3 Balls in a second and a half
 

Team 326 having fun testing.

No full pics or videos yet, but here's a taste of this years robot starting with our turret design, doing some 360's.

http://youtu.be/Yg-sjXOvCvw

Next, we have a two videos of test shooting from the middle of the key. Yes we are on wrestling mats, the cheerleading squad uses the room where we have our hoop, bridge and ball return. We really didn't feel like moving the mats.

http://youtu.be/7wAI1Q3pU_E

http://youtu.be/k3Yjbh7YZ28

These were rough tests, and the third video is more of the spacing in shots we are looking for.

Questions? Comments?

Re: 3 Balls in a second and a half
 

Comment: Your links are.. erm... were broken.

Re: 3 Balls in a second and a half
 

It might just be me, but none of these videos seem to work. :(

Re: 3 Balls in a second and a half
 

try it on an iphone if you can. that works

Re: 3 Balls in a second and a half
 

Fixed! Screw-up on my part..

Re: 3 Balls in a second and a half
 

shiny!:ahh: :D :ahh:
very nice fabrication on the shooter! very smooth shooting!

Re: 3 Balls in a second and a half
 

Man that shooter is nice. What is the weight of the the whole assembly with the motors? Seems like it would be on the heavier side of things...

Re: 3 Balls in a second and a half
 

After cutting out some weight its about 15 lbs... Yes heavy, but very effective so far...

Re: 3 Balls in a second and a half
 

Very cool.

The competition field has the bottom of the net zip tied to the chute. This severely constricts the bottom opening and causes two balls coming in simultaneously, or near simultaneously (like in your video) to get completely jammed.

You may already be aware of this. Just a heads up.

Re: 3 Balls in a second and a half
 

How are you managing the wires between the turret and frame? Nice fabrication on the shooter, by the way, sounds AND looks nice and smooth

Re: 3 Balls in a second and a half
 

Yes we are.. As I said these are rough tests and we are looking for better spacing of the balls being shot.

It's not going to be doing the full 360's, it was just for fun. We will mainly be using about only 180 degrees of it at most.

Re: 3 Balls in a second and a half
 

Is your shooter wheel direct driven by two BB RS775s? I didn't see any gearing in the video.

Re: 3 Balls in a second and a half
 

Where did you get the rollers?

Re: 3 Balls in a second and a half
 

OH My..........................................!!!!!! !!!!!!!!!!!!!!!!!!!!!!!! This is so LEGEN ----------- wait for it --------------- DARY!

Re: 3 Balls in a second and a half
 

they look custom, probably lathed.

Re: 3 Balls in a second and a half
 

Ya think? :) I wonder what they cost.

Re: 3 Balls in a second and a half
 

One mighty flywheel! Under some assumptions¹, I would say the largest roller takes about 6 seconds to spin up to full speed! Am I correct in my assumptions?


¹ - Dual RS775-18 motors directly coupled to the solid aluminum roller, approximately 100 mm wide and 100 mm in diameter with an 85 mm radius, giving a moment of inertia around its rotation axis of ~1067746.85 g-mm². Negligible frictional losses.

Re: 3 Balls in a second and a half
 

How much do each of the rollers weigh by themselves?

Re: 3 Balls in a second and a half
 

Looks fairly heavy considering how high it will be mounted, but very solid shooter.

The speed may be slightly overkill, maybe 2 seconds for all three balls but that's just me.

Re: 3 Balls in a second and a half
 

It is direct driven. The reason we went with this was because we had success with a similar design in 2006.

Very close, around 7 seconds was where we thought, but while its ramping up, we have plans to occupy the time.

Slow motion video had it 1.5 secs, but its a rough estimate. Again its not a final interval we want, it was just something that happened during testing.

For those asking about the rollers, they are custom made on a lathe. :D

Re: 3 Balls in a second and a half
 

so shiny i am jealous...

Re: 3 Balls in a second and a half
 

Epic! Reminds me a bit of the best dumpers of '09. I definitely like the aluminium rollers; you're not losing much speed as the balls come out. As for the spacing, it certainly makes sense to slow it down when you're in the key, but if you're in some other area of the field playing against defence, make sure you have the spewing ability! Unless you're a key-shooter, that is.

Re: 3 Balls in a second and a half
 

this is awesome sauce..

Re: 3 Balls in a second and a half
 

Yikes, that is heavy. Is the robot unstable to drive or balance on the bridge?

Re: 3 Balls in a second and a half
 

Nope, its reinforced very nicely...

Re: 3 Balls in a second and a half
 

Not structurally unstable, but dynamically unstable. 15lbs is a lot of mass to have so far off the ground.

What speed(s) are you geared for in the drive train?