Modified Design of a Precision Planter For a Robotic Assistant Farmer

D
raft fo
rc
e
 (
N
) 
Disc angle (Degrees) 
Tilt angle-0 
0
50
100
150
200
250
0
7
14
21
28
D
raft fo
rc
e
 (
N
) 
Disc angle (Degrees) 
Tilt angle-15 
0
50
100
150
200
250
0
7
14
21
28
D
raft fo
rc
e
 (
N
) 
Disc angle (Degrees) 
Tilt angle-20 

---

32 
Figure 2- 11- Draft force on the disc coulter for different disc angles, tilt angle=25 
We can simply see the effect of disc and tilt angle on the draft force from the graphs. 
First of all, when tilt angle is zero (Figure 2-8), increasing the disc angle increases the draft 
force. That can simply be explained; as the disc angle increases, the mirrored face of the disc on 
the plane perpendicular to the direction of motion increases. It is actually similar to the 
phenomenon of motion of a body inside a fluid. Bodies with larger face experience larger drag 
force. However, when tilt angle is not zero, the pattern changes. A single angle disc (tilt angle 
zero) opens a furrow by pushing and pressing the soil to the sides. On the other hand, a 
compound angle disc lifts up the soil and displaces it to the sides to open the furrow. It can be 
said that a using a tilt angle can help to keep the draft force from increasing intensively, when 
increasing the disc angle. 
Generally, larger disc angle means larger draft force. But, as mentioned before, having a 
disc angle is inevitable; because disc angle is the parameter that is responsible for the width of 
the furrow. So to keep the draft as low as possible, we have to choose the smallest disc angle 
possible. We can see from Table 2-4 and also Figure 2-12 that the lowest draft force with a non-
zero disc angle was obtained with a compound angle of 7º disc angle and 25º tilt angle. 
0
50
100
150
200
250
0
7
14
21
28