My senior year of highschool I had the privilege of being the Team Captain of my robotics team where I helped lead our team to our first competition win in 14 years. We compete in the FIRST Robotics Competition, a rigorous and competitive robotics league where thousands of high school teams around the world strategize, prototype, design, build, and program a robot from scratch in just 8 weeks.

Our 2020 Robot: Nari

Our 2020 robot is named Nari. The objective of this year's game was to score yellow foam dodgeballs into different goals and climb a swinging bar at the end of the match. There were countless highs and lows throughout this journey which will be glossed over but I hope to highlight some of the interesting mechanisms and design challenges when faced when building Nari.

Shooter

For this year's game we needed to shoot dodgeballs into goals. To be competitive, we needed the shooter to be consistent and be able to unload many balls at once — what we referred to as a “stream” of balls. Since we had never made a flywheel shooter before, the prototyping phase helped us find an optimal wheel size and compression ratio to shoot balls as far as possible.

As a result of our testing our shooter ended up being one of the most consistent and powerful at the competition. It also features an adjustable hood with three positions for shooting from far, mid-range, or close up. The shooter was one of the most reliable mechanisms of our robot.

Indexer

The indexer was responsible for sorting the balls and feeding them into our shooter. This was the mechanism that gave us the most trouble — dodgeballs are surprisingly soft and sticky. At first we used a “beavertail” style of criss-crossing belts to funnel the balls into the center but this led to jams.

Next we tried using a funnel and v-oriented of belts to channel the balls into the center shoot. To eliminate jams, we programmed one side of the belts to spin faster than the other. After a lot of turning this design proved to be effective.

Intake

The intake arm is incharge of accumulating balls into the robot. We wanted to follow a “touch it own it” philosophy where as soon as we touched a ball, it would be instantly in our control, eliminating slow alignment.

To achieve this we made the intake as wide as possible to be able to intake multiple balls at once. Since matches are chaotic, we also wanted the arm to be able to withstand collisions with other robots so we designed it with a virtual four bar that can compresses inwards when hit.

This was a very brief highlight of some of the features on Nari. If you are interested more details about our design process, please take a look at our technical documentation for Nari here