09-04-2007 15:25

AdamHeard

Re: pic: 25 Base Bot Climbs 1089

Intersting wheels on 1089... what are they?

Also, can we get more pics of 25's practice base?

09-04-2007 15:29

BandChick

Re: pic: 25 Base Bot Climbs 1089

You want more pictures of their practice base? Go take photos of their robot...
It's the same base (obviously rebuilt in the spirit of the FIRST competition).

And we use 7" lawnmower wheels from Home Depot on each side (I think). We filed down the tread that came with them and glued & fastened on our own strip of tread. I'm not sure of the details, but come check it out in the pits! Someone there will be able to explain it better!

09-04-2007 15:30

Brandon Holley

Re: pic: 25 Base Bot Climbs 1089

Yeah you can buy those wheels at any home depot/lowes store....i used them on a little robot i made back in high school with the tread that comes on them...they work great

09-04-2007 15:31

BandChick

Re: pic: 25 Base Bot Climbs 1089

We used 4 wheels last year on each side (2 groups of two) with the tread that came with them. They did work wonderfully!

09-04-2007 15:35

Phalanx

Re: pic: 25 Base Bot Climbs 1089

The wheels are 6 or 7 inch plastic lawnmower wheels found in Home Depot.

We machined off the plastic lawnmower tire tread and placed on it raised/ridged conveyor belting, which is glued with a silicone based adhesive(don't quote me on that, but they are indeed glued) and screwed to the wheels so they will not slip or slide. They are for certain now 7inch wheels.

This provides excellent traction, and greatly increased resistance and friction when in a pushing shoving match.

09-04-2007 15:36

sanddrag

Re: pic: 25 Base Bot Climbs 1089

Are those AndyMark two speeds? If so, I have a hard time believing that's all the reduction you need for those large wheels. Does it turn in high gear? What is the diameter of the wheels and how many teeth do the sprockets have?

EDIT: I guess I mistook the wheels as being larger. Now that I think about it, that does seem right. Nice work, and good luck!

09-04-2007 15:41

Wayne C.

Re: pic: 25 Base Bot Climbs 1089

Adam- visit our pits in Galileo- we have 1/2 of that practice base sitting on a table for all to look at

WC

09-04-2007 15:42

Kristian Calhoun

Re: pic: 25 Base Bot Climbs 1089

If you want to check out our drive train, we will actually have one of the drive modules from the practice base on display in our pits in Atlanta (as we did at NJ and UTC). Feel free to stop by and look at it. We'd be happy to answer any questions you have about it!

09-04-2007 15:44

Phalanx

Re: pic: 25 Base Bot Climbs 1089

Yes, they are Andy Mark 2-speeds servo shifter gear boxes.
The wheels are 7 inch in diameter after our modifications to them.
Yes, it turns in high gear.
I do not recall what the gear ratio on the chain and sprocket to the wheels is, but it is less than 3:1. I remember the discussion about the ratio, but I don't remember the final number.

09-04-2007 16:40

lukevanoort

Re: pic: 25 Base Bot Climbs 1089

Is 1089's chassis made from 80/20 Quickframe or similar? If so, how has that held up? I've been looking at it for 2008, but I've been a little unsure of its durability if subjected to multiple competitions. (Wierd, this is my 1089th post)

09-04-2007 17:56

BandChick

Re: pic: 25 Base Bot Climbs 1089

We haven't had any major dents in it this year. The addition of the bumpers has significantly reduced the impact of other robots smashing into us. Comparatively, we used a frame almost identical to this in 2003 (Quicksilver), and that one got bent and bruised a LOT more.

09-04-2007 18:01

Arefin Bari

Re: pic: 25 Base Bot Climbs 1089

How much are you guys selling it for?

... I will definitely stop by, I have been a fan of the evil machines since I joined FIRST.

09-04-2007 18:15

lukevanoort

Re: pic: 25 Base Bot Climbs 1089

Thanks, that's good to hear.

09-04-2007 18:46

Wayne C.

Re: pic: 25 Base Bot Climbs 1089

Arefin-

there is no need to sell it. The plans are in the new book- for the most part.

With a little luck we will be helping a lot of teams make them over the coming summer.........

WC

09-04-2007 22:32

vadyr

Re: pic: 25 Base Bot Climbs 1089

heh...we took a page out of your books and tried the 6 wheel drive again...i dont think we used any of the plans, we just tried our own 6 wheel after seeing and running with you guys for the past few years....after winning NJ last year, we realized that those caster had to go! with that said, i know 25 has been a big help to other teams and their drivetrains, but 103 is also available for questions...check us out in galileo!

10-04-2007 00:12

Arefin Bari

Re: pic: 25 Base Bot Climbs 1089

6wd isn't a problem for team 1345. I just would like to know how to turn on dime without lowering your middle wheel. Thank you for your offer and I will definitely like to look into the chassis you guys designed this year. =)

10-04-2007 00:17

EricH

Re: pic: 25 Base Bot Climbs 1089

What about a slightly (just slightly) larger center wheel? That would slightly lower the center (less than a lower hole), but could be compensated for. Then again, you would run into issues with the wheels running different speeds. (Easily solvable, but not pretty if not solved.)

10-04-2007 00:22

Arefin Bari

Re: pic: 25 Base Bot Climbs 1089

You are right, but I was told that team 25 never lower their middle wheel when they design a 6wd. I would like to know how...

10-04-2007 00:52

Bharat Nain

Re: pic: 25 Base Bot Climbs 1089

A lot of thought go into our machines. The simple answer to why we can do that is 'Brute Force'. But I am sure you do not want to hear that. We pay close attention to detail - the materials we use for gears and the alignment/construction of the drive train. We do all this simply to ensure peak performance or in engineering terms - efficiency. Another thing we do is make the drive train as modular as possible. Therefore, if we do make a mistake, we have a chance to correct ourselves during the season without any major re-designs.

10-04-2007 00:57

AdamHeard

Re: pic: 25 Base Bot Climbs 1089

I know this has been asked and answered before, but what is the benefit to this?

If I remember right, it causes you to bounce while turning (atleast it did last year)... Isn't that hard to control?

I know you have good reasons for it, enlighten us.

10-04-2007 00:59

DanDon

Re: pic: 25 Base Bot Climbs 1089

Haha, the famous (or infamous) "brute force."

Psssst, people......guess what....it works.

10-04-2007 01:01

Bharat Nain

Re: pic: 25 Base Bot Climbs 1089

Depending on the game, or event, we configure our robots to suit our needs. This year, our outer wheels were cut slightly smaller than our inner wheels so we could turn easy. Last year, it was not that easy to push us around which allowed us to shoot the balls in the goal when needed.

10-04-2007 01:04

AdamHeard

Re: pic: 25 Base Bot Climbs 1089

So, since it takes x amount more force to turn, It's that much harder for other teams to turn you?

That makes a great deal of sense actually. Taking a problem that has plagued inexperienced teams and using it (with precise calculations I'm guessing) to your advantage.

10-04-2007 06:44

nparikh

Re: pic: 25 Base Bot Climbs 1089

Absolutely. Having great precision allows maximum efficiency output from the time the current is applied through the circuit box to the time the wheels hit the floor. But as Bharat said, modularity is also key.

If you get a chance, stop by our pits in Galileo and see, but our entire motor setup is rather flexible. With multiple input shafts on each side, we can shift the motor plates to any of multiple locations depending on where we want the weight and placement to be. This year with our mast in the front it was beneficial to have more weight towards the back and so our mounting is reflective of that. Each of the plates has a spot for the servo brakes and only one brake needs to be inserted per side to effectively lock down the entire drive train.

Because our transmissions are modular as well, and rather small in size, it allows for easy changes in gearing depending on what the game calls for--they simply "pop in and out".

Finally, from the time we first started using gear driven drive trains we've learned from our mistakes and improved on future bases. Each year its modified as we see fit, but the underlying principles for each remain the same--simplicity, simplicity, simplicity.