Experimental Design and Validation of an Adjustable Straw Guide Structure for a Grain Combine Harvester Thresher Based on a Material Movement Model

Round 1

Reviewer 1 Report

This paper studies the DOE (design of experiments) of drum rotation speed, operating speed, and spiral angle of straw guide board through response surface method for PBR (percentage of broken rate),  PLR (percentage of loss rate),  and PIR (percentage of impurities rate). The effects of different parameters were analyzed and the optimized parameters were found (drum rotation speed 550 r/min, operating speed 3 km/h, and spiral angle of straw guide board 28° ) for the low PBR, PLR, and PIR.  In addition, the range of the spiral angle of the straw guide board was calculated theoretically with different friction coefficients for different humidity conditions. It is good to see this paper investigate the effect of the spiral angle of straw guide board with adjustable straw guide structure and its interactions with drum rotation speed and operating speed.

However, some critical information should be stated clearly so that the contribution of this paper is easier to be identified.

For overall recommendation, this paper will be good to be published with proper revisions.

My detailed questions/comments/suggestions on the content:

1. In abstract line 17, it is claimed that “an adjustable straw guide board was designed……”. Then in the introduction line 95, it is claimed that “To this end, we have designed a new type of ……”. However, in line 2.2 lines 135-136, it is mentioned that “The 4LZ-4.0 harvester in this study adopts a new type of threshing device with adjustable straw guide structure……”, which looks like the adjustable straw guide is designed and adopted by the harvester vendor, not by the author of this paper. As a result, the conflict descriptions make whether the adjustable straw guide is one of the contributions of this paper not clear.
   
   Therefore, please state clearly whether the author designed the adjustable straw guide or the harvester vendor did it, and whether designing the adjustable straw guide is the contribution of this paper.
2. Both 3.2.1 and 3.2.2 are titled “Evaluation Index”, please correct it.

Author Response

Commented [1]: In abstract line 17, it is claimed that "an adjustable straw guide board was designed. Then in the introduction line 95, it is claimed that “To this end, we have designed a new type of ......".However, in line 2.2 lines 135-136. it is mentioned that “The 4LZ-4.0 harvester in this study adopts a new type of threshing device with adjustable straw guide structure......”, which looks like the adjustable straw guide is designed and adopted by the harvester vendor, not by the author of this paper. As a result, the conflict descriptions make whether the adjustable straw guide is one of the contributions of this paper not clear

Therefore. please state clearly whether the author designed the adjustable straw guide or the harvester vendor did it and whether designing the adjustable straw guide is the contribution of this paper.

Response: 

Thank you very much for your suggestions. The adjustable grass guide structure is researched and designed by us, and has been applied in the product at this stage, as described in lines 11-13 of the article. The 4LZ-4.0 prototype used in the test was developed together with the cooperative unit (Jiangxi Liangtian Agricultural Machinery Co., LTD.).The revised paper has made a supplementary explanation on page 3, lines 114-115.

Commented [2]: Both 3.2.1 and 3.2.2 are titled “Evaluation Index” please correct it.

Response:

It has been modified as required. The title of 3.2.2 was changed to "Experimental Design".

Reviewer 2 Report

There is no rationale for why this problem is being solved in the work. The authors claim that the work is aimed at reducing losses during the harvesting process. At the moment, rice harvesters are sold all over the world, which are regulated in terms of productivity and loss rates.

     Comparative analysis of performance indicators and losses of various types of combines is not given. In the introduction, there are no indicators of losses during the harvesting process; it is impossible to assess the scale and significance of the ongoing work and research.

   In paragraph 2, there is no justification for choosing this type of combine, its technological scheme of operation is not given, there is no kinematic diagram of the drive of the threshing group and modernized working bodies of the combine.

    Table 1 shows the Feeding amount /(kg·s-1) not the productivity of the combine (tons / hour)
     p.142 No numerical indicators of effort.

Assumptions 2.3.1 do not take into account humidity straw!!!!!

 192-193 «the correction coefficient ƺ (ƺ is related to the crop characteristics, structural clearance, etc., and according to the experiment, 0<ƺ<1), the following»- 

210-211 …..«According to some scholars [19,20], the crop humidity and friction coefficient 210 myopia have a linear relationship; therefore, setting μ=0.2 reflects the low moisture state  of straw, and setting μ=1.0 reflects the high moisture state of straw» -  The authors contradict themselves, since the assumptions in paragraph 2.3.1 do not take into account the moisture content of the straw

421 ……«the relative error of some indexes is large»  - does not correspond to the confidence interval according to the Fisher criterion.

5.2. Discussion  - «(1)The authors agree that humidity is a key factor in the ongoing research. And they give an argument why this factor cannot be taken into account when conducting these studies. « - If the authors include this moisture parameter in their studies and obtain regression models taking into account this factor, I will be happy to review this work and, if there are high-quality results, give a positive assessment and recommendations for publication. At the moment, I am against this publication, since the work does not reflect and does not model the process of the threshing group, taking into account its modernization;

5.2. Discussion (2) «The effects of the rice varieties, material characteristics, and agronomy on the 479 threshing equipment were not fully considered in this experiment» - n the obtained regression models, the authors had to give the numerical limits for the main rice varieties grown in the region and the average parameters of the harvesting process and agronomy (average yield, average length of the field, its area, the method of movement of the combine across the field to choose one of the most massive)

Author Response

Commented [1]: There is no rationale for why this problem is being solved in the work. The authors claim that the work is aimed at reducing losses during the harvesting process. At the moment. rice harvesters are sold all over the world, which are regulated in terms of productivity and loss rates.

Response: 

This is good advice. We have revised the introduction part to clarify the research objectives, and the specific modifications are as follows “To solve the aforementioned problems, we designed a new type of adjustable straw guide structure on the threshing device of the grain combine harvester. By analyzing the mathematical model of the movement of the material on the straw guide board and by using the response surface method to optimize the operating speed, drum rotation speed, and spiral angle of the straw guide board, it is hoped to obtain better working performance of the harvester.” Please see to page 3, lines 106-111.

Commented [2]: Comparative analysis of performance indicators and losses of various types of combines is not given. In the introduction, there are no indicators of losses during the harvesting process; it is impossible to assess the scale and significance of the ongoing work and research.

Response: 

This is a good question. The operational performance of harvester is evaluated according to the operational quality standard (NY/T 498-2013) in the study. For the full-feed harvester, the standard requirements are PLR≤3.5%, PIR≤2.5%, and PBR≤2.5%. The optimized PLR of the machine in our study is 1.26%, the PIR is 0.73%, and the PBR is 0.61%. These three indexes are significantly better than the standard, indicating that the machine has a good operating performance. Please refer to page 8, lines 259-260.

Reference: 

Agricultural industry standard of the P. R. China. (2013). NY/T 498-2013: Operating quality for rice combine harvesters. Lan Xinmin, et al.

Standard download address: http://down.foodmate.net/standard/sort/5/42657.html

Commented [3]: In paragraph 2, there is no justification for choosing this type of combine, its technological scheme of operation is not given, there is no kinematic diagram of the drive of the threshing group and modernized working bodies of the combine.

Response：

Thank you for your suggestions. The prototype used in this study was developed together with a cooperative unit (Jiangxi Liangtian Agricultural Machinery Co., LTD.).The revised paper has made a supplementary explanation on page 3, lines 114-115.

In addition, the revised paper supplements the working principle and transmission scheme of the machine as follows “…The straw guide device is installed on the cover plate directly above the threshing drum so that the crops can move smoothly in the threshing chamber. Moreover, the threshing device is connected to the power output through the transmission belt to drive the drum assembly to rotate. When the threshing device works….” For details, see to page 4, lines 131-142.

Commented [4]: Table 1 shows the Feeding amount /(kg·s^-1) not the productivity of the combine (tons / hour)

Response: 

According to the Chinese standard "Harvesting machinery combine and functional parts Part 1: Vocabulary" (GB/T 6979.1-2005), the corresponding term is defined. Feeding amount is the "sum of the grain and stem mass passing through the machine per unit time". And the usual unit is: kg·s^-1

Reference:

Agricultural industry standard of the P. R. China. (2005). GB-T 6979.1-2005: Equipment for harvesting-Combines and functional components-Part 1: Vocabulary, Zhou Chunlin, et al.

Standard download address: http://down.foodmate.net/standard/sort/3/14503.html

Commented [5]: p.142 No numerical indicators of effort

Response:

The adjusting pull rod adopts a lever structure, which can easily adjusted the angle of the straw guide board as a whole, as shown in Figure 2. Therefore, we did not measure the force index of the adjusting pull rod.

Commented [6]: Assumptions 2.3.1 do not take into account humidity straw!!!!!

Response:

This is a good suggestion. The original expression is not rigorous. What we want to express is "The state of the fed straw is consistent, so that the friction coefficient between the straw and the straw guide board is a fixed value" the revised expression is as follows: "(a) The straw is assumed to be fed continuously and evenly, and the humidity of the straw is assumed consistent." Please refer to pages 5, lines 170-171.

Commented [7]: 192-193 <the correction coefficient ƺ ( ƺ is related to the crop characteristics, structural clearance, etc., and according to the experiment,0<ƺ<1), the following>

Response:

Due to our negligence, the value range of the coefficient here was not introduced into the relevant references, and the revised paper supplemented the relevant references. See to pages 6, line 204.

Reference: 

Yang Fangfei, Yan Chuliang. Movement analysis of cereal in axial flow threshing roller space[J]. Transactions of the Chinese Society for Agricultural Engineering, 2008, 39(11): 48-50.

Commented [8]: 210-211 .....According to some scholars [19,20], the crop humidity and friction coefficient 210 myopia have a linear relationship; therefore, setting µ=0.2 reflects the low moisture state of straw, and setting µ=1.0 reflects the high moisture state of straw》 - The authors contradict themselves, since the assumptions in paragraph 2.3.1 do not take into account the moisture content of the straw.

Response:

Thanks for your suggestion, just like Commented [6], this section is not accurate. Relevant assumptions have been revised as follows "(a) The straw is assumed to be fed continuously and evenly, and the humidity of the straw is assumed consistent." Please see to pages 5, lines 170-171.

Commented [9]: 421 ......the relative error of some indexes is large》 - does not correspond to the confidence interval according to the Fisher criterion.

Response:

For the low base of the above evaluation indicators, it is easy to introduce a large test error in the field test, but the maximum relative error is less than 13%.In order to better evaluate the performance of the machine, we have supplemented the analysis of the absolute error of the corresponding data, and the analysis results show that the absolute error is very small, which also indicates that the optimized machine can achieve a better working state. The absolute error after modification is shown in Table 6. It is expressed as follows " The results show that the predicted value of the optimized PLR is 1.18%, the verified value is 1.26%, the relative error is 6.78%, and the absolute error is 0.08%; ….. The predicted PIR value is 0.72%, the verified PIR value is 0.73%, the relative error is 1.39%, and the absolute error is 0.01%; ….. the PBR predicted value is 0.54%, the PBR verified value is 0.61%, the relative error is 12.96%, and the absolute error is 0.07%", Please refer to page 14, lines 425-435.

Commented [10]: 5.2. Discussion - 《(1)The authors agree that humidity is a key factor in the ongoing research And they give an argument why this factor cannot be taken into account when conducting these studies. 《 - If the authors include this moisture parameter in their studies and obtain regression models taking into account this factor, I will be happy to review this work and, if there are high quality results, give a positive assessment and recommendations for publication. At the moment am against this publication, since the work does not reflect and does not model the process of the threshing group, taking into account its modernization;

Response:

(1)This paper analyzed the influence of friction factor and spiral angle of straw guide board on straw movement in the threshing device in 2.3.3, and the friction factor was positively correlated with the moisture of rice straw [Reference:22-23]. Here we further supplement Figure 5 as follows: "….. On the other hand, at a constant spiral angle, the µ value increases with increasing humidity, the axial velocity of straw particles decreases, and the residence time of straw in the threshing device increases. This helps improve the threshing effect but may increase grain damage and the content of impurities. Therefore, an increase in the straw moisture and a decrease in the spiral angle have the same effect on the axial velocity of straw particles in some situations. This implies that the influence of different straw humidity levels on threshing can be dealt with by adjusting the spiral angle of the straw guide board." Please see to page 7, lines 231-238.

(2) In the actual test, the moisture content of rice in the test area is the inherent characteristic of the crop, which is difficult to control, so the humidity is not studied as an independent factor involved in the test.

Commented [11]: 5.2. Discussion (2) 《The effects of the rice varieties, material characteristics, and agronomy on the 479 threshing equipment were not fully considered in this experiment》 - n the obtained regression models, the authors had to give the numerical limits for the main rice varieties grown in the region and the average parameters of the harvesting process and agronomy (average yield, average length of the field, its area, the method of movement of the combine across the field to choose one of the most massive)

Response:

Thank you for your suggestion, the revised paper has been added some varieties characteristics of the corresponding rice and the description of experimental field. According to the statistics of local rice varieties, Jianyou 718 rice yield is about 7650 kg/ hm2, and the plant height is approximately 113 cm, and the experimental field is approximately rectangular, 85 m × 52 m. See page 7, lines 248-252.

Author Response File: Author Response.doc

Reviewer 3 Report

The topic is relevant to the field of research. Overall, few work has been done on this aspect of research in agricultural engineering. Previously, the threshing device's guiding structure could not optimize machine performance by altering the spiral angle. An adjustable straw guide board was constructed and the straw's movement model was analyzed in this study. This paper is well-written scientifically. 

I would like to congratulate the authors for their work. 

Author Response

Reviewer: 3

Commented [1]: This is an interesting paper which has originality and appropriateness for this journal. In the Introduction chapter, it can be seen that the authors gave an overview of the current situation, but there is still a lot of literature that is not included in the list and more worldwide not only local, which would still give a more precise picture of a better understanding of the grain combine harvester thresher.

Response:

Thanks for your suggestion. The revised paper has been added some worldwide literature. As follows: "Tang et al. [11] analyzed the state response of rice straw under the action of threshing teeth. The force of the threshing rod in the threshing process ranged from 36.4 to 121.0 N, and the analysis results showed that straw, stem nodes, and leaves were crushed, and that stem roots and stem nodes might be damaged by stretching." See Page 2, lines 55-58. "Lenaerts et al. [12] obtained a quadratic relationship between the straw crushing quality, screen clearance of the concave plate, and drum rotation speed through liDAR sensing. The results show that the relationship between the machine parameters and straw crushing quality can be explained as a combination of the force on the crop and the time the crop remains in the threshing device." See Page 2, lines 58-63. "Zhenjie et al. [17] conducted dynamic modeling and analysis on the flexible threshing mechanism, and the analysis results showed that the flexible threshing teeth produce multiple continuous normal shocks, and the peak value of normal impact increases with increasing rotational speed. The sustained strike force produces higher threshing and cleaning capabilities, and the lower strike force reduces the rate of grain loss." See Page 2, lines 79-83.

Reference: 

Zhong Tang,Yu Li,Xiyao Li, et al. Structural damage modes for rice stalks undergoing threshing[J]. Biosystems Engineering, 2019, 186: 323-336.

Bart Lenaerts,Bart Missotten,Josse De Baerdemaeker, et al. LiDaR sensing to monitor straw output quality of a combine harvester[J]. Computers and Electronics in Agriculture, 2012, 85: 40-44.

Zhenjie Qian,Chengqian Jin,Youliang Ni, et al. Modelling threshing using an entropy regularisation approach with frictional contact dynamics and a flexible threshing mechanism[J]. Biosystems Engineering, 2023, 226: 144-154.

Commented [2]: The paper is generally well structured, but without a somewhat too clear goal.

Response:

Thank you for your comments. In order to highlight the research objectives, the introduction part of the revised paper is supplemented and improved, as follows: "In order to solve the above problems, we designed a new type of adjustable straw guide structure on the threshing device of cereal combine harvester. By analyzing the mathematical model of the movement of the material on the straw guide plate, and using the response surface method to optimize the parameters of operating speed, drum rotation speed and the spiral angle straw guide plate, it is hoped to obtain better working performance of the harvester." Please refer to page 3, lines 106-111.

Commented [3]: Author could better explain how the data was collected.

Response:

The value range here is the research of other scholars. The reference has been added to corresponding data. Please see to page 6, lines 202-204.

Commented [4]: Figure 4 and 5 should be merged in some way, and figure 7 isn't clear, it is not representative.

Response:

This is a good suggestion. Figures 4 and 5 have been merged in the revised paper. And the original Figure 7 has been replaced and renumbered as Figure 6 in the revised paper.

Commented [5]: Table 3 and 4 in some way could be reorganized in order to connect to better explanation, for better understanding of problem which is observed.

Response:

Thank you for your suggestion. Refer to the following literature, experimental results and ANOVA are usually separated, and we also adopt such a structure.

Reference:

Fenglei Wang, Shaochun Ma, Wenli Ke, et al. Optimization of base cutter structural parameters for under-the-ground sugarcane base cutting[J]. Applied Engineering in Agriculture, 2021, 37(2): 233–242.

Yang Guang, Chen Qiaomin, Xia Xianfei, et al. Design and optimization of the key components for 4DL-5A faba bean combine harvester[J]. Transactions of the Chinese Society of Agricultural Engineering, 2021, 37(23): 10–18. (in Chinese with English abstract)

Commented [6]: In my opinion chapter 5 must be divided into discussion and conclusion. The conclusion chapter is not a summary of the work. It must be clear and concise and I suggest that in the chapter conclusion should be add some explanation how this research has moved the issue of scientific knowledge forward.

Response:

Thank you for your advice. The two chapters of “Discussion” and “Conclusion” have been separated in the revised paper. And the first part of the conclusion chapter has been concise and supplemented, as follows “（1）A straw guide structure with an adjustable spiral angle and its threshing device was designed, and the mathematical model of material movement on the straw guide board was analyzed. The model analysis shows that show that the axial velocity of the straw particle has an inverse parabola relationship with the spiral angle of the straw guide, and the increase in straw moisture and the decrease in spiral angle have the same effect on decreases the axial velocity of straw particles in some situations. This may help improve the threshing effect but may increase grain damage and the content of impurities. Therefore, adjusting the spiral angle of the straw guide board can be considered to cope with the influence of straw humidity on the threshing effect.” Please refer to page 15, lines 464-472.

Author Response File: Author Response.doc

Reviewer 4 Report

This is an interesting paper which has originality and appropriateness for this journal. In the Introduction chapter, it can be seen that the authors gave an overview of the current situation, but there is still a lot of literature that is not included in the list and more worldwide not only local, which would still give a more precise picture of a better understanding of the grain combine harvester thresher. The paper is generally well structured, but without a somewhat too clear goal. Author could better explain how the data was collected. Figure 4 and 5 should be merged in some way, and figure 7 isn’t clear, it is not representative.  Table 3 and 4 in some way could be reorganized in order to connect to better explanation, for better understanding of problem which is observed. In my opinion chapter 5 must be divided into discussion and conclusion. The conclusion chapter is not a summary of the work. It must be clear and concise and I suggest that in the chapter conclusion should be add some explanation how this research has moved the issue of scientific knowledge forward.

Author Response

Reviewer:4

Commented [1]: This is an interesting paper which has originality and appropriateness for this journal. In the Introduction chapter, it can be seen that the authors gave an overview of the current situation, but there is still a lot of literature that is not included in the list and more worldwide not only local, which would still give a more precise picture of a better understanding of the grain combine harvester thresher.

Response:

Thanks for your suggestion. The revised paper has been added some worldwide literature. As follows: "Tang et al. [11] analyzed the state response of rice straw under the action of threshing teeth. The force of the threshing rod in the threshing process ranged from 36.4 to 121.0 N, and the analysis results showed that straw, stem nodes, and leaves were crushed, and that stem roots and stem nodes might be damaged by stretching." See Page 2, lines 55-58. "Lenaerts et al. [12] obtained a quadratic relationship between the straw crushing quality, screen clearance of the concave plate, and drum rotation speed through liDAR sensing. The results show that the relationship between the machine parameters and straw crushing quality can be explained as a combination of the force on the crop and the time the crop remains in the threshing device." See Page 2, lines 58-63. "Zhenjie et al. [17] conducted dynamic modeling and analysis on the flexible threshing mechanism, and the analysis results showed that the flexible threshing teeth produce multiple continuous normal shocks, and the peak value of normal impact increases with increasing rotational speed. The sustained strike force produces higher threshing and cleaning capabilities, and the lower strike force reduces the rate of grain loss." See Page 2, lines 79-83.

Reference: 

Zhong Tang,Yu Li,Xiyao Li, et al. Structural damage modes for rice stalks undergoing threshing[J]. Biosystems Engineering, 2019, 186: 323-336.

Bart Lenaerts,Bart Missotten,Josse De Baerdemaeker, et al. LiDaR sensing to monitor straw output quality of a combine harvester[J]. Computers and Electronics in Agriculture, 2012, 85: 40-44.

Zhenjie Qian,Chengqian Jin,Youliang Ni, et al. Modelling threshing using an entropy regularisation approach with frictional contact dynamics and a flexible threshing mechanism[J]. Biosystems Engineering, 2023, 226: 144-154.

Commented [2]: The paper is generally well structured, but without a somewhat too clear goal.

Response:

Thank you for your comments. In order to highlight the research objectives, the introduction part of the revised paper is supplemented and improved, as follows: "In order to solve the above problems, we designed a new type of adjustable straw guide structure on the threshing device of cereal combine harvester. By analyzing the mathematical model of the movement of the material on the straw guide plate, and using the response surface method to optimize the parameters of operating speed, drum rotation speed and the spiral angle straw guide plate, it is hoped to obtain better working performance of the harvester." Please refer to page 3, lines 106-111.

Commented [3]: Author could better explain how the data was collected.

Response:

The value range here is the research of other scholars. The reference has been added to corresponding data. Please see to page 6, lines 202-204.

Commented [4]: Figure 4 and 5 should be merged in some way, and figure 7 isn't clear, it is not representative.

Response:

This is a good suggestion. Figures 4 and 5 have been merged in the revised paper. And the original Figure 7 has been replaced and renumbered as Figure 6 in the revised paper.

Commented [5]: Table 3 and 4 in some way could be reorganized in order to connect to better explanation, for better understanding of problem which is observed.

Response:

Thank you for your suggestion. Refer to the following literature, experimental results and ANOVA are usually separated, and we also adopt such a structure.

Reference:

Fenglei Wang, Shaochun Ma, Wenli Ke, et al. Optimization of base cutter structural parameters for under-the-ground sugarcane base cutting[J]. Applied Engineering in Agriculture, 2021, 37(2): 233–242.

Yang Guang, Chen Qiaomin, Xia Xianfei, et al. Design and optimization of the key components for 4DL-5A faba bean combine harvester[J]. Transactions of the Chinese Society of Agricultural Engineering, 2021, 37(23): 10–18. (in Chinese with English abstract)

Commented [6]: In my opinion chapter 5 must be divided into discussion and conclusion. The conclusion chapter is not a summary of the work. It must be clear and concise and I suggest that in the chapter conclusion should be add some explanation how this research has moved the issue of scientific knowledge forward.

Response:

Thank you for your advice. The two chapters of “Discussion” and “Conclusion” have been separated in the revised paper. And the first part of the conclusion chapter has been concise and supplemented, as follows “（1）A straw guide structure with an adjustable spiral angle and its threshing device was designed, and the mathematical model of material movement on the straw guide board was analyzed. The model analysis shows that show that the axial velocity of the straw particle has an inverse parabola relationship with the spiral angle of the straw guide, and the increase in straw moisture and the decrease in spiral angle have the same effect on decreases the axial velocity of straw particles in some situations. This may help improve the threshing effect but may increase grain damage and the content of impurities. Therefore, adjusting the spiral angle of the straw guide board can be considered to cope with the influence of straw humidity on the threshing effect.” Please refer to page 15, lines 464-472.

Author Response File: Author Response.doc