Chief Delphi - 3883 ball grabber prototype

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FRC3883FRC

10-01-2012 17:02

3883 ball grabber prototype

Hey guys first time on chiefdelhi, thought I would start out and show you guys our ball grabbing prototype. It actually works really well! Rolling the ball to the roller simulated the robot driving to ball. Tell me what you guys think!
http://www.youtube.com/watch?v=fIofU...acAUAAAAAAAAAA
:]

Ninja_Bait

10-01-2012 17:07

Re: 3883 ball grabber prototype

Why did you choose to use surgical rubber fingers? What does that add to the roller?

notmattlythgoe

10-01-2012 17:11

Re: 3883 ball grabber prototype

We did something similar back in 09 but with pneumatic tubing instead of surgical tubing.

FRC3883FRC

10-01-2012 17:18

Re: 3883 ball grabber prototype

It starts to grab the ball before it gets to the roller. The roller is only pvc tube and that wont grab the ball as well. When our robot goes for a ball we want it to be ours.

Ninja_Bait

10-01-2012 17:20

Re: 3883 ball grabber prototype

Why not use tread on the roller to grip the ball?

FRC3883FRC

10-01-2012 17:23

Re: 3883 ball grabber prototype

Its what we had and its seems to be easy on the balls. Why fix something thats not broken?

cooldude8181

10-01-2012 17:48

Re: 3883 ball grabber prototype

The fingers also help if you approach the ball rather quickly. Instead of having a solid bar ramming into the ball trying to get a grip, you have things that will be pushing it down and toward the collector.

come-at-me-bro

10-01-2012 18:29

Re: 3883 ball grabber prototype

Interesting idea!!! Keep on working on it!

FRC3883FRC

10-01-2012 18:32

Re: 3883 ball grabber prototype

Thanks for the comments! Hope to show more when we start shooting!

Aren Siekmeier

10-01-2012 19:31

Re: 3883 ball grabber prototype

Looking good across town guys! Can't wait to see more!

Peyton Yeung

10-01-2012 19:34

Re: 3883 ball grabber prototype

Looks like I beat SuperNerd So

WELCOME TO CHIEF DELPHI!!!!!!! :)

I like it btw

DonRotolo

10-01-2012 21:46

Re: 3883 ball grabber prototype

Like our collector in Breakaway.
If you find the tubing wrapping around the cylinder and causing problems, a few pieces of pneumatic tubing in addition to the latex will help a lot.

RedLeader342

10-01-2012 21:55

Re: 3883 ball grabber prototype

may i suggest a paddle wheel kind of thing with the paddles made out of pneumatic hose

FRC3883FRC

10-01-2012 22:19

Re: 3883 ball grabber prototype

Thanks guys for the comments. Any help is welcome. This is why it is a prototype can still try out different variations of tubes, paddles, and any other things. I think we will try some of the ideas on here. Thanks for all the input again!

DetectiveWind

10-01-2012 22:28

Re: 3883 ball grabber prototype

Interesting mechanism I must say. We are working on something just as that and the added fingers makes this an even better way to pick balls.

We figured that something like this might help us get two or even three balls at a time (depending on their length).

FRC3883FRC

10-01-2012 22:52

Re: 3883 ball grabber prototype

Well I hope we can help get the ideas rolling for you guys!

Ian Curtis

10-01-2012 23:10

Re: 3883 ball grabber prototype

Quote:

Originally Posted by FRC3883FRC (Post 1102121)

It's great that people are posting prototyping! Something to consider is that sometimes the dynamics of the intake change depending on what is moving. We built a great collector in 2006 when the balls were rolled into the collector, but it did not work when the collector rolled into the balls. :o

Be careful when you stick outside of your frame perimeter with those fingers if you mount it on an outer edge too.

As an aside,
Is there really a huge need for "Welcome to CD Posts"? I like to think it's a pretty welcoming community on it's own and posting "Welcome to CD" in really big font really just takes up space. CD doesn't bite. :cool:

Andrew Lawrence

10-01-2012 23:15

Re: 3883 ball grabber prototype

Quote:

Originally Posted by Ian Curtis (Post 1102171)

It's great that people are posting prototyping! Something to consider is that sometimes the dynamics of how the intake changes depending on what is moving. We built a great collector in 2006 when the balls were rolled into the collector, but it did not work when the collector rolled into the balls. :o

Be careful when you stick outside of your frame perimeter with those fingers if you mount it on an outer edge too.

As an aside,
Is there really a huge need for "Welcome to CD Posts"? I like to think it's a pretty welcoming community on it's own and posting "Welcome to CD" in really big font really just takes up space. CD doesn't bite. :cool:

A "Welcome to CD!" post has no value. I only put it as an aside from an actual reply to the post, with useful information in it. Plus, it makes the welcomed feel fuzzy inside! :D

peyton122995

10-01-2012 23:22

Re: 3883 ball grabber prototype

Quote:

Originally Posted by SuperNerd256 (Post 1102126)

No fair! I've been at a meeting! :p Glad to see my welcome used though, and thanks for referencing me. :)

My team was planning on useing the red zip-tie things. And adding two of them on top of eachother to suck it up and force it vertically. But I like the Rubber idea it grabs a lot better than plastic.

And can I have a welcome?

Andrew Lawrence

10-01-2012 23:25

Re: 3883 ball grabber prototype

Quote:

Originally Posted by peyton122995 (Post 1102187)

Unfortunately, I only give it to people who just did their first post when I see it. You have 2. :| I'll give you a smaller welcome anyways, though: welcome

Back to the thread, I love the ball grabber prototype! I think we may be using something like this on our bot! Is that regular surgical tubing, or is it a special kind?

FRC3883FRC

10-01-2012 23:37

Re: 3883 ball grabber prototype

It regular surgical tubing that comes with the kit. The rubber really seemed to grab and pull the ball in even at slow speeds. Like I have said before Im glad you all are liking and suggesting ways to improve. Thats way its a prototype. Glad to help out other teams with ideas. Hope to see what others come up with!

SenorZ

11-01-2012 22:52

Re: 3883 ball grabber prototype

Doubt the tubing is really needed. I connected a 1.5" ABS tube to a drill and it compressed the ball about 2" and pulled it under, even with the drill at a very low speed.

These balls are very grippy.

Alex.q

11-01-2012 23:25

Re: 3883 ball grabber prototype

Hey you just gave me an idea... Now to figure out how to build what's in my head. Oh, and I like how you made a fast prototype with cardboard and and drill. My team's is not as good at that; we tend to over complicate prototypes.

Quote:

Originally Posted by SenorZ (Post 1103154)

So you only used the bare ABS, no grippy material? Interesting...

Related Question: How much do people plan on compressing the ball to collect it?

Andrew Lawrence

11-01-2012 23:29

Re: 3883 ball grabber prototype

Quote:

Originally Posted by Alex.q (Post 1103201)

Related Question: How much do people plan on compressing the ball to collect it?

Not much, maybe by a half an inch to an inch. You still want to be able to go over it, but too little compression and you won't be able to collect it.

EricH

11-01-2012 23:30

Re: 3883 ball grabber prototype

Quote:

Originally Posted by peyton122995 (Post 1102187)

My team was planning on useing the red zip-tie things. And adding two of them on top of eachother to suck it up and force it vertically.

The red zip-tie things from the Kit? The ones with numbers on them? Are those what you're talking about?

If they are, DO NOT DO IT! Those are for bagging the robot. Use those only for that purpose.

Use other zip ties instead.

Ninja_Bait

11-01-2012 23:31

Re: 3883 ball grabber prototype

Quote:

Originally Posted by Alex.q (Post 1103201)

Related Question: How much do people plan on compressing the ball to collect it?

We're doing rollers that are at a height a little bit less than the ball. Either it'll squish the ball or the robot will jump up a little bit, but either way it'll acquire.

viper196

12-01-2012 00:31

Re: 3883 ball grabber prototype

On my team im in charge of the collection process. So im curious would it be ran on a motor so you can stop it if you have three balls collected? Or what would you do? And ill give a big welcome to you since this is my first time also haha WELCOME TO CD :)

Aren Siekmeier

12-01-2012 01:45

Re: 3883 ball grabber prototype

Quote:

Originally Posted by Alex.q (Post 1103201)

So you only used the bare ABS, no grippy material? Interesting...

Related Question: How much do people plan on compressing the ball to collect it?

We tested just a bare PVC pipe and that worked fine. However adding some little foam fingers we had lying around greatly improved the speed with which it attained control over the ball (there's a video somewhere, maybe a week 1 compilation coming out soon?). It looks like the bare pipe does the job, but adding something usually makes it even better.

For compression I think we had like half an inch. The guys who did would know exactly. For shooting we needed a fair bit more, like 1.5" total compression I think.

Elgin Clock

12-01-2012 02:01

Re: 3883 ball grabber prototype

If you find the tubing you are using to be a little less than desirable as far as rigidity, try upgrading to poly cord as shown here.

http://www.chiefdelphi.com/media/photos/32576

We've used this countless times in the past with much success just the way you are using your tubing.

Here's an overview of one robot of ours showing the poly cord holding the balls in place ready to spin & eject them.
http://www.chiefdelphi.com/media/photos/32893

FRC3883FRC

12-01-2012 08:45

Re: 3883 ball grabber prototype

Thanks for all the input guys really liking all the other options our team can try out. Also you guys did a great job breaking the view counter on youtube! Never had a video do that. Its great to see that its still getting a lot of views! Will update today, finally get to work on the robot again!

JesseK

12-01-2012 09:04

Re: 3883 ball grabber prototype

No one has talked about speed of the intake. How fast should it go?

Should the edge of the roller go at a set rate?
Should it go at the speed of the drive train?
Should it go at a faster speed that the drive train?
Should the driver be able to control the speeds, directions, or both?

A good prototype can answer these questions. You aren't done -- keep going!

Brandon Holley

12-01-2012 09:09

Re: 3883 ball grabber prototype

Quote:

FRC Manual
[G21]

Robots may extend one appendage up to 14in. beyond a single edge of their frame perimeter at any time. Violation: Foul for exceeding size allotments; Technical-Foul for continuous or repeated violations.

If the fingers on your roller are constantly spinning outside your frame perimeter, I would say that you would be constantly violating G21 (each finger being a different appendage).

I think there are simple ways to design around this, but its something to consider in your final design.

Keep up the good work.

-Brando

mathking

12-01-2012 09:30

Re: 3883 ball grabber prototype

Quote:

Originally Posted by Brandon Holley (Post 1103405)

Good work so far! Welcome to CD.

One thing that hasn't been pointed out is the final implementation of this device. Be careful about how long those fingers are in respect to your frame perimeter. The rules are still a tad gray in my eyes with respect to rule [G21].

If the fingers on your roller are constantly spinning outside your frame perimeter, I would say that you would be constantly violating G21 (each finger being a different appendage).

I think there are simple ways to design around this, but its something to consider in your final design.

Keep up the good work.

-Brando

This is a good question for the GDC. One a lot of teams should pay attention to.

I tend to think you might be right here since the only part(s) moving outside the perimeter are the pieces of tubing, so it might well count as multiple appendages. (I guess if you were really clever you could engineer it so that there was only ever one outside the frame perimeter at a time.)

On the other hand if the whole mechanism moved then it might well count as one appendage and so as long as the spinning parts didn't violate the 14" rule it would be OK. As I said, a question for the GDC.

FRC3883FRC

12-01-2012 09:39

Re: 3883 ball grabber prototype

Thanks for all the help. Our team is meeting today and I will bring these point up to the team. Thanks for all the help again! :]

Alex.q

13-01-2012 00:09

Re: 3883 ball grabber prototype

Quote:

Originally Posted by Brandon Holley (Post 1103405)

oh whoops. The way I interpreted this rule was that as many things as you want can extend 14" outside frame as long as they were all on the same side of the robot. Good catch. When someone submits this to Q&A, please post the answer back here.

ThaineP

13-01-2012 08:38

Re: 3883 ball grabber prototype

It looks like a minesweeping tank. Nice design, too. I've seen a design like that used before in 2009 and 2010, they seem to work well. I think my team will use a similar thing for the ball collector.

Jengles

16-01-2012 12:15

Re: 3883 ball grabber prototype

What size is the tubing?

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