Fig 1.
Manual harvesting process.
Fig 2.
Structural diagram of the green soybean harvester.
Note: 1- Reel part 2-A drum for separating pods from stalks 3- Chassis 4- Material delivery part 5- Blade cleaning part 6- Pod-stalk cleaning part 7- Grain tank.
Fig 3.
1. Green soybean plants; 2. Material granular particles inside the drum; 3. Contour wheel; 4. Chassis system; 5. Material granular particles in the delivery mechanism; 6. Frame assembly; 7. Lifting cylinder; 8. Pod unloading cylinder; 9. Material granular particles of the cleaning device; 10. Stalk and pod granular particles; 11.Leaf granular particles; 12.Pod granular particles; 13.Impurities. Note: The direction of the arrow was the direction of material flow.
Fig 4.
Schematic diagram of the drum mechanism for separating pods from stalks.
1. Reel; 2. Side enclosure; 3. Drive motor; 4. Lifting cylinder; 5. Bearing frame; 6. Support base; 7. Hanger; 8. Enclosure; 9. Drive sprocket assembly; 10. Reinforcing rib; 11. Roller; 12. Baffle; 13. Adjustment hydraulic cylinder I; 14. Adjustment hydraulic cylinder II; 15. Drum drive motor 16. Drum.
Fig 5.
Schematic diagram of measuring points.
Note: hf is the height of soybean stalk, m; α1 is the angle between ground and plant before harvest, rad; h1 is the lowest distance from the ground to green soybean, cm; α2 is the angle between plants and ground in the feeding area, rad; α3~α4 is the angle between plants and ground in harvest area, rad; α5 is the angle between plants and ground in extraction state, rad; h is the distance of the drum to ground, cm; v is the travel speed of the device, m/s; ω is the rotational speed of drum, rpm/min; r is the inner diameter of the drum (mounting comb teeth), mm; Hg is the distance of drum axis from ground, cm; θ is the rotation angle of the drum, rad; Rm is the tangential point between the plant located at position C and the inner diameter of the roller; Rn is the tangential point between plant located at position D and the inner circle of drum; vt is the advance distance of C to E, m.
Fig 6.
Schematic diagram of the drum.
1. Driveshaft; 2. Drum enclosure; 3. Drum; 4. Teeth; 5.Riveting slot. Note: d is the inner diameter of the drum (mm); D is the outer diameter of the drum (mm); L is the length of the drum (mm); ls is the length of a single tooth; c is the minimum teeth distance (axial direction of the drum).
Fig 7.
Pod stalk tension-displacement curve.
Fig 8.
Pressure-displacement curve of the pods.
Fig 9.
Teeth arrangement and plant combing and feeding.
Note: b is the width of a green soybean pod, mm.
Fig 10.
Note: L is the length of the drum; πD is the perimeter of the drum; a1, a2, a3, …, an are in the first column in the radial direction of the drum; b1, b2, b3, …, bn; m1, m2, m3, …, mn, which are in the second and the m-th columns, respectively; a is the axial distance of two neighboring teeth; δ is the radial distance of two neighboring teeth after unfolding the drum; c is the minimum distance of two neighboring teeth in the radial direction.
Fig 11.
Kinematic analysis on the collision between materials and the teeth.
Note: R is the outer diameter of the drum, mm; v is the travel speed of the device, m/s; Ff is the friction when throwing back the green soybeans, N; h is the minimum drum-ground distance, mm; H is the drum-ground distance when the teeth start to hull soybeans, mm; G is the gravity of pods, N; β is the angle between the bending section of the comb and the centrifugal force, (rad); Fr is the centrifugal force of the soybean pods, N, γ is the angle between the gravity of pods G and the centrifugal direction of Fr, (rad); Fn is the collision force from teeth to pods, N; l1 is the distance between the bending section of the teeth and center of the drum, mm; l2 is the length of the bending section of the teeth, mm.
Fig 12.
Structure of the elastic tooth.
Note: α is the bending angle of the tooth, (rad); l1 is the distance between the bending point of the finger and the base, mm; l2 is the length of the bending section of the tooth, mm; φ is the diameter of the tooth, mm.
Fig 13.
Practicality picture of the drum teeth.
Fig 14.
Note: hf was plant height; h2 was the height of the soybean pod from the ground.
Table 1.
Physical characteristics of fresh soybean plants.
Fig 15.
The experimental equipment.
Fig 16.
The harvest quality situation under different drum rotational speeds.
Fig 17.
The harvest quality situation under different axial minimum teeth distances.
Fig 18.
The harvest quality situation under different travel speeds.
Table 2.
Test factors and levels.
Table 3.
Test scheme and results.
Table 4.
Results of variance analysis.
Fig 19.
Influence of test factors on pods detachment rate Y1.
(a) Y1 (380, A2, A3). (b) Y1 (A1, 4.1, A3). (c) Y1 (A1, A2, 0.65).
Fig 20.
Influence of interaction effect of test factors on damage rate Y2.
(a) Y2 (380, A2, A3). (b) Y2 (A1, 4.1, A3). (c) Y2 (A1, A2, 0.65).
Fig 21.
Field test of 4GQD-160 type self-propelled green soybean harvester.
Fig 22.
Green soybean pods and plants after harvesting.
a) Green soybean pods after harvesting. b) Plants after harvesting.
Table 5.
Statistics of the operation process of the harvester.