Nonlinear Trajectory Tracking Controller for Underwater Vehicles with Shifted Center of Mass Model

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors Here is a more detailed version of my review report.

This paper presents a tracking control algorithm for AUVs in the presence of parameter perturbations. The author adopts a 5-DOF AUV model, which is not new, but the overall scientific work is sound, including the rigorous definition the problem and the detailed derivations for the newly proposed technical route, i.e., a combination of backstepping method, adaptive integral sliding mode control scheme and velocity transformation resulting from decomposition of inertia matrix. The simulation results are sufficient for the verification of the algorithms, which includes the scenarios with and without couplings, and for simple and complex trajectories. The English is well written. This paper can be accepted for publication after minor revision. Below are some detailed comments for the author to improve the manuscript.

1. The author doesn't explain the logic why all forms of considered perturbations are finally modelled as the shift of mass center from the geometry center.

2. In line 59, "Thus, it seems that designing control algorithms for 5 DOF models makes practical sense". Although the author listed some literature on simplifying the vehicle to 5 DOF, that doesn't explain why it is practical. Please rewrite this sentence to avoid logical problem.

3. The section 4 the author doesn't compare the results with any baseline algorithms in the field. If there is no baseline for this case, please emphasize this fact and explain convincedly why there does not even exist a baseline.

4. It is better to give some insights of the convergence time the results in Sec 4. For example, what does such convergence time (50~100s) mean for AUV applications? Is it higher or lower than SOTA? etc.

Author Response

Thank you very much for your review. Please see the attached file for answers to questions and suggestions.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper is good, and only minor aspects must be fixed.

“DOF” is not defined”.

Neural network is usually abbreviating with ANN.

“The article’s contributions are as follows:” period at the end of the introductions is out of context.

Think about moving some theoretical part into supplementary material in order to reduce the load of part to read to readers. In fact, the paper seems actually a bit long.

Author Response

Thank you very much for your review. Please see the attached file for answers to questions and suggestions.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The paper presents the control in the presence perturbations and disturbances.

 

The structure of the paper is good.

 

Minor comments:

 

Row 460:

The settling time in Figure 6 and in other figures should be analyzed and compared.

 

Row 462:

The analysis should be explained numerically.

 

Row 475:

Could results be analyzed more numerically and in which ratio some value is larger.

 

Row 544

In conclusions, the main results should be also shortly described.

Author Response

Thank you very much for your review. Please see the attached file for answers to questions and suggestions.

Author Response File: Author Response.pdf