pic: Can anybody give me advice on my Butterfly drive that I am working on?

[Dunngeon]

Originally Posted by dragon_pilot

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What's the justification behind using belts to connect the two sides? One of the major benefits of a Butterfly setup is the increased mobility of the 4 Omni wheels when driven independently.

Another question, with the traction wheels on the outside, its possible that with a scrub-steer setup and 4wd; That the robot won't be able to turn smoothly since the wheelbase is so long. It would essentially jitter (bounce) over the ground as the side wheels move in opposite directions. Not saying it would happen to this robot, since I don't know it's final weight; but my recommendation would be to place the omni's on the outside and the traction on the interior. It's what nearly every other implementation of Butterfly uses. See this butterfly implementation



Good Luck from your Cross-Town Rivals, see you at BB

[Electronica1]

Originally Posted by Dunngeon

What's the justification behind using belts/chain to connect the two sides? One of the major benefits of a Butterfly setup is the increased mobility of the 4 Omni wheels when driven independently.

From what I understand, a lot of teams with butterfly link the wheels on each side together so that they don't loose power during a pushing match due to a wheel loosing contact with the ground.

Originally Posted by Dunngeon

Another question, with the traction wheels on the outside, its possible that with a scrub-steer setup and 4wd; That the robot won't be able to turn smoothly since the wheelbase is so long. It would essentially jitter (bounce) over the ground as the side wheels move in opposite directions. Not saying it would happen to this robot, since I don't know it's final weight; but my recommendation would be to place the omni's on the outside and the traction on the interior. It's what nearly every other implementation of Butterfly uses. See this butterfly implementation

Just an fyi, they had the traction wheels on the outside.

[Dunngeon]

Originally Posted by Electronica1

From what I understand, a lot of teams with butterfly link the wheels on each side together so that they don't loose power during a pushing match due to a wheel loosing contact with the ground.

Oh, that makes sense; especially when up against the stronger drivebases.

Just an fyi, they had the traction wheels on the outside.

Suppose I should have made that clearer. Most teams I've seen run on the Omni's the majority of the time, and the axle is run through that wheel because it's the primary wheel. The axle placement on the traction wheel, at least to me, implied that the traction wheel was the primary.

[runneals]

We found that the pneumatic pistons worked really well (and were pretty small) to switch between omni and traction mode (plus gave the effect of low rider )

If you have any questions, feel free to ask me or the team and they can probably field your questions about it.

[Gregor]

Originally Posted by Dunngeon

Another question, with the traction wheels on the outside, its possible that with a scrub-steer setup and 4wd; That the robot won't be able to turn smoothly since the wheelbase is so long. It would essentially jitter (bounce) over the ground as the side wheels move in opposite directions. Not saying it would happen to this robot, since I don't know it's final weight; but my recommendation would be to place the omni's on the outside and the traction on the interior. It's what nearly every other implementation of Butterfly uses. See this butterfly implementation



Good Luck from your Cross-Town Rivals, see you at BB

http://www.chiefdelphi.com/forums/sh...#post139026 6

[75vs1885]

I am having trouble seeing how the Omni wheels get their power. Also, I didnt see a shaft for the omni wheels....

[Lexlukener]

You could flip the orientation of the ball-shifter and puting on a double 25 chain sprocket inside the 1x2 and route chains to either module.

[Munchskull]

Originally Posted by 75vs1885

I am having trouble seeing how the Omni wheels get their power. Also, I didnt see a shaft for the omni wheels....

In Butterfly drive Omni wheels go unpowered, the use of them if is for drifting around.

[R.C.]

Originally Posted by Munchskull

In Butterfly drive Omni wheels go unpowered, the use of them if is for drifting around.

Negative sir, they are powered and normally connected by gear or belt.

http://www.teamneutrino.org/seasons/...bot/butterfly/

[Munchskull]

My mistake. I seem to reamber team 118's robot having passive omni wheels on their Buttyfly drive. The designer of thus drive train is on my team so I can ask him about the unpowered omni's.

[Dunngeon]

Originally Posted by Munchskull

My mistake. I seem to reamber team 118's robot having passive omni wheels on their Buttyfly drive. The designer of thus drive train is on my team so I can ask him about the unpowered omni's.

Robonauts did have Omni-wheels on their drive last year, but it wasn't anything close to butterfly. They used the omni's in conjunction with their WCD 8wd to perform J-turns and mad drifts.

[Munchskull]

Originally Posted by Dunngeon

Robonauts did have Omni-wheels on their drive last year, but it wasn't anything close to butterfly. They used the omni's in conjunction with their WCD 8wd to perform J-turns and mad drifts.

Actually Robonaut's drive was a subset of Butterfly called Texas Coast, the unpowered wheels are what makes it Texas Coast.

[JesseK]

Originally Posted by Munchskull

Actually Robonaut's drive was a subset of Butterfly called Texas Coast, the unpowered wheels are what makes it Texas Coast.

While we're grumbling about what someone else called their bot, we may as well aim for accuracy -

Did the Robonauts call it grasshopper drive, or a subset grasshopper drive? Where's the proof either way? I don't recall them calling it anything other than 'drop down omnis'.

Then again there is no formal definition of grasshopper, butterfly or other insect-based drive. IMO, they're all just derivatives of the Armadillo Drive and none of them ever give it credit. To me, "Texas Coast" isn't a subset of Armadillo Drive since they serve 2 different purposes and are designed quite differently.

Am I crazy? Was there one before 2010? My memory is getting bad these days...

/sarcasm

[Dunngeon]

Originally Posted by JesseK

While we're grumbling about what someone else called their bot, we may as well aim for accuracy -

Did the Robonauts call it grasshopper drive, or a subset grasshopper drive? Where's the proof either way? I don't recall them calling it anything other than 'drop down omnis'.

Then again there is no formal definition of grasshopper, butterfly or other insect-based drive. IMO, they're all just derivatives of the Armadillo Drive and none of them ever give it credit. To me, "Texas Coast" isn't a subset of Armadillo Drive since they serve 2 different purposes and are designed quite differently.

Am I crazy? Was there one before 2010? My memory is getting bad these days...

/sarcasm

Haha, I get your point. It's just a little bit easier to talk about drivetrain styles when you have some specialized vocabulary.

Also, I thought Tex-coast was a few of the Texas teams feeling left out of the WCD hype train and they tried to rename butterfly.

[Electronica1]

Originally Posted by 75vs1885

I am having trouble seeing how the Omni wheels get their power. Also, I didnt see a shaft for the omni wheels....

He did say it wasn't done. I assume the the final design doesn't have floating omni wheels. (please correct me if I'm wrong)