Robust Adaptive Path Following Control Strategy for Underactuated Unmanned Surface Vehicles with Model Deviation and Actuator Saturation

Round 1

Reviewer 1 Report

The article is not suitable for the journal Applied Sciences. It is not general enough for Applied Sciences. It should be submitted to a journal dealing with the topic of the article.

Author Response

Thank you very much for the valuable suggestions that the reviewer 1 gave me to optimize my manuscript. Please see the attachment for my specific reply.

Author Response File: Author Response.doc

Reviewer 2 Report

1. Introduction
- presents general information about the unmanned surface vehicle (USV), different strategies for the control of USV,  as are studied in the literature;
- presents the main characteristic of the proposed control scheme.

2. Problem formulation
- this section describes the dynamic of the USV (kinematic equation);
- in my opinion, here it is necessary a diagram to explain the coordinate systems (reference system, position, angle, velocity etc.);

3. LOS Guidance Algorithms
- the mathematical formalism is, for sure, correct, but, without notations/symbols on a diagram it is uncomplete.

4. Control System Design
- the Lyapunov approach is correct but there are some symbols without explanations;
- again, in my opinion, a diagram (draw, picture, scheme) is necessary to explain the yaw (roll, pitch); 

5. Stability Analysis
- from the point of view of the control systems engineering, the treating of the stability problem only in terms of mathematics is good but not enough;
- here, it is necessary to present the stability plane, the upper limits etc.

6. Numerical Simulations
- first, here it is necessary a block diagram of the simulation scenarios;
- the results presented in Figures 1,2,3,4 are compelling; however, the time axis is too long (if we are interested in the transient behaviour).

Author Response

Thank you very much for the valuable suggestions that the reviewer 2 gave me to optimize my manuscript. I have answered your comments one by one. Please see the attachment for my specific modification method.

Author Response File: Author Response.doc

Reviewer 3 Report

Dear Authors, thank you very much for submitting your paper "Robust Adaptive Path Following Control Strategy for Underactuated Unmanned Surface Vehicle with Model Deviation and Actuator Saturation

"

After reviewing heavily reviewing your paper i came to the following conclusions: The paper need to be revised.

 

The paper is overall of good merit but lacks some information, state of the art literature, structural refinements and some additional explanations. In the following i will display what needs to be added to the paper:

1. Overall Feedback:

• Overall good paper, mainly minor changes need to be done
• Interesting approach and well-presented methods
• Extensive results available
• structure needs to refined

 

2. Abstract, Introduction and General Objective:

• The general objective as well as a clear list of contributions is missing. What is the news value of this paper in contrast to the state of the art? 
  - What are your contribution in this work and why is it necessary to display this work?
• - Make a clear structure cut between the introduction and the state of the art

 

3. State of the Art and Literature used:

It is necessary to extend the literature review in the introductory paragraph. For example, it is suggested to consider the development of AVs in the light of high acceleration and high velocity (autonomous racing). In here many work is covering learning-based control to define the external disturbances. Therefore, we recommend reading the following research works 

MPC Path Planning (with and Important here: Learning MPC)

 

U. Rosolia  et al. "Autonomous racing using learning model predictive control" American Control Conf pp. 5115-5120 2017.

 

U. Rosolia and F. Borrelli, “Learning Model Predictive Control for Iterative Tasks: A Computationally Efficient Approach for Linear System,” IFAC-PapersOnLine, vol. 50, no. 1. Elsevier BV, pp. 3142–3147, Jul. 2017. doi: 10.1016/j.ifacol.2017.08.324.

 

F. Borrelli P. Falcone T. Keviczky J. Asgari and D. Hrovat "MPC-based approach to active steering for autonomous vehicle systems" Int. J. Vehicle Auto. Syst. vol. 3 no. 2 pp. 265-291 2005.

 

Gaussian Path planning and Learning based MPC

L. Hewing et al. "Cautious model predictive control using gaussian process regression" IEEE Transactions on Control Systems Technology 2019.

 

A. Wischnewski et al. “Real-Time Learning of Non-Gaussian Uncertainty Models for Autonomous Racing,” presented at the 2020 59th IEEE Conference on Decision and Control (CDC), Dec. 2020, doi: 10.1109/cdc42340.2020.9304230.

 

Wischnewski, et al. , “A Model-Free Algorithm to Safely Approach the Handling Limit of an Autonomous Racecar,” 2019 IEEE International Conference on Connected Vehicles and Expo (ICCVE). IEEE, Nov. 2019. doi: 10.1109/iccve45908.2019.8965218.

4. Methods/Algorithms/Approaches:

• you are having an underactuated vehicle, why are you not displaying a nonlinear vehiicle model that is covering the tires? Especially when you are focusing on sideslip angle caculation the tire paramters have the biggest influence on that?
• THis is the biggest flaw of the paper, it is unclear how you can use this type of kinematic model for lateral vehicle behavior?
• What kind of simulation are you using for your results? explain the simulation setup and environment

 

5. Results:

- You only show qualitative overview of the results but not quantiative numbers. Go into detail and explain lateral/longitudinal deviation from the path and its quantitative numbers

 

6. Discussion: You are missing your discussion section completely. From a scientific paper point of view you need to enter a critical and reflective discussion. Explain to the reader what is good on your approach and what is bad. Be really honest here what needs to be done in addition to enhance your approach further. In addition you can draw here conclusions to other authors.

 

Author Response

Thank you very much for the valuable suggestions that the reviewer 3 gave me to optimize my manuscript. I have answered your comments one by one. Please see the attachment for my specific modification method.

Author Response File: Author Response.doc

Round 2

Reviewer 1 Report

The article is not at all suitable for Applied Sciences. Actually it is too much modelling in it. It shall be submitted to an appropriate journal.

Reviewer 3 Report

Dear Authors,

thank you very much for revising your paper and adding the suggested comments.