Comprehensive Comparative Analysis of Lower Limb Exoskeleton Research: Control, Design, and Application

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Authors present a literature review about the advancements in lowerlimb exoskeleton systems, focusing on applications, control strategies, hardware architecture, sensing modalities, human-robot interaction, evaluation methods, and technical innovations.

According to the abstract, the literature review covers the advancements in lowerlimb exoskeleton systems, focusing on applications, control strategies, hardware architecture, sensing modalities, human-robot interaction, evaluation methods, and technical innovations. The are presented through the manuscript sections, listing the main research works found by the author. However, it looks like a list of many works, sometimes without a relationship between them and even worse, excluding the main contributions of each case. In this sense, It would be more comprehensive if the results were presented in table format for each section, showing the weaknesses and strengths of each approach in comparison with the others. For example, in those using ML techniques, what are the purpose of them (classify? predict? what variables are expected to predict or what classes they expect to classify and what are the scores in terms of performance metrics?i.e., a comparison between works using multiple techniques in a table could be more descriptive than text). In the case of the controllers, a comparison between the multiple types of controllers and the achieved performance with them. The same could be applicable to the other sections.

Additionally, it is not clear the purpose of the figures presented in the manuscript. Most of them give some superficial descriptions that are already clear in the text. I consider that the images should be to support the understanding of complex descriptions, however in this case, they do not have this purpose. 

 

It has no sense to list a big set of references as in the following case:

[19], [20], [21], [22], [23] [24], [25], [26], 232
[27], [28] [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], 233
[45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61]

 

The word Reference before each reference is redundant. 

 

I consider that the manuscript must be improved before re-submission. the way in which it is presented looks like a list of small fragments of research works. More analysis and presentation tools, especially about the findings, pros and cons of each work should be included (e.g. comparative tables). Presented Figures seem unnecessary.

Author Response

Authors present a literature review about the advancements in lowerlimb exoskeleton systems, focusing on applications, control strategies, hardware architecture, sensing modalities, human-robot interaction, evaluation methods, and technical innovations.

According to the abstract, the literature review covers the advancements in lowerlimb exoskeleton systems, focusing on applications, control strategies, hardware architecture, sensing modalities, human-robot interaction, evaluation methods, and technical innovations. The are presented through the manuscript sections, listing the main research works found by the author. However, it looks like a list of many works, sometimes without a relationship between them and even worse, excluding the main contributions of each case. In this sense, It would be more comprehensive if the results were presented in table format for each section, showing the weaknesses and strengths of each approach in comparison with the others. For example, in those using ML techniques, what are the purpose of them (classify? predict? what variables are expected to predict or what classes they expect to classify and what are the scores in terms of performance metrics?i.e., a comparison between works using multiple techniques in a table could be more descriptive than text). In the case of the controllers, a comparison between the multiple types of controllers and the achieved performance with them. The same could be applicable to the other sections.

Additionally, it is not clear the purpose of the figures presented in the manuscript. Most of them give some superficial descriptions that are already clear in the text. I consider that the images should be to support the understanding of complex descriptions, however in this case, they do not have this purpose. 

• The figures have been included to enhance reader engagement, and each one is accompanied by a reference to ChatGPT.

It has no sense to list a big set of references as in the following case:

[19], [20], [21], [22], [23] [24], [25], [26], 232
[27], [28] [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], 233
[45], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], [57], [58], [59], [60], [61]

• We have fixed the big set of references 

The word Reference before each reference is redundant. 

• We have fixed it at multiple places.

I consider that the manuscript must be improved before re-submission. the way in which it is presented looks like a list of small fragments of research works. More analysis and presentation tools, especially about the findings, pros and cons of each work should be included (e.g. comparative tables). Presented Figures seem unnecessary.

• We have included multiple tables to improve presentation and ensure information is easily accessible.

Thank you very much for your time and consideration

Reviewer 2 Report

Comments and Suggestions for Authors

This comprehensive review on recent lower limb exoskeletons summarized their applications, control strategies, hardware, sensing, HMI, validation, and innovations, which provides a detailed guidance for researchers and professional interested in knowing its current technology and tendency. Here are some suggestions to highlight this review. 

1. It is highly recommended to include some typical illustrations (actual/design pictures) when mentioning and discussing the specific types of prototypes (e.g., actuation, design, mechanism).
2. It is suggested to group commercial and research R&D level lower limb exoskeletons, and compare their features and predict the tendency in future development and applications, which will highlight the value of this systematic review. 
3. Like the authors mentioned scatteredly throughout the review, the adoptions of smart soft materials/soft-rigid hybrid materials have been popular in exoskeleton development. For those smart materials, it can be applied as both mechanical sensors and regional actuators to facilitate the application of exoskeletons. 

Author Response

This comprehensive review on recent lower limb exoskeletons summarized their applications, control strategies, hardware, sensing, HMI, validation, and innovations, which provides a detailed guidance for researchers and professional interested in knowing its current technology and tendency. Here are some suggestions to highlight this review. 

1. It is highly recommended to include some typical illustrations (actual/design pictures) when mentioning and discussing the specific types of prototypes (e.g., actuation, design, mechanism).

• We always prefer to use original illustrations from the referenced articles; however, copyright restrictions prevent us from doing so. This is the sole reason we have not included any copyrighted figures.

2. It is suggested to group commercial and research R&D level lower limb exoskeletons, and compare their features and predict the tendency in future development and applications, which will highlight the value of this systematic review. 

• This criterion falls outside the scope of this systematic review, and such titles did not appear during the database search.

3. Like the authors mentioned scatteredly throughout the review, the adoptions of smart soft materials/soft-rigid hybrid materials have been popular in exoskeleton development. For those smart materials, it can be applied as both mechanical sensors and regional actuators to facilitate the application of exoskeletons. 

• Soft robotics or soft materials or hybrid materials based exoskeleton robot didn’t appear in the search

Thank you very much for your time and consideration

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The previous suggestions and observations have been addressed in an acceptable way. Please, evaluate the relevance of all figures. Be sure that they are really informative.

Author Response

Please, evaluate the relevance of all figures. Be sure that they are really informative.

Figures have been incorporated into the article to promote reader engagement and mitigate cognitive fatigue. Although the inclusion of real visuals from reviewed articles could further enrich the content, the primary constraint lies in getting permission to use copyrighted materials.

Thank you so much.

Regards,

Hasan

Reviewer 2 Report

Comments and Suggestions for Authors

Thanks the authors for the reply and the existing content on lower limb exoskeleton is adequate.

Author Response

Thank you very much for your time and consideration