Omni drive

[Laaba 80]

Our team went with a omni drive this year. 4 wheels, each at 45 degree angles. Our team participated in a webcast earlier in the season, and people kept telling us how that type of omni drive doesnt work well, and that it is useless. We decided to go with it anyways because my team had an Omni drive at the Milwaukee Vex league this year and it worked well for us. So far I have liked what I have seen from our FRC bot. I was wondering why people dont like this type of drive.
Joey

[Kellen Hill]

In my opinion they get pushed around too easily.

[Laaba 80]

Originally Posted by hill

In my opinion they get pushed around too easily.

I do see where people get this from, however they do have a suprising amount of push. The whole reason of an Omni drive however is to not get in a pushing match. It can move any direction, just spin or strafe away from whoever is trying to push you.
Joey

[David]

They get pushed easily, but their goal is to offset getting pushed by greatly increasing maneuverability. Like you are describing, omni drive will be very effective for this year's game. A lot of teams fear being pushed or not being able to push, but few realize that you don't get points from pushing

[AndyB]

At times, its as if your driving a robot on Ice... and pushing against a Zamboni. But in this game I think your decision was just fine. Can't wait to see you guys at Milwaukee. Can we see any pics?

[MrForbes]

Originally Posted by David

A lot of teams fear being pushed or not being able to push, but few realize that you don't get points from pushing

The problem is that it's hard to score points when you're being pushed around, or can't push another robot out of the way.

Then again, the game this year appears to be set up to favor manuverability, we'll see how it works out!

[Laaba 80]

I'll try to get some pics. I had some pics on my flash drive, but I dropped it in our mentors truck on the way home from the FTC competition this weekend. It is again almost all clear. I really like how it looks.
Joey

[Kellen Hill]

All I know is that if I was a driver, I would hate getting pushed around.

But of course if you really want maneuverability, I guess you guys made an okay choice in drive train.

[Laaba 80]

Originally Posted by hill

All I know is that if I was a driver, I would hate getting pushed around.

But of course if you really want maneuverability, I guess you guys made an okay choice in drive train.

I agree. Last year I would have hated being pushed around, but this year why would someone push you around? I think manuverability will be HUGE this year. I am hearing about many teams that can go 20+ feet per second but I havent seen any with drivers that have been able to control them. I think many teams may have overlooked manuverability in favor of power or speed.
Joey

[Lil' Lavery]

Of those saying omni-drives get pushed around, how many have actually driven an FRC scale holonomic drive robot?
I've driven FRC scale holonomic bots (116 '05), and "tank drive" (116 '04) at off-season events, and the difference in maintaining position wasn't very large. The holonomic bot wasn't able to push other robots nearly as well, but it didn't give up much ground when attempting to stay in position either.

[Kellen Hill]

Of course that depends who you are pushing against.

And I know just from watching, and the fact that they are only on omni wheels makes them easy to push around.

[Stuart]

well we had this talk at the beginning and came up with a design very similar to whats being talked about. the big point is that if some one is pushing you . . they will be doing so in a forwardish way. so it will some what help you out. also having no turning radius will be a good thing.

[Lil' Lavery]

Originally Posted by hill

And I know just from watching, and the fact that they are only on omni wheels makes them easy to push around.

I beg to differ, greatly. As I mentioned, I drove a bot, driven solely by omni-wheels, and we were not easily pushed around. In fact, on more than one occasion we actually played defense by intercepting an offensive bot before it reached the goal. We weren't able to move them, but they weren't able to move us either.
Static friction isn't affected by the amount of contact you have, and with most roller shapes, the angle you're rollers are pointing. Or tractive force was only limited by what material we put on the wheels. Early iterations had slick, hard plastic rollers, but the final version had softer white neoprene rollers that had coefficients of friction competitive to those in traction wheels.