Hybrid Adaptive Impedance and Admittance Control Based on the Sensorless Estimation of Interaction Joint Torque for Exoskeletons: A Case Study of an Upper Limb Rehabilitation Robot

Round 1

Reviewer 1 Report

This paper proposed a hybrid adaptive impedance and admittance control based on 2 sensorless estimation of interaction joint torque for exoskele-3 tons: a case study of an upper-limb rehabilitation robot.

Comments:

1.    Fig.5 and 6 are not consistent. And how to get the joint torque in fig. 7 in experiments?

2.    Show out the intermediate results of the estimator and comment on its performance.

3.    Why does the control signal vibrate? It is not reasonable in impedance control or admittance control.

4.    How the parameters are adapted and what is the adaptable performance?

5.    Real experiments are essential.

6.    In fig 5 and 11, how to get the desired and reference values and what is their relationship?

proofreading 

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 2 Report

This work presents a hybrid adaptive impedance and position-based admittance control (HAIPC) in series, comprising of a proportional derivative-based admittance position controller with gravitational torque compensation and an adaptive impedance controller. An extended state observer is used to estimate the interaction joint torque due to human stiff contact with the exoskeleton. Simulation experiments were conducted to validate the performance of the proposed scheme.

The main question addressed by the research is the suitability of the hybrid adaptive impedance and position-based admittance control for limb rehabilitation.

The part relevant for the field is the series implementation of the controllers.

The proposed algorithm is compared with other published algorithms.

The manuscript should be revised to improve readability. The limitations and issues to address for the practical implementation of this method should be discussed.

The Conclusion section should include quantitative results, advantages and disadvantages, limitations, and recommendations for the implementations. Recommendations and guidelines for future work should be provided.

The references are appropriate.

Some issues should be addressed before this manuscript can be considered for publication.

1) The manuscript should be revised to improve readability:

Line 145. “torque. . A”

Lines 154 to 150. Page number overlapping.

Figure 4. A doted arrow is going nowhere, and one arrow entering the “2DOF Exoskeleton” has no beginning.

2) What are the limitations and issues to address for the practical implementation of this method?

3) The Conclusion section should include quantitative results, advantages and disadvantages, limitations, and recommendations for the implementations. Recommendations and guidelines for future work should be provided.

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Reviewer 3 Report

The article is well written and worth further proceeding.

It contains an up-to-date literature review and an appropriately described research process.

I only have two comments:

1. the article uses a large number of variables and constants. In order not to describe each symbol under each equation and at the same time make it easier for the reader to read the content of the article, I suggest making a list of these symbols in the table at the end of the article.

2. Table 2 contains the unit (Kgm^2), but it should be (kg*m^2)

Author Response

"Please see the attachment."

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The validation is implemented in simulations. What is the simulation platform and how to get the joint torque?

proofreading

Author Response

Please see the attachment.

Author Response File: Author Response.pdf