Hello,

I'm new to robotics and, thus, this forum.

I'm trying to use the RMF calculator to get a feel for the size of a motor I may want. I'm doing something wrong... most suredly messing up the unit conversations but am not certain.

Here are my assumptions:

20lb robot

4 ft/s velocity (walking speed)

.25 ft/ss accelleration

75% efficiency

10% incline

.5 foot wheel (6")

2 powered wheels

This produced a RMF of 61.6. Yikes. I presume this is to maintain speed up the inclince.

It also produced a 2.65 RMF (zero incline).

Other numbers were 100 for momentum, 191 rpm, and 1.08 watts.

As I look around at motors... I see that most motors will fall well below the 2.65 RMF needed for level movement, much less the 61.6 RMF.

I did stumble across the IG52-04 (

http://www.superdroidrobots.com/shop/item.aspx?itemid=873 ). This unit produces 23 kgf-cm at 136 rpm. I presume that I convert the 23 kgf-cm to lb-ft by multiplying by 0.07234 to arrive at 1.66 lb-ft.

Plugging 1.66 lb-ft and 136rpm results in 3.77 RMF.

So... Two of these motors will keep the robot going at 5 ft/s on level ground and have a *little* grunt left over for inclines. But I'm going to see serious degradation as it climbs up a slope.

This seems like a pretty heavy duty motor for such low performance like this.

Is my math off? Should I be somehow considering the fact that this motor has a 1:26 reduction gearbox?

-Mike