We built a 6-CIM Kiwi Drive. Criticisms please!

[Nate Laverdure]

Originally Posted by asid61

Have you tested the electrical current levels against a 4-wheel or 6-wheel drive for the same speed?

What's interesting about omni and mecanum drives is that the rollers have small but significant friction (especially when you apply an axial thrust load!). When you arrange 4 omni wheels in a rectangle, you get a drivetrain that prefers to travel in the cardinal directions and dislikes traveling in arbitrary, off-cardinal directions. With a triangular design you don't have this issue, but with a hexagonal design you would. When it comes to the number of drive wheels on a kiwi-bot, any odd number greater than 2 would work!

Originally Posted by asid61

How much does the basic chassis weigh, not including electronics (with or without motors)?

Originally Posted by asid61

Did you have tipping problems due to the 3-wheel design?

Nope. The wide-set front wheels ensured that a very small amount of weight was cantilevered outside of the supported triangle. Also the robot's CG was extremely low even when carrying a ball. Bumpers were slammed to the bottom of the bumper zone. I just wish I could have gotten the battery lower and less exposed.

Originally Posted by asid61

Did the pointyness help you very much?

Actually, the flatness did. The chassis shape gave us an extremely wide, flat front that we used for ball corralling and a blocking-style defense.

Originally Posted by asid61

What kind of traction did you see with this?

Wheel static COF in the direction of travel is supposedly 1.0 (compare to the KOP HiGrip). We did not test this. We also chose this design path with the understanding that we would avoid pushing matches and attempt to avoid defenders instead. Even with an open field, I find that you can do a lot of high-quality defense without needing to touch your opponent. Unless they're really aggressive, most drivers will choose to avoid defenders instead of barreling straight through them.