Modified Design of a Precision Planter For a Robotic Assistant Farmer

Chapter 5-Prototyping, test-rig and verification 
5-1- Fabrication of the prototype 
The plan was to fabricate two planters which their disc and tilt angles are mirrored with 
respect to each other. Using two planters with mirrored angles will cancel out the lateral force on 
the connection and make the mobile robot to move forward easier. In the industrial similar 
planters also use the same method to cancel out side forces. 
As mentioned in previous chapters, some of the parts are used from the donated existing 
planters. These parts are either doing nothing specific with respect to seeding and soil interaction 
(e.g. frame), or the study of their performance was not part of the objectives of this research (e.g. 
precision seed metering system). 
Figure 5- 1- Parts that are designed or modified are shown in blue 
Other parts that are completely redesigned by the author, or modified partially, are shown 
in Figure 5-1 in blue. The drawings for these parts were prepared and sent to a fabrication facility 

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for fabrication. All the drawings are given in appendix D. Some other parts were bought off the 
shelf, such as ball bearings and sprockets and chains and winch.
After gathering up all the parts together, they were assembled by the author and it is 
attached to the mobile robot, and tests are performed. Figure 5-2 shows the designed and 
assembled planters. More pictures of the developed planter can be found in appendix A. 
A few of tests are designed for this planter to study its performance and efficiency. The 
results of these tests are given later in this chapter. 
5-2- Tests 
Several tests are designed and performed in outdoor and indoor settings, to study the 
performance of the designed planter. The aspects that are studied in these tests are given below, 
- Draft force: Draft force needed to pull the implement when performing seeding was 
measured. The measured value must be comparable with theoretical value found in 
chapter 3. 
- Opening and closing the furrow: The effectiveness of the planter in opening a furrow 
and then closing it to cover the seed must be appropriate. The width of the furrow 
must be wide enough to accommodate a seed and be comparable with existing 
planter. 
- Seed drop accuracy: The distance between seeds must be measured to verify the 
performance of the new power transmission system, using press wheel. 
- Lifting of the planter off the ground for transportation
Among these parameters, the draft force is the most critical one for this research project. 
Other parameters can help to show that the performance of the new planter is as good as the 
existing planter. 

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(a) 
(b) 
Figure 5- 2- a) The assembled new planter, b) Existing CNH planter 

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Two tests are performed in two different test settings, outdoor and indoor. The outdoor 
test is performed to study the ability of the planter in opening and closing a hard soil in presence 
of crop residue. Also the depth of the cut and its consistency is studied. Besides that, the lifting 
mechanism is used to lift the planter off the ground for transportation. The main objective of the 
indoor test is to measure the draft force. Depth of cut and seed drop accuracy is also studied 
through the tests.