Modal Characterization of Manual Wheelchairs

Round 1

Reviewer 1 Report

 

A) General remarks

The research presents in this paper a very interesting topic, as well as results that are of wider significance when it comes to the modal analysis and its usefulness for simulation improvements. The paper is concise and clear. The literature in the paper is adequately cited.

The abstract gives a basic overview of the paper. However, the novelty of the paper is not presented here and from the abstract, this is more a report of engineering measurements rather than a scientific paper. This issue is not also pointed out strongly in the introduction. 

 

The conclusions are basic and mostly repeat what was already pointed out in the abstract.

The authors focus mostly on wheelchairs and their analysis in the introduction and don’t give sufficient introduction to EMA and possible methods. Taking into account that later authors are connecting the results to the simulations it is worth mentioning in the introduction other testing methods especially useful for testing in free-free conditions like 3D laser vibrometry (Non-invasive measurements of ultra-lightweight composite materials using laser Doppler Vibrometry system,Scislo, L., Guinchard, M., Proceedings of the 26th International Congress on Sound and Vibration, ICSV 2019). The authors write “The main limitation of the study arises from the complexity and diversity of MWC structures. The modal identification of such 3D system made of numerous elements of various materials and mechanical linkages is still a challenge” (line 262) – this actually can be solved with this kind of equipment. This may be interesting in case this is a part of the PhD thesis (and from the way the paper is written it looks like this is a case).

There are no photos of the experiential setup. Please include this in the paper. Especially so the boundary conditions during the tests (free- free setup) are visible. Also, although the photos of each of the tested vehicles are presented in tab.1, the photos are very small. Consider enlarging or also presenting them as an additional figure so the reader has a clear overview of what was tested.

Methods and methodology. The reviewer has some doubts about the used techniques in connection to the paper's aims. The authors are conducting EMA in free-free conditions which is correct if the aim is to get modal parameters and connect the results with the simulations. However, the authors are aiming to see if their modes which are potentially harmful to the human body are present and later connect the results to eventual improvements. In this case, there is a big difference between performing EMA on just a wheelchair and the wheelchair with the mass simulation of a person sitting on it. When we include the mass of the sitting person the modal parameters will change significantly. Especially, since most modern wheelchairs are lightweight structures.  Moreover, if the aim is to see what is a real impact on each of the wheelchair models on the human sitting it may be more significant to see use the transfer function approach and see what is real gain between the ground and body of the person sitting on the chair and also between different parts and additional upgrades. This approach also allows seeing what is changing/improving with additional parts/elements when changing the design. Also performing the operational modal analysis (OMA) would be a better choice for the authors' aims. In the current stage, the reviewer does not see a strong connection between the aims of the study and the analysis performed. This must be cleared before eventual publication.

 

B) Items and editing remarks

Some language check is required. In many places, the commas are missing and the problem with word repetitions is visible.

Table 1 is not fully visible. Probably due to page orientation in the original file set to landscape one some columns were cut off when the pdf was created.

Fig.1-7 is very nice. Good job with a clear presentation of the results.

C) Conclusions:

In the current stage, the reviewer does not see a strong connection between the aims of the study and the analysis performed. Also, the novelty of the paper is not really present. With those two problems, the paper is mostly an engineering report on EMA used for a specific case study. The reviewer asks for some major reviews at this stage.

Author Response

Please kindly check the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

A study on the modal characterization of Manual Wheelchairs (MWCs) is presented.

Experimental Modal Analysis (EMA) on eleven MWCs has been performed, and data have been post-processed to evaluate the modal properties of the testing articles.

Results are presented by using FRF diagrams, and a section on the discussion of the results is given.

In my opinion, the analysis is precise, but the following questions arise while reading the manuscript:

 

- Lines 102-104; It does not make sense to cite Ref.[11] at the end of the sentence.

-  Please resize Table 1 to fit the table within the page.

- Lines 30-31; for the sake of clarity, specify the meaning of the acronym SD.

- Lines 29-31; focusing on the first identified eigenmode, MWC 01 and 02 have different eigenfrequencies, and the FRFs are not following the same trend in the range 10-30Hz. In my opinion, using the standard deviation in parallel with the statement “…exhibited similar modal properties” could be misleading in this case. Therefore, I suggest adding some clarifications on this point characterized by a high SD value.

- Figures 1,3; the references (a), (b), and (c) reported in the captions are not reported on the figures.

- Section 3 would benefit from introducing a table listing the FRFs magnitude, eigenfrequencies, and identified damping ratios. In this way the paper could provide a direct, clear, and accessible database for future users.

 

In conclusion, the manuscript deserves minor revisions.

Best regards.

Author Response

Please kindly check the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Dear Authors,

Thank you for revising the previous version of the manuscript.

Concerning the previous comments, all the points were addressed and the reviewer can state that the paper is of sufficient quality for publication in the present form.

Best regards,

The reviewer