Optimized Design and Experiment on Novel Combination Vacuum and Spoon Belt Metering Device for Potato Planters

Table 4

Test protocol and response values.

Test number	Factor level			Response values
	Belt speed x1	Spoon aperture x2	Cleaning air pressure x3	Missing seed index (%)	Multiple seed index (%)	Qualified seed index (%)
1	0	0	0	2.5	5.6	91.9
2	−1	1	0	1.2	9.4	89.4
3	0	0	0	2.5	4.5	93.0
4	1	1	0	3.6	8.2	88.2
5	0	0	0	2.8	5.7	91.5
6	−1	−1	0	1.8	3.8	94.4
7	0	−1	1	5.4	2.8	91.8
8	0	−1	−1	4.4	6.6	89.0
9	0	0	0	3.1	5.9	91.0
10	−1	0	−1	1.3	6.1	92.6
11	0	1	−1	2.2	8.9	88.9
12	1	0	1	4.6	5.8	89.6
13	0	0	0	2.8	4.9	92.3
14	0	1	1	5.3	5.5	89.2
15	1	−1	0	4.6	9.6	85.8
16	−1	0	1	3.1	5.1	91.8
17	1	0	−1	5.2	8.5	86.3