Tank Drive vs. Omni Directional Drive

[MrForbes]

I don't understand the question....I don't understand how/why you'd use mecanum wheels with tank drive control?

[jamie_1930]

Originally Posted by squirrel

I don't understand the question....I don't understand how/why you'd use mecanum wheels with tank drive control?

It would be the same controls as a normal 4wd tank drive where you spin the right side forward and left backward to turn in left in place, and vice versa. The thought is that by switching out normal wheels with mecanum, coupled with the tank drive control method, you can increase your maneuverability.

[Alan Anderson]

Jamie is right. You get amazing turning performance by using mecanum wheels on an otherwise plain vanilla four-wheel tank drive robot. You sacrifice almost 30 percent of your theoretical maximum power in the process, though playing with the friction on the roller axles can get a lot of it back while still retaining the ability to turn in place without hopping or overloading the motors.

[MrForbes]

Interesting, thanks for pointing that out!

[FRC4ME]

Originally Posted by ratdude747

tank with omni's in the back. the thought was to increase traction and be able to turn around the ball.

This is what we're doing. It will be difficult to drive but easy to aim, IMO.

[SteveJanesch]

We're using the kit chassis (tank drive) with sticky wheels in the front and whatever works best in the back - slick, omni, or mecanum (we have a set of each). We're going to test each type and let the driving decide. We had to cut the opening of the kit wheel bracket (leg) wider to accommodate the extra width of the dual omni. We'll have to make our own wheel brackets to use the mecanum wheels.

We've tested the slick and the omni wheels so far, and the omnis do an interesting thing - if they're in the back when going slowly over the bump, the chassis will self-align. Since they give much better forward traction than they resist the sideways movement, the trailing omni wheel in the back just pushes that side of the chassis right up to the bump. It's the coolest thing I've seen so far during build season (within our team).

I expect that the mecanum wheels will give similar or better pivoting than the omni wheels, less forward traction but a bit more resistance to being pushed sideways. It'll probably be about a week until we get them tested, though.

- Steve