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Unread 21-02-2007, 23:45
Ben Piecuch Ben Piecuch is offline
Bengineer
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Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 2000
Location: Providence, RI
Posts: 336
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Re: Problems turning

Bochek,

You didn't tell us what your drivetrain consists of, and your video doesn't give us much insight into it either. However, based on a previous picture you posted of your kitbot, I'm going to assume that you're using the standard kitbot setup with 4 kit wheels, a single motor Banebot 56mm tranny, and 2wd.

Your problem comes with the fact that your robot requires more power to turn than the single motor setup provides. The kit wheels provide a lot of traction in both the lateral (front/back) and transverse (side) directions. You need to either:
a) increase the supplied turning force.
b) reduce the required turning force.

You can solve (a) by adding more power with more motors, or by reducing the gear ratio to reduce your speed and increase your torque. With your existing weight problem, adding more motors doesn't help your cause.

You can solve (b) by reducing the transverse friction in your wheels. Most teams accomplish this by adding one set of "omniwheels" to their drivetrain. For 2wd setups, you would add the omniwheels to the non-driven wheels. Andy-Mark makes a nice omni-wheel, but they are not the only ones on the market. There are cheaping and lighter alternatives, such as ones found at McMaster.com or Omniwheel.com You can also reduce your required turning force by reducing your wheelbase, or powering all 4 wheels.

There are several whitepapers, as well as numerous threads on this site that explain this problem in more detail. Some simple changes should be able to be made at your competition to have you up and running in no time. Best of luck,

BEN