Hybrid Modeling of Deformable Linear Objects for Their Cooperative Transportation by Teams of Quadrotors
Round 1
Reviewer 1 Report
The paper has been well written, some minor comments may help for improvements:
-Highlight the basic contributions in introduction or abstract
-Add some comparisons with similar approaches
-Refer the basic equations to the original papers such as 1
-Add some remark about potential improvement using type-3 fuzzy logic such as
Fractional-order fuzzy control approach for photovoltaic/battery systems under unknown dynamics, variable irradiation and temperature;
A new online learned interval type-3 fuzzy control system for solar energy management systems;
-A general block diagram in beginning will be helpful
Author Response
The paper has been well written, some minor comments may help for improvements:
Response: Thanks for the positive comment. Changes in the manuscript are highlighted in red font.
-Highlight the basic contributions in introduction or abstract
Response: Thanks for the comment. The basic contributions are highlighted both in the abstract and in the introduction. We have modified the writing to emphasize them.
-Add some comparisons with similar approaches
Response: we did not have access to the software of other research works dealing with similar problem of DLO transportation by 2 UAVs. In this time, our attemps to reproduced their simulations in order to answer the reviewer’s comment have failed. Moreover, they do not tackle aggressive maneuvers such as the ones we are simulating, thus they do not suffer from the sagging singularities that we try to solve in this paper.
In the last paragraph of Section 3, we added some discussion of hybrid modelling in UAVS (“In drone team operation modeling, there is some previous work on hybrid modelling…).
Moreover, we added the last paragraph at the section 2 and try to make a clear evolution of the DLO modelling tendencies and inspiration of cable structures.
-Refer the basic equations to the original papers such as 1
Response: we have included references for the equations in sections 4 and 5.
-Add some remark about potential improvement using type-3 fuzzy logic such as
Fractional-order fuzzy control approach for photovoltaic/battery systems under unknown dynamics, variable irradiation and temperature;
A new online learned interval type-3 fuzzy control system for solar energy management systems;
Response: we have included the required references in the conclusions section as future research working lines.
-A general block diagram in beginning will be helpful
response. Thanks for the recommendation. We have included a block diagram in the Introduction section.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The subject is important in terms of practice.
1- The literature review was well done, but it seems that there is not enough discussion about the literature presented. The two main contributions of the method presented in this paper appear in many articles. It would be nice for the reader to include a comparison chart.
2- The experiments performed remain very simple. 3D trajectory needs to be added. For example, it would be nice to add a spiral or random orbital. In addition, modeling the behavior during take-off and landing is one of the most intriguing parts. Adding at least one of these parts will add richness.
3- It is necessary to provide information about the simulation environment, physics engine or simulation software, and even share the model.
4- In the method part, especially the PD controller operation is a well-known method. In this section, there is a high similarity with the previous publications of the authors. It would be nice if this part could be reduced with a citation or correction. There is a high similarity in sentences starting on lines 26, 101, 102, 191, 198, 206 and 244. It is not a requirement, it is a suggestion to the authors in order to prevent situations such as plagiarism.
Author Response
1- The literature review was well done, but it seems that there is not enough discussion about the literature presented. The two main contributions of the method presented in this paper appear in many articles. It would be nice for the reader to include a comparison chart.
Response: We have included a table summarizing the literature in Section 2. We added an extra paragraph at the end of the section 2 trying to describe a clear evolution of the DLO modelling tendencies.
2- The experiments performed remain very simple. 3D trajectory needs to be added. For example, it would be nice to add a spiral or random orbital. In addition, modeling the behavior during take-off and landing is one of the most intriguing parts. Adding at least one of these parts will add richness.
Response: The proposed modeling approach is set in the quasi-stationary regime corresponding to the cruising of the system of UAVs and the DLO between origin and destination after take off and before landing manoeuvrers. These manoeuvrers introduce deformations on the DLO that can not be modelled by our approach. We had a previous related work dealing with a single DLO hanging from a UAV during take off which can serve as a basis for such research.
Estévez, J., & Loṕez-Guede, J. M. (2019, June). Control of transitory take-off regime in the transportation of a pendulum by a quadrotor. In International Work-Conference on the Interplay Between Natural and Artificial Computation (pp. 117-126). Springer, Cham.
Please notice that the few examples of works in the literature that deal with similar problem of DLO transportation do not discuss the take off and landing transitory regimes. Also, they only consider 2 drones, which a much simpler case than the one we are tackling.
Following the reviewer’s suggestion, we have added Experiment 3, where the three drones cooperative system must follow a 3D ascending spiral path, where we test if the hybrid DLO system is able to cope precisely and smoothly with trajectories along 3 directions in the space.
3- It is necessary to provide information about the simulation environment, physics engine or simulation software, and even share the model.
Response: we have included a link to the github environment where we have published the code of the simulations developed in Scilab.
4- In the method part, especially the PD controller operation is a well-known method. In this section, there is a high similarity with the previous publications of the authors. It would be nice if this part could be reduced with a citation or correction. There is a high similarity in sentences starting on lines 26, 101, 102, 191, 198, 206 and 244. It is not a requirement, it is a suggestion to the authors in order to prevent situations such as plagiarism.
Response: thanks for your kind comment. In order to avoid plagiarism we have carefully rewritten the indicated phrases, and we have removed some figures that might also be detected as plagiarism. Additionally, we have concentrated our claimed contribution in the hybrid modelling of the DLO, because the adaptive fuzzy rules were already proposed and validated in a previous referred publication. We clarify this in section 5, as well as in the introduction and abstract.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Accept in present form
