Discrete Integral Optimal Controller for Quadrotor Attitude Stabilization: Experimental Results
, Omar-Jacobo Santos-Sánchez 1, Hugo Romero-Trejo 1,* and Orlando GarcÃa-Pérez 1Round 1
Reviewer 1 Report
In this paper, a discrete controller based on the LQR improved by adding an integral action is synthesized, to stabilize the altitude of a quadrotor helicopter. My comments/suggestions are given as follows.
a. The main contribution of this paper should be mentioned in the abstract.
b. The topic is interesting.
c. Please add a nomenclature section for improving the quality of the reading before the introduction.
d. Please add the table of symbols.
e. The introduction section is too short.
f. All contributions of this paper should be further summarized and demonstrated point by point.
g. The literature survey is insufficient. More papers should be added and reviewed critically about the LQR and PID controllers like: (Robust output feedback-based neuro-fuzzy controller for seismically excited tall buildings with ATMD accounting for variations in the type of supporting soil), (Seismic structural control using magneto-rheological dampers: A decentralized interval type-2 fractional-order fuzzy PID controller optimized based on energy concepts), (Semi-active control of nonlinear smart base-isolated structures using MR damper: sensitivity and reliability analyses).
h. In the Reference part, they are some old references that may be not necessary, concerning the number of references.
i. The text should be revised to edit some grammar errors.
j. Explain more about your proposed methods with other methods.
k. The results and discussion section must be rewritten.
l. Figure 13 is unclear. What is it about?
m. Figures should be revised completely.
n. Future works must be added to the conclusion section.
Author Response
Please see the attached file, which includes the response letter and the corrected version of the article
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Because the attitude angles (Euler angles) are the states of the system, the dynamic model equations must be revised.
In Fig 2 Clarify reference frames used - body frame; - reference frame;
Define rotation order of the attitude angles (Euler angles)
File with observations is attached.
Comments for author File: Comments.pdf
Author Response
Please see the attached file, which includes the response letter and the corrected version of the article
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors did every attempt to improve the quality of the presentation. So, I suggest this manuscript for publication.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 2 Report
You must have 2 frames:
- an inertial frame , already defined;
- a frame connected to the quadcopter body.
The attitude angles (roll, pitch and yaw) describe the rotation between
these 2 frames.
Usually, for an rotation in order 3-2-1 the yaw angle describes a rotation around the z-axis of the inertial frame, while the roll angle describes a rotation around the x-axis of the frame connected to the body.
The pitch angle describe a rotation around an intermediate frame (not inertial and not body).
Since the definition of the attitude angles (roll, pitch and yaw) is not correct, these equations (1) are not correctly written either.
Since these are the starting equations, the entire work must be revised.
File with observations are attached.
Comments for author File: Comments.pdf
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 3
Reviewer 2 Report
As I have already stated, you must have 2 frames:
The attitude angles (roll, pitch and yaw) describe the rotation between these 2 frames.
Since the definition of the attitude angles (roll, pitch and yaw) is not correct, the equations (1) are not correctly written either
Author Response
Please see the attachmen
Author Response File: Author Response.pdf
