Re: Using Treads this year?
 

Some folks on our team are batting around the concept as well. Don't know if its the best choice, but we are in agreement that if there ever was a game where they could be useful, this is it.

Other than looking at previous FRC robots, I would encourage anyone looking at crawler tracks to check out real world designs. There are many VERY different concepts in use in various industries. They all have specific strengths and weaknesses. Earthmoving equipment and large cranes have very different designs....and as a hint, crawler cranes are actually the ones designed to be more maneuverable and smooth.

Military and classic "tank" tracks are another ball of wax from anything in construction. Construction equipment actually rides on small rollers in the middle of a crawler "side frame" and roll smoothly by keeping the roller spacing different from the track pad spacing. As such, they have no suspension. Tanks do have suspension and killer obstacle-climbing ability, but that introduces all kinds of track tension issues. There are many different ways that military designers keep a nice, bouncy track system that doesn't want to jump off the idlers and sprockets.

And, of course, for FRC, you want to crawl all over those obstacles but also not have a robot that's bouncing and leaning all over the place.

Very interesting stuff...

Re: Using Treads this year?
 

Alligator clips can be used to connect tread together.

Re: Using Treads this year?
 

We've already ordered the Andymark ones, they're a bit expensive but basically deal with the entire Outer Works problem for us. The only foreseeable problem is using them with bumpers, which he haven't figured out, anyone have any ideas?

Re: Using Treads this year?
 

We are doing Rhino too... as far as I can tell you would need 4 corner bumpers minimum they all could be fairly small corner ones. 8" and 8" (5" tall)

Mounting them to ends of Rhino track (between 4-12" off floor) could be done assuming body is smaller than drive base, but you have to plan for tread and angled ramps and obstacles.

So basically angle brackets of track, some support (and mount with 1.5 inch play up or down from center.
No matter what you do the bumper will cross the horizontal plane of the tracks themselves IMO.

Or go up... with a larger body than track footprint. So the structure makes the outer corners (at least 4) anywhere from a foot to 4 inches off floor.

If larger which is more likely I think then it has to be on body corners with top of bumper placed at no more than 12" level, but you could make you body larger than the drive base and not mess with the treads as much. Depending on how wide and long you make it.

The treads are 9.498" at max height , bumpers have 12" max height 4" min height and are 5" tall.

So if you make the track itself an outer corner, or your body (above track) an outer corner is your choice. Definitely an important choice .

Re: Using Treads this year?
 

I'm a derp and can't find the edit button, but we just had a PDR and we decided to go with the am-3322 tread module. We'll test it out on a simple bot base, and if it doesn't go well, we're going to replace the tread rollers with 8" or 10" wheels and use the same frame. The real wheel v. tread debate was manueverability vs clearance, and we chose clearance.

EDIT: just found the edit button, but it's not appearing on my original comment. Not as stupid as I thought.

Re: Using Treads this year?
 

Hello,

All my name is Josh Updyke and I have actually designed a modular tack system which I think might be helpful to some of the teams. I actually got a few people sending me emails about it which is what lead me to this forum.

I tried to make a formal post about our product, but it did not seem to go through. But I saw this thread while looking for my original post and thought I would post a link.

www.tankchain.com

We are happy to get track to anyone that would like it. I know that there are a lot of teams interested in tracks. We do the molding in house right now, but have established a relationship with a partner injection molding company and have plans to get these made in bulk. However, our demand has not been high enough to need this. Our break even point to do injection molding is right around 25 kits. If we acted quickly I think we could get the parts in 4-5 weeks. Which is cutting it close from what I hear. But our standard delivery is is around 2 weeks, for all the orders up until we max out our production capabilities.

Josh

Re: Using Treads this year?
 

John Crombe, Team 910 - The Foley Freeze coach here. Talked to the engineer Josh at TankChain and he sent me a sample of their treads for testing. I did a coefficient of friction test for it on aluminum, Lexan, and carpet as that pretty closely simulates what we'll be traveling over. I found that it was about 1.07 on aluminum, 1.13 on Lexan and 1.13 on carpet. As a reference, using the blue nitrile tread, we got .71 on aluminum, .71 on Lexan and 1.42 on carpet. We actually climbed the barriers with the nitrile tread and it didn't do well on them (with that .71 value we're not surprised). It was only because of the driving wheels behind on carpet that we were able to get over them. It looks like the TankChain will do well on all surfaces.

I think the TankChain solution can be a good solution as it's easy to use in place of wheels and eliminates all of the width for drive chains connecting all of your axles. You just power the TankChain's double #35 chains with double sprockets once, and every other place you want to change the path of your tread, you just drop in idler sprockets. VexPro and Andymark have some pretty light and inexpensive aluminum ones.

We didn't have enough tread to do a whole robot. They're in the middle of getting a big production run going to try and meet the demand from teams. It will be interesting to see a complete system in action. I understand there's a team in New York that used them last year.

Worth a look anyway. Nice people to work with.

John