Anti-Roll Characteristics of Marine Gyrostabilizer Based on Adaptive Control and Hydrodynamic Simulation

Round 1

Reviewer 1 Report

Please address all the comments in the paper which is in the file

All underlined text needs major revision of sentences

OTHER ADDITIONAL QUERIES/COMMENTS

1. Please specify the type of gyrostabilizer used in the study (i.e., either horizontal or Vertical axis gyrostabilizer) although given in the picture
2. In page 4-line 139, what is the basis for phi value less than equal to 10
3. Section – 4 Control rate design Give reference to the for the precision angle control rate (Equation 8)
4. The control standard parameter has taken as 9.545, the feedback gain of precession angle has taken as 1.2, How these parameters were obtained
5. How the variable control gain was selected-Any particular theorem/technique is used to estimate that?
6. In section 5 – Hydrodynamics numerical simulation  Whether mesh convergence study has been done, if so, provide the details
7. It was mentioned that overset method has been adopted-give the details of mesh with boundary condition
8. The computational domain was mentioned as 200m 268 × 100m × 32m – On what basis the domain was selected?
9. In Starccm+, How the gyrostabilizer reactional moment due precision of flywheel was considered for reducing roll? Need clear input/assumption details
10. How the adaptive control scheme was implemented in Starccm+
11. Response comparison in the frequency domain will give the visualization of reduction for wide exciting frequency
12.  Details on computational time in star ccm may be added

Comments for author File: Comments.pdf

Author Response

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Reviewer 2 Report

The manuscript ``Research on the Anti-roll Characteristic of Marine Gyrostabilizer Based on Adaptive Control and Hydrodynamic Simulation'' addresses the design of an adaptive controller based on the variable gain control strategy based on a gyrostabilizer. This topic is significant to the field of ship hydrodynamics and engineers. However, the paper does not discuss the results nor presents a proper discussion of the numerical simulations. Since the necessary changes are not amenable for major revision, I do not recommend the paper for publication. My suggestions and comments are below.

• page 2, ``The hydrodynamic parameters in the model equations are generally replaced by empirical values or approximate values that obtained from the ship model tests or full-scale ship experiment. This method has the advantages of clear principle and simple calculation'' - I understand why this is performed, but the authors could discuss the impact/limitations of using such simplified models;
• page 2, ``high cost'' - In comparison to other methods, what is the cost increase of the gyrostabilizer?
• page 4, ``In this paper, a mathematical model of ship roll motion with gyrostabilizer is established to explain its anti-roll principle.''- It is important to be more specific on how the authors obtain these equations. Perhaps a reference.
• page 7 - What are the values of phib, phia, and R for other techniques? It is hard to understand the potential of the new method without this information.
• page 8 - What does it mean high mesh precision? Please define a criterion for this expression, like numerical errors smaller than a certain value.
• page 9, ``The grid independence and step-length independence are verified for numerical simulation to ensure the credibility of the simulation results. - How is this accomplished? For example, how much do the solutions vary when the grid is refined or coarsened by a factor of 2?
• What are the grid resolution and numerical uncertainty? What is the iterative convergence criterion? What is the time step? ... The authors need to describe the simulations adequately. Otherwise, it is not possible to evaluate their quality.
• The results are not discussed, only reported in a couple of lines.

Author Response

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Reviewer 3 Report

This work presents an adaptive controller for a marine gyrostabilizer. The work is clearly workout and the theory, methods and results are clearly presented.

please include a minor corrections:

1.- margins on eq. (13)

2.- margins on the symbols table.

Author Response

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Round 2

Reviewer 1 Report

Please carry out the suggested corrections.  Please recheck all new statements introduced.  It will be nice to proof read by an expert with good english technical writing skills  Conclusions has to be rewritten in a format /language that can be acceptable

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The authors addressed most of my comments. I recommend the paper for publication.

Author Response

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Author Response File: Author Response.pdf