Controller for an Asymmetric Underactuated Hovercraft in Terms of Quasi-Velocities
Round 1
Reviewer 1 Report
The proposed technique is interesting. Please find the attachment for the detailed comments.
Comments for author File: 
Comments.pdf
Author Response
The manuscript has been revised according to the comments made.
Author Response File: Author Response.pdf
Reviewer 2 Report
This paper considered an asymmetric hovercraft control problem, where the mass center may be shifted. Then, following the existing control method in Ref.[22], authors presented the controller for the current problem. After reviewing, there exist some points which should be further addressed as follows,
1. Authors apply the coordinate transformation based on known center of mass (CM) drift. Need to explain how can get CM’s drift? It is usually not easy to know in a real system.
2. Eq.(3), how to get the coefficients for drags and frictions? It is also very hard to know the exact value. It is canceled in the controller (30).
3. With the discontinuous frictions, the dynamic system is discontinuous. Thus, the solution should be discussed in sense of Fillippov. Otherwise, some assumptions should be made.
4. The stability proof should be improved. Needs to show how to obtain exponential stability, what Laypunov stability theorem was used? Also, needs to indicate the conclusion for zero dynamics, because Theorem is for the whole system.
5. In the simulation, results should be compared with the existing controller in Ref. [22], because you mentioned this is an extension of their work to an asymmetric hovercraft.
Author Response
The manuscript has been revised according to the comments made.
Author Response File: Author Response.pdf
Reviewer 3 Report
The presented manuscript deals with a nonlinear controller for tracking a desired trajectory for an underactuated hovercraft. A new modification of a control algorithm for asymmetric hovercraft is proposed. It is justified by simulations. The contributions of the author is stated and the advantages and drawbacks of the proposed controller are discussed.
However, the methodology of the simulation is not fully presented. Basically, the description contains just some references to the previous works. One of them [37] is not freely accessible being an unpublished project.
Author Response
The manuscript has been revised according to the comments made.
Author Response File: Author Response.pdf
