Omniwheel question

[psychoCHIPMUNKK]

In your vast travels, has anyone seen an idea for a locking omniwheel? What i mean by that is one that can have all the normal functions of an omniwheel, but then be able to lock the smaller wheels to become a normal wheel that can rotate in only two directions? (Sorry if this is confusing)

[Kyle]

Originally Posted by psychoCHIPMUNKK

In your vast travels, has anyone seen an idea for a locking omniwheel? What i mean by that is one that can have all the normal functions of an omniwheel, but then be able to lock the smaller wheels to become a normal wheel that can rotate in only two directions? (Sorry if this is confusing)

I know what you mean but I have not seen anything like that, not that I am the master of all things omni, but if you cant find one then you could try making one. also when we have used them in the past we had no need to stop the smaller wheels because they didnt do anything but good, I was just wondering why you might want to stop the smaller ones?

[sanddrag]

Perhaps a good compromise would be to have the transverse rollers with higher friction on their pin/axle.

[Greg Ross]

Originally Posted by psychoCHIPMUNKK

has anyone seen an idea for a locking omniwheel?

I believe I have heard of such a thing. Don't remember where. I may have seen it online, or ChrisH may have mentioned it to me.

I will see if I can find it again. If I come up with anything, I'll get back to you.

[sanddrag]

I'm just trying to envision how such a thing would even work. What would actuate the locking mechanism on the rollers?

[Alan Anderson]

Originally Posted by sanddrag

I'm just trying to envision how such a thing would even work. What would actuate the locking mechanism on the rollers?

Simple. Add a slotted plate on the axle which turns with the omniwheel and normally lets the small sidewheels spin freely. Rotate the plate a few degrees relative to the hub and the edges of the slots touch the sidewheels, keeping them from spinning. I think a servo with appropriate leverage might have enough oomph to act as an effective brake; all you need is a rotating connection for three wires.

Or maybe I'm all wet -- I'm a programmer by training and inclination, so my mechanical ideas are sometimes rather, um, loosely constrained by physical reality.

[Greg Ross]

Originally Posted by gwross

I believe I have heard of such a thing. Don't remember where. I may have seen it online, or ChrisH may have mentioned it to me.

I will see if I can find it again. If I come up with anything, I'll get back to you.

Here's what I was remembering: Improved Mecanum Wheel Design for Omni-directional Robots. I believe the "brake" system described in this paper is quite similar to the method Alan mentioned.

[Bleric]

Well, if you aren't planning on powering the said omniwheel, you could lock the large wheel itself, and have the small outside wheels do the rolling.

...Just an idea =P

[greencactus3]

if you go a killough platform id think itd be easy. but then again. if teams can make shift on the fly dog shifters, dog brakes? or you get it dont you? will be easy. id say it be on the heavy side tho. i say if you wanna do that have pop down caster/ omni on a traditional 4wd