Drive Question

I’m from a rookie team and I’m trying to figure out the drive setup. It sounds like most teams use 4 cims for drive. Is this true – all four for drive and not just 4 cims on the bot total. Also, we are using the Cimple box. Does this mean we should put two cims on each box or get 4 boxes and 4 cims, one cim per box?

It may be up to us but could you give us your opinion from experience??

PS we are not using omi wheels – just the wheels from the kop. We could use better wheels but don’t want to venture into omni. Could you suggest an alternative to the wheels provided in the Kop?

Thanks

You have it right, most teams use 4 cims in the drive, two per side, installed in one transmission.

There are a lot of wheels, look at AndyMark’s web page

http://www.andymark.com/Wheel-s/229.htm

also IFI (now VexPro)

http://www.vexrobotics.com/products/vexpro?vex_navigation_vexpro=4536

also some teams make their own, or adapt other wheels to fit robots (both of which takes some effort).

Thanks for your input! When you say one transmission what exactly do you mean?

Should we put chain to all 6 wheels or should we just power 4? My mentor is saying that putting chain to all 6 is not necessary but I just don’t know if he’s right or not.

Always power all wheels. Unpowered wheels are wasted weight and offer an additional way to get the robot stuck on something. It also offers redunceny in the drive train so if you throw a chain you still have some mobility. The extra 2-3 lbs it takes to power all the wheels is worth it.

Chain to all 6. Better yet check out the Kitbot on Steroids by 1114
It gives full instructions on how to build a kick-butt drivetrain from mostly the KoP.

While you technically don’t have to power all the wheels, doing so will allow you more traction because all your weight would be on driven wheels. A couple years ago, we had the battery and a few other components over undriven wheels, so we lost several pushing matches. I’m not sure how to explain the physics behind this, but here goes. f=un (friction = coefficient of friction*normal force). The normal force at the drive wheels is basically the weight of your robot at that point. The more weight you have on your drive wheels the more traction you can get. Additionally, if you plan to go over the barrier, or possibly even the ramp, powering on the wheels will help prevent you from high centering (yes, there will be other factors, but everything helps).

Additionally, I think most teams use plaction wheels from Andymark for a tank drive.