From the specification, we get to know that the maximum speed of the robot is 0.35 m/s. We took the wheel radius as 4.5 cm in the preceding section, and one of the other specifications we need to satisfy is ground clearance. The specified ground clearance is 3 cm, so this wheel is satisfying those requirements too. We can find the rotations per minute (RPM) of the motors using the following equation:

RPM = ((60 x Speed / (3.14 x Diameter of wheel)

RPM = (60 x 0.35) / (3.14 x 0.09) = 21 / 0.2826 = 74 RPM

We can choose a standard 80 RPM or 100 RPM for this robot.