Robogames 2018

This year, I competed in a combat robot competition called Robogames. If you are familiar with the show "BattleBots", Robogames is essentially the same thing. There are many different events, such as combat, hockey, autonomous or even things like robotic bar tending. I participated in the Junior League one pound combat category. In this event, your team has to build a robot less than a pound that will face others in a boxing-style combat arena with a dual-elimination tournament setup. I did this same event last year, and lost both my games. I pretty much built my robot the night before the competition and it didn't turn out too well. This year, I wanted to do a lot more planning and not procrastinate as much. I thought my design from last year, a horizontal spinning drum attached to the front of the robot, was decent, and I decided to stick with it. My friend and I formed a team and started researching. I saw a video by YouTuber Robert Cowan (link here) that seemed to match perfectly with the design I had in mind. I messaged Robert for the chassis and weapon files so that I could modify them for my particular components. I planned to 3D print the chassis and weapon, but would've liked to CNC the weapon out of steel or titanium if I was able to gain access to proper machinery. For electronics, I used the same parts from last year, with a quadcopter motor powering the weapon and Fingertech brushed motors and ESCs feeding power to the wheels. After modifying the chassis and weapon to fit the components, my friend and I 3D printed them in my engineering class at school. We printed duplicates of each so that we would have back-ups if anything broke during the competition. In Robert's design, he uses a plastic called Garolite G10 that is screwed onto the top and bottom of his chassis to cover and protect the internals. I went to my local Tap Plastics store and purchased some high-impact resistant acrylic plastic instead of Garolite G10, as it wasn't available. In school, we used the laser cutter in our engineering class to cut the acrylic to our specifications (again, we cut multiple plates so that we would have replacements for the competition). Finally, we assembled all the parts together. We used a skateboard bearing and a bolt to hold the drum into the chassis, and the motor was simply press-fit into the 3D printed weapon. After soldering and installing all the parts, we added some hot glue to strengthen the electrical connections. Next, we weighed the robot and found that we still had about 100g to spare. At that moment, it was the day before the competition, so we decided not to add any weight. We tested the robot and were pleasantly surprised at the strength of the 3D printed weapon and chassis. At the competition, we realized that we could've improved our design a bit. There were six screws that held the acrylic plates to the chassis, and were a pain to remove when we wanted to change the battery or fix something. Unfortunately, in the first fight, the weapon motor seemed to be stuck and not spin up very fast or at all. After the fight, I realized the battery we used, a 2S LiPo, could not sustain that constant spinning of the weapon for the full 3 minutes of fighting. This was the main issue for why our robot lost the first fight. Luckily, I had brought a larger 3S LiPo, and it barely fit the chassis. Also, it left about 20g of weight to spare. Thinking about it now, we should've used this battery from the very beginning, not just as a backup. I used the 2S LiPo batteries in the first match since I had only one 3S, and four 2S LiPo batteries, meaning I wouldn’t have to charge during the competiton. In the next fight (using the 3S), the robot worked properly, but we still lost. In this fight, the opponent had a robot shaped almost like a dustpan, with a very thin lower lip that was able to go underneath the spinning drum, essentially making it useless. This fight exposed another flaw of our design. However, all the other robots in this competition didn't have this dustpan design, and I think our robot would've competed better against any of the other bots. Next year, I plan to compete again in Robogames, but revise my design a lot more. I still do believe that the spinning drum is a great weapon, because it keeps the rotational forces balanced across the width of robot chassis, and it can flip/destroy other robots pretty easily. My revisions for next year's design would be to make the weapon out of metal, some how reduce the risk of failing against dustpan style robots, and make sure to use 3S batteries. See photos of the event

here.