Adaptive Nonsingular Fast Terminal Sliding Mode Control for Shape Memory Alloy Actuated System
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript presents a novel ANFTSMC method, which is a fusion of NFTSMC and VGESO. It is able to estimate the unmodeled dynamics, compensate for the hysteresis nonlinearity and improve the control performance of prosthetic finger actuated by shape memory alloy. The NFTSMC control scheme can avoid singular problems and decrease chattering. The superiority of the proposed ANFTSMC control algorithm against the ESCM control algorithm is experimentally demonstrated. The ANFTSMC algorithm is applied to a prosthetic hand robot system experimentally.
The manuscript is well written, quite easy to read. Of course, the Lypunov stability analysis is difficult to follow. I found some ideas how to improve the text:
Q1: What are functions f1(*) and g1(*) in eq. (1)? I couldn't find the detailed description of the both functions in [36] (line 129) as is written in the text. Is the numbering of the literature [36] correct?
Q2: I also don't understand the parameters in the Table 1, because the mathematical model is unknown (not described in the manuscript). Remark: I tried to open the link Download the un-published material, but I was unable to open it. Maybe, the mathematical model and Table 1 parameters are described there, but I couldn't see them (???).
Q3: Lines 171, 178, 208: Lemma 1 is unknown, again! It doesn't exist in [37].
Q4: Figs. 3, 4, 5 and 6: The actual output curves are dotted black lines and not solid lines as described in the captions of the figures. You should make them equal!
Q5: According to explanation in lines 302-309, there is something wrong in the fig. 19. I think, the color of curves (red and blue) for both signals must be opposite!
Q6: The experiments shown in the manuscript show, that an angular movement of the fingers are quite slow in comparison to human hand. Can you describe what is the highest angular speed of the finger in the closed loop control experiment?
Q7: Can you also describe, what is the highest force of the finger?
Q8: According to strict rules of the MDPI Actuators journal "all manuscripts must contain the required sections: Author Information, Abstract, Keywords, Introduction, Materials & Methods, Results, Conclusions". Your organization of section does not contain the section Materials@Methods. So I advise you to reorganize the section names according to the above mentioned rules. I also suggest to simply introduce the new section Materials&Methods as section 2 and make present sections 2,3 and 4 as subsections of the new section 2. The name of section 5 has to be changed to Results.
Comments on the Quality of English LanguageIt is good!
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe article is well written and interesting for the reader. It presents theoretical and experimental studies carried out on shape memory alloy. All parameters and details are listed in the article. However, I would recommend that the geometrical properties are given. Because it is not only the material or the length of the SMA that matters.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
