Incremental Backstepping Sliding-Mode Trajectory Control for Tailless Aircraft with Stability Enhancer

Round 1

Reviewer 1 Report

The authors present a well written paper on applied control theory for tailless aircraft. The background and introduction covers the research field well.

On major remark on the work would be that is theoretical/computational without experimental validation. This need to be commented on as reality often prooves to be slightly more difficult than theory. Doing this some comments on disturbances, erroneous sensors and other real worlb bias in the control system would make the paper even better.

Smaller comments:
r43-36  "difficult to obtain aircraft model" -is it really more difficutt to get an accurat aircraft model for a tailless aircraft, than other types of aircraft?

r128. remark 1. Indeed a polynomial wouldn't be a good option. I'm not sure it even have to be mentionen though. Splines or another reduced order method is the more or less "standard" way of doing it.

figures: all of them are a bit hard to read, but in particular fingure 14 - this one needs to be re-thinked about what you want to show.

 

Author Response

Dear Reviewer: Thanks for your comments concerning our manuscript entitled "Incremental backstepping sliding-mode trajectory control for tailless aircraft with stability enhancer" (ID: aerospace-1745174). Those comments are valuable and helpful for revising and improving our paper and the important guiding significance to our research. We have studied comments carefully and have made corrections which we hope meet with approval. The main corrections in the paper and the responses to the reviewer's comments are as follows: Reply to reviewer No.1: 1.On major remark on the work would be that is theoretical/computational without experimental validation. This need to be commented on as reality often proves to be slightly more difficult than theory. Doing this some comments on disturbances, erroneous sensors and other real-world biases in the control system would make the paper even better. REPLY: In our revised paper, we have done this comment in the conclusion section. You can find this in r358-361: Owing to the disturbances, sensor error, and real-world bias, verifying the result in the experiment would be slightly more difficult than in simulation. But it also should be noted that, since the high-fidelity aerodynamic data in the simulation, we believe the result still could be well supported. 2. r34-36 "difficult to obtain aircraft model" -is it really more difficult to get an accurate aircraft model for a tailless aircraft, than other types of aircraft? REPLY: We may not convey ourselves very well. Of course, the aerodynamic data of any kind of aircraft can be obtained through the wind-tunnel test, but for the tailless aircraft involved in this paper, owing to the coupling effect between effectors it would be much harder to extract useful model knowledge for controller designing. We have made such correctness in r34: it is not easy to extract useful model knowledge, such as control effectiveness, from aerodynamic data 3. r128. remark 1. Indeed a polynomial wouldn't be a good option. I'm not sure it even have to be mentioned though. Splines or another reduced order method is the more or less "standard" way of doing it. REPLY: It should be noted that there are still many researchers using polynomial model to support their result in control field, even in most recent papers. That’s why we mentioned the advantage of spline method in the Remark 1. Still, we are very thankful for your comments, which remind us that such a discussion may be very unprofessional for researchers in other fields. Consider the Remark 1 only aims to further illustrate the model construction method. In our revision, we have already deleted the content that involves polynomial in Remark 1. 4. figures: all of them are a bit hard to read, but in particular figure 14 - this one needs to be re-thinked about what you want to show. REPLY: In our revision, all the figures are presented in vector format, and all the figures can be enlarged losslessly. We hope this could help the readers understand them better. Besides, the simulation 1 aims to prove the robustness of the proposed method, and the simulation 2 aims to verify the effectiveness of the stability enhancer. Obviously, the results are mainly supported by the state of aircraft. In contrast, effector deflection is not a very significant concern. We presented the effectors' deflection angle only to make the simulation more convincing. Considering there are up to 11 effectors, it would take up too much space to introduce them one by one. Therefore, we think it will be OK to present the effector deflection this way.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is interesting, well written, and fits the journal scope. The TurnItIn similarity index is only 20%, which is a very good value. However, a few issues must be addressed, and thus I recommend a minor review.

1. Nomenclature should be present in the text and not in the Table (inside the Introduction)

2. I suggest adding a paragraph regarding the paper structure (at the end of the Introduction) and explicitly underlying the main novelty of the paper (even though it is presented in the Introduction) in a single sentence in the same paragraph.

3. Typos and missing references can be found in the text e.g. page 14 ”…3-dimensional space are give in figure ??... “

4. In the next study, I would recommend including turbulence (Dryden model) as an additional disturbance for controller assessment.

For now, this is all for me. I hope that those remarks will help authors to improve their paper.

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf