Review of the Research Progress in Soft Robots

Round 1

Reviewer 1 Report

The manuscript This paper discusses  the manufacturing processes such as stereolithography, digital light processing, fused deposition modeling, and so on. The main reason is that the traditional lapper pouring method for the soft robots is too unitary and the printing efficiency is low. The paper is interesting. A few changes are required before acceptance. I recommend a major revision.

Address these comments:

However, the major and critical points are:

(1)     [QUESTION] What is stereolithography exactly?

(2)     [SUGGESTION] Define the novelty of your analysis.

(2)     [SUGGESTION] The introduction needs improvement. Kindly provide the background and proper literature survey.

(3)     [QUESTION] you mentioned on page 3 x0=0.1, a1=30, a2 goes from 0.1 to 100 with step 0.1. For the 1000 parameters, iterate f 500 times, filtering the first 200 times, and depict the values of x for the

last 300 times, as shown in Figure 1. Why these particular values?

(4)    [LIMITATIONS] What are the limitations of the current study? It should be added in a separate section.The rest of my review presents other weak points, comments, and opinions in detail.

Overall Comments:

(1)     [KEYWORDS] The keywords (i.e., index terms) should be sorted in alphabetical order.

(2)     [ABSTRACT] The abstract should contain the best-achieved results from the performed analysis.

(3)     [ABSTRACT] The abstract should reflect the contributions of the manuscript. I suggest rewriting it.

(4)     [INTRODUCTION] The authors should provide a clear problem definition and contributions in the introduction section.

(5)     [RELATED WORK] Where are the related studies? They should be declared in a separate section.

(6)     There are many abbrevations I suggest numanclature.

(7)     [EQUATIONS] The authors should follow the journal authors' guidance in writing the equations, symbols, and variables. Please, refer to the authors guidelines on the journal official website.

(9)    [METHODOLOGY] Where is the overall pseudocode? Flowchart? of the suggested approach?

(10)    [EXPERIMENTS] The working environment (i.e., software and hardware) should be declared and added to a table.

 (12)    [SYMBOLS] The authors should add a table of symbols in the revised manuscript.

(13)    [CONCLUSIONS] The conclusions in this manuscript are primitive. Please, write your conclusions.

(14)    [PROOFING] The manuscript should be checked again to fix any typos such as missing spaces and commas.

 (15)    [REFERENCES IN INTRODUCTION] Recent citations should be added to the manuscript.

Cite these numerical studies related to micobots:

* Electro-osmotically driven generalized Newtonian blood flow in a divergent micro-channel

* Channel flow of non-Newtonian fluid due to peristalsis under external electric and magnetic field

* A computational approach to model gliding motion of an organism on a sticky slime layer over a solid substrate

* Mathematical Modeling Related to Bacterial Gliding Mechanism at Low Reynolds Number with Ellis Slime

* Impact of viscoelastic ooze slime on complex wavy gliders near a solid boundary

 

* Controlling kinetics of self-propelled rod-like swimmers near multi sinusoidal substrate

The modified finite element method for heat and mass transfer of unsteady reacting flow with mixed convection. Frontiers in Physics. https://doi.org/10.3389/fphy.2022.952787.

"An Application of the Finite Element Method for Heat and Mass Transfer of Boundary Layer Flow Using Variable Thermal Conductivity and Mass Diffusivity," in HINDAWI, Sep-2022, doi: 10.1155/2022.

"A New Explicit Numerical Schemes for Time-Dependent PDEs with Application to Pressure Driven Fluid Flow in a Rectangular Duct," in MDPI, Jul-2022, doi: 10.3390/en15145145.

 

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

This review paper is talking about current soft robotics material, actuation method, and application. It is an interesting topic that the researchers are concerned about. However, this review is written on the super facial aspects that didn’t go deeply about the soft robotic area. It is basically listed some papers that other papers work on, with a lot of detail missing. Some comments and suggestions are listed below: 

1.       In Lines 92-94, “However, with the development of production technology, liquid-driven can be combined with other driven methods in the future design of soft robots to overcome the shortcomings of liquid-driven and amplify its advantages.” Can you make an example of what kind of driven method can be used to combine, and why other methods should be used to combine instead of using other driven methods? 

2.       In lines 98-109, described in detail how these methods work. For example, how the circular muscle fibers work in Eco flex 00-30 to achieve self-recuperating capability. In the snailfish paper, how deep the soft fish could reach, and what kind of exploration does the fish do? 

3.       In chapter 2.1, the title is fluid-driven methods and their materials, while it is not obvious what kind of driven method are they using, it keeps saying liquid-driven method. Furthermore, in Figure 2, none of the soft robots are driven by liquid. 

4.       In chapter 2.2, the author only listed some soft robots that use smart materials. They didn’t tell what the principle of the SMM is, how they keep the shape, and how to actuate. There is no detail about the method and material. 

5.       At the end of Chapter 2.2, there is a comparison table, but only listed the parameter, there is no description. The response time is fast and slow, how fast it is, and how slow it could be. They are not clear. 

6.       In chapter 4, the author is planning to talk about application, it should be something like disaster rescue, industrial production, medical services, exploration, and surveying that is illustrated in their abstract, but not their motion that is listed in chapter 4. The results shown in Figure 8 are not applications, they are just prototypes.

 

 

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

1. The authors should explain the actuation mechanism of a soft actuator.

2. Recently, twisted and coiled actuators (TCPA) is attracted research topics for soft robots. I suggest that the authors add a new explanation about TCPA and its application.

3. What is the "Controllability" of Table 2? 

Author Response

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Author Response File: Author Response.docx

Reviewer 4 Report

Soft robotics is an emerging research fields. There are very many related review articles and more research progresses. However, this manuscript does not show well what is fresh than the existing review manuscripts, and does not bring about new enlightenment to the research community. For the high-quality publication, I suggest that the authors can handle the following issues delicately.

1. The pictures and the text in the pictures are not clear enough, so the author should provide clearer pictures as possible.

2. The section of INTRODUCTION is very short and should be more informative about the background related to the field. More relevant references need to be added. The introduction of the manuscript contains only three citations, which do not provide a comprehensive background of previous research work and the current status of research.

3. In the section of DRIVEN METHODS AND MATERIALS FOR SOFT ROBOTS, more types of driving materials could be supplemented , such as bioactive materials, liquid crystal elastomer and polymer materials, etc.

4. In the section of DRIVEN METHODS AND MATERIALS FOR SOFT ROBOTS, it does not clearly indicate the advantages and disadvantages of the objects described in each subsection. The author can elaborate on the advantages and disadvantages according to the presented content .

5. Figure 1(b) after line 94 is not aligned with (a)(c), the author can resize Figure 1(b) to look better.

6. Line 173, ... Elastomeric actuator (DEA) This soft freestanding actuator.... ,There is a missing period before "This" in this sentence. I think the author may have missed it, so a slight correction can be made.

7. Line 275, Table 1 is relatively simple and does not clearly show the differences in properties between different materials and does not reflect the regularity of them.

8. The words "big", "small" and "fast" in Table 2 in line 307 are only described qualitatively, and there is no good reference object to compare the two, so the author can add some references to illustrate the efficiency of their reactions.

9. The section on 3D PRINTING MANUFACTURING PROCESS in line 309 does not clearly explain the application scenarios of each printing technology and the characteristics of the printed products

11. The manuscript lacks a statement of the purpose of this survey and does not indicate what research gap it fills.

12. The summary section of the paper in line 518 is more concise and the author should provide a comprehensive and adequate summary of the overall article. The outlook section for soft robotics is better summarized.

13. Many new concepts in the soft robotics are not covered. For example, origami-inspired robot, 4D/3D printable soft robot, and the plant-inspired robot. The following papers but not limited to these may help to argue this point.

 "Biologically inspired vine-like and tendril-like robots." 2015 Science and Information Conference (SAI). IEEE, 2015.

"Origami spring–inspired metamaterials and robots: An attempt at fully programmable robotics." Science Progress 103.3 (2020): 0036850420946162.

"Toward growing robots: a historical evolution from cellular to plant-inspired robotics." Frontiers in Robotics and AI 5 (2018): 16.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

This review paper looks great. Only one recommendation is listed below.

(1) Line 40, ‘FAN’ should be ‘Fan’.

Author Response

Thank you very much for your suggestion. We have changed "FAN" to "Fan".

Reviewer 4 Report

1. Line 15, summarize should be summarized.

2. In Table 3, what's the discharge form for the FDM process?

3. Line 143, what's the stretching, bending, and torsion for a rigid robot?

4. In the Conclusions, the authors also use problem to explain problem of the section 5, rather than suggestions.

5. What's the contribution of this survey? Please make it clearer.

 

Author Response

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Author Response File: Author Response.docx