Modified Design of a Precision Planter For a Robotic Assistant Farmer

2-3- Test Parameters: 
We can split all the parameters in the series of experiments into two main group, constant 
parameters and variable parameters. Table 2-1 shows the parameters that were kept constant 
Wedge 

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during all the experiments. Table 2-2 shows the variables of the experiments and their range of 
change.
Table 2- 1- Constant parameters of the experiments 
Constant parameter name 
Value 
Unit 
Soil moisture(water content) 
13% 
NA 
Carriage Speed 
6 
Km/hr 
Cutting depth 
50 
mm 
Packing Level 
Medium 
NA 
Disc size 
460 
mm 
Disc Thickness 
4 
mm 
Table 2- 2- Variable parameters of the experiments 
Variable name 
Range 
(Degrees) 
Step 
(Degrees) 
Disc angle (ɣ) 
0-28
7
Tilt angle (β) 
15-25 
5
2-4- Test procedure: 
Before doing any tests, the soil was prepared. The process of soil preparation usually 
takes about 3 hours. First, water was sprayed on the soil to increase the water content of the soil 
to a desired level. The common soil water content used for corn planting is about 13%. So, it was 
tried to keep the soil moisture about the same level. The water penetrates into the soil after about 
1.5-2 hours. After that the roto-tiller was used to loosen and mix the soil. Two passes of roto-
tiller would be enough to thoroughly mix and loosen the soil. Then to pack the sub-surface soil, 

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sheep foot drum was used. The drum can be attached to the carriage and as indicated in table 2-3, 
4 passes of sheep foot would be enough for medium packing. After that, the smooth heavy drum 
was attached to the carriage to do the final flattening and surface packing of the soil. Again, as 
shown in Table 2-3, 4 passes will result in medium packing level.
When the soil bin was ready, the disc coulter was attached to the carriage with the proper 
disc angle and tilt angle. Then the disc was lowered till it touches the leveled soil. This point will 
be depth zero. From this point the disc was lowered for another 50 mm, as the cutting depth is 50 
mm. Then the carriage speed was set to 6 km/hr. Then start button was pressed, the carriage 
moved forward and as soon as it touches first trigger switch, which starts recording data, until it 
touches the end switch. Before it reaches to the end of soil bin, the stop button was pressed to 
stop the carriage. 
Table 2- 3- Compaction Level of the soil in the soil bin 
Compaction Level 
Number of passes for packing drums 
Low Compaction 
2 
Medium Compaction 
4 
High Compaction 
6 
Each test was repeated 4 times to confirm the results and have sufficient repeatability of 
data. 
After each soil preparation, 3 samples of the soil were collected to measure the soil 
moisture content. The samples were weighed and placed in the oven for 24 hours to dry. The 

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difference between the weight of the samples before and after drying indicated the percentage of 
the water content of the soil.