# Parameter Optimization and Testing of a Self-Propelled Combine Cabbage Harvester

^{1}

^{2}

^{3}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Machine Structure and Working Principles

#### 2.1. Structure of the Machine

#### 2.2. Principles of Harvesting

## 3. Analysis of the Working Process and the Selection of Key Parameters

#### 3.1. Analysis of the Cabbage Harvesting Process

_{1}; the time required from the conveying mechanism to the root-cutting mechanism is set as t

_{2}; the time required for the one-time root-cutting of a cabbage is t

_{3}. The possible relations between them are as follows:

_{1}: the walking speed of the machine v is too fast; before the first cabbage is pulled up and sent into the conveying mechanism, the second cabbage has entered the pulling mechanism. There are three situations in this case; if t < t

_{2}, that is, the rotating speed of the conveyor belt is too low, the number of cabbages entering the conveying mechanism is too large per unit time, the cabbages will then be clogged at the feeding mouth of the conveying mechanism, and will be extruded, rubbed and collided, thus reducing the qualifying rate of mechanized harvesting. If t > t

_{3}> t

_{2}, that is, if the rotating speed of the conveyor belt is high and the rotating speed of the cutter-head is low, before the cabbage root is cut completely, the cabbage is conveyed backward; thus, the qualifying rate of mechanized harvesting of cabbages is reduced. In this case, the lower limit value of the rotating speed of the cutter-head can be determined. If t > t

_{2}> t

_{3}, that is, if the conveying device conveys cabbages one after another, the rotating speed of the conveyor belt is low and the rotating speed of the cutter-head is high; in this case, the cabbages can be conveyed and the root can be cut efficiently, and the lower limit value of the rotating speed of the conveyor belt can also be determined.

_{1}: the advancing speed of the machine v is too slow, since the working distance is constant (the length of the pulling roller is constant), the acting time on the cabbage by the pulling roller per unit of time is increased, and the cabbages are rubbed and damaged; thus, the qualifying rate of harvesting is reduced. At the same time, if t is too long, the working efficiency of the machine is reduced; thus, the advancing speed should be set to a reasonable rate [17,18].

#### 3.2. Analysis of the Cabbage Pulling Process

_{M}is the constraint reaction of the whole rigid body;${\mathit{a}}_{\mathit{r}}$ is the relative acceleration of the cabbage, in m/s

^{2}; ${\mathit{a}}_{\mathit{e}}$ is the walking acceleration of the harvester, in m/s

^{2}; δ is the angle between the cone on the pulling roller and the horizontal line (°); ${\mathit{F}}_{\mathit{j}}$ is the supporting force from the pulling roller to the cabbage, N; ${\mathit{a}}_{\mathit{j}}$ is the absolute acceleration of the cabbage harvester, in m/s

^{2}; ${\mathit{m}}_{\mathit{j}}$ is the weight of the single cone on the pulling roller, in kg; ${\mathit{f}}_{\mathit{N}}$ is the friction between the cabbage and the pulling roller, N; ${\mathit{K}}_{\mathit{M}}$ is the ratio between the weight of the pulling roller and the weight of the cabbage.

#### 3.3. Analysis of the Cabbage Clamping and Conveying Process

_{1}is the linear velocity of the conveyor belt, in m/s; α is the ascending angle of the delivery mechanism (°); v

_{0}is the operation velocity of the harvester, in m/s.

_{A}and F

_{C}, are:

_{1}= L

_{2}, the deformation deflection of the section of cabbage at the base level after it is clamped, $\Delta $y, is:

_{1}is the length of AB, in mm; L

_{2}is the length of BC, in mm.

#### 3.4. Root-Cutting Process Analysis

## 4. Test and Result Analysis

#### 4.1. Test Location, Materials, and Equipment

#### 4.2. Test Method and Evaluation Indexes

_{1}is the number of unqualified harvested cabbages; Q is the total number of cabbages in the test.

#### 4.3. Single-Factor Test of Cabbage Harvesting Performance

#### 4.3.1. Single-Factor Test Design

#### 4.3.2. Test Results and Analysis

#### Influence of Advancing Speed on the Qualifying rate of Cabbage Harvesting

#### Influence of the Rotating Speed of the Pulling Roller on the Qualifying Rate of Cabbage Harvesting

#### Influence of the Rotating Speed of the Conveyor Belt on the Qualifying Rate of Cabbage Harvesting

#### Influence of the Rotating Speed of the Cutter-head on the Qualifying Rate of Cabbage Harvesting

#### 4.4. Parameter Optimization Test of Cabbage Harvesting Performance

#### 4.4.1. Design of the Multi-Factor Test

_{1}, the rotating speed of the pulling roller, x

_{2}, the rotating speed of the conveyor belt, x

_{3}, and the rotating speed of the cutter-head, x

_{4,}as test factors. Then, response surface analysis was used to explore the correlation of all test factors and their interaction effects. In the test, the qualifying rate of cabbage harvesting, y (%), was measured as the response value. The factor-level coding table is shown in Table 1.

#### 4.4.2. Test Results

#### 4.4.3. Regression Modeling and Significance Analysis

#### Establishment of the Regression Model and Significance Test

_{1}and x

_{4}, and quadratic terms, x

_{1}

^{2}and x

_{3}

^{2}, were highly significant; the first-order term x

_{3}, the interaction term x

_{3}x

_{4}was significant, and the other terms were insignificant. The contribution of test factors to the qualifying rate as the test index is determined by the F-value. The higher the F-value, the greater the effect on the test index. The influence order of all test factors on the qualifying rate of cabbage harvesting is: rotating speed of the cutter-head (x

_{4}) > advancing speed (x

_{1}) > rotating speed of the conveyor belt (x

_{3}) > rotating speed of the pulling roller (x

_{2}).

#### Analysis of the Two-Factor Interaction Effect

_{3}x

_{4}had a significant effect on the qualifying rate of cabbage harvesting, according to the regression model (21), a response surface between the rotating speed of the conveyor belt, x

_{3,}and the rotating speed of the cutter-head, x

_{4}, based on the regression model (21), is shown in Figure 15.

#### 4.5. Parameter Optimization and Validation Test

#### 4.5.1. Parameter Optimization and Analysis

#### 4.5.2. Field Verification Test

## 5. Discussion

- (1)
- In this study, the influence of the advancing speed of the cabbage harvester, the rotating speed of the pulling roller, the rotating speed of the conveyor belt, and the rotating speed of the cutter-head on the qualifying rate of cabbage harvesting was analyzed. When the walking speed is 1.2 km/h, the speed of the plucking roller is 100 r/min, the speed of the conveyor belt is 180–220 r/min, and the speed of the cutter is 350–400 r/min, a high qualifying rate of kale harvesting can be obtained. Further studies will be made on the influence of the angle of the pulling roller, the material of the flexible conveyor belt, the structure of the tensioning mechanism, and the cutting methods on harvesting performance in the future.
- (2)
- It was found in the test that there is the problem of the failure of harvesting due to the skewing or lodging of cabbages, thus undermining the qualifying rate of cabbage harvesting. To solve this problem, subsequent studies will adopt an automatic row-alignment mechanism. By installing an angle sensor and developing an automatic row-alignment system, this problem will be solved.
- (3)
- At present, China has imported mature machine types from European and American countries in terms of mechanized cabbage harvesting. They are mainly large-scale mechanized equipment designed for large pieces of land, and harvest cabbages in single rows with a unilateral harvester hung on a tractor, the power of which is over 120 hp and the harvesting efficiency is 0.07–0.10 hectare/h. They are suitable for the conventional planting of cabbages and are not suitable for the agronomic requirements of cabbage planting in China, especially in terms of ridge planting. Thus, they showed a poor harvesting effect and required 2–6 workers to cut roots or strip leaves at the same time. The self-propelled cabbage harvester designed in this paper has improved harvesting quality, saved labor costs, and reduced labor intensity; however, its marketability should be further improved. Further research should be made into high-efficiency and low-loss harvesting technologies, to realize commercialized harvesting.

## 6. Conclusions

- (1)
- Through an in-depth analysis of the status of the cabbage industry in China and the requirement of harvesting technologies, the 4GCSD-1200 type cabbage harvester was designed. It includes a crawler walking chassis and cabbage harvesting header; the header is composed of the pulling mechanism, the flexible clamping and conveying mechanism, and the double-disk root-cutting mechanism. The harvester can realize low-loss cabbage pulling, conveying, and precision root-cutting.
- (2)
- Based on the theoretical analysis and single-factor test, following the design principles of the Box–Behnken test, by taking the advancing speed, rotating speed of the pulling roller, rotating speed of the conveyor belt, rotating speed of the cutter-head as influencing factors, a four-factor three-level response surface analysis was adopted to carry out a test of the working parameter optimization of the cabbage harvester. Moreover, a mathematical regression model between the influencing factors and the qualifying rate of cabbage harvesting was established; the influence order of the factors on the qualifying rate of cabbage harvesting was: rotating speed of the cutter-head > advancing speed > rotating speed of conveyor belt > rotating speed of the pulling roller.
- (3)
- By taking the optimal qualifying rate of cabbage harvesting as the objective, the optimal working parameters for the harvester were obtained: the advancing speed was 1.1 km/h, the rotating speed of the pulling roller was 90 r/min, the rotating speed of the conveyor belt was 205 r/min; the rotating speed of the cutterphead was 395 r/min. A verification test showed that the qualifying rate of cabbage harvesting was 96.3%, with high root-cutting uniformity and low loss. It shows that optimizing the working parameters could reduce the loss during the mechanized harvesting of cabbages and improve the qualifying rate of harvesting, and its operation effect could meet the marketization requirements of cabbage harvesting.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 1.**Cabbage harvester: (

**a**) The structure of the conveying header of the cabbage harvester. (

**b**) The structure of the whole machine. (1) Pulling mechanism. (2) Reel. (3) Flexible clamping and conveyor belt. (4) Belt tensioner. (5) Transmission gearbox of the conveying mechanism. (6) Body frame. (7) Chief drive shaft. (8) Transmission gearbox of the root-cutting mechanism. (9) Transmission gearbox of the reel mechanism. (10) Ground wheel. (11) Double-disk root-cutting mechanism. (12) Fixed plate in trifilar suspension hinge.

**Figure 2.**Cabbage pulling device: (1) Pulling roller. (2) Reel. (3) Transmission gear of the reel. (4) Universal drive shaft. (5) Straight-toothed gearbox. (6) Drive shaft of the reel.

**Figure 4.**Flexible clamping and conveying mechanism: (1) Flexible clamping and conveyor belt. (2) Driven wheel. (3) Fixed plate of the driven wheel. (4) Mounting rack of the clamping and conveying mechanism. (5) T2 gearbox. (6) Main drive shaft of the conveyor belt. (7) Tension mechanism.

**Figure 7.**Schematic diagram of deformation in cabbage clamping and conveying. (

**a**) Schematic diagram of transport local deformation analysis. (

**b**) Analysis of local deformation.

**Figure 8.**Double-disk root-cutting mechanism. (1) Cutter fixed bearing seat. (2) Circular. (3) Circular saw. (4) Cutter drive shaft. (5) Limit bearing. (6) Variable direction gear box. (7) Cutting root mechanism drive shaft.

**Figure 12.**Influence of rotating speed of pulling roller on the qualifying rate of cabbage harvesting.

**Figure 13.**Influence of the rotating speed of the conveyor belt on the qualifying rate of cabbage harvesting.

Levels | Test Factors | |||
---|---|---|---|---|

Advancing Speed x_{1}(km · h ^{−}^{1}) | Rotating Speed of the Pulling Roller x_{2}(r · min ^{−}^{1}) | Rotating Speed of the Conveyor Belt x_{3}(r · min ^{−}^{1}) | Rotating Speed of the Cutter-Head (r · min ^{−}^{1}) | |

+1 | 1.4 | 120 | 240 | 400 |

0 | 1.2 | 100 | 200 | 350 |

−1 | 1.0 | 80 | 160 | 300 |

Test No. | x_{1} | x_{2} | x_{3} | x_{4} | y/% |
---|---|---|---|---|---|

1 | 0 | 0 | 0 | 0 | 97.5 |

2 | 0 | −1 | 0 | −1 | 93.1 |

3 | 0 | 1 | 1 | 0 | 92.4 |

4 | −1 | 0 | −1 | 0 | 93.7 |

5 | 1 | 1 | 0 | 0 | 92.9 |

6 | −1 | −1 | 0 | 0 | 97.2 |

7 | −1 | 0 | 0 | −1 | 93.8 |

8 | 0 | 0 | 0 | 0 | 97.1 |

9 | 0 | 0 | 0 | 0 | 96.8 |

10 | 0 | 0 | 1 | −1 | 90.1 |

11 | 0 | 1 | 0 | −1 | 93.3 |

12 | 1 | −1 | 0 | 0 | 92.8 |

13 | 1 | 0 | 0 | 1 | 93.3 |

14 | 0 | 0 | −1 | −1 | 94.2 |

15 | −1 | 0 | 1 | 0 | 92.1 |

16 | 0 | −1 | 1 | 0 | 92.6 |

17 | 1 | 0 | 1 | 0 | 91.1 |

18 | 1 | 0 | −1 | 0 | 91.3 |

19 | 0 | 1 | 0 | 1 | 94.6 |

20 | 0 | −1 | 0 | 1 | 95.9 |

21 | 0 | 0 | 1 | 1 | 97.3 |

22 | 0 | 0 | −1 | 1 | 95.7 |

23 | 0 | 0 | 0 | 0 | 94.9 |

24 | −1 | 0 | 0 | 1 | 95.2 |

25 | 0 | 0 | 0 | 0 | 96.8 |

26 | 0 | 1 | −1 | 0 | 94.9 |

27 | 0 | −1 | −1 | 0 | 95.5 |

28 | −1 | 1 | 0 | 0 | 94.3 |

29 | 1 | 0 | 0 | −1 | 92.7 |

Sources of Variance | Regression Coefficients | Variance Sum | Degree of Freedom | Mean Square Error | F | P |
---|---|---|---|---|---|---|

Model | 94.62 | 95.53 | 14 | 6.82 | 5.03 | 0.0023 ** |

x_{1} | −1.02 | 12.40 | 1 | 12.40 | 9.14 | 0.0091 ** |

x_{2} | −0.39 | 1.84 | 1 | 1.84 | 1.36 | 0.2637 |

x_{3} | −0.81 | 7.84 | 1 | 7.84 | 5.78 | 0.0307 * |

x_{4} | 1.23 | 18.25 | 1 | 18.25 | 13.45 | 0.0025 ** |

x_{1}x_{2} | 0.75 | 2.25 | 1 | 2.25 | 1.66 | 0.2188 |

x_{1}x_{3} | 0.35 | 0.49 | 1 | 0.49 | 0.36 | 0.5575 |

x_{1}x_{4} | −0.20 | 0.16 | 1 | 0.16 | 0.12 | 0.7364 |

x_{2}x_{3} | 0.10 | 0.04 | 1 | 0.04 | 0.03 | 0.8662 |

x_{2}x_{4} | −0.38 | 0.56 | 1 | 0.56 | 0.41 | 0.5301 |

x_{3}x_{4} | 1.43 | 8.12 | 1 | 8.12 | 5.98 | 0.0282 * |

x_{1}^{2} | −2.01 | 26.21 | 1 | 26.21 | 19.31 | 0.0006 ** |

x_{2}^{2} | −0.87 | 4.94 | 1 | 4.94 | 3.64 | 0.0772 |

x_{3}^{2} | −1.95 | 24.60 | 1 | 24.60 | 18.13 | 0.0008 ** |

x_{4}^{2} | −0.91 | 5.37 | 1 | 5.37 | 3.96 | 0.0666 |

Residual error | 19.00 | 14 | 1.36 | |||

Lack-of-fit | 14.97 | 10 | 1.50 | 1.49 | 0.3741 | |

Error | 4.03 | 4 | 1.01 | |||

Sum | 114.53 | 28 |

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## Share and Cite

**MDPI and ACS Style**

Zhang, J.; Cao, G.; Jin, Y.; Tong, W.; Zhao, Y.; Song, Z.
Parameter Optimization and Testing of a Self-Propelled Combine Cabbage Harvester. *Agriculture* **2022**, *12*, 1610.
https://doi.org/10.3390/agriculture12101610

**AMA Style**

Zhang J, Cao G, Jin Y, Tong W, Zhao Y, Song Z.
Parameter Optimization and Testing of a Self-Propelled Combine Cabbage Harvester. *Agriculture*. 2022; 12(10):1610.
https://doi.org/10.3390/agriculture12101610

**Chicago/Turabian Style**

Zhang, Jianfei, Guangqiao Cao, Yue Jin, Wenyu Tong, Ying Zhao, and Zhiyu Song.
2022. "Parameter Optimization and Testing of a Self-Propelled Combine Cabbage Harvester" *Agriculture* 12, no. 10: 1610.
https://doi.org/10.3390/agriculture12101610