Sumo Robot

Date started: December 2021, Sophomore year of college

In my winter quarter of my Sophomore year of MSOE, I, along with all of the other Sophomore Electrical Engineering students at MSOE (around 40 or so) took the last course in our embedded systems track, which is called systems interfacing. The goal of this class, was to put our embedded systems knowledge to use to design and build a functional "sumo robot", that would compete in a competition against against everyone else's sumo robot at the end of the quarter in an elimination style tournament where the top three students received plaques. These robots are completely autonomous, meaning that they do not have a remote control or driver but instead they "think" and drive by themselves.

The end of the year competition is sponsored by Milwaukee Tool. Everyone in the class got a Milwaukee Tool Sumo Bot T-shirt (which is pretty awesome). In the past years Milwaukee Tool would also donate tools to the winning students.

Here are the official rules and regulations for the competition if you are interested. If you don't want to read through them all, I will give a brief outline of the competition below.

Each robot must be 6 inches by 6 inches or less. It can be any height. It must be less than 1.5 pounds. Robots play in a wooden circular ring which has a black surface, and a white tape perimeter.

Every robot has to use the same base components, as in the same 2 motors and 2 wheels, the same batteries etc.. Because we all had the same components, the challenge of making a winning robot came down to physical design and efficient programming, not who could buy the most expensive parts. 

The competitions are held in best two out of three, elimination style matches. A match is won when your opponent's robot touches anywhere outside of the competition area (the ring). In the first of the three matches, the robots start facing 90 degrees away from each other. In the second match, both robots face 90 degrees away from each other in the opposite direction. If there is a third match for the tie breaker, both robots will face 180 degrees from each other, essentially back to back (keep this rule in mind as it was what allowed my design to dominate :) ).

Here are some matches from previous years to get an idea of what the competition would look like.

In the kit of parts that we got from the school, we were given all of the electronics that we would need, as well as two large pieces of metal to make the robot body out of. Many of the robots in the videos you will see below are made of metal. I decided however to design my robot in CAD, and then 3D print i. I like this style of manufacturing, because I can lay out the entire design on the computer before I start building. Also, if I need to change the design, because it is so cheap to 3D print, I can just print an entire new robot.

I started with version 1. Here are the CAD drawings for version 1, as well as a video of the robot when it was roughly half done.

The green parts in the CAD drawings are what was to be 3D printed.

I ultimately decided to scrap this robot to make a second design.

The first reason why was because I was so excited about this class that I finished my first robot about halfway through the quarter, and I was kind of bored. 

The second reason was that with a new design, I could shrink the robot dimensions just enough to put a ramp on the front and on the back of my robot. 

The third reason why was because I wasn't liking the color scheme. I wanted my robot to work well, and look cool, so I made version 2 in red and white plastic to match Milwaukee Tool's color scheme, as the competition is sponsored by Milwaukee Tool.

Here are the final CAD drawings for the second design, the (slightly messy) electrical schematic, and some fun pictures and videos of the build process.

Again, everything in green in the CAD drawings it to be 3D printed.

In the above picture, you can see the robot on the scale. One of the requirements for the competition is that the robot had to be less than or equal to 1.5 pounds. This design was heavier than the 1.5 pound requirement initially, so I had to remove some non essential parts to make it under weight.

At the end of the quarter, it was time for our competition!

During the beginning stage of the competition, 8 pools of 5 students in each pool did "pool play".

Every person played against every other person in their pool. Every time your robot pushed your opponents robot out of the ring, you would get 1 point. You could get a max of 2 points vs any given opponent because you played the opponent in best 2 out of 3 matches.

The top 2 students from their pools moved on to the elimination portion of the competition.

Here are some videos of my robot competing in the pool play rounds of the competition.

In the next two videos, I win one match, and loose one match against the same opponent.

Because we were tied, we went to the third match, where you start back to back. Here you can see how my design could out preform a lot of other designs, because my robot had two fronts. While my opponents robot was still turning to face me, my robot was already pushing hers.

I finished my pool play section with 8 points, which was the most points you could get from pool play. That moved me into the elimination rounds of the tournament!

Once in the eliminations rounds, I won in every one of the best 2 out of 3 matches! I ended up winning the entire tournament!

Here is a video of me in the final match, winning the tournament.

Here is a picture of the plaque that I won, and a picture of my section of the class, taught by Dr. Johnson.

Here are some final thoughts of my robot, and the design considerations that I believed helped me win.

First, having my robot have two "fronts". I have ramps on both sides of my robot, and 2 object sensors on both sides. In my program, if any side "sees" something, the robot will snap onto it and try to push it out of the ring. Having two fronts, my robot would almost always see the opponent first, and then start pushing the opponent first. Also, when the robots compete back to back, my robot just drives straight at my opponent, pushing it out of the ring before they have even turned around.

Second, my wheels are centered in the robot, and the center of mass is low. This allows my robot to spin around its center, vs having the wheels far on the back side, where the robot would then spin with its center being the back center. Having my robots wheels centered in this way allows my robot to spin very quickly to see other opponents.

Third, my ramps are touching the ground, and are white. I designed my robot to have its points of contact with the ground be its wheels, and the ramps. There are no additional casters for it to ride on. Because of this, my ramp would get underneath everyone else's ramp, which gave me a huge pushing advantage. Also, I intentionally made my ramps white. Along the edge of the ring, there is a piece of white tape. The white tape is there to provide contrast with the black surface so that sensors on the bottom of the robots can see the line, and back up when they get to it, so that they don't drive off of the edge. With my ramps being white, sometimes when I would get underneath an opponent's robot with the ramps, the ramps would be under their sensors, which would cause their robots to think that they had made it to the edge. They would then start to back up away from me, which made it much easier for me to push them (as I wasn't really pushing them, they were driving backwards, away from me, towards the edge of the ring).

Fourth, ensuring that my object detection worked. I spent a lot of time fine tuning my object sensors to see objects consistently, while also not seeing objects so far away that my robot would lock onto a person in the room and try to hit them. This was crucial in making my robot succeed.

This was a super fun competition! I put a lot of time and effort into my robot, and it payed off!

The winners of the tournament were promised power tools, like were donated every previous year from Milauakee tool. However, because of the COVID pandemic, no tools were donated to the winners of the 2022 year. I put a lot of effort in to hopefully win a tool by winning the tournament, but when I won the tournament, I was saddened to find there was no drill for the winner :( 

Update May 2024:

I got the chance to volunteer at this year's competition for the sophomores. I brought my bot with me, and it was beaten by this year's champion! It was super fun to watch all of the good designs!

I had so much fun with sumo bots when I was a freshman, that I asked: "Why don't more people know about this awesome event we do each year?"

To answer that question for myself, I invited the MSOE marketing team to come to the event, as well as the news stations, and look at the video they made!

And the last update, I talked to the higher-ups at Milwaukee Tool, and they were able to donate in 2024, the tools to the winners of 2022! I mentioned above I was sad to not have received a drill, but in 2024 I got a sawzall instead :)