Build Blitz Robot Reveal - Team JVN

[Grant Cox]

(click for high resolution version)

After one of the most intense three days of their lives, Team JVN is proud to present their final creation. Features include:

• New 2014 Drive in a Day chassis that is now available to all teams, with four omni wheels and direct-mounted CIMs
• Launcher with 60 ft-lb of surgical tubing, pulled back by a custom cam actuated radial release mechanism (or "choo-choo")
• Optimized shot to score anywhere 7-18 ft from the goal using "Aren's Sweet Spot"
• Intake roller using 3.25" VersaWheels and passive side rollers, run by a Mini CIM motor mounted on a 9:1 VersaPlanetary

Check out the official reveal video here: http://www.youtube.com/watch?v=Gm96S8gdhR0

For more information on how this robot came to be, be sure to check out BuildBlitz.com, where you can find team bios and a full CAD assembly. The mission of Build Blitz is, and has always been, to educate teams on the process these designers went through when designing their robot. As such, check out the liveblogs on the homepage of BuildBlitz.com, and feel free to use this thread to discuss or ask questions about Team JVN's final product.

[Thad House]

You linked Copioli's video in the post instead of JVN's.

But otherwise, I LOVE team JVN's robot. It great, and fairly simple at the same time.

[Grant Cox]

Originally Posted by sst.thad

You linked Copioli's video in the post instead of JVN's.

You made it in right before I edited it. Should be fixed now!

[DampRobot]

I have to say, I was rooting for Team Copioli from the beginning, but I really have to hand it to Team JVN. They pulled off an extremely effective robot, even for a six week timescale.

[Ether]

Question. The choo-choo cam appears to be spinning at roughly 5 sec/rev = ~12 RPM. So the BAG motor would be spinning at roughly 5*100*84/18 = 5600 RPM, or 37% of free speed. Is full voltage being applied to the BAG motor?

[Aren_Hill]

Originally Posted by Ether

Question. The choo-choo cam appears to be spinning at roughly 5 sec/rev = ~12 RPM. So the BAG motor would be spinning at roughly 5*100*84/18 = 5600 RPM, or 37% of free speed. Is full voltage being applied to the BAG motor?

Ether,

That video clip is slowed down, in actuality it take about 2 seconds to reload.
We are giving the BAG full voltage.

[MrRiedemanJACC]

Love the four bar mechanism for getting the reload. Extremely ingenious!

One question though, why did you use omni wheels rather than Mecanum? Was it availability or was it programming (I think I remember you guys using a VEX system, not the C-Rio with Labview) or just easier to do it with Omniwheels?

[Ether]

Originally Posted by Aren_Hill

That video clip is slowed down...

I thought that might be the answer. Your new numbers put the BAG in a happier place on the motor curve :-)

[Aren_Hill]

Originally Posted by Ether

I thought that might be the answer. Your new numbers put the BAG in a happier place on the motor curve :-)

Yeah, I'm looking forward to next year with the new PD board with current monitoring built in, we did test some with a clamp on ammeter and saw ~12amp peak draw for the windback.

[Richard Wallace]

Thanks for that bit of data, Aren. Seems like the mini-CIM BAG is a bit oversized for this mechanism, electromagnetically speaking. I like that.

[Thad House]

Originally Posted by Richard Wallace

Thanks for that bit of data, Aren. Seems like the mini-CIM BAG is a bit oversized for this mechanism, electromagnetically speaking. I like that.

We are currently looking at testing a choo-choo, and we are planning on using a 775, thru a 63:1 versaplanetary, then a similar 18:84 ratio. At 25 amps, it should spin at about 30 rpms, and pull about 350 lbs at a point 2 inches out from the rotation. Overkill a little, but more speed and power is always the answer.

[Ether]

Originally Posted by sst.thad

We are currently looking at testing a choo-choo, and we are planning on using a 775, thru a 63:1 versaplanetary, then a similar 18:84 ratio. At 25 amps, it should spin at about 30 rpms, and pull about 350 lbs at a point 2 inches out from the rotation.

How did you calculate the 350 lbs number ?

[cbale2000]

What did team JVN use for surgical tubing on the launcher (and where do you get it)? The tubing we've been prototyping with has been less than effective.

[Aren_Hill]

Originally Posted by cbale2000

What did team JVN use for surgical tubing on the launcher (and where do you get it)? The tubing we've been prototyping with has been less than effective.

Just black Latex tubing from McMaster.
http://www.mcmaster.com/#latex-tubing/=q9fexw

I think that stuff was 5234K46 (1/2" OD, 1/4" ID)

[Ryan Dognaux]

I don't remember seeing this anywhere so I figured I'd ask - what material are the ball holding posts made from and is there a vendor where we could pick up a few?