Integrated Control Scheme for an Improved Disturbance-Free Payload Spacecraft

Round 1

Reviewer 1 Report

1. The terminology is not entirely clear. According to the Reviewer, oscillations with a frequency of 0.01 Hz can hardly be called "vibrations". What is the typical frequency range of the closed-loop attitude control system in your case?

2. Sec. 3.1. Dynamics Modeling - usage of the special symbols for coordinate systems notation is not common and unsympathetic typographically, so I can't tell that this is convenient for readers (Let's imagine, for example, that someone wanted to tell colleagues or students about this work. Will he/she draw these icons too?). Why the Authors didn't use the habitual notations (as triples of the coordinate frames), best of all - borrowed from ISO TC? 

3. "The FS_Ctr generated by the thrusters and the MS_Ctr generated by the fly-wheels are the control forces and torques of the SM, respectively, the measured by the capacitive sensors are the relative motions of the SM with respect to the TM, etc." - The authors talk about the elements of the system as if they did not have dynamic and static errors, and measurement noise, while modeling shows that the system provides very high accuracy. It is clear that it is not always possible to conduct experiments with satellites, but in a computer simulation, one should get as close as possible to the real situation.

 

Some editorial recommendations.

 

1.  "and THE vibration attenuation" - extra THE

2. "micro vibrations" - "micro-vibrations" is suggested throughout the paper

3. "In addition, the wireless" - "In addition, wireless" is suggested

4. "owing to the flexible" - "owing to its flexible"  is suggested

5.  "the micro vibrations ... cables is very small" - are very small

6. "Regehr analyzed ... of payloads [13]." - please reformulate; maybe "Regehr [13] analyzed ..." In the case of LaTeX text-processing, \citet{} is useful.

7. " attitude pointing control loop" -  attitude-pointing is suggested

Author Response

Dear Reviewer,

Thank you for allowing us to revise our paper entitled “Integrated Control Scheme for an Improved Disturbance-Free Payload Spacecraft (aerospace-1897372). We are also grateful for your valuable comments on this manuscript, including the typical frequency range of the control system, the habitual notations of coordinate systems notation, the method for simulation verification, etc. We are very grateful to the reviewer for pointing out some mistakes in the manuscript and giving professional revision opinions. The comments and suggestions have been taken into account and the modifications are highlighted in red in the revised manuscript. We hope the revised manuscript can be accepted for publication under the condition of your professional comments and our careful revision. Thank you again for your great help. For detailed responses, please check the document named Responses-to-Reviewer-1.doc.

Author Response File: Author Response.docx

Reviewer 2 Report

This paper proposes an improved DFP spacecraft and its integrated control 14 scheme is designed to enhance the pointing accuracy and the vibration attenuation performance. The research is interesting and the technique is efficient. I have the following comments to improve the readability. 

 

—”The improved DFP spacecraft consists of a Payload Module (PM), a Support Module (SM), and a 16 Test Mass (TM). The integrated control system is subdivided into three interconnected control 17 loops. An active vibration isolation control loop is used to isolate the PM from vibrations in the 18 high-frequency bands, and control the PM to track the attitude of the SM. “ what is the relationship among the three loops?

 

—“The precise disturbance model of the umbilical 60 cables is difficult to establish owing to the flexible characteristics. ” what is the specific effect on the model?

 

—“The main contributions of the paper include the configuration of the improved DFP 73 spacecraft and its integrated control scheme. ” what is the new feature compared with “Referring to the control concept of a drag-free satellite [18,19] ”?

 

—What is the definition of the matrices $E_i$ in equation 4?

 

-The PID control for single spacecraft is efficient. Could the proposed method can be used in the attitude control of multiple spacecraft using intelligent algorithms like A nonlinear observer-based approach to robust cooperative tracking for heterogeneous spacecraft attitude control and formation applications or Global cooperative control framework for multiagent systems subject to actuator saturation with industrial applications? 

 

—“Since the low-frequency disturbance of the SM is attenuated with the drag-free control, the micro vibrations transmitted by the umbilical cables is very small or even negligible 69 in the low-frequency band. “ this should be verified in the simulations. 

 

Author Response

Dear Reviewer,

Thank you for allowing us to revise our paper entitled “Integrated Control Scheme for an Improved Disturbance-Free Payload Spacecraft (aerospace-1897372). We are also grateful for your valuable comments on this manuscript. Some professional comments and suggestions are raised, including the control strategy of the improved DFP spacecraft, the force model of the umbilical cables, the architecture of the improved DFP spacecraft, the application of the PID control, simulation verification, etc., which give us a lot of inspiration. These comments and suggestions have been taken into account and the modifications are highlighted in red in the revised manuscript. We would be very grateful if our revised manuscript is accepted for publication. Thank you for your great help. For detailed responses, please check the document named Responses-to-Reviewer-2.doc.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors carefully considered my comments and suggestions, providing adequate answers and correcting the manuscript accordingly. There are no more criticisms from my side.