2363 prototype pickup arm

[ToddF]

This year we decided to focus on scoring high in autonomous, gather disks from the floor when they are available and the feeder when necessary, then hang for 10 points at the end. One key to a high scoring autonomous mode is gathering from the floor. Here is a video of our prototype floor pickup mechanism. While not perfect (it is, after all, a prototype), this has given us the confidence to proceed with final design and fabrication of a competition quality version.

http://www.youtube.com/watch?v=XVD6P...ature=youtu.be

The arm is mounted on our practice bot chassis. The software team has been working with the competition bot drive train for a week and a half (the second key to a high scoring autonomous mode).

[JCharlton]

Looks great! Hard to tell, will you be inside the 54" cylinder with your bumpers? We were finding it's pretty restrictive.

Where do the frisbees go from there?

[ToddF]

Originally Posted by JCharlton

Looks great! Hard to tell, will you be inside the 54" cylinder with your bumpers? We were finding it's pretty restrictive.

Our first prototype (over the front bumper) exceeded the cylinder by quite a bit. This one fits the cylinder exactly with the arm horizontal (maximum extent of the arm) and is a little within the cylinder when down on the floor.

The width of the scooper matches the width of our frame, for maximum disk gathering. The length of the arm is the maximum allowable by the cylinder.

Restrictive is an understatement.

[The_ShamWOW88]

What do you guys plan on doing from there? Conveying them to some sort of shooter or do you plan on dumping the low goal?

Great looking design though, works well too!

[JesseK]

If you were to change the pickup funnel so it's not centered, you could hit 2 discs simultaneously and not worry about the first one clearing before the 2nd disc comes in and jams the whole thing. You may also be able to increase the belt speed on that side slightly such that the offset side rollers pull disc #1 in faster, making it clear the intake before the 2nd disc's apex gets in front of it. It's pretty easy to increase the belt linear speed by increasing its drive roller slightly.

[ToddF]

Originally Posted by JesseK

If you were to change the pickup funnel so it's not centered, you could hit 2 discs simultaneously and not worry about the first one clearing before the 2nd disc comes in and jams the whole thing.

This was our original idea. If the "funnel" is offset, it has to go over top of the bumpers. Without going into a bunch of the other constraints (non-interference with the shooter, shallow scoop angle), an arm that was long enough to go over the bumpers broke the 54" cylinder when horizontal. With a couple more weeks to tweak, we probably could have made it work. But, this year we are following the motto: Having a good robot early is better than having a perfect robot late.

Originally Posted by JesseK

You may also be able to increase the belt speed on that side slightly such that the offset side rollers pull disc #1 in faster, making it clear the intake before the 2nd disc's apex gets in front of it. It's pretty easy to increase the belt linear speed by increasing its drive roller slightly.

This is one of the things we may try, if jamming proves to be a problem. There are many tiny tweaks possible to speed up one side, or slow down the other.

[TheCrayButton]

I love it! Nice work! We are hoping to do something similar to this too.

[Kettering]

What kind of belts are you using? Where did you get them?

[ToddF]

Originally Posted by Kettering

What kind of belts are you using? Where did you get them?

http://www.mcmaster.com/#endless-flat-belts/=l9hqh3

Splicing: https://www.youtube.com/watch?v=auJt...nVjw& index=4

[BobbyVanNess]

This looks awesome! I've been working on something very similar, only different . Does your bottom plate scrape the ground? If so, how does this affect driving?

[ToddF]

Competition pickup arm was assembled last night.

[ToddF]

For those of you wondering where the frisbees go after leaving the pickup arm, here's a photo.



The disks go from the pickup arm to a simple conveyer, which drops them in the top of the hopper. The hopper holds four disks. When full, (or anytime, really) the hopper flips up to the shooter, and the disks are rapid fired by the shooter arm.

[Lil' Lavery]

How are you moving the disks from the hopper to the shooter? I see a cylinder on the top level that I assume is involved, but can't quite tell what it's designed to do.

[Greg Needel]

Originally Posted by Lil' Lavery

How are you moving the disks from the hopper to the shooter? I see a cylinder on the top level that I assume is involved, but can't quite tell what it's designed to do.

My guess is that the whole hopper assembly rotates up, a really nice compact way to move frisbees (conveyors take up alot of room). The only negative is it looks like they won't be able to pickup and shoot at the same time, although I am not sure how required that will be this year.