# Research on Seeding Performance of Self-Propelled Industrial Hemp Seeder
## 3 Parameter Design and Analysis of Critical Components of Seed Metering Device
### Parameter Design of the Metering Wheel
#### 3.2.5 Analysis of the Process of Seed Protection and Seed Arrangement  
In order to reasonably design the diameter of the seeding wheel and avoid the phenomenon of carrying seeds, feeding seeds, and rubbing seeds between the hole and the seed protection chip in the process of seed protection, ensure the stability of seed transportation in the process of seed protection, and analyze the stress of the seeds in the process of seed protection. Figure 7 shows the process of seed protection. A specific lateral seed in the hole was taken as the research object to facilitate the theoretical analysis of the seed protection process. If the radial resultant force acting on the seed in the hole were less than the centrifugal force, the seed would produce a movement trend from the bottom to the outside, making the seed contact with the seed protection chip. It was easily damaged by the friction force generated by the seed protection plate on the seed. Therefore, the force of the seed in the seed protection process should meet the formula:  
\[\left\{ \begin{array}{l}\sum F_{y}=0,\quad G_{2}\cos\gamma_{2}+F_{2}-F_{e}=0 \\ \sum F_{x}=0,\quad G_{2}\sin\gamma_{2}-F_{2}=0\\ F_{2}=f\cdot N\cos\gamma_{2}\\ F_{e}=mr\omega^{2}\\ G_{2}=mg\end{array} \right. \tag{12}\]  
where \(G_{2}\) is the gravity of the seed in the process of conservation, N; \(\gamma_{2}\) is the seed protection angle, (\({}^{\circ}\));\(f_{2}\) is the resultant force of interaction force between seeds during seed protection, N; \(F_{e}\) is the centrifugal force of seeds during seed protection, \(N\) is the normal reaction, N; \(r\) The distance between the centroid of the seed and the center of the runner, mm. From Formula (12):  
\[\omega=\sqrt{\frac{g(\cos\gamma_{2}+\sin\gamma_{2})}{r}} \tag{13}\]  
The results showed that when the protecting angle \(\gamma_{2}\) was constant, the smaller the diameter of the seed row wheel was, that is, the smaller the distance from the centroid of the seed to the circular rotation center of the shaped hole was, and the larger the angular velocity of the seed row wheel was, the greater the effect of the seed guard plate on the seed was. In order to reduce seed breakage, the diameter of the seed row wheel should be increased. To further explore the influence of seed row wheel diameter on seed row, the seed row process was analyzed, as shown in Figure 8. The type of hole cannot arrange seeds smoothly, which will directly affect the precision of the seed metering device and cause uneven seed metering. In order to determine the conditions of seed arrangement, the stress analysis was carried out in the process of seed arrangement. Figure 7: Analysis of seed protection process. The seeds fall under the action of centrifugal force and gravity. The seed group in the hole is regarded as a rigid whole, and its geometric center is its centroid. The \(xOy\) rectangular coordinate system is established. Assuming that the interaction between seeds is ignored during seeding, the plane velocity can be decomposed into the horizontal velocity \(v_{x}\) and the vertical downward velocity \(v_{y}\), and the seed trajectory equation is obtained as follows [35]:  
\[\left\{ \begin{array}{l}X=v_{x}t\\ Y=v_{y}t+\frac{gt^{2}}{2}\\ V_{x}=v\cdot\sin\gamma_{3}\\ v_{y}=v\cdot\cos\gamma_{3}\\ V=\frac{n\pi R}{30}\end{array} \right. \tag{14}\]  
where \(X\) is horizontal displacement, mm; \(v_{x}\) is the horizontal component of seeding speed, m/s; \(t\) for seeding time, \(s\); \(y\) is the displacement in the vertical direction, mm; \(v_{y}\) is the vertical component of seeding speed, m/s; \(\gamma_{3}\) is the seeding angle, (\({}^{\circ}\)); \(v\) is seeding speed, m/s. From Formula (14):  
\[\left\{ \begin{array}{l}X=\frac{n\pi R\sin\gamma_{3}t}{30}\\ Y=\frac{n\pi R\cos\gamma_{3}t}{30}+\frac{gt^{2}}{2}\end{array} \right. \tag{15}\]  
To prevent the seeds from a collision with each other when the seeds are entirely separated from the hole in the hole and fall from the adjacent hole, it is necessary to meet the below formula. \[\left\{