Team 931 used them for the first time this year. We wanted a robot design that was longer than it was wide, for stability with a long arm, and knew that our robot would not turn well with four standard wheels. There are two omnis on the front and two pneumatics on the back.
When we switched to the omnis, it turned too well. Think about it - omnis act as casters when the robot turns. The operator would push the stick to turn and the robot would turn, but it would keep turning when the operator moved the stick back to neutral! The polar moment of inertia kept us going. If you want to go with omnis, I recommend one of three things:
-holonomic drive
-exponential stick control for better turning sensitivity at low speeds
-(best option in my mind) a gyro to counteract the overshoot
I'm trying to get a white paper out on these wheels by midsummer.
Brandon Heller
Mentor Team 931
Alum Team 449
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Originally Posted by rforystek
Hi, I'm starting this thread to get a feel of how well omni-wheels worked for the teams that actually used them. I've been looking at many possible things for out robot for next year, this being one of them. The one problem I've always wondered about is the omni wheels making the robot easily pushable. I'm wondering if they have the same effect of casters, where they allow another robot to push you around easily. If anyone out there with omni wheels could tell me about your experiances with them and especially if you got into pushing matches with other robots, that would be appreciated.
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