The past two weeks, the changes made to the robot have been so radical in some areas that I have decided it was not worth my time to discuss our progress until all of the changes were made. During the first meeting following the Mount Vernon qualifier, our lead programmer and I were ready to make some changes to the robot that we had been considering even during the competition. After some debate between Danny and me, we devised a plan that was easy to make progress on and that was much cheaper than some of the more adventurous ideas I had thought of earlier.
Eventually we decided that we must replace the steel shell we had with a lighter weight and more space efficient Tetrix frame. While I am still reluctant to use Tetrix [due to its poorly designed parts] we knew that doing this would drastically reduce the weight of the robot. Lightening the robot was one of the most crucial aspects to the robot-overhaul we tasked ourselves with. Having a lighter robot was necessary for the robot to hang, and it did not take us long to come to the conclusion that hanging the robot was going to be the difference between having a winning robot or having an almost-winning robot.
During competition, it’s easier to remember and document the characteristics of other robots by making generalizations. At Mount Vernon, it appeared there were two kinds of successful robots – those who could lift easily, and those who could score blocks fast. We could score blocks faster than any robot we had seen at the qualifier; by far. If we could lift too yet, our robot would certainly be a finalist. In order to give the arm the power it needed to lift the robot, we developed a new way of gearing the arm which allowed us to hang the robot using a high torque ratio of 1:36. Instead of using three sets of gears that each cut the ratio by a third [1:27], we decided to test out Tetrix’s new worm gear box, which would give us a 1:12 ratio in a smaller amount of space, with fewer moving parts. We geared this ratio down to the aforementioned 1:36 in order to keep the speed-to-torque ratio similar to what our arm had previously been. Although all of us [Danny, Tyler and myself] recognized that the 1:27 gear ratio wasn’t too far off could be brought down a bit further, we agreed that it wasn’t too far off what we felt was optimal. By moving the motor that we had used on the flag spinner to the arm, we were able to reduce the stress on an individual motor.
On top of the addition of a second motor [and second worm gear] we also came up with a simple solution to the earlier problem of tipping by attaching a piece of steel underneath the frame, behind the wheels. this piece resembles a backwards ‘J ‘or ‘U’ and acts like a sled/ raft as its smooth surface allows the robot to move freely while not allowing it to tip backwards when the arm extends behind the bot.
Going into the competition, I was feeling anxious. I felt that the robot had not been driven enough and I was worried that the set screws on the arm would dislodge [this took us over an hour to fix when it happened during practice]. However, I was feeling better following the first few matches. We won our two matches before lunch with relative ease, and even Danny wasn’t showing signs of concern. For the most part, the robot was functioning perfectly. The rest of the matches went just as smoothly, and we finished as first place choosing alliance captain. Unlike with the Mount Vernon competition, I was lost as to who I should pick for alliance partners. Being in first place, I knew we would be able to get almost any team to be our first pick alliance. Danny suggested that we pick team Super Ninjas from Linn-Mar due to their high block scoring arm design. This still left me with a second alliance partner to figure out. With time running short, I hastily picked a team that Thomas suggested had a decent flag spinning design. Both teams gladly accepted our offers.
The finals did not go as smoothly as our preliminary matches had gone. In the first match of the semi finals, Kenny had a battery connection issue. We ended up with a spastic robot that couldn’t score blocks and had no ability to hang. Super Ninjas tried their best, but could not pull a win in the first match. With our connection issues not resolving themselves quickly, we were forced to play our two alliance partners for the second match. I kept an eye on the match while Danny and one of the T.A.s tried to resolve the issue with Kenny. Super Ninjas and George Washington Carver won the second match by inches. They had scored both autonomous bricks on random chance, which allowed us to stay in the game long enough to compete in the third match. Luckily, we had Kenny back and running and with the help of the Super Ninjas, we won the third match comfortably were able to advance to the finals. With three matches to go, we were hoping to not see any more connection issues. We were lucky enough to get our wish for the first match, which gave us a close but functional win. Just after the match ended however, we started having the same connection issues. Unlike in the semi finals, our competitors had much higher scoring robots and worked well with each other. For this reason, I felt it was unwise to play our alliance partners if we could get Kenny up and running. We used our time out which gave us an additional 3 minutes to solidify the connections. After the three minutes, we still needed more time, and we took the opposing team’s offer to use their time out to give us more time. This is a very classy thing to do that we see a lot on FTC, and we are grateful to The Who from Jefferson high school for this. despite the excessive use of time outs, Kenny still had a crushing amount of lag and to make matters worse, a collision between Kenny and the George Washington Carver’s robot during the autonomous round put GWC’s robot out of action. Going into the third match of the finals was intense. Neither alliance had a time out to use, both had one win under their belt, and each was down a robot due to mechanical difficulties. We fixed up Kenny as best as we could and sent him in to the third match with the Super Ninjas. We were immediately heart-sunken when Kenny began showing the signs of connection lost. Nevertheless, Danny still had a weak but somewhat consistent connection, and was able to bring Kenny to the bar to hang in the end game. Super ninjas were scoring as fast as they could and kept us competitive. During the end game, we attempted to hang, but we were unable to get Kenny entirely off of the ground. I expected that we had lost. Although we had two autonomous blocks scored and one was over the IR beacon, I still felt that we had not scored enough to constitute a win. After we walked around the field to shake hands with The Who we noticed that they had not scored either autonomous block over the IR beacon, which meant the score was much closer than I had originally thought. We stood there awaiting the announcement of the final score, which was taking abnormally long to count. Finally, Jerry got on the mike to reveal the score. Being the showman that he is, he dramatized his announcement. He told the crowd that despite the rumors, the match was not a tie, however the winner had won by only one point. He then pointed to The Who and announced “blue alliance finished with a score of one-thirty-three..” then turned to face us and said “and the red alliance finished with a score of …[pause for dramatic effect]… one-thirty-four! Red alliance wins the match!”