# Design and Test of Vertical Axis Rotating Cutters for Cutting Corn Roots and Crown
## 4 Conclusions  
The bionic cutter for cutting crowns was designed through reverse engineering technology, and the multi-curve cutter for cutting roots was designed based on the distribution characteristics of roots in different soil layers. A full-factorial test was designed, and DEM was employed to simulate the process of cutting the root-crown. A field test was conducted to validate the accuracy of the simulation results. The significance and effect of the forward  
Figure 10: Consistency of the results in the field and simulation tests. (**a**) The comparison of indicators. (**b**) The effects of soil disturbance. (**c**) The effects of cutting the root–crown. speed and rotational speed of the cutter shaft on the qualified rate of the root-crown length, the rate of soil disturbance, and the power consumption of the device were investigated. The qualified rate of the root-crown length was significantly affected by the forward speed and the rotational speed of the cutter shaft. The moving cutters followed a cycloidal trajectory and cooperated with the fixed cutter to support and cut the crown. The multi-curve cutter sequentially carried, pulled, and cut in the soil through curves at different positions, achieving effective root cutting. As the rotational speed of the cutter shaft increased, the qualified rate of the root-crown length increased. An increase in forward speed led to a decrease in the qualified rate of the root-crown length. When the forward speed was 0.71 m\(\cdot\)s\({}^{-1}\) and the rotational speed of the cutter shaft was 540 r\(\cdot\)min\({}^{-1}\), the qualified rate of the root-crown length was highest, and the value was 98.51%. When the forward speed was 1.43 m\(\cdot\)s\({}^{-1}\) and the rotational speed of the cutter shaft was 360 r\(\cdot\)min\({}^{-1}\), the qualified rate of the root-crown length was lowest, and the value was 83.13%. The rate of soil disturbance was significantly affected by the forward speed and the rotational speed of the cutter shaft. Due to the presence of the roots-soil composite, soil disturbance was exacerbated when the cutters contacted and cut the roots. As the rotational speed of the cutter shaft increased, the rate of soil disturbance increased, and a similar trend was observed with the increase in forward speed. When the forward speed was 1.43 m\(\cdot\)s\({}^{-1}\) and the rotational speed of the cutter shaft was 540 r\(\cdot\)min\({}^{-1}\), the rate of soil disturbance was highest, and the value was 35.28%. When the forward speed was 0.71 m\(\cdot\)s\({}^{-1}\) and the rotational speed of the cutter shaft was 380 r\(\cdot\)min\({}^{-1}\), the rate of soil disturbance was lowest, and the value was 18.56%. The power consumption of the device was significantly affected by the forward speed and the rotational speed of the cutter shaft. As the rotational speed of the cutter shaft increased, the power consumption of the device increased. Similarly, as the forward speed increased, more energy was required to overcome the soil resistance, resulting in higher power consumption of the device. When the forward speed was 1.43 m\(\cdot\)s\({}^{-1}\) and the rotational speed of the cutter shaft was 540 r\(\cdot\)min\({}^{-1}\), the power consumption of the device reached the highest value of 8.239 kW. When the forward speed was 0.71 m\(\cdot\)s\({}^{-1}\) and the rotational speed of the cutter shaft was 380 r\(\cdot\)min\({}^{-1}\), the power consumption was lowest, and the value was 3.835 kW. To pursue lower power consumption of the device and minimize soil disturbance, it was recommended to adopt the lower rotational speed of the cutter shaft and forward speed in practical applications. Although this might result in a slight decrease in the qualified rate of root-crown length, the national standard of 90% could still be met. However, the operational efficiency of the device would be affected at lower forward speeds.