An Attitude Adaptive Integral Sliding Mode Control Algorithm with Disturbance Observer for Microsatellites to Track High-Speed Moving Targets
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
The High-Speed Moving Targets attitude tracking control problem of Microsatellites is studied in this paper, and the Adaptive Integral Sliding Mode Control approach are investigated to achieve the high-precision tracking under uncertainties. In this paper, the disturbance observer and adaptive technique are incorporated into the control design, such that the external disturbance and chattering are relieved. There are some problems should be considered:
1. In Introduction Section, please describe in detail the motivation behind this work.
2. Authors should add a remark to further explain the effects of the main design parameters on the control performances.
3. The adaptive law (25) is not correct, the author should check it carefully.
4. In (2), $\Gamma(.)$ is different from those in the above equation.
5. In (29), there are some errors in the derivation procedure, please check it.
6. For the results presented in the Figures in the simulation, more explanations on them seem necessary and helpful to readers.
Comments on the Quality of English Language
The English should be minor edited.
Author Response
Manuscript Title: An Attitude Adaptive Integral Sliding Mode Control Algorithm with Feedforward Compensation Disturbance Observer for Microsatellites to Track High-Speed Moving Targets
Authors: Xinyan Yang, Lei Li, Yurong Liao and Zhaoming Li
Dear Editor,
Thank you very much for the excellent professional comments and guidelines. We are pleased to answer the questions of the reviewers’ and revise the manuscript in accordance with the reviewers’ suggestions as raised in the comments below.
- In Introduction Section, please describe in detail the motivation behind this work.
Response: In Introduction Section, the motivation which is gaze tracking for targets with unknown positions has been described in detail.
- Authors should add a remark to further explain the effects of the main design parameters on the control performances.
Response: In line 240, the impact of interference observer performance parameters on system convergence has been analyzed.
- The adaptive law (25) is not correct, the author should check it carefully.
Response: has been changed to .
- In (2), $\Gamma(.)$ is different from those in the above equation.
Response: The formula has been corrected.
- In (29), there are some errors in the derivation procedure, please check it.
Response: The formula (29) has been checked and modified.
- For the results presented in the Figures in the simulation, more explanations on them seem necessary and helpful to readers.
Response: A comparative simulation was conducted between the controller without disturbance observer and the controller with feedforward compensation disturbance observer，and added graphs and comparative explanations.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
An adaptive integral sliding mode variable structure attitude controller is proposed. The controller incorporates feedforward compensation and a disturbance observer to tackle the challenge of achieving stable tracking of high-speed moving targets by low Earth orbit microsatellites. The paper is well-written and can be accepted if the following comments are addressed.
1- The necessity of gaze tracking has not been clearly stated.
2- The estimation error of the observer is stabilized if time tends to infinity. How can it be extended to finite-time observers such as "Disturbance observer-based constrained attitude control for flexible spacecraft"?
3- In adaptive law (25), how can you guarantee that the estimated parameter \hat{k} remains bounded?
4- Regarding 'high-precision tracking control', which part of the manuscript can reflect the content?
5- There is a typo in (26). Please check.
6- The introduction needs some improvements. It misses some relevant works such as 10.1007/s11071-022-07727-6 ; 10.1080/00207179.2021.1971300; 10.34133/space.0079 ; 10.1155/2021/8812187
7- Please show the system response to the external disturbance.
8- Future works should be mentioned in the conclusion.
9- Graphs and explanations should be added on how the new controller and observers' gains have an effect on the system.
Author Response
Manuscript Title: An Attitude Adaptive Integral Sliding Mode Control Algorithm with Feedforward Compensation Disturbance Observer for Microsatellites to Track High-Speed Moving Targets
Authors: Xinyan Yang, Lei Li, Yurong Liao and Zhaoming Li
Dear Editor,
Thank you very much for the excellent professional comments and guidelines. We are pleased to answer the questions of the reviewers’ and revise the manuscript in accordance with the reviewers’ suggestions as raised in the comments below.
- The necessity of gaze tracking has not been clearly stated.
Response: The problem studied in this article is gaze tracking for targets with unknown positions, so it is necessary to use image feedback to determine the relative position of the target. The necessity of gaze tracking has been added in the introduction.
- The estimation error of the observer is stabilized if time tends to infinity. How can it be extended to finite-time observers such as "Disturbance observer-based constrained attitude control for flexible spacecraft"?
Response: The article of "Disturbance observer-based constrained attitude control for flexible spacecraft" present a general framework of fixed-time disturbance observer-based attitude control for flexible spacecraft. it is effective for a larger initial state. However，the problem studied in this article is gaze tracking for targets with unknown positions，the initial state is tiny in general, so fixed-time disturbance observer-based attitude control is unnecessary. The system state only needs to converge to a very small region in short time. The controller designed in this article can achieve this goal.
- In adaptive law (25), how can you guarantee that the estimated parameter \hat{k} remains bounded?
Response: A global integral sliding mode vector is adopted in this article. This structure ensures the system's initial state is already on the sliding surface , eliminating the approaching phase. However, due to external disturbances, uncertain system models, and other factors, the system state cannot be accurately 0. Therefore, is introduced in the controller structure to converge the sliding surface S to 0 by changing the structure. When S is 0, the value of S no longer increases, that is, it remains bounded.
- Regarding 'high-precision tracking control', which part of the manuscript can reflect the content?
Response: The disturbance observer designed in this article compensates for the disturbance torque to reduce external interference effects, and an adaptive integral sliding mode controller is designed to reduce control errors from the perspective of controller structure. Through simulation, it has been verified that the controller designed in this paper achieves an Euler angle control accuracy of 0.03° and an angular velocity control accuracy of during high-speed moving target gaze tracking.
- There is a typo in (26). Please check.
Response: Formula (26) has been modified.
- The introduction needs some improvements. It misses some relevant works such as 10.1007/s11071-022-07727-6; 10.1080/00207179.2021.1971300; 10.34133/space.0079; 10.1155/2021/8812187.
Response: Some relevant works have been supplemented as required.
- Please show the system response to the external disturbance.
Response: All simulation results in the original text were generated under external environmental disturbance. It can be seen that the controller can achieve high-precision tracking control and has a certain degree of robustness from the results.
- Future works should be mentioned in the conclusion.
Response: Future works have been added to the conclusion.
- Graphs and explanations should be added on how the new controller and observers' gains have an effect on the system.
Response: A comparative simulation was conducted between the controller without disturbance observer and the controller with feedforward compensation disturbance observer, and added graphs and comparative explanations.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for Authors
This paper investigates the attitude control of microsatellites. This paper designs an adaptive integral sliding mode attitude control algorithm with a feed-forward compensated disturbance observer. Moreover, the simulation seems to have achieved the desired effect. However, there are still problems with some of the language and formatting of this paper. Thus, a major revision is required, and the final decision cannot be made until the following problems are solved.
The following are the comments.
1. The equations in this paper are not aligned. For example, equations 2 and 3. Authors should improve the format of equations in their papers.
2. In this paper, the figure captions poor understanding and provide not enough details. The author should clarify the figures in the captions in more detail.
3. On page 10, table 2's typography is sloppy and much out of line with the text's recommended spacing. The author should reformat Table 2.
4. Some statements within the article are challenging to comprehend. For instance, the first sentence of the conclusion on page 13 is exceedingly verbose and presents a challenge. The author should further refine the articulations in the manuscript to enhance clarity and ease of understanding.
5. The paper is predicated on a sliding mode control method for attitude control during gliding. Sliding mode control can induce chattering in the control process. However, the simulation results appear smoother and do not exhibit chattering. What is the reason for these smooth simulation outcomes?
Author Response
Manuscript Title: An Attitude Adaptive Integral Sliding Mode Control Algorithm with Feedforward Compensation Disturbance Observer for Microsatellites to Track High-Speed Moving Targets
Authors: Xinyan Yang, Lei Li, Yurong Liao and Zhaoming Li
Dear Editor,
Thank you very much for the excellent professional comments and guidelines. We are pleased to answer the questions of the reviewers’ and revise the manuscript in accordance with the reviewers’ suggestions as raised in the comments below.
- The equations in this paper are not aligned. For example, equations 2 and 3. Authors should improve the format of equations in their papers.
Response: All have been improved as required.
- In this paper, the figure captions poor understanding and provide not enough details. The author should clarify the figures in the captions in more detail.
Response: Figure 5, Figure 6 and Figures 8 to 13 have been clarified in more detail.
- On page 10, table 2's typography is sloppy and much out of line with the text's recommended spacing. The author should reformat Table 2.
Response: Table 2 has been reformatted.
- Some statements within the article are challenging to comprehend. For instance, the first sentence of the conclusion on page 13 is exceedingly verbose and presents a challenge. The author should further refine the articulations in the manuscript to enhance clarity and ease of understanding.
Response: The first sentence of the conclusion on page 13 and some other sentences have been further refined.
- The paper is predicated on a sliding mode control method for attitude control during gliding. Sliding mode control can induce chattering in the control process. However, the simulation results appear smoother and do not exhibit chattering. What is the reason for these smooth simulation outcomes?
Response: The reason for chattering caused by sliding mode control is that the controller contains discontinuous functions . This paper uses saturation function instead of and the chattering has been reduced, and it can be clearly seen from Figure 8 that there is still slight chattering in the control process.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for Authors
The paper can be accepted.
Reviewer 3 Report
Comments and Suggestions for Authors
I have no further comment
Comments on the Quality of English Language
I have no further comment
