I was hoping y'all could verify that I'm on the right track for motor calculations. I expect these numbers to be reasonable, but not exact (for example, friction isn't included). The robot will be similar to a tilted mover's dolly, weigh about 22.6 kg (roughly 50 lbs), and be powered by two motors. The wheels right now are inline skate wheels, but I may have to get bigger wheels if I can't find a pair of motors to match the RPMs.
robot weight: 22.6 kg
max incline: 20 degrees
velocity: 167 cm/s (or 100 m/min, just above the average speed of a walking male)
acceleration: 80 cm/s^2 (half of velocity, advice from Robot Dynamics tutorial http://www.societyofrobots.com/mechanics_dynamics.shtml
acceleration from incline: 335.5 cm/s^2 (from 981 cm/s^2 * sin (20 * pi / 180))
total acceleration: 415.5 cm/s^2
wheel height: 7.6 cm (inline skate wheel)
wheel circumference: 23.876 cm (pi * diameter, so pi * 7.6 cm)
force: 93.9 N (mass * acceleration, so 22.6 kg * 415.5 cm/s^2)
total torque: 3.5682 N m (force * wheel radius, so 93.9 N * 3.8 cm)
torque per motor: 1.7841 N m (torque / 2)
rpm: 419 rpm (velocity / wheel circumference, so (10,000 cm / min) / 23.876 cm)
I put these numbers into the RMF calculator (http://www.societyofrobots.com/RMF_calculator.shtml
) and received an RMF score of 54.3 kg*m*rps.
I'm concerned because if I put the calculated torque (.18 kg*m, from 1.7841 N m) and speed (420 RPM) into the Motor Characteristic section, I get an RMF score of 1.26 kg*m*rps, not even close to the 54.3 kg*m*rps.