Ya we think its a gamble but if it pays off it should help us a lot going over the humps hope it works >_< crosses fingers
How about a half track?
You would need to do some rather extensive thinking about the suspension. Our team is kicking this idea around and my hint is to go look at the mechanical structures of military tanks. Any other comments about tank treads and teams that are planning to use them are highly appreciated. 
Half track?
Wheels on one end, tank tracks on the other.
We were considering that, but in the end we decided to go with a whole tread. I forget the reasoning, however. But even so, it would still not change the question of where to get some treads for a reasonable price 
As Andrew said we did consider it but then we decided not to because we think that the tracks will help us navigate the humps easier
As of now we were thinking about maybe adapting snowblower tracks to suit our needs
Me and Bill were discussing finding synchronous conveyor belts, but they were rather expensive, like $400 a piece.
You could try http://www.andymark.biz/am-0566.html or http://www.andymark.biz/am-0565.html for some belting material. AndyMark also sells 1" wide x 10ā long pieces, officially for use on a plaction wheel. Nothing says you canāt put some 1" wide pieces of different types side-by-side to get a tread. Youād still have to figure out how to connect the ends, though.
Thank you, EricH, that might work well! Itās cheap too! Just have to figure out how to rig it to workā¦
As Madison said Brecoflex belts are expensive, and in heavy defense they can and will fail. Team 195 used Brecoflex belt tracks in 2005 or 2006
Iād check with someone from 195, but I recall hearing a failure rate of 10-12 belts over the competition season because of the heavy defense (pushing matches). Thatās a LOT of cash in replacement parts.
Thanks! thats good to know as we donāt have a huge budget to spend and if they break that could really put us in the hole.
Just wondering do you guys think snowblower tracks might work if they were somehow cut down to size?
Hi, Could you use the Tank Tread kit from Vex??
Read this thread:
There is a Canadian company that supplied conveyor belting to both 1114 and 2056 whose name escapes me right now. Iāll have to dig through my 2008 orders to find out the name. They had, in my opinion, a ābetterā way of joining the ends of their tank tread conveyor belts together to provide a stronger seam. They sell products that are compatible with Brecoflex pulleys.
Last I checked, Brecoflex provides discounts to FIRST teams for their products, but even so, the materials are expensive, especially when you factor in spare parts costs - you WILL want to purchase spare belts.
Brecoflex CAN work without becoming a total horror story - weāve had success, as has 379, and others. But all tank tread systems are relatively heavy and expensive, and require numerous spares on hand to give a team a decent sense of security.
All Iāve got to say about full-length tank treads is - think what happens when a 25"+ long tread starts climbing a 45 degree bump. Consider what a bot waiting on the other side might do in such a leverage-advantageous situation when contact outside of the bumper zone on a bump is permitted per the rules.
For a self-inflicted simulation of the potential situation Iām describing, check out http://www.youtube.com/watch?v=CjHMb55EXmY. Proceed accordingly.
One of the biggest problems youāll find with treads is difficulty turning. In fact, 1718 had custom treads their first year that turned out to be a disaster. The treads were so sticky that they worked great when the robot was 40 pounds. When the team finished the robot the right before ship, they discovered that at full weight the robot would not turn. In fact if you tried to turn the treads would stay stuck linearly to the floor and the robot would drive right out of them.
Treads are NOT a trivial design excercise, and I would caution anyone against trying them without realizing you may have to make a very sizeable time and engineering investment (not to mention weight and cash) to make them work correctly.
I think this is something all teams need to keep in mind. Basically the GDC has declared āthe bumpsā as a kind of free for all zone. i can definately see teams trying to take advantage of this leverage situationā¦
Iād be glad to answer anything about this design. Iād offer to send out the CAD, but I donāt exactly own the rights to the design of some components. A team Iām currently involved with is considering this system (nearly an analogous design to that one, actually) with some minor changes, and Iām fairly certain a gearbox redesign as well. The Outback system is fantastic, and this is one of the first games since 2004/5 to really want tracks for climbing things.
A properly designed track system for robotics use should have a few factors:
-Self tensioning
-Robust
-No need for suspension
-Lightweight
-Very rigid to avoid torsion when turning in place
-High CoF for pushing traction (>1.5 is preferable. Red Linatex is 1.6, IRC)
If you can do all of these, your track system will succeed. Any failures in the above list can lead to some fairly catastrophic breakdowns, and a large cost in belts.
Roughtop or wedgetop would be totally useless as the backing is smooth. You want a tread with backing. Transmitting power through a slick surface is not a very good idea.
I would recommend Brecoflex for the final design but for prototyping, inverted and double sided timing belt is an appropriate substitute as the pulleys (wheel?) for Brecoflex would take time to order and ship.
one thing you may want to look into are blower belts. aka supercharger belts. they come 2-3āā wide and youāre not gonna skip or strip the teeth off of or break or stretch one of those puppies. ever. they can be pricey but come in a wide range of sizes.