presented issues.
6. All references have been modified according the requested format.
7. All figures will be uploaded as a supplementary files. They are original, but the journal format will not allow us to display them on a larger area.

Reviewer 2 Report

Paper describe the evaluation of already designed control techniques on a real flying platform.

Definitely, authors should improve the abstract, it doesn´t describe well the paper and the contribution.

In general, the paper is well structured and written. However, the sections are so long so it can difficult the reading.

Introduction is well structure and include the state of the art well presented.

Experimental results section could be organized in a better way. Probably sub-divide the sections regarding main components could be a good idea. Maybe as was presented the test design in the second section?

I also suggest the authors to include a section to describe the study limitations.

Although this kind of citations is used:

The controller parameters had to be newly tuned because when parameters derived in [35] were applied the quadrotor shows unstable behaviour. There can be various reasons why it is so.

I always recommend write the paper considering that if the citations are eliminated, the paper should continue having sense. It is not the case using that kind of citation style.

Finally I recommend to read and review these references:

Sudin MN, Abdullah SS, Nasudin MF. Humanoid Localization on Robocup Field using Corner Intersection and Geometric Distance Estimation. International Journal of Interactive Multimedia and Artificial Intelligence. 2019;5(7):50-56. DOI 10.9781/ijimai.2019.04.001   García CG, Núñez-Valdez ER, García-Díaz V, Pelayo G-Bustelo C, Cueva-Lovelle JM. A Review of Artificial Intelligence in the Internet of Things. International Journal of Interactive Multimedia and Artificial Intelligence. 2019;5(4):9-20
DOI 10.9781/ijimai.2018.03.004   AA Pereira, JP Espada, RG Crespo, SR Aguilar, Platform for controlling and getting data from network connected drones in indoor environments Future Generation Computer Systems 92, 656-662, 2019    

 

Author Response

First of all we want to thank the reviewer for all the comments. We believe that they have helped us to improve the quality of our article.

All the changes the text are indicated with yellow background. As you can see, there are many of changes.

1. Abstract was improved and the main contribution has been highlighted.
2. Subsections, especially in Section 3, were included. We believe that the clarity of the article was thus increased.
3. Incorrect citations were removed.
4. The recommended references were added.
5. Limitations of the study are discussed in the Conclusion.

Round 2

Reviewer 1 Report

N/A.

Reviewer 2 Report

Accept as is