A Wireless Hand Grip Device for Motion and Force Analysis

Round 1

Reviewer 1 Report

There are some weaknesses through the manuscript which need improvement. Therefore, the submitted manuscript cannot be accepted for publication in this form, but it has a chance of acceptance after a minor revision. My comments and suggestions are as follows:

1- Abstract gives information on the main feature of the performed study, but some details about the obtained results  must be added.

2- Authors must clarify necessity of the performed research. Objectives of the study must be clearly mentioned in introduction.

3- The literature study must be enriched. In this respect, authors must read and refer to the following papers: (a) https://doi.org/10.1016/j.sna.2020.112105 (b) https://doi.org/10.1016/j.enbuild.2020.110399

4- It would be nice, if authors could name of the parts in Fig. 1 (second part). All figures must be presented in a high quality.

5- The main reference of each formula must be cited. Moreover, each parameters in equations must be introduced. Please double check this issue.

6- Details of calculation must be presented. Standard deviation is the presented curves must be discussed. In addition, error in calculation must be considered and discussed.

7- In its language layer, the manuscript should be considered for English language editing. There are sentences which have to be rewritten.

8- The conclusion must be more than just a summary of the manuscript. List of references must be updated based on the proposed papers. Please provide all changes by red color in the revised version.

Author Response

There are some weaknesses through the manuscript which need improvement. Therefore, the submitted manuscript cannot be accepted for publication in this form, but it has a chance of acceptance after a minor revision. My comments and suggestions are as follows:

• Abstract gives information on the main feature of the performed study, but some details about the obtained results  must be added.

Many thanks to reviewer 1 by positive comments. The abstract and introduction section has been improved in order to fix our main new contributions. We reduce technical device aspects and we concentrate all our efforts in measurements and empirical validations

• Authors must clarify necessity of the performed research. Objectives of the study must be clearly mentioned in introduction.

A list of the main objectives are provided to focus our research in this paper.

• The literature study must be enriched. In this respect, authors must read and refer to the following papers: (a) https://doi.org/10.1016/j.sna.2020.112105 (b) https://doi.org/10.1016/j.enbuild.2020.110399

The papers suggested by reviewer 1 are include in bibliography, commented, and evaluated in introduction section

• It would be nice, if authors could name of the parts in Fig. 1 (second part). All figures must be presented in a high quality.

Figure 1 has been simplified and each component description has been added

• The main reference of each formula must be cited. Moreover, each parameters in equations must be introduced. Please double check this issue.

This issue has been exhaustively checked.

• Details of calculation must be presented. Standard deviation is the presented curves must be discussed. In addition, error in calculation must be considered and discussed.

New comments and sentences are added in this point in order to fix the error values and the formulas has been referenced and parameters described.

• In its language layer, the manuscript should be considered for English language editing. There are sentences which have to be rewritten.

We have revised the English typos, but in any case if the paper will be accepted we will submit the paper to editorial board English supervision.

• The conclusion must be more than just a summary of the manuscript. List of references must be updated based on the proposed papers. Please provide all changes by red color in the revised version.

Conclusion and future work section has been rewritten including the main research contributions of this work. Also the proposed papers by reviewer 1 are added to reference section. All changes are in red in the revised version.

Reviewer 2 Report

This study proposes a wireless transmission grip with 6 DOF data that can measure grip force and finger pressure. It uses minimal sensors, does not affect the natural motion of the hand, and is a low-intrusive controller prototype. According to the test evaluation of the device, the system can simulate hand movements and finger motions and can be applied to the operation of virtual objects in VR environments. The study concluded that the application is oriented towards the rehabilitation of serious games or in recreational play.

1. The research concept is not innovative enough and lacks clear scientific contribution except for grip force measurement. The large number of pictures of electronic hardware components reads like a technical manual.
2. The literature in this paper needs to be updated appropriately, there are already many similar wireless transmission handles with 6 DOF and gesture detection in VR applications, such as Oculus Touch, Oculus Index Controller, and even the upcoming PS5 VR control handle. The current VR grips basically have wireless, 6DOF, gesture detection, pressure sensing, and motion feedback, but the prototype proposed in this study only features grip force measurement and lacks feedback mechanism. For now, the contribution of this study should be clarified and more precisely formulated.
3. The study concluded that the proposed prototype is indeed more flexible, less intrusive, less invasive and easier to use than traditional gloves. However, the lack of design feedback may affect the interactivity and realism of virtual object manipulation. It also lacks the freedom of control beyond gripping.
4.  (Lines 361) Prototype weight 390 grams, in the interactive application of grip and finger pressure environment, there may be a risk of throwing or dropping.
5. (Lines 461-463) Academic data is required to demonstrate that the error is within one degree of availability in the rehabilitation setting.

In summary, this paper describes the technical aspects of a wireless grip that can be used in serious gaming or rehabilitation environments. Considering the rapid development of similar devices in VR, the results of this paper are not sufficiently contributed, and most of the content appears to be a technical report of a project.

Author Response

This study proposes a wireless transmission grip with 6 DOF data that can measure grip force and finger pressure. It uses minimal sensors, does not affect the natural motion of the hand, and is a low-intrusive controller prototype. According to the test evaluation of the device, the system can simulate hand movements and finger motions and can be applied to the operation of virtual objects in VR environments. The study concluded that the application is oriented towards the rehabilitation of serious games or in recreational play.

1. The research concept is not innovative enough and lacks clear scientific contribution except for grip force measurement. The large number of pictures of electronic hardware components reads like a technical manual.

 

Many thanks to reviewer 2 by positive comments. The abstract and introduction section has been improved in order to fix our main new contributions. We reduce technical device aspects and we concentrate all our efforts in measurements and empirical validations. A list of the main objectives are provided to focus our research in this paper.

Figures 3, 4 and 5 are combined and figure 7 has been removed. All components are described in figure 1.

1. The literature in this paper needs to be updated appropriately, there are already many similar wireless transmission handles with 6 DOF and gesture detection in VR applications, such as Oculus Touch, Oculus Index Controller, and even the upcoming PS5 VR control handle. The current VR grips basically have wireless, 6DOF, gesture detection, pressure sensing, and motion feedback, but the prototype proposed in this study only features grip force measurement and lacks feedback mechanism. For now, the contribution of this study should be clarified and more precisely formulated.

 

 

Up to our knowledge, we don’t know any portable, wireless and low cost (<300$) device that measures hand motion and PRECISE grip force in parallel.

In addition, we can detect all the fingers touching the handgrip device. The grip force values are similar in precision and error to different commercial dynamometers (Takei model 5101 TKK, Constant 14192-709E) The Takei model is used as medical device to evaluate some pathologies. So our device is not only a videogame controller for VR applications. The Takei dynamometer don’t have the possibility to know hand and fingers position. We have visual feedback about the motion done over a virtual object if is needed, also visual numerical values about forces are displayed to user in some test applications. See figure 9,10 in paper and also video demo additional material.

 

Papers: Amaral JF, Mancini M, Novo Junior JM, “Comparison of three hand dynamometers in relation to the accuracy and precision of the measurements”, Rev Bras Fisioter. 2012 Jun; 16 (3):216-24

Gatt I, Smith-Moore S, Steggles C, Loosemore M. The Takei Handheld Dynamometer: An Effective Clinical Outcome Measure Tool for Hand and Wrist Function in Boxing. Hand (N Y). 2018 May;13(3):319-324. doi: 10.1177/1558944717707831. Epub 2017 May 10. PMID: 28490195; PMCID: PMC5987983.

 

1. The study concluded that the proposed prototype is indeed more flexible, less intrusive, less invasive and easier to use than traditional gloves. However, the lack of design feedback may affect the interactivity and realism of virtual object manipulation. It also lacks the freedom of control beyond gripping.

 

The hand grip is more easy to use that a glove and have the advantage to adapt to different hand sizes. Also, the feedback is guaranteed by visual VR signals inside application.

 

(Lines 361) Prototype weight 390 grams, in the interactive application of grip and finger pressure environment, there may be a risk of throwing or dropping.

 

In the actual version, a “Velcro” band (similar to Valve Index Controllers) is included to guarantee that the hand grip is in contact with the hand all time also when the person open totally the hand.

 

 

1. (Lines 461-463) Academic data is required to demonstrate that the error is within one degree of availability in the rehabilitation setting.

 

From this study, we conclude that noise is less than one degree, which indicates that the data obtained can be used in a rehabilitation environment, where orientation measurement errors less than one degree are acceptable. Physiotherapists were consulted at the time, indicating that the precision was more than sufficient. Other works like [38] carry out wrist rehabilitation with lower accuracy.

In summary, this paper describes the technical aspects of a wireless grip that can be used in serious gaming or rehabilitation environments. Considering the rapid development of similar devices in VR, the results of this paper are not sufficiently contributed, and most of the content appears to be a technical report of a project.

We agree about the positive suggestions of the reviewer 2, and the paper has been rewritten in order to remark the research aspects and main contributions, in particular in the area of rehabilitation procedures for patients with using low cost devices but with precise range of measurement similar to commercial medical devices. This allow the possibility to evaluate patient evolution.

VR devices are more oriented to videogames, in our cases the videogames proposed for our device are “serious games”. That means that the person that use our device is recovering some physical activity in a ludic way (cerebral palsy, stroke rehabilitation, upper arm controlling, etc..) The device is not oriented only for videogames in general.

Reviewer 3 Report

The article deals with the problem of motion and force analysis of a handheld device that is intended to mimic hand kinetic and posal parameters capture device.

Despite interesting topic and authors presented work, there is still a lot of aspects for improvement in order to make this article completed.

First of all authors mustn't focus much on irrelevant factorial details of used hardware in favor of stressing more on idea and working principle. Avoid  listing (and describing) irrelevant facts such technical characteristics of a used hardware that can be easily known and obtained from manufacturer specs. Only if it is really necessary (really relevant for the purpose of explanation) emphasize a specific propertiy (or more of them) of used hardware that significantly contribute to your goal.

Figure 7. is not meaningfull and informational in any way. It is not either electrical nor structural schematic. As it is, it represents only a paper space filler! Completely irrelevant and not worth to ocupy a paper space. Please, redraw it completely or make it significantly meaningfull. 

There is no mention of software support, algorithm or data processing path in any way nor processing procedures of the signal at all. Describe it in a proper and meaningfull way (by respecting patent considerations). Despite patent public protections you can laid out basics of data processing in a more meaningful and scientific way make it more understandable.

Chapter 3. should be rewritten completely in a way where you firstly describe testing procedures, result expectation and result impact predictions and then conduct a proper testing procedures. Yet given results of "testing" have to be betterly evaluated and graphically presented. The results, laid out as they are now, are insufficient. Figure 11. is a good and nice try but lacks of basics in interpretation and axial description. Also, a test of all sensors should be conducted, in a statistically meaningfull way, and results congregated into overal meritt of the system that is either graphically and descriptionally given.

Be very careful in formating, drawing and describing tables and graphs/images! All tables and graphs have to be clearly designated and described, giving no room for misjudgement of what is shown on them.

Overally, 

the paper have great potential but lacks in many segments that can make this article great and scientifically acceptable.

Author Response

The paper is well-written and the developed device is presented in precise and accurate way, nonetheless it should be improved with a more robust analysis of the related works.
Differences and improvements between the current work and the related ones cited in the paper are clear, but the reported citations are outdated. 
The vast majority of the works are dated before 2016, not adequate to present the current work to the reader.

Many thanks to reviewer 3 by positive comments. The abstract and introduction section has been improved in order to fix our main new contributions. The reported citations are updated with relevant actual papers.

35. Gatt I, Smith-Moore S, Steggles C, Loosemore M. The Takei Handheld Dynamometer: An Effective Clinical Outcome Measure Tool for Hand and Wrist Function in Boxing. Hand (N Y). 2018 May;13(3):319-324. doi: 10.1177/1558944717707831. Epub 2017 May 10. PMID: 28490195; PMCID: PMC5987983.
36. Sara Nasiri, Mohammad Reza Khosravani, Progress and challenges in fabrication of wearable sensors for health monitoring, Sensors and Actuators A: Physical,Volume 312,2020,112105, ISSN 0924-4247,
37. Sandro Nižetić, Nikolina Pivac, Vlasta Zanki, Agis M. Papadopoulos,Application of smart wearable sensors in office buildings for modelling of occupants’ metabolic responses,Energy and Buildings,Volume 226,2020,110399,ISSN 0378-7788,https://doi.org/10.1016/j.enbuild.2020.110399.

 

Another aspect to improve should be the final application description.
I understand that the paper is focused on describing the device from a technical point of view, nonetheless a deepening on the potential final applications would be appreciated.
Several times "ludic or rehabilitation purposes" are mentioned, perhaps authors should be more specific with some use-cases.

We focus our main application with our device in the rehabilitation area. We plan to develop serious videogames in order to use this device to recover functionality in a ludic way. In the demo figures and video we show a test application where some parameters (finger and hand position & force) are translate to a size and position variations of the virtual object. This information has been added in the new revised version.

 

are tr 
TYPOS

Line 347: shows -> show.
Line 377: easy -> easily.
It should be better to avoid contracted form. Line 99: doesn't -> does not.

We have revised the English typos, but in any case if the paper will be accepted with submit the paper to editorial board English supervision

LAYOUT
 
Caption of Figure 8 should be separated from the text with a blank line.

Done

Check the other captions in terms of font and style and make them coherent each other.

Done

Reviewer 4 Report

CONTENT

The paper is well-written and the developed device is presented in precise and accurate way, nonetheless it should be improved with a more robust analysis of the related works.
Differences and improvements between the current work and the related ones cited in the paper are clear, but the reported citations are outdated. 
The vast majority of the works are dated before 2016, not adequate to present the current work to the reader.

Another aspect to improve should be the final application description.
I understand that the paper is focused on describing the device from a technical point of view, nonetheless a deepening on the potential final applications would be appreciated.
Several times "ludic or rehabilitation purposes" are mentioned, perhaps authors should be more specific with some use-cases.
 
TYPOS

Line 347: shows -> show.
Line 377: easy -> easily.
It should be better to avoid contracted form. Line 99: doesn't -> does not.

LAYOUT
 
Caption of Figure 8 should be separated from the text with a blank line.
Check the other captions in terms of font and style and make them coherent each other.

Author Response

The article deals with the problem of motion and force analysis of a handheld device that is intended to mimic hand kinetic and posal parameters capture device.

Despite interesting topic and authors presented work, there is still a lot of aspects for improvement in order to make this article completed.

Many thanks to reviewer 4 by positive comments. We agree in all comments and suggestions proposed.

First of all authors mustn't focus much on irrelevant factorial details of used hardware in favor of stressing more on idea and working principle. Avoid  listing (and describing) irrelevant facts such technical characteristics of a used hardware that can be easily known and obtained from manufacturer specs. Only if it is really necessary (really relevant for the purpose of explanation) emphasize a specific propertiy (or more of them) of used hardware that significantly contribute to your goal.

The abstract and introduction section has been improved in order to fix our main new contributions. We reduce technical device aspects and we concentrate all our efforts in measurements and empirical validations. A list of the main objectives are provided to focus our research in this paper. Also some new references are added to bibliography section. The figures 3, 4 and 5 are combined and Figure 1 simplified and comented.

Figure 7. is not meaningfull and informational in any way. It is not either electrical nor structural schematic. As it is, it represents only a paper space filler! Completely irrelevant and not worth to ocupy a paper space. Please, redraw it completely or make it significantly meaningfull.

Figure 7 has been removed.

There is no mention of software support, algorithm or data processing path in any way nor processing procedures of the signal at all. Describe it in a proper and meaningfull way (by respecting patent considerations). Despite patent public protections you can laid out basics of data processing in a more meaningful and scientific way make it more understandable.

New software data implementation has been included. A UML communication diagram between Arduino, server and client was described. Server Data Processing is presented in a more precise manner.

Chapter 3. should be rewritten completely in a way where you firstly describe testing procedures, result expectation and result impact predictions and then conduct a proper testing procedures. Yet given results of "testing" have to be betterly evaluated and graphically presented. The results, laid out as they are now, are insufficient. Figure 11. is a good and nice try but lacks of basics in interpretation and axial description. Also, a test of all sensors should be conducted, in a statistically meaningfull way, and results congregated into overal meritt of the system that is either graphically and descriptionally given.

In the new version, results and validation section has been rewritten and improved.

Be very careful in formating, drawing and describing tables and graphs/images! All tables and graphs have to be clearly designated and described, giving no room for misjudgement of what is shown on them.

Revision about these points are done.

Overally, the paper have great potential but lacks in many segments that can make this article great and scientifically acceptable.

All main suggestions proposed by reviewer 4 are assumed.

Reviewer 5 Report

Dear authors, 

Interesting work. The produced device can provide haptic feedback with affordable consumer electronics comparable to newer approaches seen by Valve's Index controller. While the technical development is sound, the rest of the document presents several areas of improvement. The first notorious aspect to look into is the abstract as it is lacking context that highlights the relevance of your work. Next, the intro is populated with outdated references and missing context to better position the problem you are trying to solve. There are several vague statements and little to no analysis of citations in the text. The materials and methods are missing the analysis of the actions to be performed with your system, technical requirements are presented but anything related to the expected hand and finger interactions is nowhere to be found. The authors mention a low-cost system, and while that is true from the electronics components being presented, the case was produced using an industrial CNC milling machine that may not be easily accessible, why not use 3D printing? Results focus on testing done to prove the device works, here the work's contribution becomes clear in terms of the haptic feedback. However, the authors should have laid out their study design and research question to emphasize this aspect.

In the discussion, the authors state that "The intention of this paper is to 542 show the feasibility of the system", however, costs and comparisons with other systems along cross-platform integration are not presented. Making it difficult to agree with. By spending time in the materials and methods and results compared to other systems, the conclusion "this device goes beyond pressure sensing and gesture recognition" would make more sense.

Finally, a thorough English revision is required, there are very difficult to understand sentences, informal expression (e.g., little bit invasive), and formatting issues with figures, product names, and citation formatting.

Comments for author File: Comments.pdf

Author Response

Interesting work. The produced device can provide haptic feedback with affordable consumer electronics comparable to newer approaches seen by Valve's Index controller. While the technical development is sound, the rest of the document presents several areas of improvement. The first notorious aspect to look into is the abstract as it is lacking context that highlights the relevance of your work. Next, the intro is populated with outdated references and missing context to better position the problem you are trying to solve. There are several vague statements and little to no analysis of citations in the text. The materials and methods are missing the analysis of the actions to be performed with your system, technical requirements are presented but anything related to the expected hand and finger interactions is nowhere to be found. The authors mention a low-cost system, and while that is true from the electronics components being presented, the case was produced using an industrial CNC milling machine that may not be easily accessible, why not use 3D printing? Results focus on testing done to prove the device works, here the work's contribution becomes clear in terms of the haptic feedback. However, the authors should have laid out their study design and research question to emphasize this aspect.

Many thanks to reviewer 5 by positive comments. The abstract and introduction section has been improved in order to fix our main new contributions. We reduce technical device aspects and we concentrate all our efforts in measurements and empirical validations. A list of the main objectives are provided to focus our research in this paper.

The first prototype was done using a CNC machine because it is accessible for us in our laboratory at the University. The quality is higher than a 3D printer. Otherwise in the case of commercial industrial production we will create a mechanical design using plastic injection. In this case, the final cost will be cheaper.

 

We have explored the Valve Index Controllers, but we can’t find any technical specifications about force precision sensors. From videos, users feedback we assume that are good controllers for VR ludic applications but we have serious doubts about its usefulness in medical rehabilitation applications.

By its design the grip of the force sensor is only possible to perform it with 3 fingers (the index finger is used for the trigger). This limitation suggests that the user cannot make the maximum grip force and therefore in case of real tasks of an extreme force of the whole hand the system would not be adequate. Regardless of this limitation, the accuracy of the force with those three fingers is not known. The final price of the Valve VR system is expensive (1079€) and its installation and compatibility with other systems is not easy. Our system connect to any device through Bluetooth device.

In the discussion, the authors state that "The intention of this paper is to 542 show the feasibility of the system", however, costs and comparisons with other systems along cross-platform integration are not presented. Making it difficult to agree with. By spending time in the materials and methods and results compared to other systems, the conclusion "this device goes beyond pressure sensing and gesture recognition" would make more sense.

We have included a more detailed Information about the serious games developed but not yet evaluated with the device proposed. The section 3.3 client application has been improved in order to explain the main features of demo applications. We show some experimental variations of a user in a demo application.

Finally, a thorough English revision is required, there are very difficult to understand sentences, informal expression (e.g., little bit invasive), and formatting issues with figures, product names, and citation formatting.

We have revised the English typos, but in any case if the paper will be accepted with submit the paper to editorial board English supervision

Round 2

Reviewer 2 Report

The modification and response have sufficiently addressed the issue of the advantage of low cost and the application field is not video games for entertainment, and the device proposed in this study has a definite contribution.

Author Response

Many thanks to reviewer 2 by positive comments.

Reviewer 3 Report

Dear author(s), the article is now in much better state than previous was. I have no further objections to the content nor structure of it.

Author Response

Many thanks to reviewer 3 by positive comments.

Reviewer 5 Report

Dear Authors, 

Thank you for addressing the review comments. Improvements are visible, but the manuscript requires more work to further enhance its quality. For example, informal language and subjective expressions prevail in the document. Expressions like "a little bit invasive" do not belong in a scientific manuscript. Like this one, there are many others that need to be revised. The manuscript faces two main challenges, better structure, and language clarity. With respect to the structure, the research objective and hypotheses need to be clearly stated, the literature review needs to be current (i.e., novelty or relevance of outdated citations do not reflect properly the state of the art), the results should only present the results and not items that belong in the Methods section, and finally, the conclusion and discussion should be centered around the research question by articulating the methods, review and results findings. Finally, while some reviews were addressed, some others were not. I believe your manuscript requires an extensive grammar review, redistribution of content from the results section to the methods, an updated literature review, and the incorporation of the 3D printed device (if possible), but definitely the qualitative user study. 

Comments for author File: Comments.pdf

Author Response

Many thanks to reviewer by positive comments. All informal languages expression are removed or modified. If the paper will be accepted we will submit the paper to editorial board English supervision. The outdated citations are removed and new recent equivalent papers are added. Following your suggestions some paragraphs are moved from Results Section to Method sections (software explanation). The numerical data analysis, from our point of view, helps understanding the way how statistical data have been obtained. So it is maintained in results section. Attached to this answer letter we include a pdf file of the new device developed in 3D printer, but we decide do not include it in this paper because the all validation has been done with CNC version. We are now evaluating the material resistance of 3D version.

Finally about the consideration of qualitative user study, at the moment we are designing a precise statistical validation in two directions: a usability testing (non medical applications) and biomechanical rehabilitation for patients. Due to complexity and extension of this study we are considering in a new work involving medical staff. The main contribution of actual paper deals with the technical (hardware and software) aspects and feature and error analysis.

Author Response File: Author Response.pdf

Round 3

Reviewer 5 Report

Dear Authors, 

The revised manuscript shows significant improvements. It is my opinion that the updated version better reflects the quality of the work being presented. I believe that grammar and English checks will help to further enhance its quality.