Analysis of Whole-Body Vibration Using Electric Powered Wheelchairs on Surface Transitions
Round 1
Reviewer 1 Report
The paper presents to evaluate WBV when driving various kind of EPW over surfaces with
different thresholds. The paper is well-written and may be worth publication after few clarifications.
Abstract:
- The problematic of the paper is presented under the Methods section. It should be stated before.
Introduction:
- L45: it would be interesting to compare the WBV exposure reported in the literature for both EPW and MWC.
- As the authors aim at investigating various kind of EPW, especially the suspension element, it would it interesting to add a part discussing the actual knowledge regarding suspension. For instance, regarding MWC, the review proposed by Lariviere 2019 revealed that suspension efficiency is often questionnable.
- The introduction indicates clearly the need to assess WBV for various surfaces transition and threshold. However, the interest in comparing various EPW should be justified.
- The problematic and the underlying hypotheses are not clear enough. It is clear that authors want to present a comparison, but what is its purpose? From a scientific as well as from a practical/recommendations (for the user and/or the designer) point of view?
Method:
- L77: 6 should be written in letters
- L99: Please justify the choice of a low sampling frequency for the accelerometer. 100 Hz is not high enough to measure the EPW vibration, especially knowing that WBV deleterious for the human body is up to 80 Hz. This point is noteworthy and may jeopardize the entire paper.
- L101-110: this part is misplaced. It should be placed in the data analyses section.
- L103: Authors present x, y, and z axes but they are not defined.
- L120: How the authors used the magnetometer and gyroscopic data?
- L144: The section should be renamed Statistics
Results:
- Fig4: errorbars are quite huge for three repetition of a totally controled task. The only unfixed parameter seems to be the EPW path that is remotely controled by the user. Could the authors explained the obtained standard deviation values? It should be discussed.
Discussion:
4.1
- L187: Are the EPW users driving one hour per day across surfaces with threshold over 1.0in? I woud assume they are not continuously encountering surface thresholds.
- Globally obtained results were expected, and the three EPW seem to be the same with respect to exposure to vibrations. The novelty and the relevance of this study is not clear. Please complete the discussion to state the contributions to EPW users/designers.
4.2
- L. 247: What arguments allow to state that « MEBot-DS can be configured to use the shock absorbers for small thresholds while its active suspension will be beneficial on inclined surfaces for power efficiency ». Results tend to indicate that the three tested EPW are equivalent whatever the context.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Please see the attached file
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 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 characterization of the impact of the transfer of vibrations on a wheelchair and its user. The paper is concise and clear. The literature in the paper is adequately cited.
The abstract gives the basic overview of the paper, however, some issues have to be noted. The authors’ were trying to fit the overview of each chapter in the abstract. This is especially visible due to elements emphasizing which chapter is being summarized. Elements like “Background:”, “Methods:”, “Conclusion:” are not to be used in the abstract. The abstract has to be one element allowing the reader to get the sense of the authors' works presented in the paper. Additionally, the abstract should be written in a clear and not too sophisticated way so the reader who is not familiar with this specific field can still get a sense of the article. That’s why the abbreviations should not be used in the abstract, especially, since the same elements will be used in the introduction where abbreviations can be introduced. Due to a large number of abbreviations, the abstract in the current form is not clear. It is strongly suggested to improve the abstract.
The main problem through the article is the use of two unit systems US Customary/Imperial and SI/metric system. This is understandable taking into account the authors’ origins but makes the article difficult to track by the international scientific community. It is visible that the authors designed the experiment using the US Customary units but preparing the article are referencing the findings according to the norms using SI units. In many parts of the paper, the authors are trying to give values in both units but in many places, this is not present (eq. 52, 62, 187 and many others). This duality of the unit systems makes the article really hard to follow. It is strongly suggested that the authors rethink the matter of dual systems units and their use in the article.
The authors do not provide data for the accelerometer placed in the EPW seat. From the picture, it looks like a wearable accelerometer not a professional sensor for vibration measurements (like eq. PCB accelerometers). The question of accuracy, calibration, sensitivity must be asked. Please provide the data of your whole acquisition system.
Why the authors are performing the measurements at 100Hz? Is it cause this frequency falls into the region of flat response for most sensors? However, the highest amplitudes coming from the use of the wheelchair, transferred by ground from road traffic etc. will be in the below 50Hz range (10-50 Hz preferable). If the maximal values of acceleration amplitudes were recorded in the range 0-100Hz please clearly indicate this information. If this is coming straight from the ISO 2631-1 guideline please make sure that the crucial elements of those guidelines are mentioned, especially for the reader with no access to the norm.
The tested devices have different constructions thus their dynamic response will be different. However, there is no evaluation of this problem in the article. A good idea would be to present what is a transfer function between the ground and the seat. The gain factor would be a good indicator of how suspicion is limiting the negative effects of the surface.
The tests were performed with laboratory conditions with no significant additional sources of vibrations. In the real world, the user will be submitted also to ground vibration transfer in case of vibration coming from cars, civil engineering works, trams etc. which may be of significant value. For example, if the wheelchair user is using a sidewalk next to the road where compactor type of equipment is working. The authors give some information about limitations but mostly coming to the surface but not additional vibration sources.
The conclusions are basic and mostly repeat what was already pointed out in the abstract.
- B) Item remarks
The aims presented 64-71 require some adjustment to the way they are presented. Instead of writing them as a continuous text, it is better to present them as a pointed list to give the reader chance to follow the authors reasoning.
Figure 1- the pictures are quite small. Try placing them in the 2x2 format instead of 4x1.
Figure 2- the text is out of focus and quite small. The reader will have a problem reading it.
Figures 4,5, the axis in two different unit systems.
Author Response
Please see attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thank you to the authors for their answers and corrections! Congratulations
