Bionic Design of a Miniature Jumping Robot
Round 1
Reviewer 1 Report
Comment 1. The paper needs an overall English revision. There are typos or grammar errors that need to be corrected.
A non-exhaustive list of typos that need correction is shown next. Please note that it is not enough to correct this list, as the paper still needs an overall English revision to improve spelling.
Line 59: SMA BER heating. What is ber heating? This seems a typo.
Lines 113 -114: low subs? kinematic sub? high subs? kinematic sub? What is sub? Do the authors mean lower and higher pairs/joints, and kinematic chains?
Figure 4: it has Z1 repeated, no Z4.
Lines 156 and 158: the same idea is repeated at the beginning and at the end of the sentence: A secondary reduction mechanism was employed in this study … a secondary reduction mechanism was introduced in this study.
Lines 223-224: this sentence is difficult to understand, please rewrite it more clearly.
Line 194 misses a point between spring and To.
Line 284: sentence misses IS verb: The trajectory of the robot’s center of mass motion IS determined from simulation…
Lines 349-350 say: the energy storage of the robot IN THIS PAPER is higher than that of the robot IN THIS PAPER. They should make reference to different papers, not the same paper.
Comment 2. Whenever a figure is referenced in the text, the authors included the number and the whole caption in the text. This yields lengthy sentences that are very difficult to read. Please remove the captions from the main body of the text, reference only figure numbers.
Comment 3. Conclusions should mention future work.
Comment 4. Caption of Figure 8 says that this figure shows a NUMERICAL METHOD. But no numerical method is shown in this figure, it shows the results of integrating the equations of motion numerically. Moreover, the authors should indicate which numerical method they used to do the numeric integration.
Comment 5. The authors claim that there are minor errors between the graphs obtained by numerical integration and those obtained by ADAMS. However, these errors are not small: the graphs are notably different. For example, the graph of Femur starts slightly below 140 in Figure 8a, but it starts slightly above 140 in Figure 8b. The initial value of both graphs should be exactly the same, as the initial conditions do not depend on the method used to obtain the trajectory (numerical method or ADAMS simulation). One may expect a slightly different evolution between Figure 8a and 8b as time progresses, but both graphs should have exactly the same values at the beginning of the simulation. Thus, maybe there is some error in the setting of the initial conditions of any of these two simulations.
Author Response
Teacher, my reply is as follows：
Point 1: The paper needs an overall English revision. There are typos or grammar errors that need to be corrected.
Response 1: I have revised the English content of this paper comprehensively and made targeted improvements according to the teacher's feedback. Specifically, as the teacher said, I have made the following changes:
First: "BER" is deleted.
Second: The terminology has been corrected to "sports pairs, high pairs, and low pairs".
Third: Fixed bug where Z4 did not exist because there were two gears with Z1 teeth.
Fourth: The repetition at the end of the sentence is deleted.
Fifth: Change to a clearer way of saying things.
Sixth: Adding missing points.
Seventh: Adding IS verb.
Eighth: The expression semantics are changed, and the robots in this paper are compared with those in the list.
In addition, there may be typos or grammatical errors in other parts of the text and I have corrected them accordingly.
Point 2: Whenever a figure is referenced in the text, the authors included the number and the whole caption in the text. This yields lengthy sentences that are very difficult to read. Please remove the captions from the main body of the text, reference only figure numbers.
Response 2: I have deleted or replaced the text that was duplicated with the figure captions.
Point 3: Conclusions should mention future work.
Response 3: Further work for the future is added to the summary of the full text.
Point 4: Caption of Figure 8 says that this figure shows a NUMERICAL METHOD. But no numerical method is shown in this figure, it shows the results of integrating the equations of motion numerically. Moreover, the authors should indicate which numerical method they used to do the numeric integration.
Response 4: I have made the addition in the text above Figure 8 that the numerical method is based on the Lagrange method of solving the dynamic equations numerically.
Point 5: The authors claim that there are minor errors between the graphs obtained by numerical integration and those obtained by ADAMS. However, these errors are not small: the graphs are notably different. For example, the graph of Femur starts slightly below 140 in Figure 8a, but it starts slightly above 140 in Figure 8b. The initial value of both graphs should be exactly the same, as the initial conditions do not depend on the method used to obtain the trajectory (numerical method or ADAMS simulation). One may expect a slightly different evolution between Figure 8a and 8b as time progresses, but both graphs should have exactly the same values at the beginning of the simulation. Thus, maybe there is some error in the setting of the initial conditions of any of these two simulations.
Response 5: Certain problems arose when performing the calculations for the numerical methods. The modification has now been completed and the initial condition for is 88° so that the initial value of the interarticular angle between the femur and tibia is 144.6°. As the mathematical models and algorithms of the two methods are different, the results they obtain may have certain errors, which may come from a number of aspects such as modeling errors, calculation errors, and parameter errors of the system, so the joint angle curves derived by the two methods There will be a slight error in the joint angle curves obtained by the two methods. To make it easier for others to compare, I have combined the images of the data obtained by the two methods into a single graph in Figure 8.
In addition, in Figure 9 I lengthened the length of the ground in the simulation environment and replaced the original picture with another picture obtained that embodies the trajectory of the bouncing robot. This replacement had no effect on factors such as the bouncing performance of the robot but simply replaced it with a more embodied picture. In Table 3, to better represent the bouncing performance of the bouncing robot in this paper, I also present a reference factor Г based on the bouncing performance of the bouncing robot per unit weight.
In addition, I have uploaded the details of the changes I have made to your comments in the section below.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The study aimed to design a parallel single-degree-of-freedom double six-link jumping robot by imitating the physiological structure and jumping mechanism of wax cicadas. The design presented in the study overcomes the limitations of previous miniature jumping robots by improving the energy storage density of the robot. The design approach is very thorough. The design mechanism was first mathematically modeled followed by the optimization of key parameters. Finally, the feasibility of the proposed design was first tested using simulations, and then further verified using experimental testing of a developed prototype. The proposed design is innovative and has immense potential in the field of footed jumping robots.
The manuscript is well written except for some minor grammatical and punctuation errors. However, the manuscript can be further improved based on the following recommendations:
1. Corresponding author: Please make sure the author list identifies a correct corresponding author with an asterisk mark
2. Line 18: The abstract mentions that the “robot has good jumping performance”. What criteria determine a good performance? I agree that the jump height and jump distance of the proposed robot is within range of previously developed miniature jumping robots. However, how do these values translate to real-world applications?
3. Line 51: Please define the abbreviation SMA before use
4. Rationale of study: The rationale for needing greater energy storage density can be improved. Lines 67-69 hint that greater energy storage density can improve the jumping potential of the robot. However, the data in Table 3 shows otherwise. The jumping potential of the robot is multifactorial, where the limitations of low energy storage can be compensated with a combination of jumping mechanisms and less weight. A different argument for why greater energy storage density is advantageous could strengthen the manuscript.
5. In-text Figure citations: Please do not provide a full caption while citing a figure within the paragraph. For eg. in Lines 80-81, only write Figure 1(a) or Figure 1(b) instead of a full caption. Please rectify it throughout the manuscript for other figures
6. Please make sure Figures 1 (a) & (b) do not have copyright issues. If so, please get the usage approval and provide the appropriate credit
7. Line 89: Do you mean wax “cicada” instead of “hopper”? Please verify
8. Line 100: Need reference for the claim that the pleural arch has higher energy storage capacity compared to muscle alone. Depending on the muscle volume and fiber orientation, the muscle alone can have a higher energy storage capacity in theory
9. Lines 158-159: The phrase “a secondary reduction mechanism was introduced in this study” is repetitive in the sentence. Please update
10. Equations (2) & (3): Please define what is Z4 in the equations
11. Section 2.5: The details seem repetitive with the information provided in Lines 138-154. Can club both these information into a single section
12. Figure 6: Please label L0 in the figure
13. Should the “L” in equation (7) be replaced by “L0”? Similarly for the Lines 218 and 220
14. Figure 7: Keeping the alphabet labeling convention the same as Figures 2 & 6 would provide consistency and will make the figure easier to follow
15. Figure 8: Looks like the Femur_Tibia curve is shifted between the numerical and simulation results. Any possibility of systemic error in calculations? Please verify
16. Experimental testing: How was the unique point of reference identified while calculating the vertical height and horizontal distance?
17. Line 344: “better jumping performance”. How is the better jumping performance concluded? The proposed robot has 20 times more energy storage capacity than the compared robot. The difference in energy storage capacity is significantly greater than the difference in weight between the two robots. Shouldn’t the proposed robot also demonstrate a proportionately greater jump height and distance?
18. In-text citation of reference 21 is missing in the manuscript
19. Some of the sentences in the manuscript are very long (eg. Lines 92-98, Lines 194-199, Lines 202-212, Lines 229-234). Please rewrite them into shorter sentences for better readability and maintaining the train of thought
Author Response
Teacher, my changes in response to your comments are as follows:
Point 1: Corresponding author: Please make sure the author list identifies a correct corresponding author with an asterisk mark.
Response 1: The corresponding author is Deyi Kong, which I have corrected and marked with an asterisk.
Point 2: Line 18: The abstract mentions that the “robot has good jumping performance”. What criteria determine a good performance? I agree that the jump height and jump distance of the proposed robot is within range of previously developed miniature jumping robots. However, how do these values translate to real-world applications?
Response 2: The miniature bouncing robot proposed in this paper has a higher energy storage density, compared to the miniature bouncing robots in Table 3. To better show the bouncing performance of the bouncing robots in this paper, we introduced a reference factor Г based on the bouncing performance of the bouncing robots per unit weight and compared the Г values of the representative robots listed in Table 3. Although the reference factors introduced may not fully and accurately reflect the relationship between robot weight and jumping ability, they can to some extent reflect the robot's bouncing performance per unit mass. The results show that the energy storage density of the bouncing robot in this paper is 600.12mJ and its reference factor Г is 11.454. Compared with existing miniature bouncing robots, the energy storage density of the bouncing robot in this paper is higher and the bouncing performance per unit weight has a greater advantage.
The weight and load of the robot greatly affect the bouncing performance of the robot. Therefore, for bouncing robots, differences in weight or load can greatly affect the bouncing performance of the bouncing robot, which is unfair for realistic robots of different weights suitable for different environments. The bouncing performance of bouncing robots can be better compared under the characterization of the reference factor Г.
Point 3: Line 51: Please define the abbreviation SMA before use.
Response 3: It has been modified to state that it is a shape memory alloy before mentioning SMA.
Point 4: Rationale of study: The rationale for needing greater energy storage density can be improved. Lines 67-69 hint that greater energy storage density can improve the jumping potential of the robot. However, the data in Table 3 shows otherwise. The jumping potential of the robot is multifactorial, where the limitations of low energy storage can be compensated with a combination of jumping mechanisms and less weight. A different argument for why greater energy storage density is advantageous could strengthen the manuscript.
Response 4: To better demonstrate the bouncing performance of the robots in this paper, we have introduced a reference factor Г in Table 3, which reflects the bouncing performance of the robot per unit weight. By comparing it with the representative bouncing robots in the table, we find that the Г value of the robots in this paper is high. Combined with the results of the energy storage density comparison, we can conclude that the robot in this paper has a high energy storage density and good bouncing performance.
Point 5: In-text Figure citations: Please do not provide a full caption while citing a figure within the paragraph. For eg. in Lines 80-81, only write Figure 1(a) or Figure 1(b) instead of a full caption. Please rectify it throughout the manuscript for other figures.
Response 5: I have deleted or replaced the text that was duplicated with the figure captions.
Point 6: Please make sure Figures 1 (a) & (b) do not have copyright issues. If so, please get the usage approval and provide the appropriate credit.
Response 6: I made sure that there would be no copyright issues with Figure 1(a) and that the citation was added after the title of Figure 1(b), so there would be no problems.
Point 7: Line 89: Do you mean wax “cicada” instead of “hopper”? Please verify.
Response 7: As the teacher said, it was a small error, "wax cicada", and I have fixed it.
Point 8: Line 100: Need reference for the claim that the pleural arch has higher energy storage capacity compared to muscle alone. Depending on the muscle volume and fiber orientation, the muscle alone can have a higher energy storage capacity in theory.
Response 8: Teacher, you are correct. Specifically, the muscular mechanism uses levers to make jumps, and this mechanism is suitable for animals with longer legs. However, the hind legs of an insect like the wax cicada are only 0.5 times the length of its body, so it uses a catapult mechanism to jump. This mechanism is short-lived but allows for greater jumping speed. In addition, the pleural arch is a structure capable of storing large amounts of energy. The words "such as muscle alone" after "single elastic element" are deleted here to avoid ambiguity.
Point 9: Lines 158-159: The phrase “a secondary reduction mechanism was introduced in this study” is repetitive in the sentence. Please update.
Response 9: Repeated semantic parts have been removed from the end of the sentence to avoid repetition.
Point 10: Equations (2) & (3): Please define what is Z4 in the equations.
Response 10: Fixed bug where Z4 did not exist because there were two gears with Z1 teeth.
Point 11: Section 2.5: The details seem repetitive with the information provided in Lines 138-154. Can club both these information into a single section.
Response 11: Teacher, this is what I was thinking of. Lines 138-154 focus on the bouncing principle of the robot, and there is an inaccuracy here, it should be "bouncing principle" instead of "bouncing mechanism". "After the explanation of the principle, a flow chart of the robot's bouncing motion is given in section 2.5.
Point 12: Figure 6: Please label L0 in the figure.
Response 12: I have marked and on the diagram.
Point 13: Should the “L” in equation (7) be replaced by “L0”? Similarly for the Lines 218 and 220.
Response 13: In response to two minor errors, I have replaced L in equation 7 and lines 218-220 with .
Point 14: Figure 7: Keeping the alphabet labeling convention the same as Figures 2 & 6 would provide consistency and will make the figure easier to follow.
Response 14: I have modified the format of the letter labels in Figure 7 so that they are similar to the previous figure.
Point 15: Figure 8: Looks like the Femur_Tibia curve is shifted between the numerical and simulation results. Any possibility of systemic error in calculations? Please verify.
Response 15: Certain problems arose when performing the calculations for the numerical methods. The modification has now been completed and the initial condition for is 88° so that the initial value of the interarticular angle between the femur and tibia is 144.6°. As the mathematical models and algorithms of the two methods are different, the results they obtain may have certain errors, which may come from a number of aspects such as modeling errors, calculation errors, and parameter errors of the system, so the joint angle curves derived by the two methods There will be a slight error in the joint angle curves obtained by the two methods. To make it easier for others to compare, I have combined the images of the data obtained by the two methods into a single graph in Figure 8.
Point 16: Experimental testing: How was the unique point of reference identified while calculating the vertical height and horizontal distance?
Response 16: Calculate the height and distance of the bounce based on the center of mass.
Point 17: Line 344: “better jumping performance”. How is the better jumping performance concluded? The proposed robot has 20 times more energy storage capacity than the compared robot. The difference in energy storage capacity is significantly greater than the difference in weight between the two robots. Shouldn’t the proposed robot also demonstrate a proportionately greater jump height and distance?
Response 17: The weight or load of the robot greatly affects the bouncing performance of the bouncing robot, so although the robot in this paper has a much larger energy store, it does not exhibit better bouncing height and distance than the Miniature jumping robot.
Point 18: In-text citation of reference 21 is missing in the manuscript.
Response 18: I found that reference 21 was not cited in this paper, which was a minor error. We have therefore removed it from the references.
Point 19: Some of the sentences in the manuscript are very long (eg. Lines 92-98, Lines 194-199, Lines 202-212, Lines 229-234). Please rewrite them into shorter sentences for better readability and maintaining the train of thought.
Response 19: To make some of the excessively long sentences in the text more concise and clear, I have broken them up into several short sentences.
In addition, in Figure 9 I lengthened the length of the ground in the simulation environment and replaced the original picture with another picture obtained that embodies the trajectory of the bouncing robot. This replacement had no effect on factors such as the bouncing performance of the robot but simply replaced it with a more embodied picture. In Table 3, to better represent the bouncing performance of the bouncing robot in this paper, I also present a reference factor Г based on the bouncing performance of the bouncing robot per unit weight.
In addition, I have uploaded the details of the changes I have made to your comments in the section below
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The authors have improved the paper according to the comments of the reviewers.
Please check two final points:
Point 1. There are still some references to figures that include the full caption in the text (figure 8).
Point 2. The authors again do not indicate the numerical method they used to solve the motion of the robot. They said that they use Lagrange. But Lagrange is a method to build the differential equation of motion of the robot, then you need to solve it with a numerical solver of differential equations (eg: Euler, Heun, Runge-Kutta...). Please indicate the solver used.
Author Response
Teacher, my amendments are as follows:
Point 1: There are still some references to figures that include the full caption in the text (figure 8).
Response 1: Teacher, I have fixed this using the track changes function to ensure that references in the text do not include the full figure name.
Point 2. The authors again do not indicate the numerical method they used to solve the motion of the robot. They said that they use Lagrange. But Lagrange is a method to build the differential equation of motion of the robot, then you need to solve it with a numerical solver of differential equations (eg: Euler, Heun, Runge-Kutta...). Please indicate the solver used.
Response 2: This paper uses the Runge-Kutta method for the numerical solution of the dynamic equations and has been completed in the paper as a supplement.
Author Response File: Author Response.docx
