AURA2 College Reveal (Woodpecker and Dragon)

Continuing on from the reveals that we’ve been making all season, we’re revealing two of our robots for the Vex Robotics World Championships here. Each robot description is written by a different person, so the style might change a little bit. Feel free to ask questions below! Also come see our pit at worlds - we have kiwi chocolate!

http://dl.dropbox.com/u/35471757/woodpeckerdragon.jpg

Woodpecker
Woodpecker was the extension of one of our first interaction robot designs, Carwash. Carwash was designed to be an interaction robot which colour sorted objects in the interaction zone, and passed to the isolation robot. We later realised that it was better to also have the robot scoring in the closest two isolation 30" goals. For this design, we used what we know works: A very long six bar. Furthermore, we had recently aquirred mecanum wheels, and strafe was a good bonus for this robot as it would be able to easily score both 30" goals autonomously.

8 Motor drive (6x 269, 2 x 393, 1.2 Drive ratio)
2 393 Lift, 1:7
Side suckers with folding out front ramp, holds 5 - 6 objects.

Scores two closest 30” goals in the isolation zone from the interaction zone in autonomous with 1:7 lift
8 motor drive with strafe, 1.2 drive ratio with mecanum

Dragon
Dragon is a robot that is competing in Gateway college division, in the isolation zone. Dragon is a unique robot that has a backwards six bar in order to get more height and forward reach as it lifts. The backwards six bar also helps the arm not to stick out so far when it is scoring in the 20” goals. Dragon is not ideal for high school competitions because it cannot score 11.5” goals or the far 20” goals, although it can score the 30” interaction goal from isolation. There is a descoring fork on the back of the ramp. Because isolation robots are purely isolated in college, not many motors are needed for pushing power. Dragon can hold up to 6 objects.

4x393 4” drive wheels internally speed geared
2x269 2.75” strafe wheels 24:15 (1.1:1 relative to 4” wheels)
4x269 backwards six bar lift geared 1:7
2x269 side sucker intake (18T sprockets)

More photos of all four of our robots at http://www.flickr.com/photos/aucklandrobotics/sets/72157629379340192/

So many motors…

They look great, and I love the reverse 6-bar. Nice solution to be able to hold loads of objects. A chain lift would have allowed you to get over to the front of the robot to probably score in the far side 20", no?

I hope I have a chance to watch some college matches, looks like it will be very interesting.

By the way, your flickr link appears to have been cut short in the middle and no longer works.
But this works: http://www.flickr.com/photos/aucklandrobotics

We tried this, but it didn’t really work because the chain sagged too much. It works for other robots because you can pivot from the front, and it doesn’t matter that the ramp is marginally stable.

Just for the record, in the college game it’s a far side 30" goal.

Possibly just a typo, but others may not realise that we have a different field.

Also just to add to this, there IS a far side 20" but it’s quuuuiiiiiiiiite far away for the college field :stuck_out_tongue: When we tried the chain lift (Ostrich, I don’t think we had any photos to put on flickr) it could score in the far 20" from interaction, but it was too wobbly and replaced.

The chain sagged? I don’t have any experience with chain lifts but it seems like with enough tension they should be able to work flawlessly (I’m probably being too idealistic).

I forgot we were dealing with far-side 30" goals, whoops. The “far side 20” would be quite a reach, although I wouldn’t say impossible to get to.
At least there are no 40" goals for you guys this year…

You wouldn’t have noticed any sag with a front chain lift because the pivot is right at the intake and you can adjust the tension to your liking. With a backwards chain lift, the pivot is much further back from the intake, so you notice the sag much more. I have actually tried a backwards chain lift, backwards swing lift, backwards 6 bar lift that inverts to go further and found that the 6 bar we have now works the best.

Over very long distances the chain needs excessive tension to remove sagging. We decided the benefits didn’t outweigh the costs in terms of reliability.

Describe any college-only materials you have used:

  • any sheet metal?
  • any 6x6x1" plastic block?

We used sheet metal to make guards for the lift motors on Dragon. Otherwise, apart from the two extra motors, its high school legal.

Couldn’t help but chuckle when I read this. Just a warning for those that don’t know, it is bad. Very, very bad. ^.^

Just a warning for those that don’t know, Kerey likes to troll.

That I do, but seriously, I stand by my point. Unless it is Whittakers chocolate, in which case, it isn’t bad, it is actually really, really average.

a nice spin on an overused design

http://cdn.memegenerator.net/instances/400x/19036065.jpg