Comprehensive Stable Control Strategy for a Typical Underactuated Manipulator Considering Several Uncertainties

Round 1

Reviewer 1 Report

The article is a very relevant subject and written at a good level.

However, some points need to be corrected.

The title of the article completely corresponds to it.

The article has a few points that need to be corrected:

·       The paper is completely theoretical and is not even tied to any particular application or problem (which is strange from the point of view of submitting a paper to Applied Sciences). Therefore, the authors should justify in more detail the motivation for conducting this study from the point of view of applied research.

·       The authors have already attached themselves to the specific kinematics of the manipulator. However, it is not clear from the article why the authors chose this kinematic scheme. Where is a manipulator with such kinematics used? How will solving the control problem of this manipulator affect the operation, etc.?

·       In each Case subsection, the last sentence begins with "According to the experimental findings....". What experiments are we talking about (the work is based on simulation)?

·       In Fig. 2-7, the description in captions a, b, c, d is not carried out.

·       The authors do not analyze the limitations of this work. How will changing the kinematic scheme affect the effectiveness of the developed control system?

·       There is no Discussion section in the article, where the authors would analyze the obtained data comparing AAP and AAAP systems. The authors need to numerically compare the obtained results so that the conclusions are based on these data.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

After reading the work, I evaluate it very positively. However, due to the great similarity to other works of the authors, I propose to introduce significant changes in the content. In its current form, the article is too similar to previously published works. Simply changing the model parameters and showing subsequent simulation results does not constitute significant research progress. We should move towards validating the developed control scheme on the example of a real facility.

To sum up, in its current form it is not suitable for printing.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The paper proposes a control strategy for underactuated systems.

The paper seems to be correct but lacks of clear contribution. For instance, I have the following comments:

1) The introduction requires more details in the methods used by previous authors since it is not clear what are their contribution and the difference with your current approach.

2) The proposed model uses a simple dynamic model, but does not consider dissipative terms, measurement noise and model uncertainties, which reduces the complexity of the approach.

3) The use of the DE algorithm is not well motivates. Is it the only option? In this case you are dealing with underactuaded and redundant robot. Why not simple use the Jacobian for the mapping?

4) In the results, are the oscillations expected? How do these oscillations affect the life cycle of your actuators?

5) How the parameters Pi and Di were selected?

6) The disturbance rejection section is not convincing, since you are using a small torque disturbance which does not show a real compensation effect. More experiments need to be conducted.

7) The approach is not compared with other methods of the SOTA. It is required to show your contributions in contrast to other methods. Otherwise, your method is not well motivated.

8) Your method needs to be challenged with a high-redundant manipulator to show their benefits.

Proofread the paper. The tables have twice Li(m) which seems to not be correct since one is the position of the center of mass of the link i.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors addressed all comments and made a significant number of corrections, which allowed the article to be accepted.

Author Response

Thank you very much for your careful reading and recognition of the revised paper!

Reviewer 2 Report

I accept the authors' explanations and wish them success in obtaining funds for research on real objects. The article in its current form is suitable for publication.

Author Response

Thank you very much for your careful reading and recognition of the revised paper!

Reviewer 3 Report

The paper is improved and highly appreciated.

However, the experiment results need more work. It is not sufficient to say that other works have not addressed the topic before or that is valid for high-order systems. Otherwise the contribution of the paper is not convincing.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf