Optimization of Fuzzy Logic Controller Used for a Differential Drive Wheeled Mobile Robot
Round 1
Reviewer 1 Report
- Interesting research in an excellently prepared manuscript that needs some mild revisions.
- Abstract is okay but is not likely to entice the readership to continue reading the rest of the manuscript.
- Results are only presented in weak, qualitative fashion. Highest quality expression of main conclusions or interpretations is quantitative results discussed in the broadest context possible, e.g., percent performance improvement compared to a declared benchmark. “…optimized controller is significantly better…” is very weakly stated results compared to “…xxx percent performance improvement over conventional methods was achieved….”
- Introduction is decently done with some omitted very recent literature and some mild abuse of multi-citation without elaboration.
- Please elaborate a reason for the reader to investigate each of the cited references for motion control of mobile robots [4,5,7,12,13].
- Optimal robot whiplash compensation was omitted from the literature review as a competing alternative that uses Pontryagin’s minimization of Hamiltonian systems to derive controls that account for interaction with structural dynamics.
- Deterministic artificial intelligence (as recently applied to unmanned underwater vehicles and DC motors) stemming from the same cited nonlinear adaptive control lineage was omitted as a competing alternative: https://doi.org/10.3390/jmse8080578.
- Please elaborate a reason for the reader to investigate each of the quintuple cited references [19-23].
- Great rationales were provided for the reader to seek each of the septuple cited references [24-30].
- Equations are scientifically sound and well presented, enhancing the manuscript quality.
- Figures are excellent with some mandatory improvements to ensure the readership has access to the content.
- Internal font size is frequently illegibly small. Please notice the smallest font size permissible in the manuscript template (to ensure legibility by the reader) is the figure caption which provides a conveniently proximal prototype for sizing figures. Please re-compare each figures’ internal font (especially legends and abscissa and ordinate texts) and increase font sizes to no-smaller than the figure captions. While making that correction, normalizing the font to the manuscript standard Palatino Linotype will increase the professionalism of the manuscript further (it is already very professionally presented).
- Line styles and sizes are identical in some data lines in most figures rendering the disparate data indistinguishable when the manuscript is read in printed hardcopy (particularly in black and white) negating the value of the figures. Please modify line sizes/thickness in duplicated line styles of figure 12,14 to ensure legibility. Please modify line styles and sizes/thicknesses in figure 13 to ensure legibility.
- Tables are excellent to introduce problem formation (aiding repeatability) and present quantitative results.
- The discussion of results is very weakly presented, negating so much wonder research by hiding it rather than highlighting it in an fashion that is easy for the readers to discern. Section 4.1 presented so very much wonderful quantitative results, but no broadly stated summary was provided in the discussion of conclusions (nor the abstract), e.g. “52% reduction of energy consumption was achieved using the proposed method compared to the best of seven alternatives studied.” The current assertion of results includes qualitative statements (e.g. “…significantly worse…”) and exact quantitative statements that might mean very little to the novice reader (e.g. “…E = 30.29 J, s = 49.47 m…”). Please consider adding broadly stated results as suggested to section 4.2 and to the abstract’s final sentence.
- Inclusion of the appendix is requested with variable and acronym definitions.
The reviewer's private comments to the Editor follow:
Excellent, excellent work in a well prepared manuscript. Some improvements are needed: 1) results are masked from the reader by omission of broadly stated figures of merit, 2) literature review is weak and poorly done in some places, very well done in others. 3) figures are likely illegible to readers of printed hardcopies.
Following these minor revisions, this scientifically sound research should be published.
Author Response
Dear reviewer
We thank you very much for your careful reading of our manuscript. Also thanks for all your useful comments.
According to your comments, we have uploaded a file of point-by-point responses to your comments. We hope that our answer will satisfy your comments.
Best regards.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments to the authors
Manuscript ID: applsci-1263139
Title: Optimization of Fuzzy Logic Controller Used for a Differential Drive Wheeled Mobile Robot
1) Consider explaining how the robot determines the waypoints in Figure 1. Are they given by a supervisory controller?
2) How parameters in Table 1 and Table 2 are determined.
3) According to Table 3 and 4, Delta_D has no impact on the determined action, if Delta_theta is BN, N, P, or BP. This point needs to be justified and explained in detail.
4) Why are triangular membership function selected for the considered problem? Justify.
5) Robustness of the developed FL controller is a very important issue that should be addressed. Take a look at 10.1109/FUZZY.2011.6007344 and 10.1016/j.cnsns.2019.104953, and other relevant work, and discuss this issue (maybe as a remark or future work, if not addressed in the current work).
6) Blue line in Figure 12 (d) show catastrophic fluctuation. What is the reason for that?
7) According to Figure 12, although the developed controller uses less energy, it does not yield the best performance (figure (b)). This raises the natural question: is it ok to hamper performance for the sake of energy consumption? Provide some examples that this attitude is plausible.
Author Response
Dear reviewer
We thank you very much for your careful reading of our manuscript. Also thanks for all your useful comments.
According to your comments, we have uploaded a file of point-by-point responses to your comments. We hope that our answer will satisfy your comments.
Best regards.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
No further comment.
