Path Tracking of an Underwater Snake Robot and Locomotion Efficiency Optimization Based on Improved Pigeon-Inspired Algorithm
Round 1
Reviewer 1 Report
Thanks for the authors for their interesting paper. Well, efficient locomotion of serpent-like robots is the trend of study for the last two decades. The authors have made a good choice for theoretical work with the appropriate numerical simulation.
Anyway, as reviewer I have to put against them o couple of questions which is necessary to clarify before the paper will be published, as I think.
- In references: in the 2.1.2 Locomotion pattern you wrote about "Hirose in Japan first proposed the Serpenoid curve..." - but you did not showed which is it in reference list - I guess - you mean [31] - if so, please fix it.
- The name of the paper is "Tracking of Underwater Snake Robot ... etc..."... Here is the other set of questions:
1. If you discuss about underwater robotics - you have a lot of mechanical equations, discussed within the paper frames. But none of them reflect difference between serpentoid motion on ground and within water/underwater conditions. Could you clarify what is the differences if you see them?
2. In part 3 you discuss about water resistance, but still I did not see any reflection of water conditions affection on the robot? I think there is important things like water density, currents flow, directions between robot motion and water flow...
3. How about your robots properties? Part 4 is dedicated to simulation, as I understand, but I did not caught what kind of motion you have? If you will move within water column - there is one case, and if by or over the bottom - the other one. It is not clearly explained in the paper. What kind of buoynancy do you have? Zero? Changable? I hope you can clarify. - Also, I would like, if possible ask the authors to upload their code which make a simulation to the github and make the reference on it at the end of paper in the reference list. This insight can greatly appove their results to people, who would like to test such kind of algorithms for their robots.
In any case I suggest that those changes to your paper is minor and could easily could be added or fixed. Looking forward to see soon your brilliant paper in printed form.
With best wishes,
Reviewer.
Author Response
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Reviewer 2 Report
The article discusses the path tracking of snake robot and presents an interesting approach to this problem based on improved pigeon-inspired algorithm. However, I would like to mention some issues that could be hopefully fixed and improved:
1) There is a strange empty line in the abstract after words "spline interpolation".
2) On page 3 in the system of equations (1) there is no "i" index in the equations, but "i" is mentioned in the explaining text underneath. Please rewrite the equastions.
3) Why exactly these matrices are chosen as matrices A and D on page 4?
4) Both subchapters of Chapter 4.2 are numbered the same "4.2.1".
5) Formulas in general look odd in the sense of formatting. For example, comma between v_x(t) and v_y(t) after Equation (10) is not comma at all, it seems. Also in Equation (14) primes above functions f and y look different. Please make all the formulas look approprietly.
I believe, that after dealing with these questions article can be accepted for publication.
Author Response
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Reviewer 3 Report
The authors consider the tracking control of curved paths for underwater snake robots and investigate methods to improve energy efficiency. The authors propose improved Light of Sight method to design the controller and guide the robot to move along the desired path. In addition, the work included a discussion about the energy efficiency of robot locomotion. The presented simulation results show that the proposed controller enables the robot to follow the curved path accurately and that the QPIO algorithm effectively improves robot energy efficiency. The work is a well written scientific work. However, before accepting some minor revisions must be done. I have only two comments to improve:
1. English should be improved (native speaker will be helpful);
2. In the abstract and Introduction should be more emphasis what is the connection of this paper with the journal scope.
Author Response
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