Oh boy, story time! :rolleyes:
Team 703 - 2007 West Michigan Regional - Finals Match 2/3
We played as a primarily defensive bot this year (ramp bot, so not much to do during the match), our objective was basically to shut down the most effective scoring bot on the opposing alliance starting in Auto all the way up to ~30 seconds left in the match. In previous years we had built “Tank Tread” robots but this was the first year we had come up with a 14-wheeled tank drive as an alternative to treads, trying to keep the advantages of treads without all the drawbacks.
In any case, we managed to seed high at the West Michigan Regional and with the help of our alliance partners, 469 and 494, got all the way into the finals. Per our role, during the Finals we were tasked with shutting down 111 for as long as possible. Throughout the finals we opted to use 469s ramps instead of ours due to their size and ease of use, allowing us to play defense longer. This worked well for us throughout the elims until the last ~50 seconds of Finals Match #2, when a small bearing on the first idler gear of the right side of our drive system broke, allowing the idler gear to pop out of the gear chain, effectively disabling it. The nature of the drive system still allowed for some limited control as the gear would occasionally still engage under limited load scenarios, however it prevented consistent controlled driving and we ended up missing our climb in match 2, taking us to a 3rd match.
Finals Match 2 video: https://www.youtube.com/watch?v=qLQxDyJP92c
After the match we quickly realized the problem was worse than we though, as the bearing was nested in the drive system in such a way that it required not only the side panel of the drive system to be removed (something like 30+ bolts, plus 13 shafts that had to stay aligned), but also required entirely removing the gearbox in order to get to a snap ring that held the shaft in place. It was literally the hardest part to get to on the entire robot. Needless to say, we did not have enough time to actually resolve the issue, and being too late to call a sub we put the robot back on the field and hoped for the best. This leads us to Finals Match #3…
Match 3 started out bad, as we realized we had forgotten to disable our autonomous, which resulted in our robot driving 3 circles around our partners, 469 (and somehow not actually hitting them until the very end of auto), at this point, I (the driver, in case it wasn’t obvious) assumed the robot had basically no control on the right side of the robot, but through some quick trial end error, I figured out a few seconds into the match that the robot WAS controllable when driven in reverse. As it turned out, driving the robot in reverse caused the disabled idler gear to be pulled down into the geartrain and stay engaged, as a result, we were able to stay somewhat effective during the rest of the match, and coupled with a few well timed penalties from the other alliance, our alliance managed to pull off the win.
Finals Match 3 video: https://www.youtube.com/watch?v=TtEVJ2xxiwM
Needless to say, after that event we replaced the bearing with a bushing, reprogrammed the robot to reverse the “forward” direction, and, in subsequent iterations of the drive years later, corrected the design flaw that lead to the issue.