Attitude and Altitude Control Design and Implementation of Quadrotor Using NI myRIO

Round 1

Reviewer 1 Report

1) Subsection 2.1 provides details of modeling a quad rotor, while most of the details can be easily found in the literature. I recommend summarizing this subsection by citing relevant references.

2) Cascade control scheme presents din Figure 7 has been discussed in prior work, e.g., [R1]-[R2]. The authors need to cite these publications for clarification on the contributions of the manuscript. 

[R1]. "Constrained Control of UAVs in Geofencing Applications", 2018. [http://doi.org/10.1109/MED.2018.8443035]

[R2]. "Barrier Functions in Cascaded Controller: Safe Quadrotor Control", 2020. [http://doi.org/10.23919/ACC45564.2020.9147864]

3) Provide a list of contributions of the manuscript at the end of Section 1. Also, consider providing a brief outline of the manuscript. 

4) What method do you use to communicate with the quadrotor? The current time delay is 6 ms, which may cause instability in rapid maneuvers. Do you use Python? WiFi? Bluetooth? 

5) Consider providing some future directions. This would help the readers to understand possible applications/advancements of the proposed work. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper presents the design of the attitude and altitude controller for a quadrotor constructed by the authors of the paper. The design is validated both numerically and experimentally.

The paper covers many areas which makes it interesting. However, the use of the English language should be substantially improved before the paper can be published.

Minor comment

Page 4

[\dot phi; \dot theta; \dot psi] is not the angular velocity in Earth coordinates.

The angular velocity in Earth coordinates omega is obtained as

omega = R omega_B

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

No further comment.