Robot 24
In one of my classes, I teamed up with a group to build a machine that is able to accomplish a set of tasks themed around basketball. Our goal was to launch two ping pong balls into a target zone, collect three other balls that were randomly placed in a set area, and then "dunk" collected balls into a specific hole in an hexagonal array of holes.
There were a number of rules tol follow:
1) Dimensions of Robot cannot be greater than a 20 inch cube.
2) Destruction of any of the arena props is prohibited.
3) The entire run should not take more than two minutes, one minute to set up and one minute to achieve all the specified tasks.
4) The entire robot's final cost must not exceed $100.
Failing to follow any of these rules would result in a disqualified run.
First it tested my CAD skills
Using the CAD drawing as a reference, the team first began by manufacturing the frame, made from 1/4" thick MDF, and laser cut to the desired shape. The frame was assembled like a jig-saw puzzle, then secured using brackets and screws.
To launch the ping pong ball, we experimented with multiple designs:
We first tried a stylish approach that involved shooting the ball from an air cannon. After 3D printing the parts needed, a few tests proved the air cannon to be inconsistent and unreliable.
The team then opted for a catapult which uses a lever approach to launch the ping pong balls at different angles. When the lever was printed, the catapult was an astounding success.
Both the catapult and the air cannon utilized a pneumatic system to function.
Another part that went through many alterations is the gear. Although many online websites sell well functioning gears, they were out of the $100 budget. The drawer slide alone cost around $30. Moreover, COVID related shipping issues were spreading across the country. However, alot was learned when making gears:
The MDF gear teeth were too brittle, and the 3D printed PLA gear's shaft always sheared after an extended period of testing. The aluminum gear was cut using an AWJ (Abrasive Waterjet), which did not mesh well due the nature of the cutting process. The final alteration that proved the best was the 3D printed PLA gear with an aluminum core pressed in the center. This solved the shaft shearing issue of the PLA and the mating issue for the aluminum.
The most challenging part of building the robot was the collect and dunk functions, and therefore the most satisfying success story. A funnel with strategically placed hole and specific height was used for collecting the balls. A drawer slide and a simple pulley system extended the "arm" to reach the desired distance.
Finally, the brain of the robot was placed on top. The microcontroller controlled the motors, actuated the pneumatic system on command, and made sure all the tasks were done in under a minute.
After months of hard work, planning, and many iterations, "Robot 24" was ready to compete.
We got one of the highest scores of the 2020 ME2110 GT competion. I am very proud of 24, and the opportunity to bring it to life!