23-09-2011 11:31

Borisdamole

Re: pic: FRC973 offseason teaser #7

Cant wait for this weekend!

anyone notice the small reflection off the sheet metal on the right?

23-09-2011 12:38

James Tonthat

Re: pic: FRC973 offseason teaser #7

New elevator on your drivetrain? Beast.

23-09-2011 12:40

Jared Russell

Re: pic: FRC973 offseason teaser #7

Make sure you get some video

23-09-2011 12:43

BrendanB

Re: pic: FRC973 offseason teaser #7

I'm sick of teasers! Don't you think 7 is a little obsessive!

Second a request for video!

23-09-2011 13:37

Borisdamole

Re: pic: FRC973 offseason teaser #7

I will make sure to get atleast SOME video of it at the Fall classic

23-09-2011 14:13

Chris is me

Re: pic: FRC973 offseason teaser #7

Awesome elevator and all, but where's robot #3? I bet there's some Pink clone hiding under that picture.

I love how that lift keeps the visual appearance of the arm robot's mast such that it takes a second to see if it's different.

23-09-2011 14:25

AdamHeard

Re: pic: FRC973 offseason teaser #7

You can see the mast of the super stripped down and kiddie-proofed practice bot directly behind the mast of the comp bot.

23-09-2011 14:51

EagleEngineer

Re: pic: FRC973 offseason teaser #7

i cant wait for tommorrow, its going to be amazing playing with/against you guys. And the elevator looks great.

23-09-2011 15:01

Brandon Holley

Re: pic: FRC973 offseason teaser #7

I believe I see some constant-force springs on the lift. What force rating do they have and where did you guys get yours?

Looks good! Can we see a whole picture now?

-Brando

23-09-2011 15:50

Tom Bottiglieri

Re: pic: FRC973 offseason teaser #7

Hate, Hate, Hate those things.

23-09-2011 15:57

AdamHeard

Re: pic: FRC973 offseason teaser #7

We'll post a full picture tomorrow, we've been so busy preparing that we just haven't really had time for this stuff. It was really hard to get the robot programmed as all the programming mentors just got back to school Monday.

They're 7 lb I believe, from mcmaster. Both mcmaster and sdp-si seem to have a similar and pretty decent selection.

Tom, these guys aren't too bad at 7 lbs, easy enough to handle by hand without cutting yourself (although I have a few times already). The 40 pounder we have but didn't use scares the heck out of me however.

24-09-2011 07:55

Audrey Chu

Re: pic: FRC973 offseason teaser #7

Sean lied to me! He said you were all too busy with that last robot to build an elevator.......

24-09-2011 11:30

rsisk

Re: pic: FRC973 offseason teaser #7

Looking forward to seeing your stuff this afternoon!

24-09-2011 14:02

techtiger1

Re: pic: FRC973 offseason teaser #7

Adam the color scheme on those bots looks really familiar =). I applaud the amount of off-season work you guys do. The robots look great, best of luck in the off season. Tom those elevators in general are not my friends. They work great when they are working but keeping them working is certainly a challenge. As 125 well knows I am sure.

24-09-2011 14:11

sdcantrell56

Re: pic: FRC973 offseason teaser #7

Interesting thought on the elevator. We ran an extremely similar elevator all season long that was incredibly quick and never once had a single problem. That is through 3 regionals, champs, and IRI. We're heading to our second offseason in a couple weeks and the elevator still is perfect.

I guarantee you that Adam and company will have no problems with this elevator. The engineering that has gone into it is more than I have ever heard of on a FIRST team.

24-09-2011 14:17

techtiger1

Re: pic: FRC973 offseason teaser #7

Sean,

We were missing the pesky constant force spring Tom is so in love with haha. So needless to say the elevator cable on our robot if it was full forced powered down would continually jump off our spool. I know 973 probably didn't have any problems with that elevator. We used a similar elevator style setup as well which is why I was commenting.

24-09-2011 14:22

Aren_Hill

Re: pic: FRC973 offseason teaser #7

973's elevator has no spools for anything to jump off of

24-09-2011 14:33

techtiger1

Re: pic: FRC973 offseason teaser #7

Aren,

I haven't seen there exact setup as I am stuck on the east coast but I actually pm'd Adam to see if would mind sending some pics of their setup or giving some advice on implementing the constant force springs into the design. I am interested to see how they accomplished a similar design better then the one my team used in an effort to try to better my teams knowledge of this mechanism. I thank you guys for your comments.

24-09-2011 14:37

sdcantrell56

Re: pic: FRC973 offseason teaser #7

The key to not having cable/rope/whatever jump off a spool is to not use a spool plain and simple. We used 25 chain to drive the first stage and then cascaded the second stage. Adam has an even cooler setup but again no spool. As you found managing rope is a pain and is why many teams this year especially avoided it in lift designs.

24-09-2011 14:52

techtiger1

Re: pic: FRC973 offseason teaser #7

Sean after this season I completely agree with your above statement. Trying to find out about all the alternatives and from our teams own opinions on the best way for us to accomplish this better if we do a similar design again.

24-09-2011 15:09

sdcantrell56

Re: pic: FRC973 offseason teaser #7

I'm a big fan of the chain route and also the way that 973 is doing it, although chain is easier with less machining resources, there's is cleaner though. You can alsu use timing belt like 971 did although it has to be gt2 or else it will slip. Stick to cascading if possible as it is much easier to counterbalance the elevator.

24-09-2011 15:23

apalrd

Re: pic: FRC973 offseason teaser #7

You could just use a wide spool and thin cable. That would be much lighter than 25 chain.

We used an aluminum tube (2" diameter, about .030 thick) for our spool, with a sprocket on each end (driven by a banebot transmission/550 each). We used Spectra cable (high strength kite string), which is very VERY strong, light, and very thin (roughtly 1/8" diameter). The spool/drum runs between two sheet metal plates that support the elevator, so the drum is as wide as the elevator (about 20").

We used two 20lb constant force springs for 20lb of total force all the way up, which is actually more than the weight of the carrier assembly. So, if you tip our robot on its side, the elevator begins to go up by itself. We decided it was more important to go up fast than down fast, so we like this. We got our springs from Mcmaster. They are "fun" to work with.

24-09-2011 16:58

=Martin=Taylor=

Re: pic: FRC973 offseason teaser #7

Why didn't you copy 254 to begin with?

24-09-2011 17:04

Aren_Hill

Re: pic: FRC973 offseason teaser #7

Only real thing that's like 254 is the fact its an elevator made out of 2x1 tubing

24-09-2011 23:36

rcmolloy

Re: pic: FRC973 offseason teaser #7

Honestly, were not "copying" because everything was derived from pure ideas that 973 had actually adapted. When the full release is made, the chassis and most connections are not even welded.

254 has created one hell of a bot for 2011 and it is arguably one of the best things to emulate in the offseason if you have the materials and time to create it all.

25-09-2011 09:16

BrendanB

Re: pic: FRC973 offseason teaser #7

I had a dream last night that it had an 8 wheel crab drive.

25-09-2011 11:49

Akash Rastogi

Re: pic: FRC973 offseason teaser #7

That's sort of insulting to what 973 put into this. From what I've heard, they spent a lot of time and work to develop advanced systems that are lighter than anything we've seen in FRC so far. Others, even in this thread, call it some of the best engineering they've seen from an FRC team. I'm really excited to get to know details.

/now if you were being sarcastic I take my comment back

25-09-2011 12:17

Andrew Schreiber

Re: pic: FRC973 offseason teaser #7

So, you've seen the rest of the bot? Cuz I have and can safely say that it is NOT a copy of 254.

25-09-2011 12:32

Chris is me

Re: pic: FRC973 offseason teaser #7

Calm down, I think he meant "Why didn't you go with the elevator and wrist concept for the real robot" rather than meaning anything about the nitty gritty technical details.

I imagine they did that to build a more simple, easier robot in the build season. I really admire teams that go all out once they are done with the season and build the most technically complex robot they can for kicks.

From what I've heard, this is some kind of magical thing of beauty.

25-09-2011 14:32

Nick Lawrence

Re: pic: FRC973 offseason teaser #7

From what I know of this robot, I freaking love it. Adam, can I have one?

-Nick

25-09-2011 15:11

lemiant

Re: pic: FRC973 offseason teaser #7

Except maybe 254 . (And Wildstang... I think)

25-09-2011 17:24

AdamHeard

Re: pic: FRC973 offseason teaser #7

Oh wow, there are a lot of responses! I'll try to get them all, but might miss some.

We chose not to do an elevator for season because of the few "gotchas" the 254-style has. They are minimal to nonexistant to 254 clearly, as they have many iterations under their belt. But, a linear driven spooled cable elevator can be a royal pain in the arse if not done correctly. We knew arms, and knew we could make an arm much faster so we chose too. It was a though choice however, as we knew the very, very best robots would likely be elevators.

As for pics, sorry guys! No hotel at the internet I'll get them up ASAP (need to get them from the photographer).

The robot itself did poorly at this event, the code worked very well (VERY VERY well considering it's a 4wd independent power and steer swerve that's only had about 5 hours of debug time), but we were plagued by electrical failures. We used the electronics off of many old and practice robots which have been thoroughly worn. For the brief time before we loaded it in the trailer when the code worked, it drove AWESOME. We immediately learned that crabs are not 6wds and require a totally different mindset to drive.

The elevator is real slick, and we spent a lot of time on it. We chose to cascade rig it to reduce parts, and the initial gearing of driving the 2nd stage are two very light 16DP rack gears. This brings the elevator to a total weight of 23 lbs with our claw from this season (which is a very, very heavy claw). We haven't coded it yet, but it works really well when hooked to a battery and I feel we'll be very happy with it. It's near-neutrally balanced with standard constant force springs.

We didn't expect to even get this robot running for this event, with our real goal being the Madtown Throwdown in November. We'll certainly use the next 7 weeks to debug and practice and get this beast truly driving smooth.

I'll post more detailed specs of the robot when we get pictures up, and ideally start a new thread, but in summary it's a sub-40 lb independent swerve (including bolts, belly pan, battery box, etc...) which is module based (each corner has a completely self contained drive module not linked to the rest). Designed separately and then implemented at the last minute is our take on a 2-stage elevator, which was heavily influenced by 254, 971, 1114, 2415, 118 and 16 in one way or another (thanks for all the advice given at IRI), but also has some cool new concepts.

Thanks for all the support guys, a few key students and myself spent a long time designing this, and then nearly the entire team busted their butts the last few weeks to get it done. We're really happy with it so far, and plan to show up ready in November.

25-09-2011 17:29

Akash Rastogi

Re: pic: FRC973 offseason teaser #7

Adam's been spending way too much time on the robot.

25-09-2011 17:31

AlecMataloni

Re: pic: FRC973 offseason teaser #7

You are correct.

25-09-2011 18:01

O'Sancheski

Re: pic: FRC973 offseason teaser #7

I need to see a complete picture of this robot. This might be one of my favorite robots of the season... and it was designed for off-season.

25-09-2011 18:32

teachsail

Re: pic: FRC973 offseason teaser #7

Congrats to Team 973 and 973 and 1538 as they are the winners of the 2011 Fall Classic in Burbank Ca. Hope to see everyone in the Spring and again in the Fall for another great Fall Classic.

25-09-2011 19:51

Audrey Chu

Re: pic: FRC973 offseason teaser #7

You guys are still here? And by the way I think it's "no internet at the hotel" Mr. Rules of the World.

26-09-2011 09:06

Brandon Holley

Re: pic: FRC973 offseason teaser #7

Iteration. Iteration. Iteration.

The devil is always in the details, and for any system, it takes time to develop a really finished design. Often, this is several build seasons as we can see with teams who continuously improve their drive designs each year.

Same goes for lifts like this. What few people realize, is that our 2010 robot actually had a linear lift just like our 2011 robot. We learned a lot from that lift, and in turn have learned alot from our 2011 lift as well. We're getting to a point now where we can really tune the details of our design and have a go-to design in our in pocket.

A lot of our issues this year came from the 775 motors which we simply could never get without a case short. We will be sure to not make the same mistake next year, and with some more added improvements, our lift design will continue to improve.


Adam- get some pictures up! I want to see this thing.

-Brando

26-09-2011 09:13

Re: pic: FRC973 offseason teaser #7

I've never had no hotel at the internet! That must be quite difficult for you.