Laboratory Test of a Vehicle Active Noise-Control System Based on an Adaptive Step Size Algorithm
Round 1
Reviewer 1 Report
This work presents: an adaptive step size FxLMS algorithm (AASFxLMS) and an adaptive step size FxLMS algorithm (AASFxLMSPSO) with particle swarm optimization. The paper is well written and all the steps from modeling, simulation and experiments are contained. The experiments seem to support the proposed algorithms. To improve the quality of the paper, some remarks are made.
- all the acronyms need to be explained even this are very common for the authors (eg NVH...)
-all the terms/factors in the equations need to be presented eg. eq.7
- for eq. 8 if possible explain the reason for this choice to adjust step size parameters, and the variable step size factor
- some editing errors appear in the paper and need attention (caps, index size, row224..., a 128 length FIR filter? )
- the format may be improved (eg. left-right justify ...)
- eq. 20 need correction
- in the analysis simulation why this values were chosen for α?
- fig.13 is not mandatory, I think that the block diagram is enough clear
-Is it really a real-time experiment (4) or is it only the noise? I see that the experiment is made off-line using real input signal. The title of 4th chapter should be changed into something more appropriate.
Author Response
Point 1: all the acronyms need to be explained even this are very common for the authors (eg NVH...)
Response 1: As requested by the reviewer we have explained the acronyms (lines 10 and 14).
Point 2: all the terms/factors in the equations need to be presented eg. eq.7
Response 2: As requested by the reviewer we give an explanation of the factors of equation 7
Point 3: for eq. 8 if possible explain the reason for this choice to adjust step size parameters, and the variable step size factor
Response 3: As suggested by the reviewer we explain the reason for adjusting the step size parameter in equation 8.
Point 4: some editing errors appear in the paper and need attention (caps, index size, row224..., a 128 length FIR filter? )
Response 4: The reviewer correctly noted that our language editing errors. Therefore, We have corrected the editing errors in the article, such as rows 257-259.
Point 5: the format may be improved (eg. left-right justify ...)
Response 5: As suggested by the reviewer we changed the formatting of the paragraphs of the article to left-right justify.
Point 6: eq. 20 need correction
Response 6: The reviewer correctly pointed out the error in equation 20, therefore, we changed equation 20.
Point 7: in the analysis simulation why this values were chosen for α?
Response 7: The value of α refers to the value of three kinds of impulse noise in the reference. And it is explained in lines 263-265 of the article.
Point 8: fig.13 is not mandatory, I think that the block diagram is enough clear
Response 8: The illustrated experimental platform is conducive to readers' understanding and reference, so it is included in the paper.
Point 9: Is it really a real-time experiment (4) or is it only the noise? I see that the experiment is made off-line using real input signal. The title of 4th chapter should be changed into something more appropriate.
Response 9: We've changed the title of chapter four to "Laboratory Experiments”.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Manuscript ID: applsci-2047590
Title: Vehicle Active Noise Control System Based on Adaptive Step Size Adaptive Algorithm
Reviewer Report
In this paper, an adaptive step size FxLMS algorithm (AASFxLMS) and an adaptive step size FxLMS algorithm (AASFxLMSPSO) with particle swarm optimization are proposed. Inorder15 to improve the performance of the algorithm, the particle swarm optimization algorithmisalso16 used to automatically adjust the parameters, so that the step size of the adaptive algorithmalways17 keeps a relatively ideal size. The simulated pulse noise of standard SαS distributionwasusedas18 reference signal for simulation, simulation results show that compared with other algorithms, the19 proposed algorithm under different degrees of pulse noise conditions, noise reductionstability20 and noise reduction amplitude are improved. Overall, the paper has innovation and significant contributions.
There is a minor revision in the paper.
1. The section of introduction is extremely limited; the author should improve it by adding references i.e.
v “Nonlinear modified positive position feedback control of a cantilever beam system carrying an intermediate lumped mass”, Alexandria Engineering Journal (2020) Vol. 59(5), pp. 3847–3862.
v “Stability and bifurcation analysis of a buckled beam via active control”, Applied Mathematical Modelling, Volume 82, (2020), pp. 649-665.
Recommendation: Accepted after minor revision as suggested above.
Author Response
Point 1: The section of introduction is extremely limited; the author should improve it by adding references i.e.
v “Nonlinear modified positive position feedback control of a cantilever beam system carrying an intermediate lumped mass”, Alexandria Engineering Journal (2020) Vol. 59(5), pp. 3847–3862.
v “Stability and bifurcation analysis of a buckled beam via active control”, Applied Mathematical Modelling, Volume 82, (2020), pp. 649-665.
Response 1: We have added references to the article, like lines 114-123.
Author Response File: Author Response.docx
Reviewer 3 Report
This manuscript proposes an “adaptive step size adaptive algorithm (ASSFxLMS)” to attenuate airborne noise due to car passage on bumps. The algorithm is complemented with a particle swarm optimization to automatically adjust some parameters.
The subject addressed by the authors is worthy of investigation and the manuscript reports an interesting preliminary work, even if it is not so original. Basically, it assemblies methods and techniques already seen in the literature - correctly cited by the authors - in a proof-of-concept of an ANC prototype tested in the lab.
However, there are some issues that must be fixed before the manuscript be accepted for publication. More details are given below.
The title and also the abstract are partially misleading. In fact, what is presented here is a purely laboratory test of the proposed algorithm; no tests have been done placing the system on a running car. Therefore, the title should be changed, e.g., like:
“Laboratory test of a Vehicle Active Noise Control System Based on Adaptive Step Size Adaptive Algorithm”
The abstract should be more explicit, too.
I do not agree that “NVH is the core performance of vehicles” as written in the Abstract. the core performance of vehicles is their ability to run efficiently giving the maximum safety and comfort to passengers. NVH is one key aspect of comfort.
Eq. (20) is wrong; Ae(n)/Ae(n) does not make sense. Please correct.
The sentence “Given particle movement ranges lima=[0.001,0.01] and limc=[0.02,0.1]” (line 260) is unclear for the general reader. I suggest to use a better notation for the limits of “a” and “c”.
Th title of section 4 “Real-time experiment” is not correct, because it is about a laboratory experiment (see figure 13) carried out using RECORDINGS of interior noise of a car running over bumps. The experiment will be real-time when the hardware will work mounted on a car running on the road.
In section 4, noise reduction effect of 10 dB and even more are presented at some definite frequency; however, this reduction is achieved in a very narrow band only; how is the real benefit in terms of the overall noise level?
Moreover, how narrow is this narrow band, i.e.: which is the frequency resolution of the figures 14-17?
In the “Discussion and Conclusion” section, it should be remarked that what is presented here is just a proof-of-concept in the lab. The necessary future development is a test on a car running over bumps.
Moreover: “Discussion and Conclusion” is section 5 not section 4.
The English/technical language needs to be improved. There are many little flaws, like:
- missing full stops, e.g.: “The simulated pulse noise of standard SαS distribution was used as reference signal for simulation, simulation results show that…” in Abstract lines 17-18.
- Unusual terms, e.g.: “The principle of active noise reduction is to form a quiet area in local space through the superposition of two columns of opposite waves…” Columns?? (Lines 40-41).
- “Finally, the fifth section makes the conclusion of the thesis”. Thesis?? This is an article (lines 124-125).
- Swapping between uppercase and lowercase letters: “A. Kinoshita et al. [6] developed A prototype ANC system…” instead of “…developed a prototype ANC system…” (lines 43-44); “FXLMS algorithm” instead of “FxLMS algorithm” (several times throughout the text); “simulink” instead of “Simulink” (line 79); etc.
- Grammar errors: “…the amplitude of the filter weight coefficient change too large due to the sudden increase of the reference signal” (lines 165-166). Probably it is “… change to much…”.
- Typos: “Vehicle internal noise acquisitionn” (line 316).
- Etc etc.
Please revise the English/technical language.
In conclusion, in my opinion this work cannot be accepted as it is; a major revision to fix the above issues is needed.
Author Response
Point 1: The title and also the abstract are partially misleading. In fact, what is presented here is a purely laboratory test of the proposed algorithm; no tests have been done placing the system on a running car. Therefore, the title should be changed, e.g., like:
“Laboratory test of a Vehicle Active Noise Control System Based on Adaptive Step Size Adaptive Algorithm”
The abstract should be more explicit, too.
Response 1: As requested by the reviewer we changed the title to “Laboratory test of a Vehicle Active Noise Control System Based on Adaptive Step Size Adaptive Algorithm”. In addition, it was clearly stated in the abstract that experiments were done in the laboratory(line 25).
Point 2: I do not agree that “NVH is the core performance of vehicles” as written in the Abstract. the core performance of vehicles is their ability to run efficiently giving the maximum safety and comfort to passengers. NVH is one key aspect of comfort.
Response 2: As requested by the reviewer we changed “NVH is the core performance of vehicles” to “NVH(Noise,Vibration,Harshness) is a key factor affecting vehicle comfort”.
Point 3: Eq. (20) is wrong; Ae(n)/Ae(n) does not make sense. Please correct.
Response 3: The reviewer correctly pointed out the error in eq.(20), therefore, we corrected eq. (20). We changed “Ae(n)/Ae(n)” to “Ae(n)/Ad(n)”.
Point 4: The sentence “Given particle movement ranges lima=[0.001,0.01] and limc=[0.02,0.1]” (line 260) is unclear for the general reader. I suggest to use a better notation for the limits of “a” and “c”.
Response 4: As suggested by the reviewer we use “alimt” and “climt” for the limits of “a” and “a”(line 277) .
Point 5: The title of section 4 “Real-time experiment” is not correct, because it is about a laboratory experiment (see figure 13) carried out using RECORDINGS of interior noise of a car running over bumps. The experiment will be real-time when the hardware will work mounted on a car running on the road.
Response 5: As suggested by the reviewer we've changed the title of section 4 to "Laboratory Experiments”.
Point 6: In section 4, noise reduction effect of 10 dB and even more are presented at some definite frequency; however, this reduction is achieved in a very narrow band only; how is the real benefit in terms of the overall noise level?
Moreover, how narrow is this narrow band, i.e.: which is the frequency resolution of the figures 14-17?
Response 6: We add the numerical value of the total noise reduction as the benefit of the overall noise level in the paper (lines 388-389, 406-407, 422-423 and 437-438). And added its calculation formula, such as eq.(20). The frequency resolution in figures 14-17 is 0.1 and is added in the text(lines374-375).
Point 7: In the “Discussion and Conclusion” section, it should be remarked that what is presented here is just a proof-of-concept in the lab. The necessary future development is a test on a car running over bumps.
Moreover: “Discussion and Conclusion” is section 5 not section 4.
Response 7: As suggested by the reviewer we added to the discussion and conclusion "In this paper, the noise reduction effect of the proposed algorithm is verified only in the laboratory. The necessary future development is a test on a car running over bumps”(lines 459-461).
Point 8: The English/technical language needs to be improved. There are many little flaws, like:
- missing full stops, e.g.: “The simulated pulse noise of standard SαS distribution was used as reference signal for simulation, simulation results show that…” in Abstract lines 17-18.
- Unusual terms, e.g.: “The principle of active noise reduction is to form a quiet area in local space through the superposition of two columns of opposite waves…” Columns?? (Lines 40-41).
- “Finally, the fifth section makes the conclusion of the thesis”. Thesis?? This is an article (lines 124-125).
- Swapping between uppercase and lowercase letters: “A. Kinoshita et al. [6] developed A prototype ANC system…” instead of “…developed a prototype ANC system…” (lines 43-44); “FXLMS algorithm” instead of “FxLMS algorithm” (several times throughout the text); “simulink” instead of “Simulink” (line 79); etc.
- Grammar errors: “…the amplitude of the filter weight coefficient change too large due to the sudden increase of the reference signal” (lines 165-166). Probably it is “… change to much…”.
- Typos: “Vehicle internal noise acquisitionn” (line 316).
- Etc etc.
Please revise the English/technical language.
Response 8: The reviewer correctly pointed out some English/technical language problems in the paper, for which we modified the technical language in the paper, like:
- The missing full stop was added in line 21.
- Deleted "columns of" in line 43.
- In line 137, replace "thesis" with" article".
- In line 47 of the text, "A" is changed to "a". In addition, in lines 57,92,101,102,107,109 and 290, replace "X" as in FXLMS with" x". Then, in line 82, change "simulink" to "Simulink".
- In line 178 of the text "... change to lagre..." Change "large" to "much".
- Remove the last letter 'n' in 'acquisitionn' in line 333 of the text.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
This manuscript is submitted for the second round of review. It is about an “adaptive step size adaptive algorithm (ASSFxLMS)” to attenuate airborne noise due to car passage on bumps. The algorithm is complemented with a particle swarm optimization to automatically adjust some parameters.
All the comments raised by this reviewer –not repeated here - have been addressed in the revised manuscript.
Therefore, the revised manuscript is acceptable for publication.
There are only two minor issues, that can be corrected in the production stage:
1. In section 4, the numerical values of the total noise reduction in dB (see comments to figures 14-17) should be expressed with one decimal digit only; nobody has the precision to check the second or third digit after the decimal point.
2. The symbol of Hertz (unit of frequency) is “Hz” not “HZ”.
In conclusion, in my opinion this work can now proceed to publication.
