pic: 2791 Starting Configuration



A clear shot of how our robot fits in the size box.

Our arm consists of two nested PVC tubes and our claw. To fit in the box, we simply slide the tubes in place and pull the arm in. The claw rests on a metal plate at the exact height of our front bumper.

When we rotate the arm even slightly out, gravity makes the inner PVC tube slide out. This extends the arm in order to reach the floor and top peg. A simple plastic wedge and stopper hold the arm comfortably in the extended position.

It’s a stupid simple solution to a complex problem. I love it!

That’s a really neat idea!

:wink:

No idea where that came from, nope…

We stepped up the PVC tube diameter for a bit more rigidity than your system. It’s paid off pretty well! Now that I think about it, our robots are dramatically similar this year…

How do you hold an ubertube for auton?

I expect they’ll have to pick it up off the floor. Probably requires a bit of forward/backward driving to get it.

Did you guys have something really cool in your base or was that guy just admiring your work?

Anyway, the bot looks awesome - get those guys some practice and it’ll do great.

Unfortunately, the gripper open breaks starting configuration, so our plan is to floor load. It probably will take more time to tune than we have to make it work (we have a Thursday) but oh well.

We’ve got a removable electronics board and cantilevered drive. They look cool!

We don’t have much time for practice, but luckily we have a veteran driver waiting to get his hands on the bot.

Chris,

Great robot, did you guys not have weight for an aluminum arm?

-RC

We’re well under. PVC was cheaper, more available, and could more easily slide within each other without the need for any actuation. It’s also easier to work with.

We bought very large (2.5" outer stage) PVC to ensure there’d be some rigidity in the arm.

We have enough rigidity with a 2" outer arm and 1.5" inner. It wiggles, but that’s not a problem. Using ABS lets us have less weight and a more robust arm, but as you noticed the only 2.5" you can find easily is gray electrical conduit.

Perhaps look into a single shot piece that holds the tube to you and your arm grabs from at the start of match. 27 did something like that in 2005 and it worked pretty well. The last thing you want is to introduce MORE human error into your auton.

There really isn’t a good place to put something like that. The arm has a very limited range of travel so it can’t bend around a corner to grab something weirdly placed.

Current plan is to put tube on ground touching bumper. Back up, extend arm, open gripper, drive into tube, close gripper, proceed with auton.

might want to add “push tube forward” in there somewhere

That’s what we did in 2007. I think we missed only once in about 50 matches.

Team 3735 is earliy similar to this but our system is a little more sturdy i think. We used 1" aluminum inside of 1.5" aluminum and instead of gravity for extension we rigged up a 1.5" bore pneumatic piston. Being able to retract the arm during the game makes driving around and placing tubes on the rack much easier.

I’m very jealous and curious of your 7 victor controlers on your electronics board. 4 are probably for the CIM motors on your drivetrain but what are the other three used for other than controling the arm?

Looks like they’ve got 3 motors per side for the drive train, along with an arm and possibly the minibot deployment mechanism (haven’t seen that yet, though). There’s still another victor on there that isn’t hooked up… maybe a quick spare?

Looks really awesome though, 2791! You guys just keep getting better :wink:

This is good to hear… though, you guys had more than Thursday at a regional to test :frowning:

We’d love to do something like that, but we wanted to keep it a little simpler and we didn’t want to commit to pneumatics when we were designing it Congrats on your accomplishment! I’m sure your robot will kick our butt on the field. :stuck_out_tongue:

I’m very jealous and curious of your 7 victor controlers on your electronics board. 4 are probably for the CIM motors on your drivetrain but what are the other three used for other than controling the arm?

As for our electronics board, we set it up before the design was finalized so it has 9 Victors. Plus one for a Spike for the compressor (we shouldn’t need it at all with our single piston and 6.5 air tanks, but free ballast!). Originally we planned for 6 drive motors, 1 arm motor, and two motors for a roller claw, but we scrapped the roller claw with the success of our pneumatic. We’re keeping the 8th and 9th on just as a spare.

I’m really proud of the extra mile we went to make a modular, removable electronics board this year. Every single plug is hooked up to an Anderson connector. Just one “click” and we’re wired up.

Aluminum will definitely be more sturdy. We chose PVC so that if our arm would become tangled with another bot or element during the match the pipe would bend instead of break. And Theotherguy is right, we have a 6 motor drive train, the seventh is for the arm. We have two spares just in case we need them.

Ha ha ha, you weren’t lying Chris when you mentioned that our bots look similar! Great job on the robot Chris and looking forward to seeing it in action. Oh btw, we changed the way our bot looks :stuck_out_tongue:

Video posted here:

http://www.chiefdelphi.com/forums/showthread.php?p=1029069#post1029069