*3.5. Orthogonal Test Verification*

Figure 12 shows an experimental prototype of the jujube picking mechanism, which is mainly composed of a pair of roller picking mechanisms, an electromagnetic speed regulating motor, a conveyor belt mechanism, a chain drive system, a collection box, and a JD1 electromagnetic speed regulating motor inverter. The jujube branch samples were placed on the conveying device, which moved steadily under the drive of the frequency conversion motor. The jujube branch samples were transported to the picking area of the pair-roller picking mechanism, and the picking mechanism performed a pair-roller picking movement to pick up the jujube branch samples on the conveyor belt and move them to the collection box.

The jujube picking mechanism test device was used for orthogonal test verification. Each variable parameter was set, among which the size of the jujube branches was 480 mm, 640 mm and 800 mm; the total number of feedings was 16, 23 and 30; and the rotation speed of the gear was 100 r/min, 120 r/min, and 150 r/min. The test plan L9 (34) was selected, and the orthogonal test was performed according to the randomness principle of the orthogonal test, as shown in Table 3.

**Table 3.** Influence factors and levels of test.


As shown in Table 4, numerical simulation values and test results showed that the size of jujube branches was an important factor affecting the picking rate. The picking rate of jujube branches was the worst when the size of jujube branches was 640 mm. When the size of jujube branches was 800 mm and 480 mm, the picking rate of jujube branches was relatively higher. From the numerical value and the test results, the picking rate was highest when the jujube branch size was 480 mm, which indicated that the jujube branches with a smaller size were easier to be collected.


**Table 4.** Experimental design and comparative analysis with simulation results.

The extreme difference between the gear rotation speed and the total number of jujube branch feeds was relatively close, and the effect on the picking rate was basically the same. From the perspective of the optimal plan, the test results were consistent with the numerical results. The optimal plan was B3C1A1, which means that when the jujube branch size was 480 mm, the total number of jujube branches was 16 and the gear rotation speed was 150 r/min, the picking rate was the highest. The test results proved the reliability of the numerical results, indicating that the use of numerical methods based on the meshless Galerkin method can solve the problem related to supernormal particle flow in the process of picking up jujube branches.
