What's the biggest fix you've had to do in between matches?

[Jared]

Between a practice and competition match-

Replace two wheels, one axle, three wheel bearings, a radio, a power distribution board, remove our shooter and everything above the drive base, re weld the upper structure, swap an air cylinder, cut, bend, rivet, and install a new lexan shooter top and feeder funnel, swap an optical sensor, disassemble the lead screw gearbox for the climber deployment, and finally unbend the 1/2 inch steel lead screw, which had been bent at over a 90 degree angle.

[Mason987]

Originally Posted by JeremyLansing

This year at Wisconsin we had a drivetrain issue in our last match before lunch. When we tried to drive forward power to one side of the drivetrain would only be applied intermittently. Since I thought it was a control issue I offered to stay in the pits and try to find it while everyone else got lunch. After I powered up the robot, I realized it was actually a gearbox issue. Myself and another mentor took apart the entire left side of our drivetrain and found that nobody had greased the gears, so during a pushing match, the already worn teeth had stripped off about 3/4 of the gear. Luckily we had some steel gears with us and were able to replace them and got them greased, the other side had been greased but we changed them out for steel and regreased any way.

Once some students got back we finished and reassembled the drive, but we basically did a complete rebuild of our drivetrain over lunch. Now people seem to think that aluminum gears are too weak for FRC, even though these held up for 1 1/2 regionals with NO GREASE. I am quite impressed they managed to hold up that long, and I am quite certain that aluminum gears, if grease properly are more than sufficient for FRC. I only wish I had a photo of all the shavings we dumped out of that Toughbox, it was quite hilarious.

My jaw just dropped and my boss just started laughing when he saw what i was looking at. that is seriously impressive. How well was it driving with less than half of the teeth intact?

[echin]

We had the potentiometer that measured our shooter height seize up while testing right before a match. In the ~5 minutes that we had to be on the field for the match, we diagnosed the proplem, removed the set screw holding in the old potentiometer, unsoldered the old potentiometer, found a new potentiometer, soldered it in, and re-mounted it. We literally finished as the match before ours ended, and managed to get onto the field and win the match.
A similar situation occured at the Pine Tree Regional last year when we had to replace an encoder on our climbing arm.

[JeremyLansing]

Originally Posted by Mason987

My jaw just dropped and my boss just started laughing when he saw what i was looking at. that is seriously impressive. How well was it driving with less than half of the teeth intact?

It wasn't really driving that well, but it was still able to move forward, we guessed that the momentum of the robot was providing a "fly-wheel" effect between tooth engagements, but it was seriously messed up. Once we stopped to inbound, we were effectively stuck the rest of the match, we just rotated back and forth.

[The Doctor]

Originally Posted by Jared

Between a practice and competition match-

Replace two wheels, one axle, three wheel bearings, a radio, a power distribution board, remove our shooter and everything above the drive base, re weld the upper structure, swap an air cylinder, cut, bend, rivet, and install a new lexan shooter top and feeder funnel, swap an optical sensor, disassemble the lead screw gearbox for the climber deployment, and finally unbend the 1/2 inch steel lead screw, which had been bent at over a 90 degree angle.

Jeez! What happened?

[jijiglobe]

In between the end of the last practice match on practice day and the closing of the pits I helped a team make their bumpers from scratch. The team in question was 5151 who had attended the regional without any bumpers. It was hectic and awesome.

[peirvine]

This year (for the second year in a row) we had to replace a cRIO between matches. The first time we had to do this 2 of us (me and our main electronics guy) had to replace it in 6 minutes (standard time out) between semi-finals of the 2013 North Star regional. However we weren't fast enough for our code guy to deploy code to the robot so we just sat there, but our alliance was able to carry us through. This year, the cRIO just died during practice day so we had some time to replace it, after convincing the CSA that it wasn't our fault that it died...

[ratdude747]

Here's a couple that stand out to me, both of which are from Crossroads regional:

-2481's fall from the top of the pyramid during the semifinals in 2013. I didn't see the details but the damage was so severe that despite the efforts of all involved and the alliance's timeout coupon the robot couldn't be restored to full functionality (it was limited to defense). It was a nasty fall; getting the robot driving was an achievement in itself IMHO.

-The winning #2 alliance in 2014. That poor alliance had some lousy luck with robot breakage (and still won no less). Due to 5188's failure in Q3-1, bye-bye went their timeout coupon. In Q3-2, 5188 broke down again, and the backup coupon also went bye-bye. The bad luck subsided until finals match 1, when 1108, the alliance captain, had (IIRC) some LED light wire pinch, short, and melt away (the insulation at least), taking out a large chunk of their wiring. below said wire. They still won the match. Due to the extensive damage, and despite the opposing #1 alliance graciously calling their timeout on 1108's behalf, they spent match 2 in the goalie zone, paralyzed. However, after a pit run during the match and fast hard work between the matches, they got it running minus the catapult and went on to win the match and the regional (and a load of other awards). I honestly don't think I've ever seen such an impressive comeback.

[nathannfm]

Not between matches, but I think the biggest fix MOE had had to do in recent memory was between the last finals match at Lenape in 2013 and the first day at Chesapeake. We went into that finals match with C clamps holding our robot together, as the welds holding the upper frame to the lower frame broke. We came to Chesapeake with a brand new welded frame and managed to move everything over in time to not miss anything.

This year we haven't really had any major issues, we had to replace a wheel due to shearing it off it's pulley as well as a failed ball shifter plunger (which JVN was gracious enough to provide 6 spares for!) on our drive. At the time we fixed it with a total gearbox swap (only 2 bolts) so that wasn't so bad. Our main source of work in the pit has been our winch which we have 2 of and can pull and swap it in no time when it has any problems.

I just have to say, this thread has been great to read.

[who716]

Originally Posted by Christopher149

This year? Replacing chain, reattaching it, struggling to find an effective tensioner, replacing busted wheels. This has included the meager time between finals matches (at TC).

Yeah, the drivetrain has misbehaved a fair bit.

Talk about broken wheels basically at our second district the defense picked up a lot and we had one or more broken wheels pretty. Much every-other match. Fortune fly for DCMP WE SERE ABLE TI FUBD A SOLUTION BY USING LEXAN SPACERS

[JohnFogarty]

This happened after being picked for elims at Orlando. We had a JVN style shooter with a "choo-choo" linkage. We had an issue because after about two regionals worth of use and some misuse and over-tensioning the shooter. We broke teeth off of our 48 tooth geat that we had machined to fit perfectly onto the end of our cantilevered shaft. So in effect our shooter not only didn't work right in our last qualifying match it also meant that it wouldn't fire in autonomous very reliably either.

We didn't have a backup gear or the required mill, and lathe to do the job.

However, our alliance captain (1592) apparently had the exact same gear made for the Versaframe and then SPAM (180) had the machining power we needed...right in their pit. So they assisted us in the machining of a new gear and in less than half and hour we had a perfectly functioning machine again. That never missed a shot in the elimination rounds at Orlando.

[Billfred]

Probably the biggest oh-hell moment I've had was with 2815 at Palmetto 2012. We got called in as the backup team just before SF2-1, so naturally we were thrilled to have a crack at the title.

Match starts, and we didn't really do autonomous due to the nature of the shooter. Alright, no sweat. Teleop begins, we move about a foot, and we die on the field for the match. We lose the first match, meaning it's win or go home.

So, six minutes to diagnose Mystery Robot Death that hadn't really hit us all season long...or the season ends. Check every wire and connection we can put hands on, throw it back on the field, and hope it holds together. Our best theory is that a main battery cable got loose on the PD board, but we couldn't confirm it since so many wires got touched. What I can confirm is that we won the four matches that followed, punching our ticket to St. Louis.

[jaykris284]

Being a first week regional really can be interesting with a lot of teams finding out for the first time that possible mechanical issues exist. From a programming stand point my team had to reprogram another team's autonomous this year while in line.

[Dunngeon]

Our fixes this year have been fairly minor, our biggest was a digital sidecar in 15 minutes. They didn't plug the ports back in right, so we were DOA for our next match but ended up winning it anyways.

[barn34]

Originally Posted by ratdude747

Here's a couple that stand out to me, both of which are from Crossroads regional:

-2481's fall from the top of the pyramid during the semifinals in 2013. I didn't see the details but the damage was so severe that despite the efforts of all involved and the alliance's timeout coupon the robot couldn't be restored to full functionality (it was limited to defense). It was a nasty fall; getting the robot driving was an achievement in itself IMHO.

Thans for the shoutout! That was truly a brutal fall and absolutely horrific to watch your robot take a peter pan off the top of that pyramid. With that said, it was the greatest showing of GP I've witnessed in my 6 years as a mentor. We were flooded with support from a ton of teams and it was truly humbling. Thanks again to all those awesome teams at Crossroads last year. We were hoping to make a return trip, but scheduling didn't allow it unfortunately. For those wanting to see the carnage, here is the video of the match.

http://youtu.be/aeyDgrnOkMs