pic: Pic 2: "caster wheel" crab drive combo

[adengler]

loading photo ...

[RyanN]

How exactly is it supposed to work on a robot. I understand how the module itself works, but when you put it on the robot 'as-is,' wouldn't it just spin in circles?

Please explain... I'm curious...

[roboticWanderor]

I LOVE IT!!! I remember putting a caster over a tough box like that one time, and then not figuring out how to turn it, which is my biggest question.....

[adengler]

Originally Posted by RyanN

How exactly is it supposed to work on a robot. I understand how the module itself works, but when you put it on the robot 'as-is,' wouldn't it just spin in circles?

Please explain... I'm curious...

We'll try to post more info/pics as it develops. The idea is to link two of these units together with a tie rod as in "ackerman steering".

[JHSmentor]

Very similar to some ideas that we had for setting up a crab drive or ackermann drive system.

did you try direct driving the wheels rather than using the chain? could save you some weight and be a little cleaner setup - not sure if you would have enough clearance for the caster setup though.

Other than that - I love it.

[Greg Peshek]

Originally Posted by JHSmentor

did you try direct driving the wheels rather than using the chain? could save you some weight and be a little cleaner setup - not sure if you would have enough clearance for the caster setup though.
Other than that - I love it.

We're doing direct drive on our 6wd, which made me think about why they weren't doing it. I figure that with the direct drive, they'd have to support the end of the shaft to keep from getting any negative cantilever forces on the wheel. Since they aren't doing a standard crab module, they really don't have an easy way to support the end of a direct drive shaft.

With the two little side plates going down to support the chain driven wheel, they instantly have a well supported wheel with no cantilevering.

At least, that's how it seems to me.

-Greg

[JHSmentor]

Originally Posted by Greg Peshek

We're doing direct drive on our 6wd, which made me think about why they weren't doing it. I figure that with the direct drive, they'd have to support the end of the shaft to keep from getting any negative cantilever forces on the wheel. Since they aren't doing a standard crab module, they really don't have an easy way to support the end of a direct drive shaft.

With the two little side plates going down to support the chain driven wheel, they instantly have a well supported wheel with no cantilevering.

At least, that's how it seems to me.

-Greg

Yes, I had the same concern with the cantilever affect but I found a way to mount the wheels very close to the toughbox as a direct drive (through some good luck while using Autodesk). with the low friction surface this year and decent weight balancing, I think this will work out fine. But, supporting the wheel on both sides eliminates that concern so it should be more robust with the only real downside being added weight.

[5n1p3r]

my suggestion is that you use wheels that turn under your control, a design like that would have you doing donuts