## 2 Working Principle and Posture Requirements  
### Working Principle and Attitude Requirements  
The proposed mechanism for transplanting rotated rice pot seedlings in this project is depicted in Figure 2, with two rotary transplanting mechanisms symmetrically installed on either side of the transmission box. To illustrate the working principle of one of the transplanting mechanisms, consider the following example. Power is input via the transmission shaft (1) into the transmission box (2). The transmission level gear (3) is fixed to the sun shaft (4), through which the power is transmitted via the bevel-gear transmission. The non-circular gear train, consisting of five non-circular gears, is fixed to the sun shaft (4) and rotates along with it. Among these gears, the sun gear (6) and flange (5) are fixed by teeth and remain relatively stationary to the transmission box (2), while the intermediate gears ((9), (13)) are fixed to the intermediate shafts ((10), (12)) and are engaged with the sun gear. The intermediate gear ((9), (13)) is the center of the relatively rotating non-circular gear system on the intermediate shaft ((10), (12)). The planetary gear ((15), (7)) is fixed to planetary shaft ((14), (8)) and rotates while engaging with the intermediate gear. In the transplanting mechanism, the planetary carrier serves as the driving part. The non-circular gear system features a planetary shaft ((14), (8)) that protrudes from one end, while a transplanting arm ((16), (11)) is fixed to the other. As the non-circular gear system rotates with the sun shaft (4), the non-circular gears engage and rotate with each other. The gearbox facilitates a uniform circular motion for the transplanting arm ((16), (11)), while the planetary shaft enables the non-circular gear system to rotate at an equal speed. These two movements work together to create a complex \"8\"-type trajectory (17) and attitude for the transplanting arm ((16), (11)). By optimizing the non-circular gear parameters and structural parameters, the transplanting arm can achieve the characteristic trajectory and attitude required for rice pot transplanting, successfully performing the three actions of rice picking, conveying, and planting. The transplanting arm is a crucial component of the transplanting mechanism, being directly responsible for picking and pushing the rice seedlings [16]. Figure 3 illustrates the structure of the transplanting arm, which consists of a fixed cam (9) on the gearbox and a transplanting arm (7) on the planetary shaft. During operation, the transplanting arm (7) rotates at an unequal speed relative to the cam (9). One end of the shifting fork (8), which is connected to the transplanting arm (7), interacts with the cam, while the other end drives the pusher rod (4) back and forth in a linear motion relative to the transplanting arm (7) through the spring seat (5). The pusher rod (4) is attached to the U-shaped clamp block (2) and pusher block (1). The two cylindrical rods of the U-shaped clamp block (2) are located outside of the two clamp slices (3), which are fixed on the transplanting arm (7). In the initial mounting position, the two clamp slices (3) remain open. As the shifting fork (8) rotates by lifting the cam (9), it retracts the pusher rod (4) and causes the U-shaped clamp block (2) to squeeze the two clamp slices (3) on the outside, firmly gripping the seedling. The two clamping flakes (3) are kept tightly closed and are followed by the movement of the transplanting-arm parts to the pushing position to complete the seedling-conveying process. When the transplanting arm moves to the position of the push seedling, one end of the shifting fork (8) moves to the return of the cam (9). The push rod (4) is quickly pushed forward by the action of the spring (6). The U-shaped clamp block (2) is disengaged from the clamp slices (3). The two clamp slices (3) open through the action of their own elasticity and release the seedlings.