Validation of a Classical Sliding Mode Control Applied to a Physical Robotic Arm with Six Degrees of Freedom

Round 1

Reviewer 1 Report

This paper introduces a comparison of CTC and SMC for a physical robotic arm with 6DOF. Simulation and experimental results are given to verify the robustness of SMC.

Some suggestions and discussions are given as follows

1. In the Introduction, this paper mentioned that one way to reduce the chattering of SMC is to add ECM to the control law. However, the author did not use ECM method in the sliding mode controller design. Only a large switching gain is used to suppress unmodeled dynamics and external disturbances, which undoubtedly requires a large switching gain. Obviously, this will lead to chattering of the system. The experimental results in Figure 15 and Figure 16 also illustrate this problem. The author needs to explain this.
2. What do you mean by “sympathy” in the line after Equation 1?
3. Section 5 introduces the implementation of the experiment with a large number of words and pictures, which is slightly redundant. For example, Figure 8 can be deleted without affecting the reader's understanding of the article.
4. What do L1-L6 stand for in Figure 14?

Author Response

We appreciate each of your comments, the article was improved in all its graphical structure and typing.
The analysis, response and planned improvements for each of your comments can be found in the PDF cited above. 

Author Response File: Author Response.pdf

Reviewer 2 Report

The following issues can be considered to further improve this manuscript.

1. What are the advantages of the proposed method and which problems in the existing works have been solved?
2. There are some sliding mode control applications where your techniques could be of some interest . such as  DOI 10.1109/TSMC.2021. 3071360  1109/TCYB.2021. 3052234.  A comment on these techniques and applications would be valuable, and could amplify the interest for this paper.
3. A detailed block diagram of the proposed approach should be added to clarify the design procedure and structure.
4. In the simulation , the comparative studies between proposed method and other method can be discussed to demonstrate the effectiveness of the proposed method. 
5. A much more clear and detailed description for the experiment set-up is highly expected in experimental section

Author Response

We appreciate each of your comments, the article was improved in all its graphical structure and typing.
The analysis, response and planned improvements for each of your comments can be found in the PDF cited above. 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have answered my questions properly, I agree to accept its publication in current form.

Reviewer 2 Report

This paper has been revised according to the comments.