Force Fight and Its Elimination in a Prototype of a Redundant Direct-Drive Avionic Actuator

Round 1

Reviewer 1 Report

In this paper, the authors propose and discuss the result obtained in a test bench for actuators. The paper, as a whole, is well structure and properly described and stressed.

I've some remarks on the presentation of the results, in particular, I suggest evaluating uncertainty and accuracy studies, for example evaluating and discussing the RMSE between:

• position command and actuator position;
• command and measured Iq current;
• the 4 motor torque, etc. 

 

Author Response

Please see attached file. 

Author Response File: Author Response.docx

Reviewer 2 Report

This paper deals with the management /control of direct drive redundancy. A quite interesting experimental set up is reported within a clear and readable paper.

 

The paper topic is interesting and the paper content is promising but extensive additional work seems needed before considering this paper for publication.

In particular,

• although interesting from practical viewpoint, this paper provides minor  scientific contribution. The key theoretical contribution is reported in section 3, which currently provides mostly state of art basic knowledge. Authors are encouraged to fully reformulate this section to propose a novel control approach  instead of ending up with the very well known and basic master slave concept approach. 
• state of art should be improved to provide more discussion on the many existing control strategies and related pros/cons
• Experimental tests should be significantly extended to consider many more cases of faults. (currently it seems only a simple + shift is considered-real fault cases are much much more than this with random variations, increasing noise, impulsive disturbances etc.)
• the analysis of the effects of faults and control should be given much more in details. Also the stability of the control should be discussed.
• given the redundancy of the drive, also the monitoring mode(s) should include some degree of redundancy and effects of measurement noise should be analysed and discussed.

Based on the above, considering also the high level of this journal, I would encourage to revise and resubmit to this journal.

Author Response

Please see attached file 

Author Response File: Author Response.docx

Reviewer 3 Report

The paper is interesting to read, some suggested changes are:

1. line 60 - need a though literature review on the design of redundency actuator
2. line 72 - No appendix attached to the paper
3. line 68 - Please explain Figure 1
4. line 86 - please annotate Figure 4
5. line 97 - please explain communication protocol used
6. Line 179 - do you monitor the temp change?
7. line 251 - Figure 11 from 0-10s there is a big difference between command Iq and measured Iq explain why?
8. line 251 - when t=0, why Iq is not zero
9. need more results to validate your design approach
10. please rewrite the conclusion

Author Response

Please see attached file 

Author Response File: Author Response.docx

Reviewer 4 Report

This paper deals with a direct drive actuator with four redundancy BrushLess Alternative Current motor. Authors proposed a monitoring method namely master/slave to cope with phenomenon of force fight problem in faulty operation mode. The proposed approach is based on monitoring and communication between lanes to merge the different position or command information. The proposed method is validated through experimental results.

The main contribution of this work is based on the development of the four redundancies BrushLess Alternative Current with the electrical/mechanical structure.

The paper presents an interesting work nevertheless further efforts are requested to authors to enhance the paper quality.  

Items are enumerated below should be considered:

• In the second section, authors are invited to include additional argumentation to justify the use of only two redundancies to develop a redundant BLAC actuator. It will be more suitable to add a table with merit and demerit of all possible options.
• Two temperatures sensor are included in the BALAC actuator. How the delivered information by each sensor will be analysed? The location of the temperature sensor is not discussed ? authors are invited to include the temperature sensor as well as all other sensor to the Fig 2.
• What authors mean by “In addition, the mass of the stators and the mutual inductances has been 80 minimized” ? is there any optimisation problem ? if this is the case please include the details to the section 2
• All used abbreviations should be defined at the end of the paper: PWM, ECU, MON …
• In section 3, the list of the information exchange between the blocks should be enumerated. Authors are invited to indicate when the actuator is considered in abnormal operation.
• Section 4, authors are invited to explain what happen in case of opposite torque? Did this is considered as an abnormal operation?
• All figures need to be improved. For example, in Fig 12 Motor 1 and Motor 4 are similar.
• Section 5 needs to be improved with further details and discussion on experiment obtained data.
• What mean negative torque on Fig. 15 ?
• Quite a lot of typos and grammar mistakes to be corrected

Author Response

Please see attached file 

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

this paper is at second review round.

authors did some valuable efforts to improve the clarity and literature coverage of the paper. However, still the scientific contribution remains very weak and below expectations of a journal paper. None of the related concerns arisen in the previous review round has been effectively addressed!

Given the above, I still remain very critical in publishing this work in the present form. On the other side I still like the clarity of the paper and the valuable experimental tests.

Maybe a possible option to reach a publishable level is to change the paper title and more clearly state the practical aim of the paper so that it is evident to the readers that the focus is mostly on (something like) "experimental tests with an existing set up for drive redundancy testing". 

Maybe authors could also add a dedicated section to outline as discussion/future work how to improve the test rig for testing other fault cases.

This would make the paper more attractive from scientific viewpoint.

Author Response

Dear Reviwer 2,

Attached the response to your comments,

Regards,

Rabia SEAHAB 

 

Author Response File: Author Response.docx

Reviewer 3 Report

The authors have made changes as the reviewers suggested. The response is O.K.

Author Response

Dear Reviwer,

Attached the response to your comments.

Regards,

Rabia SEHAB 

Author Response File: Author Response.docx

Round 3

Reviewer 2 Report

This paper is at third review round.

 

It now has reached a minimum level for publication.

 

a minor modification seems required to clarify the application field such as

 

Force Fight and its Elimination in a Prototype of a
Redundant Direct-Drive Avionic Actuator

Author Response

Dear Reviwer,

 

Thank you for the time you spent to read and to comment our paper. 

Attached the response to your comments of round 3. 

Author Response File: Author Response.docx