Motor moment of inertia

[phargo#1018]

I appreciate the inquiry. Algebra always seems to be a challenge.
Today I started with the equation from page 20 and the assumption that I had improperly derived the equations on page 21.

Attached is the work.
Based upon this,I believe that I correctly provided the equations on page 21.

I have been working on a mobility simulation, in excel.
I do not have confidence in this work - perhaps this year we can do some testing to perform validation. I have also attached this work.

I have focused on reflecting the system mass as a motor shaft inertia - as opposed to reflecting the motor shaft inertia into a system mass. Assuming a 120 pound robot, 4 CIMs, 6 inch wheels, and a 12.75:1 toughbox; I believe that the motor inertia represents 13.5 percent of the overall system inertia reflected to the motor shaft.

I quickly ran the opposite computation, and I believe that the motor appears as ~2.2 kg mass, or 8.8 kg out of 54.4 kg.