Online Walking Speed Estimation Based on Gait Phase and Kinematic Model for Intelligent Lower-Limb Prosthesis

Round 1

Reviewer 1 Report

This paper proposes accurate real time walking speed using IMU placed on thigh to phase based step frequency estimator and stride estimator based on inverted pendulum model. There are several issues that need to be addressed prior to publication. 

1. The claims in Ln.70-76 can be more specific; for instance for claim#1

which states the phase method used for real-time estimation of walking speed is more accurate, is this not already been shown by several groups? 

2. Equation 2: Can the authors explain Eqn.2 and its derivation or cite an appropriate reference? Are the authors using a four-quadrant atan2 function?

3. Ln 83, pg2: Ref [4] may be mis-referenced as it addresses hip joint movement to gait phase.

4.Figure 10 How was this data collected? More details need to be added in text.

5. Throughout the manuscript, there are several spelling & grammatical errors i.e '224 'assess'? There are also several awkward sentence constructions which make it difficult to read.

6. Is Figure 10 representative of the sound leg or prosthetic leg?

7. Figure 11: prosthetic leg is having significantly higher stride length compared to sound side and negative controls at all speeds. Is the prosthetic heavier such that it changes gait characteristics of the subject? Does this data suggest that the stride estimator cannot accurately calculate stride symmetry? Have the authors considered other modified inverted pendulum models?

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

An interesting work by the authors describes a cutting-edge online walking speed estimating technique that creates a step frequency and stride estimator. The goal of this suggestion was to improve the comfort of the Intelligent Lower-limb prosthetic user when walking at various speeds. By using Kalman filtering, the stable phase is initially obtained. The stride estimator then forecasts the user's stride based on the inverted pendulum model and the user's leg length information. The step frequency estimator then calculates the phase change rate in real time to estimate the step frequency. The text is well-written, accurate, pertinent to the subject, well-organized, and based on reliable science. Based on the information provided in the methods section, the manuscript’s findings are replicable. Please change the word "estimation" to "estimation" in line 9. Furthermore, some charts could be more significant, such as figure 5 (larger), which depicts the experimental equipment. Furthermore, I believe the paper requires a conclusion to include more information about their future work. 

Author Response

Thanks for your comments. According to your advice, the pictures are adjusted and a conclusion is added in the new version.

Reviewer 3 Report

I applaud the authors for their intent to present information that can be applied I the real world with individuals that can use this information to enhance their lives. However, there are significant formatting issues as well as issues with grammar and punctuation that must be remedied prior to any thorough review. 

Please consider reassessing the document for grammar and punctuation in an effort to make the product readable. Additionally, information presented in this document needs to be positioned or presented differently. For example, the abstract does not follow norms when summarizing the information in the paper. Also, the results section appears to be a continuation of the methods section. The discussion is not as in depth as it needs to be. 

This may take a complete re-think as far as how to present the information, but the information is present and can be molded into an appropriate format. 

Author Response

Dear reviewer,

I'm sorry that my poor English and written level have bothered you....   I will try my best to revise my paper and check the grammar mistakes.  Thanks for your comments. If there are any problems in the new version, I'm glad that you can help to point it out. Thanks again.

Yours,

Sincerely,

Yi Liu

Round 2

Reviewer 1 Report

1) Some minor points that may help to clarify the equations for thereader to better follow:

for eqn(3) please define qt_sn(t)

for eqn (11) please define phi(con).

2)To support the claim of best performance, is there any statistical 

test of significance? Ln 215-220 

 

Author Response

Thanks for your careful reading, the definition of those two variables are added.

"best performance" in the paper is wrong written and has been revised in the new version.

Reviewer 3 Report

I genuinely appreciate the effort that has been offered editing the original manuscript. There remains a number of grammatical errors in the document that must be addressed to afford the reader a viable opportunity to consume the information. 

As much as I am tempted to assist the author in making pointed suggestions as to where and what to edit, I do not believe that is within my scope of responsibility as a reviewer. Perhaps collaborating with a colleague that has more experience crafting manuscript language would help. 

Additionally, the discussion and conclusion sections must be examined. The discussion is much too compact and should be expanded. This expansion will stream to the conclusion making it just as refined. 

I do believe this material can be worthy of publication after these elements have been addressed.

Author Response

Thank you for your sincere guidance and advice.

After careful check, there are lots of grammar mistakes and misspelling and we correct them In the new version.

As what you said, the discussion and conclusion are not easy to understand...... After thinking carefully,  the discussion and conclusion are reorganized and revised in the new version. 

Round 3

Reviewer 3 Report

The refining process can be frustrating and exhausting. I applaud your continued effort to develop a sound paper that is presentable to a wide audience. 

Author Response

Thank you for your sincere guidance and advice.

In this version, the results are reorganized and revised in the new version.