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Nightmare Repairs At Competition
So I just got back from the WPI Regional and I've got a story to tell. As I was preparing this thread, I saw 237's awesome transmission repair and knew there had to be a ton more of these kinds of clever, dirty repairs in FIRST. So I thought I'd wrap our little story into a general thread so that the whole CD community can hear about different teams' ingenuity under pressure.
----  So in our last qualifying match, after we had secured the number 1 seed, we went to hang for 10 and then suddenly our arm snapped all the way back. We had sheared a 20 tooth pinion on the arm. We swapped for our spare so we'd be ready for the first quarterfinal, and what do you know, it happens again. Perhaps we should have decided not to hang, but since the gear lasted through a regional and a half we thought we were safe... At this point, panic starts to set in. We were out of 20 tooth gears, so a lot of the team thought we were done. Out of utter desperation, a few students and I dig through the pits trying to find ANYTHING that works. We ask any team we can find if they even used Vex gears. No dice. We dig through our own supply just trying to find anything that can work. One of our mechanical students finds the 19 tooth, 3/8 Hex drivetrain gears, hands them to me, and asks if they will work. We have to try. I sprint the gears down to the machine shop for secondary operations while I tell another student to let the drive team and repair crew know that a spare is on the way. I run it down the street to the machine shop (it's in another building) and then ask if they can broach it. They say yes, if they can get a hex broach. I ask them to bore it out to 1/2" while I go find one. Scrambling through the pits, I explain to the students the situation and they quickly find our hex broach. Since I'm out of shape, it's their turn to sprint to the machine shop with a part while I go explain more about the repair to the pit crew. I vaguely remember a member of the repair crew looking at me like I was crazy, but it was our only shot. The gear makes it to the field with one match to spare and... it's too thick. They hand it to me and I sprint right back to the machine shop, asking them to take 1/8" off the gear. Fortunately, the 8th alliance called a timeout for an unrelated reason, which was just enough time for me to run back with the gear and for our wonderful pit crew to get it back onto the robot. We decide to line up for the 2 point goal, because frankly we have no idea what will happen to our robot in autonomous mode, and we all cross our fingers and hope this modification does the trick. It does. We scored in autonomous that match, and while we were done trying to hang, our teleop performance looked completely unaffected. Just one change in code and we had our 3/3 top goal autonomous working every single match after this one. If we hadn't stopped hanging at this point, it would have looked like nothing had ever happened. This is one of my team's (and my own!) proudest moments in robotics. We didn't give up, we scrambled and improvised under pressure and it totally paid off. ---- So there's our story. How about yours? |
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I'd say 1592 and 801's beats everybody's story for all time.
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I can't recall the year or the team and while not technically a repair I do remember a teams robot was shipped somewhere else for nationals and they had to build a new one from scratch
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My favorite emergency repair story is from 2009. We had an intake roller made from polycarb tube. It worked perfectly through two reginals, championships, and IRI, but during practice matches at GRITS (offseason competition) we collided with another robot and broke the roller in half. We hadn't brought much in the way of tools or parts, so we thought we were done. I and another student made a dash to a local hardware store and had no luck finding anything that could be substituted. Then the student found a piece of chrome sink drain that was a tight fit inside the polycarb tube. The hardware store was kind enough to cut off a piece of the drain tube, we also bought some super glue. Back at the venue, we covered the drain tube with super glue, and pressed both broken parts over the tube. We were back in business and ended up winning the competition. |
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In 2011 the gear on our arm sheared a few teeth. The one type of gear we needed, nobody else had. So instead of taking it off, we improvised. If we wanted to raise our arm, I would go from full forward to full reverse, and the inertia would move the arm up, the lost teeth would be skipped, and the teeth from the driving gear would catch with the unsheared teeth on the arm and raise the arm up. While we weren't an effective scoring robot in Logomotion, we were able to get our arm up. The nightmarish part was for me having to go full-power forwards to full-power backwards with a top-heavy robot without tipping. I got it down after a while, but we spent a lot of time on the practice field working on me not tipping the robot over (which ultimately I did anyways).
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I won't try to top the 1592/801 story but 1902 had a crazy repair moment at Atlanta in 2007. Before our final match on Galileo one of our BaneBot motors we used to power our arm released the magic smoke. (First time we had a problem with it all season.) We called the time out a raced to replace it. The problem was we had mounted an aluminum box around the motor that refused to come off, making the exchange a challenge. With the clock ticking, and the field reset crew calling our robot to the field, one of our college mentors got out his hammer, stepped on to the robot cart, and began to persuade the casing and motor off as we were carting the robot to the field. Luckily we were able to get everything fixed just in time for the match. We won the match, won the division, and got a trip to Einstein. Still one of my favorite memories from my days as a student. |
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In 2011, our head programmer decided to build a new electronics board as a part of our 30lbs withholding allowance. It was a wonderfully compact design, and we were excited to put it on the robot at conpetition. However, he forgot to account for a pneumatic cylinder that was placed smack in the middle of where he planned to put the new board, so we spent our entire first day in Toronto fractically building a new one, and much of the next day trying to make everything work the way it did before we bagged the robot. We went on to win the regional with 1114 and 1503.
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Paging Rich Kressly, Chuck Glick, or Mike Williams. I'd want someone more involved with the actual repair to tell the story of how they fixed our claw in 2008 after it broke during the last qualification match before we had to be on the field for QF1-1 as the #8 alliance captain.
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My junior year on the team, 2006 Aim High (edit), The robot we shipped in the crate was far from perfect. The hopper to hold the balls was non existed the shooter kind of worked part of the time, and the electronics were out in the open. When we got to the Pittsburgh Regional and opened the crate there was a ton to do. Going out for our first match, everything was held on by zip ties and velcro straps. After 2 matches of not making any shots we had a team meeting, a few robots that were only dumpers were really good, and we had a vote to rebuild the robot from a shooter to a dumper. It was decided to go for the dumper, so a group of us started striping the robot down to its frame. Another group started going through all the spare parts we brought. we had angle, aluminum plate, lexan, and a ton of rivets, so we got to work. With some help from some other teams we cut the aluminum in half forming 2 triangles, while another group used a heat gun to bend the lexan into a shape that would work. After riveting everything into place onto the frame, we went out for our last practice math after missing 3, The robot worked pretty good we could pick balls up and dump them into the one point goals, but when picking up a few balls would fly right out of the hopper, and also at the end of the match we were back heavy and tipped of the ramp. Back in the pit we had a bunch of those fold up hampers, so we took and riveted one to each side of the hopper, tested and it worked great. Next we had to figure out how to stop tipping, we looked around for a bit and finally picked what to do. In the pit we had 2 steelface heads, our team mascot, cut out of steel for decoration. We bolted it to the front of our robot, and went for final inspection, we passed at the last moment.
I know it is not a nightmare repair like other teams have had but it is one that I will always remember, and I feel for teams like 1592 and 801 because I know it is not fun rebuilding a robot in one day. below is a picture of before and after.  I also remember one year a teams robot crate was shipped upside down and they had to rebuild, can't remember the team or year though. |
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I'm not sure if this was a nightmare repair, but it is a good story.
In 2010, as a mentor and coach for 816, I had the pleasure of watching our robot go up in smoke during autonomous mode in one of our qualification matches. Initially, the autonomous looked routine, the robot began to move forward slowly as it always did and then drifted to it's right. Initially, it seemed like a routine 'the robot is being dumb again' moment... And then it started smoking. I frantically hit the E-Stop and ran out of the box to the side of the field to see Pete K (FTA at the time) on the opposite side of the field with a fire extinguisher. I think I shouted something like 'No, wait!' to him, and once the match had been paused/canceled (or before by some accounts) I got on the field and opened the robot's lid to air the smoke out and found no fire. Thankfully, since the match had been stopped, we had to wait the minimum 6 minutes to reset the field. Everyone assumed that we would take the robot back to the pits to fix whatever was wrong with it, but we found the problem fairly quickly right there on the field. Turns out one of the PWM cables going to the right side of the drivetrain shorted out and burned up most of it's insulation. Some time after we found this, our 'pitmaster' was standing on the side of the field asking what we needed to fix the robot, at which point I shouted 'PWM Cables' at him. Something like 2 minutes later he came back with a ball of PWM Cables and we rigged the robot up to run without ever leaving the field... And we won the match too. Good Times. http://www.chiefdelphi.com/forums/at...8&d=1270046943 |
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It's the first story in Episode 2. |
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Then also the distance to CG of the robot from arm pivot, and the weight of the non-arm portions of the robot? For random knowledge, the trick of dropping a tooth will work in a pinch on most gear setups, but you introduce a LOT of backlash and I wouldn't recommend it for high speed systems w/ lots of loaded direction change. |
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I remember MOE doing some last second repairs at Philly in 2010. Not sure If they were nightmare-ish repairs though. Also, can we forget 75 at MAR and (I think) BE? The robot split in half, and they still fixed it. |
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Input: CIM Gear Reductions: TB3 Reductions (15:60, 14:50, 14:50) followed by two custom reductions (20:84 20:84). The pinion that failed was the final 20 tooth pinion. TB3 gears are steel as is the first 20T pinion, only the final 20T pinion was aluminum. No, that isn't backwards. The arm failed both times when attempting to hang. Hanging hooks are roughly 2 feet from the pivot point. Base weight is about 75 pounds. I would say the CG is probably six inches forward of the pivot point (yes, it's far back). |
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2006 Boilermaker Regional, 1319 had a small drive base and the top shooter was on a full turret. Either at the end of qualifications or in the first elimination match, they got smacked and the top 2/3 of their robot breaks off. Like dragging behind them.
First elimination match after that, they come out with just a drive base and play awesome defense. I think they won that match. Soon after, everything's back, working perfectly, Regional Champions. Safety Award. Spirit Award. |
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Our 2008 robot suffered a Catastrophic breakdown(the disaster occurs at 7:53 at the end of the first finals match which we won. Unfortunately we weren't coming back from this at that point. Ironically we won the Quality Award.
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One of the most memorable ones I witnessed was the last Canada's Wonderland event where 1114's robot unleashed a mushroom cloud in the finals. It was like time stopped right then and there.
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And the Quality award goes to.... The smoldering heap of metal over there |
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At Duel on the Delaware (Fantastic Off-Season hosted by 365), we were #1 seed. We selected 341 as our first pick, and 1640 as our second. Then, in the semifinals, the giant lazy susan bearing we used on our turret snapped. The turret smashed onto the ground as we crossed the bump on the field. However, with the help of our great partners, and a six minute tme-out, we managed to get enough zip ties (approximately 40 normal size and 10 ludicrously large) onto the turret to hold it in place. It didn't spin for the rest of the day, but it worked in auton and for scoring, and we wound up winning.
Moral of the story: If you don't carry about 300 14 inch zip ties, you might not be prepared for your next inevitable breakdown. Side note: 14 inch zip ties can be used for a number of things, including wiring organization, air tank mounting, turret repair, and mounting/securing almost any part on your robot. |
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Glad to hear your story, 2791. You guys did great, so close to a win. Maybe if that hadn't happened...
Team 1100 had its share of problems in eliminations at WPI. After the first match, the slider plates on our lift started to come loose. This wasn't a big problem so we got out our t-handles and tightened some and replaced some others. When we enabled the robot and moved the lift to make sure everything was working, the lift caught on some wires and cut one in half. The broken wire contacted the frame and short-circuited our digital sidecar. (although we didn't see the broken wire at the time) Over the next 4 matches, we ended up replacing the sidecar, our compressor spike, and a bunch of PWM wires, with no luck. We were able to drive after the first round of repairs and managed to win a match and advance to semis, but we didn't get the shooter back to working in time. We only found the problem in the pit after we were eliminated. We were able to fix it there in about 15 minutes. Thanks so much, team 558 and 2370 for an amazing job keeping us in it for so long despite our problems. We look forward to competing at Boston and at the championships in St. Louis! |
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At the 2011 Traverse City District Competition, 830's planetary gearbox casing sheared itself in the middle of quarterfinal matches, and there was no way for us to bring it to the site machine shop to get welded in time for the next match. In a little bit of a bind and not wanting to completely forgo scoring capability, we decided to fix it by using screws to attach a piece of aluminum to the front, middle, and back of the casing to lock the segments together. I very vividly remember saying to one of the pit crew students, "Drill through the casing until you feel the outside of the ring gear or until I hear the change in material." Surprisingly, it worked up until the last 20 seconds of Finals Match #3!
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2011, Logo Motion, was our rookie year. At the time we had, two mentors with not much machining ability, equipment, work location or experience in large scale robotics. We have done underwater robotics (MATE) the year before which was our first year as a robotics team. Our under water robot was made out of PVC so custom metal fabricating was never even considered. After building our KOP frame and getting the drive train running, which took more time then we ever imagined. Not having a programming mentor, we all had to learn Labview together as best as we could which added more delays. We then moved on to the scoring arm. With a very limited budget, we had to make the Robotics Organizing Committee and Ace Hardware’s generous grant go as far as possible. Thanks ROC and ACE! Most of which we had to reserve for travel and accommodation expenses. With extremely limited machining capability here on the big island of Hawaii we had to resort to out of the box manufacturing and parts supplies. We ended up stripping parts from cars at the schools auto shop program to create our scoring system. This helped us gain our third mentor. We recruited the teacher from the auto tech class, more like he recruited himself. We ended up using a flywheel as our rotational arm base and cut out window motors from car doors to actuate our lift and claw. We ran out of time and we were not able to tackle the pole climbing mini robot. Since this was our first time we figured that what we had finished was going to have to be good enough.
At the first day of competition during inspection we were informed that the window motors we used on our claw and lift system were not legal. We had to remove the offending motors and compete without them. Over the course of two days we were able to adapt some donated motors, from a generous FRC pit volunteer, who just so happened to have a few. I sure thought that was odd at the time. :) During the first day, practice matches, and most of the second day, qualifications, the pit crew with our new auto tech mentor rebuilt the claw and lift system to fit the new motors. Thankfully there was an onsite machine shop that made a world of difference! Thanks for being there, the BAE machine shop workers were exceptional. We were able to have a functioning scoring system for our last 3 matches and were able to actually score. What a relief! During most of the competition we had no other option but to play defense. And play it well we must of. We were selected on the third pick by the first seed alliance. We went on to receive the General Motors Industrial Design Award and the Hawaii Regional Tournament Champions! So much help was offered and given that I cannot express our thanks enough. FRC is such a great community to be part of. Not quite as nightmarish as 801 & 1502 this year. But to us, as the small fish rookie team in the big pond of FIRST, we sure thought it was. Of course the next year the window motors we used we added as legal motors, even with coupons to get from local auto recyclers. Go figure…. :ahh: |
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Psh, amateurs. Try nightmare repairs of the competition.
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The repair I remember making best is not mechanical but programming.
Our team came in on day two of competition and we realized we were not getting feedback from our tachometer on the shooter wheels. We frantically replaced the tach, only to realize it we merely unplugged... Imagine the despair we programmers faced when we realized the PID loops we worked on suddenly became untuned! About 1000 RPM short of target speed.... No sooner did we come to realize this, but we were on the field again, so running down the pits with the robot on a cart and a laptop in hand, we recalibrated PID well enough for our autonomous to work. But it does not stop there, oh no! In the first finals match, we were hit hard enough for the tach to shift, and low and behold, the values change again! Lesson learned.... Never.... Remove.... the tach.... again.... lol |
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I think my favorite repair story was from 2004. A key piece on our really cool but vastly too large and over-engineered arm broke while competing at the Championships. After a heroically fast trip by one of our college mentors to McMaster-Carr in Atlanta, we managed to get the replacement part we needed and installed. As we were heading out to the field to complete we noticed we were missing a nut. One of the mentors pulled the gum out of her mouth and stuck on the end of the bolt, and we made it out for the match.
...in the match, we drove forward for about 2-3 seconds, hit a ball and flipped the robot over on its back. Good times. |
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My Junior year (2010, Breakaway) with (now defunct) 562, we had a rack and pinion system to load our shooter. The pinion was pushed into place via pneumatics, and when released it would fire. After a match, we came back to the pit to find that the rack had actually split in half! :ahh:
A quick run to the machine shop and it was welded like new. Quite literally, if we didn't have the rack we would have been outside of the frame (ever so barely) and we would have had to not participate in the match. It was quite scary for a student who spent most of his time running around in a bulldog suit. |
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This year at the WPI regional 2168 was going through some rather serious issues with the motor/gearbox setup for their arm assembly. After struggling with this through Thursday and Friday the team made the choice (Friday night after dinner) to completely remove the motor drive and switch to a single pneumatic cylinder to achieve, at a minimum, a stored position and a position required to launch discs in autonomous.
Unfortunately this meant that we spent all morning on Saturday making the changes and dialing in a functional 3 disc autonomous. The parts were supplied by FRC558, hence the use of purple tubing if anyone saw the change. We barely made it out for our last qualification round. Throughout the regional we had been focusing on defensive driving, and being in picking position at the end of qualification matches came as a surprise. For eliminations we had dialed in the autonomous well enough and it allowed us to support our alliance with some points. We were fortunate enough to assemble a strong alliance based on defensive and smart strategy that ultimately led to the teams first regional win. |
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It happened in a qualifying match just before lunch. Our robot ran off in auto and crashed into the ramp used for climbing at the end of the match. We hit it head on at full speed and the rest was a disaster. The whole top section split off and lay a foot away from the base. We watched helplessly as other robots had to run over and around the "guts" (i.e. wires, cords, etc.) that spilled out on the floor. We worked through lunch and sent the base out the next match to do defense and climb the ramp for extra points. Then we added a beefed up scoring section on top and kept going. We were picked for the winning alliance and the worst day I've ever seen in FIRST led to my best FIRST experience. This was the most inspirational moment of my FIRST experience. It taught me something vital to this program: you can cry (I did), you can be discouraged, you can think it's all over but you have to keep going. You paid all this money, traveled all this way, and worked so hard for that robot so you owe it to yourself, to your team, and your machine to see it through to the end. The worst case scenario is your robot completely splits in half. But then again, you could always win the whole dang regional. You never know, so never quit. ;) |
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It was awful but so incredibly inspiring. Much like many of these nightmare experiences turn out to be. Because of the spirit of FIRST. Edit: And actually, the events of this Mission Mayhem, and the way in which the teams and volunteers worked together to make the competition happen, were so inspiring that I decided that I had to travel to Florida and attend Mission Mayhem and support it in some small way. And I did. And it was so much fun! I learned a lot from this off-season on the two occasions that I made the trip. Jane |
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In 2010 at the championship in our second to last match on Friday we fell off the bar when our climbing cable crimp failed.
We had to rebuild half our articulating drivetrain in 70 minutes between matches to get back out for the last match of the day. We knew we needed to prove to everyone our robot was functional before pick lists were made that evening. We had most of the inspectors in the division and a couple of nearby teams watching the whole ordeal because they couldn't believe that we had planned for this, had the parts ready and actually pulled it off. Our plan worked we were back together and played our last match. The event effect divisional picking in our favor allowing this to happen... http://www.chiefdelphi.com/media/photos/35698 I have never been prouder of our students than that day because of how they handled this situation. Our mechanical team in the pits knew what they had to do and did it no griping no issues, just get it done as fast as we can. |
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In 2011 our team used a crab drive from 221 robotic systems for our drive train. It was set up with a window motor steering all 4 modules together, but the window motor was overheating frequently at both of our regional competitions. This led to the thermal switch in the window motor tripping and our modules would stop steering as a result. At Connecticut we ended up switching out one of our modules for a spare, thinking that perhaps the axial shaft of the module was too "beaten up" (it appeared fairly marred as compared to what we expected). This turned out to be the wrong explanation, but we left the module in anyway since nothing had changed for better or worse.
Upon returning back home, we noticed a thin ring of metal that appeared shaven on the bottom plate of the swerve module. We then reasoned that the likely reason for the window motor issues was this rubbing between the bottom plate of the swerve modules and the bottom of the frame. We came up with a plan for how to deal with the issue if this was in fact the problem at Championship, since not being able to drive would be the worst thing that could happen. We gathered thrust bearings and material for spacers to be machined once we arrived if we found this was the issue. On Wednesday night at Championships, we send in our five people: me, our pit mentor, our driver, a programmer, and the programming mentor. We used a piece of paper to see if the pieces of metal that we suspected to be rubbing were. 3 out of the 4 modules had the issue, so we had to add thrust bearings in the axle shafts, get the bronze bushings that the snap rings sat on turned down, and have several delrin spacers machined to the proper height. In 3 hours we ripped apart the entire drive train, got the machine shop to precision machine 20 parts for us, put the drive train back together, then ran some systems test. The drive train worked beautifully for the rest of the competition, and had our autonomous worked or a button on our controller (of course the all important minibot deployment button) not failed, we may have been selected for eliminations. The best part was returning to the hotel and reporting back to the team what we had accomplished. One of the kids said completely seriously, "You mean you ONLY got the drive train fixed!?!?" |
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West Michigan District 2011, we destroyed our drivetrain.
One of the bolts in the drivetrain came loose during a match, and the wheels on that side stopped turning. The drivers kept driving on it because they had no way of knowing if it was an electrical, code, or mechanical problem. I didn't see the match because I was cleaning the pit, but when they brought the robot back after the match, I nearly cried.  Unfortunately, this is the best picture I have. You can't see the full extent of the damage, which is several chunks/teeth missing. I think there was some damage to the chain and maybe the axle it was on, but I don't remember - I wish that in our state of panic, we would have thought to get a picture. It was bad. That sprocket was on the center axle and was welded to a hub with another sprocket to form a sandwich. We sent the sandwich and a new sprocket with a mentor allllll the way to the machine shop on the other side of campus to be welded and worked on cleaning all the metal shavings out of the robot and fixing other problems (it turns out that 24V valves in your pneumatics won't work too well) while waiting for it to come back. Mentor comes back with the destroyed sprocket (IIRC it wasn't bent that badly before sending it there, that was just a result of getting it off of the sandwich) and the new sandwich...which was still not usable. Apparently the welding machine jumped and the result was a tooth that was completely missing and some other tooth deformation. Sent it back to see if anything else could be done, and asked frantically through the pits to see if anyone else had a spare sprocket that we could have. We found one, and decided to drill some holes in our only spare hub and bolt everything together. Ten minutes of ratcheting and two sore wrists later, we had a sandwich that was usable. It was by no means the best fix, but we had already missed several matches and our next one was in a few minutes. We made it out to the field literally just in time to play for our last match of the day. ----- Not a nightmare repair at the competition, but definitely a pain in the everything: http://www.chiefdelphi.com/media/photos/35270 See that bent corner? Having to attempt to straighten it after every match that we moved in was the bane of my existence that year. That robot was all about poor design choices, and the frame was one of them. |
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 This is a picture in the middle of the repair. The 'before' -- which I don't have a picture of, unfortunately -- was pretty terrible. We collided with 360 at full-speed midfield. Our frame, which wasn't designed to play the kind of defense we ended up playing in Portland because of a too-complicated collection system, completely collapsed. The front cross member bent inward as far as the intake roller and split in half at one of its rivet holes. The left-side frame rails collapsed as well. There are ripples in the flanges along the entire length of the left-side of the robot. The rear-mounted gearbox and final gearing stage were knocked wildly out of alignment. The gear mesh distance was busted up and destroyed the teeth on the final gear attached to our wheel. None of the wheels remain planar with one another. http://www.youtube.com/watch?v=r_OZi...ature=youtu.be at about 2:35. We fixed it with a hammer and by riveting some aluminum angle along the front edge of the robot to keep everything square. The drive gearing remained mostly broken for the rest of the event; we were able to adjust it before each match so we could drive, but it'd go bad by the end. We're replacing some of the frame parts at our event this weekend and replacing the gear stage with another chain and sprocket stage. We've also rebuilt our entire frisbee collection, storage and shooting system. |
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Some of this will be nightmare repairs, and some will be just nightmare problems. As a caution, this might be kind of long.
2009 - Troy District:
PS Why does this year seem to have more nightmares, even though we did better? It also seems to have more repairs than outright removals :D. |
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I guess we've been lucky to not have any disastrous on-field collisions/accidents. The worst repair I can remember us needing to do was during inspection in 2011. We drew quite possibly the harshest of the inspectors, and he proceeded to pick apart everything that he thought was wrong with our robot (the rounded corners were "too sharp" and had to be duct taped, every single wire connection was "too loose", the chains were too loose or too tight). After close to fifteen minutes of this, one of our mentors, frustrated, went to tighten the (already carefully tightened both during build season and earlier that day) battery terminals on the PD Board - and the entire bolt snapped off.
Due to our design that year, our power distribution board was on the lowest level of the robot (on our drive base), and a second board with all of our pneumatics equipment was mounted directly above it. Fortunately, we had an extra board with us, and it only took about 45 minutes to reach through the chains and transfer all the wires from the old board into the new board. The broken board now sits in our shop as a reminder to all team members to never let that mentor tighten any part of the robot :) |
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Look what little tidbit I stumbled across! 1712 Snapping their arm in 2008
Never realized my old team was out there that match also. :D |
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That reminds me of a team we competed against in 2012 whose shooter broke off twice and still won the Quality Award. Funny how that happens. The biggest nightmare repair I've been a part of was in 2011, we fried both our cRIO AND our 2 digital sidecars. Found out during the second and more extensive replacement session (included cRIO and multiple suspect wires) that we had pinched and shorted the connector between the two. Missed a couple matches, still ended up 8-4 alliance captain #7. Lost in the first round. :/ Funniest repair (what?) was at Sweet Repeat in 2006, we popped a pneumatic front tire and had to replace it. Got the tire and axle on, but didn't have time to put the second bolt through the aluminum pillow block, so we zip-tied it on. On the field, after auto, we drive forward and stop, but the wheel keeps rolling forward. We then proceed to leave a trail of parts behind us for about 2 feet and eventually fall over for the rest of the match. |
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Yes the drive crew did a great job with the quick adjustment to run laps. There are people that still owe me the lunch I never got that day because of the lunchtime claw replacement... Last qual match before alliance selections, we were essentially locked into our ranking before the match began, and just as I sit down in the stands to watch the match someone tells me, "We're trying a new autonomous program for more points. We're going to turn the corner." Knowing that the "new" auto program was most likely a glorified dead reckoning program (we never got the sensors or IR tweaked out the right way in that robot to "sense" for the corner), my response was, "WHAAAAAAAAT?????" "Don't worry, Kressly. What could go wrong?" Of course I'm thinking about penalties at minimum, or hitting our partners, or getting stuck, or damage... "3, 2, 1...GO..." If you look at the vid closely when the bot hits the wall, our human/hybrid player who put his hands on his head is the one who wrote that "improved program" and I'm happy to report we let him live and he's finishing his degree at Ga Tech. He was given half the claw as a reminder to ALWAYS test his work before USING IT for real. The other half of the claw is still in the 1712 lab somewhere. I never saw the end of that match...as soon as the bot hit the wall I grabbed alum mentor Zac Cohen (now leading FRC1111) and a few students and we immediately went to work prepping the spare* claw (which was nowhere near ready to mount) and continued to work through alliance selection and lunch, right up to field side at the start of QF1. There may still be pics and vid of that pit repair scene floating around somewhere. Good find, and good times indeed. * and by "spare" I mean wood structure only, maybe the grip material was stapled on, but I doubt it. No motor, roller claw, bearings, aluminum reinforcement plates where the spring pins locked in, no wiring, no holes for the wiring to path correctly, no holes (about 30-40 of em) to get the claw within weight allowance. Yeah, it was complete surgery of the ugliest kind. The roller claw never ran in QF1-1. My heart rate was probably about 230 at the time and I couldn't debug the wiring connection issue. So we ran laps and played a little ball keep away that match. Mike Williams found that issue and solved it prior to QF1-2, so 1712 was able to at least hurdle in the Quarters where we were eliminated by a strong #1 alliance led by FRC103 (how ironic is that?). So there's your story ... Now, where's my lunch??? :-) |
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I took that as "Hey Chuck, we bought you a pizza. Go stuff your face before you have to drive against the #1 alliance." Don't worry old man, I'll get you your lunch. ;) |
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At least that pizza was free...
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2012 Israel Regional. We get to the venue early in the morning of practice day with high spirits, take our robot to the boxs, try and get it in, and oops, doesn't fit. It was a tiny bit too wide.
Our drive had a KOP frame base, so what we did was take the outer c-channels out, cut their corners, and put them back in the opposite direction (with the open side pointing out) so the axle bolts' heads won't stick out. Doesn't sound like much but it took us the whole day to do, and made an already ugly bot a lot uglier... No one's proud of that year. Fortunately we compensated that this year when we bearly did any work on the robot :D |
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This story has given me nightmares ever since it happened.
It was 2002 on Einstein, the last year at Disney. I was the field coach for 308 (The Monsters) back then and our alliance of 180 (SPAM) and 311 from Islip, NY made it out of our division after some rough matches. Back in those days the matches were 2 vs 2, but the alliances had 3 robots. You had to play all three robots in each round in order to advance. The typical strategy was to have one robot be your anchor and the other two robots would swap. Our robot was the anchor of our alliance as we had the ability to quickly grab two of the goal and then lift them up to transfer the weight of each goal (at 180 lb each, if I remember correctly) to our robot. We could basically drive wherever we wanted once we had the goals lifted. We had a third arm to grab the last goal which would basically ensure us the win. We were able to win the first round on Einstein in two straight matches agains a great alliance of 118 (Robonauts), 233 (Pink), and I want to say 144 (Who?), but I'm not sure about the third. It was on to the final round for the world championship! The finals were set once 71 (The Beatty Beast), 173 (RAGE), and 66 (the Penguins back in those days) advanced in two straight in their semi-final. It was going to be epic. Team 71 seemed to be unbeatable, be we thought that we could lift the goals high enough to lift their robot's file cards off the ground (one last trick up our sleeve that we haven't shown yet). I couldn't wait. Then, the nightmare occurred. One gear in the gearbox on the left side of our drive train started to shift so there was only about 50% of the face-width engaged, and we didn't see it. The match started and we raced to the center of the field to meet 71 at the goals. A big collision occurred, and every tooth from the gear box in that reduction stage sheared off. We were useless as the left side of our drivetrain could transfer no torque. Needless to say, we lost that match. In match two, SPAM and 311 went in while our pit crew tried to see if we could make a fix. In the 2nd match, SPAM and 71 had an even bigger collision at the center goal causing 71's goal grappler to break. SPAM and 311 were able to manipulate the goals with enough authority to win match 2. One match for all the marbles... Our pit crew couldn't replace the gear in time. However, since the gear had shifted to having 50% of the facewidth engaged, only 50% of each tooth sheared off (we were using aluminum gears to save weight). The pit crew pounded the shaft over so that the remaining teeth were engaged. The drivetrain ran, but I knew it wouldn't stand up to another collision with 71. When it came time to pick who was going to play and 311 (our alliance captain) asked if we could go, I told him that 311 and 180 won the last match, they should try it again. Then, the 2nd nightmare occurred: 71 took themself out of the match, leaving 66 and 173 to play. 66 had plenty of torque, but they were a single speed robot. We had a high gear (about 10 ft/s to race to the goals), and an ultra low gear (about 1.5 ft/s for push once we got the goals lifted). I KNEW we could be 66 to the goals, get them lifted, and the match would be over. I ran to 311 and told them we could go against 66, but it was too late. The referees said that we had already submitted our two robots to the match. Needless to say, 173/71/66 won the match and I've never came that close to being on a world championship team. I tried to convince myself that "maybe the half-sheard gearbox wouldn't have even been able to drive." When we finally got the robot home, we just had to set it on the field and see what might have been. The robot raced to the goals, lifted them, shifted to low, and was able to push them into another robot with no problem. Oh what might have been. I've been haunted by that ever since. I have pictures of that gearbox that were taken immediately after that first match ended. I'll have to see if I can find them. Edit: I found the pics. Here's one of them:  |
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But I still remember being pleased we gave out enough of those fliers for Ed's to give us a free pizza. Then Chuck went and devoured it before I got any... |
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this is a GREAT thread, and I LOVE Hibner's story. |
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Thanks for the memories Chris. If you need a refresher try this link:
http://www.thebluealliance.com/match/2002cmp_f1m1 |
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Storm Robotics Team, 2729 had to do a fair amount of repairs for faults during the 2013 competition season so far, all of which carry some good and simple lesson's learned I think so I'll share briefly. The issues are not nightmares like some of the others in the thread by any means. [This is turning out to be way longer than I intended, but hopefully serves a purpose to someone out there :)]
First, nearly all the issues are related to the ruggedness (or lack of) on our electrical system. In the 5 years of Storm we haven't had issues like this. Luck be it, or possibly because we were defended on much more this year, we had several cRIO reboots, router reboots, etc. At MAR Hatboro Horsham, at the end of the competition (last match) our cRIO 'died'. 24V was verified but no LEDs came on when the bot was powered on. We had to pull the cRIO, bag it and give up. We later found that a single copper strand of wire, about 1/4 inch long had fallen into one of the cRIO module DB9 slots and lodged itself between a few of the pins, shorting them and the overall cRIO boot (would love to know the pinout of that DB9 connection to see how that is even possible). This was under the black DB9 cap which was installed. Our best guess is that the strand was sitting in the cap when it was installed. The cap had been vacuumed out once and then found in the shop vac, so possibly the strand stuck in the cap from static charge, was installed with the strand in it, and then the strand fell out later and lodged in the pins. Or it was sabotage. :) But for GP's sake we are going with bad luck :) [I wonder why NI didn't put a female DB9 on the cRIO side anyway. When the pins break the cRIO is toast, which has happened on our earliest cRIO] At the MAR Lenape regional we had a cRIO reboot early on which was traced in the pit later (after another luckily good match) to the 24V+ wire coming lose in the connector on the cRIO side. We tightened it best we could, hot glued it and continued on. Unfortunately later that day we had faults that looked similar, in another qual match and in the Finals Match 1. The Field folks said it was a router reboot. After the competition we studied the DS logs and determined it to be a router reboot in both cases. Wiring seemed fine from the PDB through the regulator and to the bridge, but we noted to make it more rugged at MAR champs. After further log analysis we saw some deep voltage dips on the matches where the router rebooted. The best guess we came up with was bad connections on the batteries or bad batteries. The Good news - we keep battery logs during the competition to help ensure we use charged batteries and we can identify bad batteries. The Bad news - the log wasn't kept after the competition, it never made it back to the school. :( So we can't prove which batteries caused the issue, but we checked and had 4 batteries with loose wires at the terminals. We replaced with better suited hardware and had no router reboots or cRIO reboots at MAR champs. [Note - we plan on posting the full log analysis on CD with screen shots when we have time to clean it up and will use them as a workshop later this year with electrical and software.] - The moral to this one is - keep (long term) your battery logs to identify problem batteries, check your wires often doing a visual spot check between matches, and whenever you think you have made your wiring 'strong' enough during build season, do some more! Inevitably something will fail when 120 lb robots collide, but you can prevent a lot of it. We learned that the hard way this year. At the MAR championship we seem to have fixed our HH and Lenape issues, but instead saw some new ones. In QF Match 2 we took a not too memorable hit from an opponent, 224 in this case. You can see Electra (Storm's robot name for 2013) roll away in a pitiful retreat, dead for the match. In the pit we found that the power pole between the PDB and the regulator unplugged. Surprising though as the hit was quite gentle compared to others survived this year. -The moral to this one - even though power poles are strong - zip tie them or use the locking pins! A simple zip tie would have absolutely prevented that failure. We had another failure at MAR champs, with only about 10 minutes to find and fix. After a match Electra had a bad "let the magic smoke out" smell. We ran through tests on every system and all were functioning without obvious issue. We continued to persistently search for a sign, and finally caught it when we saw a shiny corner (from melted plastic) on a Victor 884 that controls the drivetrain. We removed it and opened it up, and it turns out that the Victor FETs had self destructed horribly, but it was still functioning at a unit test in the pit. Interestingly the fan 12V wire looked like it had shorted to an FET. Not sure what happened first, the FET failures or the fan short (or maybe the short caused the failure). - The moral to this one - Don't ignore your nose, I doubt a smell that bad can ever be a good sign. Study your robot until you find the source, nobody knows it better than you. Never be complacent or the failure will just pop up later. |
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During Week 6 at the Pine Tree Regional after two days of no hiccups with our autonomous 30 point climber our team struck horror in the quarterfinals.
During qf1.1 when our team went to climb at 30 seconds left in the game we lifted to level one just fine but our arm that lifts the hooks to the second bar stayed on bar one without rising to level two. Our team tested the system in our pit and it worked fine. We did however find a lose power connection to our climber and a questionable battery. Problem was assumed as a power issue. During qf1.2 the same problem happened as the arm still wouldn't move from level one. We noticed our cable was unspooled meaning the arm should have been expanded but it was jammed on the bar. Back in the pits we noticed our pawls had come loose so when we hung the hooks became jammed on the bar due to the pawls being crooked. All caused by a collision in qf1.1. Our team tightened everything down and ran to the practice field to test climbing. The arm worked fine but the winch was out of whack. As our team was getting qued for the semis we noticed our encoder had been knocked out of alignment and damaged. What ensued was the scariest 15 minutes of the weekend as both the competition and practice climber were taken apart to switch encoders. Thankfully one of the quarter finals went to 3 matches giving us some more time for surgery. Once the new encoder was on we had no issues for the semis and finals! |
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Thanks! |
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We were going through inspection and had most everything checked off and then one of judges takes a closer look at our robot and says that we used a larger wire gauge. So our entire robot had to be rewired, putting all other work to halt while the electrical team scrambled to fix everything. Then of course there was the rapid swiss cheesing and filing of the corners. We ended up passing inspection moments before our first match (and here I will point out that we are a rookie team and we had the first match of the day) at exactly 120.0 pounds.
Also, please excuse my ignorance, but what happened to teams 1592 and 801? |
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The confusion is that smaller size wire has a higher gauge number, and larger size wire has a lower gauge number. Saying "larger gauge" is mixing size and number descriptions. |
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http://www.chiefdelphi.com/forums/sh...light=1592+801 |
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at 2370, our tradition is to have the pit crew travel to the competition on wednesday for load in, the rest of the team arriving during practice day. We arrived at WPI for the 2012 game eager to see what our tank of a robot (affectionately named OverKill) could do on the field. Everything was going well right up until inspection time...
Our robot weighed 20 pounds over the limit. When the rest of the team (myself included) walked in around lunch, we came to see the robot not in the tank-like form we knew and loved with its 10 inch wheels for height over the mid-field bump, but rather came to see a machine that looked something akin to a truck with prius tires installed. We had to drop down to 6 inch wheels, and got so desperate to shed weight we ended up ditching one of the polycarb protection panels in favor of mesh netting. our robot played well, but it wasn't the same monster we dreamed of seeing on the field... |
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Our shooter motors and their controllers kept going out. Maybe using BAG motors for powering a shooter is a bad idea. We went through many motors and we were still easily crippled at any time during the competition.
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2012 was an interesting year
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After rereading the first post in this topic I think the additional take away:
Less running more Segway. If only we knew someone with access to Segway :) |
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Our team had a very nerve-wracking breakdown in 2011 Logomotion at the Dallas regional.
After mitigating what we saw in the Alamo regional, we decided to add a wrist movement to our arm to allow us to pick up off the ground. Since we were already close to the 120lb mark at Alamo, we had to make light modifications, and therefore substantially weak mods compared to what we usually do. At Alamo, we had to get tubes from the human player at the end (we had not seen the "throw the tubes" idea coming) because at the arms lowest position, the gripper was still in the frame perimeter (about 8" off the ground, above the chassis). We could only hang tubes on the 2nd level because we held the tubes straight out in front of us, like we received them from the human. After being soundly destroyed at the Alamo, we looked at team 148's robot, and thought "we could add a wrist like that" so we could get tubes off of the ground. It would also allow us to score on the 3rd row. We had no practice bot, so we designed parts based on CAD and holding a measuring tape up to the robot on the other side of the bag. At the Dallas regional a few weeks later, we and added a piston-powered telescopic mechanism to the top bar of our parallelogram. We then spliced a large L shaped bracket made of lightweight .040" alum between the parallelogram and the gripper to allow us to reach the ground. It Worked! after hours and hours of Thursday work, we had a robot working great. We won most of our matches Friday and Saturday, and ended up as the #2 Seeded alliance (behind: you guessed it, team 148). They didn't pick us, they picked the #3 alliance, so we chose team 704, the #4. But then, disaster strikes! We spent our lunch trying to touch up our autonomous code on the practice field. It would usually hang a yellow tube, but not always. Our coders were tweaking and tweaking every little bit to make it operate reliably, and it was working. As lunch started wrapping up, we deployed the fatal autonomous script, containing a typo that made the robot roll forward an extra 6 inches. Since we refuse to let changes go untested (a wise strategy) we ran it on the practice field. Our previous version left the gripper within 2" of the wall, and with the extra 6" the robot was told to go, the gripper would end up -4" from the wall. Obviously, that cant happen, and the whole robot took the impact surprisingly well, but the robot lowered and reversed before we could react to the collision. The gripper got ensnared from the impact on the peg it tried to hang the yellow tube on, and held fast. The arm and robot were unyielding. What happens when an unstoppable force is tied to an immovable object? The rope breaks! The light L-bracket gave, and split in 2, right as we were being called to queue for the elimination match! In fast action, me and a few teammates flew into the pit, and attempted to get our spare l-bracket ready for mounting (it had some things attached to it). It was a fairly easy fix once it was prepped, but it took too long to prep. In the meantime, right next to the field, our mentor and our drivers proceeded to add over 150 zipties (9") to the bracket, in a desperate attempt to make it work. They worked with panicked efficiency, looping and ziptie-gunning every last ziptie team 1296 owned. The robot worked just fine (with the code fixed [we didn't get to test that one grr...]) and performed as it did before the damage, albeit a little more flimsy. We lost to the #7 seed though, because both our and 704's minibots failed for 4 different reasons in the 2 matches. |
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I don't have the video link handy, but at the 2013 MAR CMP, Team 75 was at the 30 point level...and fell off. The robot turned exactly upside down when it hit. Bounced a few inches, then fell over.
The entire crowd went :ahh: Then silence for a few seconds. During a match. Back at the pits, virtually every team was there asking if they could help. A sawzall was found to cut the 1/2" tool-steel shaft that was bent into a U away so they could get at the damage. Long story short (They'll have to tell you the long version) with a lot of help from several teams, they made it onto the field for their next match, 100% repaired. The crowd went wild. |
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