19-09-2015 12:11

Bob Z

Re: pic: 2015 robot offseason redesign

Can it take the can lying on the field? May be increase an rotating function to the container graber will help, but generally this is an awesome work!!

19-09-2015 23:23

asid61

Re: pic: 2015 robot offseason redesign

Have you tried the 4-wheel intake that 118, 254, 1114 used? It seems to be very effective.
That elevator mounting looks a little small, but I'm not clear 100% on how you're doing it.

20-09-2015 07:10

Bob Z

Re: pic: 2015 robot offseason redesign

Do you know why 4 wheel intake is so efficient?

20-09-2015 07:12

Bob Z

Re: pic: 2015 robot offseason redesign

yeah, your cassette looks a little bit short. How does it works.

20-09-2015 10:28

asid61

Re: pic: 2015 robot offseason redesign

I'm not 100% sure, having not built one myself (no time, even in the offseason) but it appears to be that the totes keeps constant contact with the wheels, even when intaking a tote diagonally (such as 1114's landfill mining thins year).

I agree that you need some kind of container flipper capable of (imo) flipping in 5 seconds or less, for maximum efficiency.

20-09-2015 11:21

Chris is me

Re: pic: 2015 robot offseason redesign

asid is pretty much right here - a four wheel intake is much, much faster at dealing with totes collected at odd angles than a two wheel intake. With the right geometry you can drive into a tote oriented horizontally relative to the robot and the robot will just spin the tote into the proper orientation without a second thought.

You can use either some kind of suspension / compliance in order to allow the pairs of wheels to articulate, or if you get the geometry right you can place the outer wheels slightly farther apart than the inner wheels, or both of these things - each of these ways seems to work.

You also need to get the right kind of traction material - a soft polyurethane is best. Colsons, kit wheels, etc. are too firm. Nitrile (white "marshmallow" wheels) are not tacky enough. Polyurethane drive rollers from McMaster work well, or you can buy polyurethane (surgical) tubing of the right OD and ID and attach them to custom wheels.

20-09-2015 11:50

traxxasracr1

Re: pic: 2015 robot offseason redesign

I'm sorry, the pictures dont make things very clear, the part you see at the top is actually just the container holder, it pivots 90 degrees to grab cans laying down, the actual cassette for lifting totes is all the way at the bottom, i will post better pictures when i get a chance

20-09-2015 11:53

traxxasracr1

Re: pic: 2015 robot offseason redesign

And again, I'm sorry for the bad pictures, this is actually the same situation, it is already a 4 wheel intake, just hard to see in the pictures. I have the soft 35a nitrile rollers from McMaster in front with hard colsons in the back, the colsons maintain constant contact with the tote, so I wanted something a little harder that wont wear as much.

20-09-2015 11:58

traxxasracr1

Re: pic: 2015 robot offseason redesign

http://imgur.com/zfpueLs

http://imgur.com/EabIYc3

http://imgur.com/V6Pc97l

http://imgur.com/HSg0UcU

http://imgur.com/qDAWJuR

Here are some more close up pictures. (ignore the colors, we were wanting to powder coat, but that dream was short lived)

20-09-2015 13:29

Chris is me

Re: pic: 2015 robot offseason redesign

We did something similar with our intake and it worked just fine. As long as the front wheels are extra grippy, your back wheels can be Colsons and it should work just as well. I've had little success with nitrile but your material might be soft enough that it works alright. Polyurethane seems to work better in general for this application.

20-09-2015 13:42

cadandcookies

Re: pic: 2015 robot offseason redesign

Looks like you're using links to your local files. I'd recommend uploading them to something like imgur so we can see them!

20-09-2015 20:29

asid61

Re: pic: 2015 robot offseason redesign

Very nice then!
Make sure your can holder has sufficient pressure to allow for rough driving.
1114 used orange BaneBots wheels and did fine early in the season, so nitrile rollers should work as well.
Apart from that, you look devastating. Good luck!

20-09-2015 21:00

akoscielski3

Re: pic: 2015 robot offseason redesign

I was the mentor that assisted the student that designed the intakes for our robot this year. Our intakes were specifically built for the landfill, so we wanted to be able to intake a tote that was in any orientation. Our intake uses 4 wheels, but only 2 of them are fixed (the inside set), and the other two are sprung. When a wheel contacts the tote the wheel starts to pull it into us, and the sprung wheels will wrap themselves around the tote, and re-orientate the tote.

The Banebot wheels were the best wheels we could find for our intakes. However we did try many other popular wheels. The banebots unfortunately wore out after a while though. We usually changed the wheels once a regional (A new set for the start, and a new set for the Elims). Regarding the orange wheels, I can not recall the reason we selected them as I do not remember trying the different colours of Banebot wheels.


If you have any questions feel free to ask me.

-AK