[Brandon Holley]

Originally Posted by crazyStone

Yes I understand there is a limit for the amount of torque that can be transmitted through the wheels. I have had a year of physics and am in AP physics now. The reason I used perhaps, is the fact of weight distribution and the surface area of wheels and material used all play into the how much of that torque can be distributed. Perhaps a configuration can be made that 3.5 ft/sec still transfers torque effectively through the wheels. That is the reason for the prototyping, in addition if we can successfully create the modules with gearing inside of them; it should be much easier task to create modules without switching speeds. This is merely a prototyped design that is being constructed. There is no belief that it will work flawlessly or be a great improvement it’s more of skill building project for preseason. The gear ratios have been made smaller in consideration for what everyone on here has been saying, the low speed has been moved up to nearer 4ft/sec.

I think what Sean was saying in one way or another, is that you don't need to prototype to get a good idea of what to expect in this particular scenario. Prototyping is certainly one way to do it, but the problem with prototypes is that they get expensive quickly. If you go on to study engineering, and eventually become an engineer, you will quickly learn that saving resources (time, money, machines, etc.) is always something to consider.

Going back to your original problem... A 135 lb robot (120 lb + battery, etc) can only exert a given force on the ground through whatever number of contact points it will have. If you have a good estimate on the coefficient of friction between the wheel and the carpet, you can easily estimate what the ideal gearing should be; no prototyping required.

-Brando