Bamm-Bamm
In the Spring of 2023 I took the class 2.007, Design and Manufacturing I. In this class, students were tasked with creating a robot to compete in a competition against other students in order to see who could score the greatest amount of points by completing a series of tasks. I created my autonomous robot, Bamm-Bamm.
My Approach
I began by examining multiple potential routes that my robot could follow in order to score the most amount of points in the allotted time. There were many things I had to consider in this phase: how long each task would take, how many points I could confidently score with each task, what mechanism was needed for each task, and how feasible everything really was. After considering multiple approaches, I ultimately decided to create an autonomous robot that would position itself at the top of a slope and repeatedly hit buttons (pictured on the right), gaining 1 point every half second. Since autonomous robots were able to start 30 seconds earlier (with 2x points awarded during this time), I felt this was the most feasible route that would allow me to be successful.
Finding a Mechanism
In order for me to complete this task, I needed to devise of a mechanism that would help me hit the buttons alternately while producing the required force. I found that my robot needed to produce 15 Newtons of force in order for the button to register as being pressed. The challenge with this was that I needed to produce this force on a downward slope, meaning I had to account for the fact that applying this force would create a moment on my robot. After brainstorming, I landed on an idea that used a similar concept to impact drills. This mechanism would allow me to create a large amount of force very quickly, allowing my robot to only feel the moment created for an instant. The core of my design was a free swinging “hammer” attached to a rotating disk, with a smaller disk attached to the outside to act as a guide for the hammer. Two disks would be equipped to my robot to allow me to press both of the top bottoms alternately. Using scrap material I had in my room, I developed a proof of concept that showed that my design was feasible. After this, I was able to create my final mechanism out of aluminum. The final design would use Delrin pucks as the weight of the hammers, and the entire thing was actuated by a servo connected to the shaft using gears. I used a gear ratio that would allow me to optimize for speed, and then used pulse-width modulation in the code to slow it down so each successive button press was half a second apart. With the basic mechanism down, now I needed to figure out how to attach it to my robot.
Incorporating the Mechanism
Something I hadn’t considered when creating my mechanism was where it would have to be placed in reference to the buttons. The buttons were hinged at the top, so the best place to press them was at the bottom. This mean that my “hammers” had to be long enough to reach the bottom of the buttons from the top of the slope. Since the hammers had to be long, the entire mechanism would have to be positioned at a high point as close to the bottom as possible. When placed on my robot at the correct position, this created a large imbalance that caused my robot to fall forward. I needed to find a way to offset the moment created by having my center of mass so far forward. I toyed with ideas such as making the base extremely heavy or having an anchor to secure me in place, but ultimately decided that a long wheelie bar that could fit between the buttons would be the most feasible and most effective. Since the wheelie bar fit between the buttons, this also ensured that my robot would remain fixed in place and not move around as it hit the buttons. This was especially important for me since my robot was completely autonomous, meaning I would not be able to control it if I saw it starting to move out of place.
Final Design + Takeaways
Since my robot in action simply looked liked a child repeatedly hitting the ground, I affectionately named him Bamm-Bamm from the beloved cartoon The Flintstones. I added velcro to the Delrin pucks in order to not break the buttons (at the request of the instructors) and to minimize the noise. I also ended up adding a hat, skirt, and pictures of clubs to really tie the whole aesthetic together. While my robot was able to win in the first round, I did not score high enough to advance. Nonetheless, I was extremely happy that I was able to build a fully autonomous robot that was capable of scoring consistently. This class taught me what it means to design something from the ground up and made me really appreciate the design process. The creation of Bamm-Bamm was very tedious and required several iterations. There were moments where I felt I pursued the idea for too long and that it was not going to ultimately be feasible. I’m glad I stuck with it and let myself fail over and over again. The hands-on experience I gained making my robot was extremely valuable, as this was my first introduction to working with metal. The feedback I gained from my instructors and peers led to my overall success, and I truly couldn’t have done this without all those who helped me along the way.
