Screwed by a Screw

Well, actually it was a bolt, but screw sounds better

This past Saturday, I went to the VEX Robotics tournament in Toronto with my School's Robotics team. We are team #211, the Robodogs (School mascot is the bulldog, hence robodogs). I was a part of the drive team for bot D, our prime robot. Our team has a total of 5 robots, D, A, W, G and S.

We left the school at about 6am on a yellow bus (with the exception of a few teachers and one returning student who took their own cars). It took us about two hours to make it up there, I slept a bit on the way. I would have listened to music, but I didn't bring my headphones because I didn't want to be distracted at the competition.

We arrived and brought all our stuff to the pit area. Everyone got batteries set up, power to all our tables, etc. 4 of our teams were lined up side by side, with the A robot on the other side of the table at the end. My robot's table was right up against the wall, so of course we had to deal with using our space for power bars/battery chargers. It was only a mild inconvience however, and we had everything set up in time for the opening cerimonaries.

They played O Canada, then we had a drivers meeting for everyone at the tourney. They basically went over the rules, who will end up qualifying for the world finals and other misc info. At this time we also recieved our match schedual. D team's first match was #11, where we were partnered up with S team.

In case anyone doesn't know about Vex Robotics, the basics are two robots on each team competing in a game that is new every year. For more info, check out this wikipedia page: Here

So, we took a final look over our robot, and brought everything we needed to the queue area. Our robot, our controller (which modeled an Xbox controler so highschool kids are already used to it), and our field kit that had misc parts and other things we may need. We waited for a bit and then were told to put our robot on the field. We put it down, turned the robot and the controller on, and waited for the match to start.

3..2..1..go! Our robot didn't move.

Turns out the VEXNet was having problems (it was early in the tourney, bound to be problems), so it ended up being a 1v1 (one of the opponent bots didn't work either). The 20 second pre-programed period went through, as well as the 2 min driver period. At the end, our partner won the game for us and we were up 1-0.

Our robot, front view

We went back to the pits after the match, and tried to figure out what was wrong with our bot. We decided to move the reciever to a higher point on the robot, thinking that all the metal was interfereing with the reception. We zip-tied it to a plate high up on the back of our robot, and went to queue for our second match, #21.

The second match went slightly smoother than the first one, our robot actually moved. I was the member of the drive team who was counting the points scored for both alliances, and the person who raises the gate that seperates the two zones. When my team asked me to raise the gate, I hesitated for a second, and just managed to raise the gate before we got QD'd (If the gate is still down with 30 seconds left, you get disqualfied.)

The VEXNet key that was raised up to recieve better connections.

After the second game, we saw that we didn't have another game until after the lunch break. The driver said that there were some driveshafts sticking out in the middle of the robot that kept getting caught on the scoring towers. He asked one of the members of our pit crew to cut them down. The coach went to find and help our next allies (who didn't have a functioning bot).

The pit crew sawed the shafts down to the proper length, we had our lunch, and we queued up for the next match. We were put onto the fields immediately, but we didn't place our robot because we had discovered a problem with the arm. One side was not lifting high enough, and we couldn't figure out why. We didn't have time to fix it, so we had to play the match with this messed up. The round was close, but we lost because of our inability to score in the highest goals.

We went back to the pit, wondering what had screwed up on the robot. After looking over our bot with precision, we found that there was a loose screw that had got caught in a gear. That gear was the thing that lifted our arm, and was blocked by this screw that had bent to a nearly right angle.

This screw was straight before...

We yelled at the person who was sawing the shafts, because the person was too lazy to remove the shafts from the robot before cutting. The shaking caused the screw to come loose and get caught in the gear. Everyone was mad, but we had to continue. We fixed our mistake and moved on to our fourth match, somewhere in the mid #50s.

We went through the same procedure, got to the field, connected and everything, and when the match started, nothing.

Our VEXNet wasn't connecting again.

We spent the match with our bot not moving and our team scrambling to figure out what happened. After the match was over, we took the bot off the field and started talking with the field technician. He said that the problem was with our controller, so we switched controllers before our next match.

At this point, the coach wanted to go do the driver skills challenge before we went for our next match. At the challenge, we noticed that the power of the robot kept cutting out. We finally figured out that the battery connectors on our microcontroller were bent and not holding the battery in properly. The power kept going out after every little bump. We quickly fixed it and queued up for our next match.

The battery connector that wasn't working.

Our fifth match came and went, and for once we actually performed like we were during practice at home. We did well, and with a clutch double point barrel, won the match. Our only problem was the pre-programed part of the match wasn't working for us. During the break between our 5th and last match, we had the programmer make a quick program that scores 3 points and puts the bot in a position that is good for when we start driver controll.

The robot from the back.

We went to our final match, and everything worked perfectly. It was another close game, and we won just by a few points. The opponent robot nearly scored the winning points like we did in match 5, but their driver couldn't straighten the robot in time to score.

We ended the competition 4-2 in 15th place. However, the first matches were simply to rank the robots. The top 8 bots had to choose two other robots each to go in an alliance for the elimination rounds. The first picks went, and our G robot was picked on alliance #5, but D was not picked. The second picks went. When alliance #5 was to pick their next bot, everyone assumed they would pick D (who was the highest ranking bot out of our 5 teams), but instead they picked A (who didn't work half the time. D bot was not picked for the alliances, and we were eliminated from the tournament.

Our robot in scoring position over a post. 211A in the background.

We theorised that the match scouts for other teams saw the first four games of our robot, decided it was crap, and chose not to pick us, even though we performed well in the final two matches. If we had gone 5-1 (won the game that the screw was jammed into our gear), there would have been a much higher chance that we were picked on one of the alliances. Hence, "Screwed by a Screw"

Both the other 211 robots were eliminated in the round of 8, and the Robodogs were eliminated from the tournament all together. We packed our stuff up, and headed out to catch the bus home. While we were disappointed that we didn't win anything, we went home with some hope that at least one of our robots can qualify at the next tournament on December 10th.

Screwed by a Screw

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