CHAPTER 19 ■ WHEELSWheel Choice for Sandwich
A couple of factors go into selecting appropriate wheels for the line-following robot. To begin with, a
minimum and maximum diameter must be considered.
Determining Minimum and Maximum Diameter
Sandwich’s motor shaft can be positioned as low as approximately 1.75 cm above the underside of the robot
(see Figure 19-10).
Figure 19-10. A ruler measuring the height from the surface to the center of the motor shaft
Therefore, to lift the robot up with margin for error, the wheels should have a radius of at least 2 cm.radius × 2 = diameter
2 cm × 2 = 4 cm
The minimum wheel diameter must be no less than 4 cm.
The distance between the front of the robot and the center of the motor shaft is a little less than 10 cm
(see Figure 19-11). A wheel with a diameter of 20 cm would lift the entire robot off the ground. When the
motors kicked in, the robot would likely start spinning around and around the center of the shaft, jerking
forward and backward.