Design and Experiment of Header Height Adaptive Adjustment System for Maize (Zea mays L.) Harvester

Round 1

Reviewer 1 Report

The manuscript primary focus on the problem of poor control precision of corn harvester header height adjustment in Northeast China. It is well known that the adaptive adjustment of header height is a specific and realistic problem. Based on the summarization, analysis of many aspects in the world, an adaptive adjustment system of corn harvester header is designed. This manuscript has certain reference value for the relevant researchers.

However, on the whole, it is not discussed in depth from the technical frontier, method innovation and practical application. The best way, I think, there are some aspects throughout the manuscript needed to be improved:

First, What impresses me most is the lack of innovation of this manuscript. It mainly designed the pressure-wheel profiling device, the microcontroller as the controller and the use of PID algorithm for cutting height adjustment. But both the structural design of the pressure-wheel profiling device and the PID control algorithm, I don't think they're innovative.

Second, It merely lists references that are similar to this manuscript, without criticizing previous research and pointing out unresolved issues. It is only in the case of objective evaluation that it is possible to determine the value of the results presented by the authors in this article.

Third, All of the images in the paper are not clear for the reader to understand the content of the article. Moreover, in the 2.3.3 summary, the simulation diagram is too ideal.

Fourth, the model parameters of key components in the system, such as the specific model of single chip microcomputer, the specific parameters of solenoid valve and the specific parameters of pressure sensor, are not detailed, so it is impossible to make a comprehensive and objective evaluation of the system.

Fifth, In terms of details of the research, what puzzles me is that the diameter of the pressure wheel in a press wheel profiling device was 110 mm, and the device was mounted vertically on the ground. Can the wheel rotate in contact with the ground during field operations? Can it eliminate the entanglement of weeds in the field? Can it resist the impact of the forward movement of the harvester?

Sixth, In the test analysis, most of domestic standards and test methods were cited. Here's what readers need to know, is it more convincing to adopt international standards? Meanwhile, the factors in the data analysis are too single, which is not conducive to the analysis of the reliability and stability of this system.

Last one, in the conclusion section, it should summarize the full text and corresponding experimental data. At the same time, even the best research has some limitations. Acknowledging these limitations is important to prove the credibility of the paper.

 In conclusion, I don't think that the manuscript has met the requirements for publication. The authors should made more in-depth modification and improvement for this manuscript.

 

Moderate editing of English language required

Author Response

Response to Reviewer 1 Comments

 

Point 1: What impresses me most is the lack of innovation of this manuscript. It mainly designed the pressure-wheel profiling device, the microcontroller as the controller and the use of PID algorithm for cutting height adjustment. But both the structural design of the pressure-wheel profiling device and the PID control algorithm, I don't think they're innovative.

 

Response 1: Many thanks to the reviewers for their valuable comments. Provide an explanation for this comment made by the reviewer: In the current research field of Chinese agricultural maize harvesting equipment, many universities and well-known agricultural machinery enterprises have not made a study on the automatic adjustment of header height in maize harvester for ridged crops in Northeast China. In this paper, the design of the automatic header height adjustment system aims to fill the technical gap of automatic header height adjustment for corn harvester in ridge crop. Therefore, the innovation of this study lies in the application of the whole system rather than the specific components within the system.

 

Point 2: It merely lists references that are similar to this manuscript, without criticizing previous research and pointing out unresolved issues. It is only in the case of objective evaluation that it is possible to determine the value of the results presented by the authors in this article.

 

Response 2: We thank the reviewers for their professional comments. The issue raised by the reviewers has been revised in introduction.

 

Point 3: All of the images in the paper are not clear for the reader to understand the content of the article. Moreover, in the 2.3.3 summary, the simulation diagram is too ideal.

 

Response 3: ①Based on the reviewers' comments, the authors reworked the images in manuscript.

②The purpose of the simulation conducted by the authors in Subsection 2.3.3 is to quickly obtain the theoretical PID optimal control parameters and to conduct a field test with the parameters obtained from simulation. The results and discussion of the field test are in section 3 of the paper, and the results of the test are able to meet the requirements of harvester operation.

 

Point 4: The model parameters of key components in the system, such as the specific model of single chip microcomputer, the specific parameters of solenoid valve and the specific parameters of pressure sensor, are not detailed, so it is impossible to make a comprehensive and objective evaluation of the system.

 

Response 4: According to the reviewer's comments, the authors have listed the model parameters of the key components of the system (microcontroller, pressure sensors, solenoid valves, linear displacement sensors and hydraulic cylinders) have been detailed, as shown in Table 1 in the manuscript.

Table 1. Instrument technical details.

Instrument	Type	Manufacturer	Range	Accuracy
Microcontroller	STM32F4072G	Guangzhou Starwing Electronic Technology Co., Ltd, Guangzhou City, Guangdong Province, China	/	/
Pressure Sensor	JHBM-H1	Bengbu Jinnuo Sensor Co., Ltd, Bengbu, Anhui Province, China	0~3000N	±10N
Solenoid-directed valve	4WE6F61B/CG24N9Z5L	Beijing Huade Hydraulic Industry Group Limited Liability Company, Beijing, China	0~31.5Mpa	0.1 Mpa
Displacement Sensor	KTR-200	Shenzhen Hongmai Technology Co., Ltd, Shenzhen, China	0~200mm	0.01mm
Hydraulic cylinder	40-25-150	Shandong Hengdingsheng Hydraulic Machinery Co., Ltd, Linyi City, Shandong Province, China	0~150mm	/

 

Point 5: In terms of details of the research, what puzzles me is that the diameter of the pressure wheel in a press wheel profiling device was 110 mm, and the device was mounted vertically on the ground. Can the wheel rotate in contact with the ground during field operations? Can it eliminate the entanglement of weeds in the field? Can it resist the impact of the forward movement of the harvester?

 

Response 5: Thank the reviewers for their valuable comments. Some explanations are made for the reviewers’ comments :

①The pressure-wheel profiling device travels on the ridges with a standard size of 290 mm for the northeast ridges. The maximum diameter of profiling device is 160 mm, taking into account the width of the link bearing, the width of pressure-wheel is 100 mm. Taking into consideration of the height of ditch and ridge, the pressure-wheel width, the length of pressure regulating spring, the thickness of pressure sensor and the size of the other connecting parts in device, the diameter of pressure-wheel was set at 110mm.

②Prior to carrying out the text studies in this paper, the team did passability tests on the pressure-wheel profiling device. The header height was adjusted to the lowest (at this time, the amount of regulating spring deformation was the largest, and the pressure sensor was subjected to the greatest force), and the 4YZL-2 crawler maize harvester was traveling at the maximum speed (2.2m/s). The impact force generated by the pressure sensor due to the terrain change could be up to 1490N, which meets the working range of the pressure sensor. The effect of passability test shows that, during the device traveling, the pressure wheel is not blocked, entangled grass and other phenomena, and the passability is well. Due to the limited length of manuscript, the authors used the passability tests of profiling device as a behind-the-scenes support.

 

Point 6: In the test analysis, most of domestic standards and test methods were cited. Here's what readers need to know, is it more convincing to adopt international standards? Meanwhile, the factors in the data analysis are too single, which is not conducive to the analysis of the reliability and stability of this system.

 

Response 6: Provide a few explanations in response to the comments made by the reviewers:
①Different countries and regions have different corn cultivation patterns, so they have different operational requirements for corn harvester cutters. This study aims to improve the performance of corn harvester cutter for ridged crop in northeast China, so domestic standards are used to judge the performance of the system.

②After reviewing more literature on harvester header, the authors found that the test method used in manuscript is widely used in numerous literature(1-5, etc.), so the method used in this paper is a more mature test method and is more convincing.

（1.Geng, A.; Zhang, M.; Zhang, J.; Zhang, Z.; Gao, A.; Zheng, J., Design and Experiment of Automatic Control System for Corn Header Height. Trans. CSAM. 2020, 51(s2), 118-125.

2.Gong, Y.; Jin, Z.; Bai, X.; Wang, S.; Wu, L.; Huang, W., Design and Experiment of Servo Control System for Sugarcane Header. Trans. CSAM. 2023, 54(2), 119-128.

3.Liao, Y.; Xiang, Y.; Wu, M.; Liu, D.; Cheng, Y.; Li, Y., Design and Test of the Adaptive Height Adjustment System for Header of the Combine–harvester. Journal of Hunan Agricultural University 2018, 44, (3), 326-329.

4.Ni, Y.; Jin, C.; Chen, M.; Yuan, W.; Qian, Z., Computational Model and Adjustment System of Header Height of Soybean Harvesters Based on Soil-machine System. Computers and Electronics in Agriculture 2021, 183, 105907

5.Geng, D.; Sun, Y.; Li, H.; Mou, X.; Zhang, G.; Wang, Z.; Lu, X., Design and experiment of crawler corn harvester for sloping fields. Trans. CSAE. 2021, 37(13), 11-19.）

③Thank the reviewers for their comments. Upon the reviewer's nudging, the authors reanalyzed the effects of harvester different forward speeds (1.25, 1.45, 1.65, 1.85, and 2.05 m/s) and different operating modes (open and unopened system) on the test indexes(Errors in the automatic adjustment of header height, Cob loss rate, Coefficient of variation in stubble height) in order to objectively evaluate the reliability and stability of the designed cutter-height adaptive adjustment system.

 

Point 7: In the conclusion section, it should summarize the full text and corresponding experimental data. At the same time, even the best research has some limitations. Acknowledging these limitations is important to prove the credibility of the paper.

 

Response 7: Thanks to the reviewers for their guidance. The authors have reworked the conclusion section of the article as requested by the reviewers.

Author Response File: Author Response.docx

Reviewer 2 Report

Stick picking is a key component of the ear picking device of a corn harvester. Therefore, it is very important to study the relationship between the movement state of corn stalks between pick sticks and the structure and movement parameters of ear picking. Please revise the MS on the basis of this.

Through the optimized design of the header system, the harvest height of the header is reduced, and the adaptability of the corn harvester to late ear droop and straw lodging is improved. Include this observation in the present MS.

At the same time, on the basis of the existing grain combine harvester, through the research of the general technology of different crop headers, corn is harvested, and the versatility of the harvesting machine is realized. Elaborate on this at the end.

I

 

 

Quality of English is fine

Author Response

Response to Reviewer 2 Comments

 

Point 1: Stick picking is a key component of the ear picking device of a corn harvester. Therefore, it is very important to study the relationship between the movement state of corn stalks between pick sticks and the structure and movement parameters of ear picking. Please revise the MS on the basis of this.

 

Response 1: Thank the reviewers for their valuable comments. As mentioned by the reviewers, the tassel picking roller is a key component of the tassel picking device in a maize harvester, and the study of the relationship between the corn stalk motion state and the tassel picking structure and motion parameters is also extremely important to improve the maize harvesting quality. However, it should be pointed out that the purpose of this study is to solve the technical gap of automatic adjustment of header height in maize harvester for ridged crop in Northeast China. In the course of this study, the aim of this research is to clarify the design and experimental effect of the height adjustment system of the cutting deck of the corn harvester for row crops. The focus of this article is to realize the automatic adjustment of the operating height of the corn harvester for row crops through the height adjustment system. All the authors of this paper accepted the reviewer's valuable suggestion of "studying the relationship between the movement state of corn stalks between pick sticks and the structure and movement parameters of ear picking" as the focus of next phase research in our team, and included this plan in conclusion.

 

Point 2: Through the optimized design of the header system, the harvest height of the header is reduced, and the adaptability of the corn harvester to late ear droop and straw lodging is improved. Include this observation in the present MS.

 

Response 2: Thank the reviewers for their valuable comments. Explanation of the reviewer's comments: In the pilot study, the authors compared the maize cob loss rates at different forward speeds of harvester and in different operating modes to validate the performance of header height adjustment system. However, when maize stalks fall over, the cobs are susceptible to being covered or crushed, resulting in increased cob loss rates. Measurements of maize cob loss rate indirectly indicate that the designed header height adjustment system is ameliorative to stover fall. In response to the comment, the authors added the following to conclusion:

“The average coefficient of variation in stubble height was lowered by 34.44%, which can effectively improve the maize harvesting quality and enhance the adaptability of header to fallen corn.”

 

Point 3: At the same time, on the basis of the existing grain combine harvester, through the research of the general technology of different crop headers, corn is harvested, and the versatility of the harvesting machine is realized. Elaborate on this at the end.

 

Response 3: Explanation of the reviewer's comments: Our team has technical cooperation with Changchun Jixin Agricultural Equipment Co., Ltd. so the authors first considered the 4YZL-2 crawler maize harvester (produced by Changchun Jixin Agricultural Equipment Co., Ltd.) when investigating the operational performance of header height adaptive adjustment system and the pressure-wheel profiling device. The authors accept the reviewer's comments, and the team plans to explore the performance of header height adaptive adjustment system on different models of harvesters in the next stage to evaluate the versatility of the system. The authors include this plan in conclusion.

Author Response File: Author Response.docx

Reviewer 3 Report

 

In this manuscript, a header height adaptive adjustment system that works well for harvesting ridge crop corn is constructed and assessed. It has good header height adjustment performance. This work by the authors closes a gap in maize harvester for ridge crop header height automated adjustment and serves as a guide for the maize harvester automation design for ridge crop. My opinion is that the work is suited to be published on Sustainability. Nevertheless, the authors should make further efforts to improve the manuscript, working in the following directions:

1. Some sentences in the manuscript are too long, please re-simplify the expression.

2. The expression of the nominative case is incorrect in a few words in the text. For instance, " the hydraulic cylinder's expansion and contraction " uses  " of " to refer to an object and " 's " to refer to a person. The authors are asked to review and edit the entire text for any issues that are similar.

3. The writers occasionally use the term "pressure-wheel," and "press-wheel" in the abstract, main text, and conclusion of the manuscript. For instance, "pressure-wheel" is used in both the title 2.3.1 and the first line of the first paragraph. It is expected of the authors to use consistent language throughout the entire document.

4. Since parameter k already represented the stiffness coefficient in Section 2.2.2 of the manuscript, it cannot be used to express the Angle in that section again; instead, the author should re-express the Angle.

5. The pressure-wheel profiling device created in this paper relies heavily on the pressure sensor. It is important to explain how the pressure sensor was chosen.

6. The author assessed the soil firmness of the ridge furrow in the experimental field in order to estimate the parameters in formula 9. Soil is what kind of soil? And at the moment of measurement, how moist is the soil? Please provide more details.

7. Please fix line 418 where the author said that the area of the chosen test plot is 2.6m× 2.6m. Figure 13a, however, reveals that the plot area is 1.3m×1.3m.

8. Why was "stubble height variation coefficient" selected as the assessment metric that can be used to interpret how well the control system is working? Please elaborate.

 

Author Response

Response to Reviewer 3 Comments

 

Point 1: Some sentences in the manuscript are too long, please re-simplify the expression.

 

Response 1: Thanks to the reviewers for their valuable comments. The authors have streamlined the long sentences throughout.

 

Point 2: The expression of the nominative case is incorrect in a few words in the text. For instance, " the hydraulic cylinder's expansion and contraction " uses  " of " to refer to an object and " 's " to refer to a person. The authors are asked to review and edit the entire text for any issues that are similar.

 

Response 2: The author has revised the improperly used noun possessive throughout.

 

Point 3: The writers occasionally use the term "pressure-wheel," and "press-wheel" in the abstract, main text, and conclusion of the manuscript. For instance, "pressure-wheel" is used in both the title 2.3.1 and the first line of the first paragraph. It is expected of the authors to use consistent language throughout the entire document.

 

Response 3: The author has revised the manuscript throughout, replacing "press-wheel" with "pressure-wheel".

 

Point 4: Since parameter k already represented the stiffness coefficient in Section 2.2.2 of the manuscript, it cannot be used to express the Angle in that section again; instead, the author should re-express the Angle.

 

Response 4: Thanks to the reviewers for their guidance. In the manuscript, the letter k was used to express both the spring stiffness coefficient and the position angle, which was overlooked by the authors in the process of writing. The parameter "k" has been replaced by "θ", and Fig. 6 and Eqs. 10-12 in the manuscript have been revised.

 

Point 5: The pressure-wheel profiling device created in this paper relies heavily on the pressure sensor. It is important to explain how the pressure sensor was chosen.

 

Response 5: A description of the contents of the selected pressure sensor has been added to the manuscript, and the specific parameters of the pressure sensor have been added in Table 1.

 

Point 6: The author assessed the soil firmness of the ridge furrow in the experimental field in order to estimate the parameters in formula 9. Soil is what kind of soil? And at the moment of measurement, how moist is the soil? Please provide more details.

 

Response 6: The authors have added the soil physical and chemical properties of the test site in Table 2.

Table 2. Soil physical and chemical properties.

Targets	Value
(Depth 0~100mm) Average soil moisture content/%	16.49
(Depth 0~50mm) Average soil firmness/kPa	126.7
(Depth 0~50mm) Soil capacity/(g·cm-3)	1.17
Soil composition/%	12.68(Viscous particles), 64.15(Powder particles), 23.17(Sand particles)
PH-value	7.04
Organic matter content/%	2.53

 

Point 7: Please fix line 418 where the author said that the area of the chosen test plot is 2.6m× 2.6m. Figure 13a, however, reveals that the plot area is 1.3m×1.3m.

 

Response 7: Thanks to the reviewers for their guidance. The authors would like to express that the selected test area measures 1.3m x 1.3m and that the manuscript has been corrected.

 

Point 8: Why was "stubble height variation coefficient" selected as the assessment metric that can be used to interpret how well the control system is working? Please elaborate.

 

Response 8: The straw return device of the ridge crop maize harvester studied in this manuscript is mounted under the header. The stability of header height affects the maize stubble height when the harvester is operating on sloping land in a ridge crop. The operator observes the terrain changes with the naked eye and manually adjusts the header height, which has a large adjustment error and increases the coefficient of variation of stubble height. The adaptive adjustment system of header height in this study can be real-time monitoring of monopoly platform height changes and timely management of the hydraulic adjustment mechanism to modify the header height. The distance between the center of the moveable knife roller of the straw returning device and the ridge platform is also steady when the operational header height is kept constant, which lowers the error of the height of the straw stubble. Therefore, "coefficient of variation in stubble height" was selected as an assessment index to evaluate the performance of system.

Author Response File: Author Response.docx