27-09-2012 12:39

ttldomination

Re: pic: Team 3647: Rebound Rumble take 2

Looking nice, just a couple of questions for you.

(1) Are you delivering the balls straight into the shooter via your belts?

(2) I can't tell if its the perspective, but it looks like your chassis might be bowing in the middle. Is that just me?

(3) Did you guys machine the tubing + things in house?

(4) What tips/advice would you recommend using the gussets? Do they provide enough rigidity?

- Sunny G.

27-09-2012 12:55

Chris is me

Re: pic: Team 3647: Rebound Rumble take 2

I like the rebuild!

It looks kinda like your wheels are sticking out of the frame. Is this going to be a problem once you add bumpers?

How consistent is the shooter?

I like the 973-style hole pattern. I wish we did something like that, but we don't exclusively use 1 wide tubing so it's less elegant.

27-09-2012 14:20

Mk.32

Re: pic: Team 3647: Rebound Rumble take 2

More Photos at: https://www.facebook.com/media/set/?...11235&type= 1

1. We are delivering the balls straight into the shooter, so far it is working well for us; the hand off from belt to shooter is pretty smooth.
2. Hm I am pretty sure that is just the way the photo is taken, the frame is pretty rigid.
3. Yes the entire robot was machined by students; we have an local machine shop sponsor us and I was allowed to use the CNC mill to run all the parts.
4. The gussets on the frame are 1/8 thick and the tower ones are 3/32. So far we have no issues and from what it looks like from other teams as well 1/8 thick on the frame is more then plenty.

The bumpers are a work in progress at the moment, the mounts may not be 2012 Legal but it's off season
The shooter so far is very consistent, we have an encoder with a PID control loop on it. In the following weeks we plan to test the crap out of this bot.

The hole pattern was so we could add/change elements as we see fit, it's consistent pattern though out.

27-09-2012 14:24

IndySam

Re: pic: Team 3647: Rebound Rumble take 2

Nice work but I look at all that hardware and think how much lighter you could be with rivets holding it together instead bolts.

27-09-2012 14:29

adam the great

Re: pic: Team 3647: Rebound Rumble take 2

Looks great guys. Interested in seeing which manipulator for the bridge you choose to go with.

27-09-2012 14:37

R.C.

Re: pic: Team 3647: Rebound Rumble take 2

Ditto, most of your hardware seems like your never going to take it apart. Even if you were, rivets are pretty easy to drill out.

You can use High strength or Normal Rivets with no issues. 3/16" Rivets and #10 bolts are interchangeable.

-RC

27-09-2012 15:28

IKE

Re: pic: Team 3647: Rebound Rumble take 2

I would like to congratulate your team on doing a great off-season project.

27-09-2012 18:40

Mk.32

Re: pic: Team 3647: Rebound Rumble take 2

Thanks everyone for the nice comments, we are quite proud of this little guy and hope it performs well at off season.

We considered using rivets however we had an bad experience with rivets before and decided that bolts are safer. Are pop rivets really suitable to replace 1/4 bolts?

27-09-2012 18:43

Chris is me

Re: pic: Team 3647: Rebound Rumble take 2

Depending on how they are loaded (i.e. mainly in shear), rivets can absolutely replace bolts. Based on the pattern of gussets on the robot, it almost looks like the robot was designed to be primarily riveted.

27-09-2012 18:47

akoscielski3

Re: pic: Team 3647: Rebound Rumble take 2

Cause they really needed to save weight eh? If anything they should add some steal plates to make it heavier.

Looks great, it just proves to al of us how small and light we could have made our bots.

27-09-2012 18:48

BrendanB

Re: pic: Team 3647: Rebound Rumble take 2

Even 1/4in rivets can be overkill but since rivets are so light it doesn't really matter. My biggest peeve with the kitbot is the 32 nuts and bolts we have to use its like dead weight!

Is your shooter designed to hit the top basket or is it a mid/low?

Overall your redesign looks great! Best of luck to you guys!

27-09-2012 18:52

AdamHeard

Re: pic: Team 3647: Rebound Rumble take 2

Talk to us at the fall classic and I'll show you how we utilized rivets.

We actually standardize on 3/16" rivets, and they are plenty strong if used right.

27-09-2012 19:04

akoscielski3

Re: pic: Team 3647: Rebound Rumble take 2

This year we used 3/16 Rivets. IMO the best decision we made was going to Rivets, so much better then bolting everything together.
Do you think we would have a problem switching over to 1/8" Rivets? I was considering doing that this year, but if 3/16" would be a better choice I will stick with those.

27-09-2012 19:23

IndySam

Re: pic: Team 3647: Rebound Rumble take 2

We have used 3/16 rivets and gussets for years without a single failure. For higher stress areas we also add epoxy.

27-09-2012 19:38

Chris is me

Re: pic: Team 3647: Rebound Rumble take 2

I won't speak to their relative strength, but one of the neat features of using 3/16 rivets everywhere is that you can standardize on a #9 clearance hole everywhere, which can be drilled out to #10 clearance really easily if you want to bolt something instead of riveting. This assumes you currently standardize on #10 bolts.

28-09-2012 03:00

Mk.32

Re: pic: Team 3647: Rebound Rumble take 2

Thanks guys, we will look into rivets for future use.

Though for this robot weight wasn't really an issue

28-09-2012 12:56

philso

Re: pic: Team 3647: Rebound Rumble take 2

If you are worried about being too light, you can add weight where you want. Perhaps you can add a steel plate to the bottom. This will lower your center of gravity and give some protection.