24-02-2010 22:35

Re: pic: 1751's 2010 robot hanging

Cool tracks! What brand belts/pulleys are those? I'd love to see some closer shots of the drive base, as I always like to see different track implementations.

24-02-2010 23:04

dmlawrence

Re: pic: 1751's 2010 robot hanging

Brecoflex TK10-K13 with red linatex backing. I'm afraid we won't have better pictures until the Long Island regional.

There are two lowered center pulleys, giving a total ground contact of about 7" per side. Turning is wonderful. One end is the drive pulley; the other end has a sliding pulley for tension adjustment.

24-02-2010 23:15

Racer26

Re: pic: 1751's 2010 robot hanging

I knew I recognized those Brecoflex belts. We used similar ones on our tracks in 2007/2008. Anybody that saw our drives knew they were cool (transversely mounted CIMs (2, room for 3 because we were allowed 6 one year) inside the loop of the belt itself) 2 bolts and 4 wires, plus the encoder, were all that was required to change a whole unit should one fail.

24-02-2010 23:53

Re: pic: 1751's 2010 robot hanging

Good choice on belts! How did you address the side slipping problem?

25-02-2010 00:55

Travis Hoffman

Re: pic: 1751's 2010 robot hanging

Cue Archie and Edith....

The belts have a self-tracking guide - you can see the v-groove in the idler pulley. http://www.brecoflex.com/index.php?CATID=7&SCATID=64

I'd ask for weight and cost, but then, I already know.

25-02-2010 02:22

Re: pic: 1751's 2010 robot hanging

Our team is using the same belts, and there is a definite side loading problem. The V groove in the middle isn't enough to stop the belt from being locked up (and breaking itself!) if the bot is pushed from the side, unless it can be addressed somehow. I was simple asking whether or not they had looked into the issue.

25-02-2010 10:12

Racer26

Re: pic: 1751's 2010 robot hanging

1075 had similar problems with snapping belts when side-loading them, we also had big problems with battery life, especially in the later iterations of our drivetrains (for FIRST Overdrive). This, and the fact that our modules were relatively heavy was one of the big reasons we moved away from it, first to a modularized 2 speed shifting 6wdDropCenter, and then in 2009 to our 2+2 swerve, and to our latest Drive train for 2010. This one is unlike anything I've ever seen before.

1625 has their 6 wheel swerve, and 148/217 have their nonadrive, both of which I love. 1075's bringing a new toy to Waterloo, GTR, Championships, KK11 and BE9. I can't wait to see what people will have to say about it.

25-02-2010 14:52

dmlawrence

Re: pic: 1751's 2010 robot hanging

In our testing, the side loading problem was not encountered. We geared our motors so that the stall torque was safely less than the belt's breaking force. Once the side load reaches about 150 pounds, the motors have difficulty moving the robot, but the belts still do not break.

In the competition, we'll try to enter only head-on pushing matches.


Dave

25-02-2010 17:06

Re: pic: 1751's 2010 robot hanging

Good strategy idea. In our testing, the Brecoflex belts didn't actually break when heavily side loaded, but rather began to delaminate. A solution that helped the problem was to bevel the corner of the belt (also made it turn better), as well as put flanges on all idler pulleys to keep the belt supported fully.

I'd love to see some videos of your team's matches once the regionals start, as it looks like you guys built a beast of a bot.

25-02-2010 18:36

dmlawrence

Re: pic: 1751's 2010 robot hanging

Beveling the belts is an interesting idea. What tool did you use do it? Our shop is not very well-stocked, so we would probably have to use a "belt" sander.

25-02-2010 18:46

Re: pic: 1751's 2010 robot hanging

I believe it was done with an angle grinder, but I'll have to ask the people who did it. I'll post back when I have an answer.

EDIT: Turns out they were custom ordered that way after the first few delammed.

27-02-2010 11:23

dmlawrence

Re: pic: 1751's 2010 robot hanging

We're ordering a set of spare belts from Brecoflex, potentially with the beveled backing. Do you by any chance have a close-up picture of the modified belts?

02-03-2010 01:23

Re: pic: 1751's 2010 robot hanging

Not personally, but I might be able to get my hands on one in a day or three. If I can I'll post it here.

20-03-2010 01:53

Punkk242

Re: pic: 1751's 2010 robot hanging

Looks awesome David. Great Job!