## 3 Results
### Orthogonal Rotation Combination Design Test
#### 3.2.1 Establishment of the Regression Model and Analysis of Variance
The main reasons are as follows: when the output air pressure is too low, the clamping force of the manipulator is not high enough to pull out the rape; when the output air pressure is too high, the clamping force of the manipulator is excessive and may damage or break off parts of the rape; when the pulling angle is small, the horizontal pulling resistance increases and only one side of the root system is under pressure, which is easy to pull out; when the pulling angle is large, the pulling force is high and it is not easy to pull out the rape; when the pulling speed is too high, the initial acceleration is too high, and the clamping is unstable, resulting in a lower rape uprooted removal rate. The effect degree of each influencing factor on the rape removal breakage rate \(Y_{2}\) is \(X_{1}\), \(X_{2}\) and \(X_{3}\) in descending order. The effect of the interaction term on \(Y_{2}\) is shown in Figure 5. In Figure 5a, at a certain pulling angle, an increase in output air pressure leads to an increase in the rape removal breakage rate; at a certain output air pressure, an increase in pulling angle initially decreases and then increases the breakage rate. Similarly, in Figure 5c, at a certain pulling angle, an increase in pulling speed results in higher breakage rates, whereas at a certain pulling speed, increasing the pulling angle first reduces and then raises the breakage rate. According to the response diagram of the test factors to \(Y_{2}\), the change rule of the response surface is consistent with the results of variance analysis (Table 9) and regression Equation (5). When the pulling angle is lower and the pulling speed is lower, the pulling force is lower; otherwise, the pulling force is higher. The pulling force is not directly related  
Figure 4: The influence of interaction factors on the rape uprooted removal rate. Figure 5: The influence of interaction factors on the rape removal breakage rate. to the output air pressure, and the pulling speed has little effect on the pulling force. The main reasons are as follows: when the pulling angle is too large, it is necessary to overcome all the pull-out resistance of the main root and lateral root, and the pulling force is high; the output air pressure directly affects the clamping force of the manipulator. The clamping force directly affects the rape uprooted removal rate and the rape removal breakage rate and has no direct effect on the pulling force. The effect degree of each influencing factor on the pulling force \(Y_{3}\) is \(X_{2}\), \(X_{3}\) and \(X_{1}\) in descending order. The effect of the interaction term on \(Y_{3}\) is shown in Figure 6. Figure 6 shows that at a certain output air pressure, the pulling force increases with the increase in pulling angle; at a certain pulling angle, the pulling force is not directly related to the output air pressure. Figure 6 shows that at a certain output air pressure, the pulling force increases with the increase in pulling speed; at a certain pulling speed, the pulling force is not directly related to the output air pressure. Figure 6 shows that the pulling force increases slightly with the increase in pulling speed at a certain pulling angle, and the pulling force increases with the increase in pulling angle at a certain pulling speed. According to the response diagram of the test factors to \(Y_{3}\), the change rule of the response surface is consistent with the results of variance analysis (Table 9) and regression Equation (6). When the pulling angle and speed are lower, the pulling force is lower; otherwise, it is higher. The pulling force is not directly related to the output air pressure, and the pulling speed has little effect on it. The main reasons are as follows: when the pulling angle is too large, it becomes necessary to overcome all pull-out resistance from both the main root and the lateral root, resulting in a higher pulling force. The output air pressure directly affects the clamping force of the manipulator, which in turn affects the rape uprooted removal rate and removal breakage rate.