Purdue SIGBots: VEX Robotics Competition 15" Robot (February - March 2024)

Deliverables

Premise

The VEX Robotics Competition is a competition for middle schoolers through university students which has its challenge change each year. During the 2023-24 season, the challenge was dubbed "Over Under" and featured 60 green reuleaux triangles named "Triballs", two elevation bars which robots could climb on top of, and two goals to deposit Triballs into. Teams could score 5 points for placing a Triball in their respective goal, 2 points for having a Triball on their half of the field, and up to 20 points for each robot elevated on an elevation bar depending on altitude. At the university level, each team is responsible for making two robots: one that fits within a 15"x15"x15" size constraint, and another fitting in a 24"x24"x24" size constraint.

Late into the 2023-24 VEX Robotics Competition season, Purdue SIGBots' competition team, known by their identifier "BLRS" intended to test the effectiveness of creating a robot with a height at or below 6 inches. The benefit of such a robot would be the ability to descore Triballs from the opponent's goal, since robots above 6 inches tall cannot perform such a feat. BLRS believed that this capability would cause opponents to play more conservatively to prevent "double-zoning". Double-zoning describes an event where two robots on the same team are in the same half of the field; in this case, the rules state that their goal is no longer protected and can have any scored Triballs tampered with.

Development

While BLRS intended to converge on creating a highly-refined robot design that would compete in the World Championship, I was made the principal designer of this new 15"x15"x15" robot in order to investigate the effectiveness of "descoring robots". I started by using decision matrices to evaluate which chassis and Triball intake designs would be optimal for this robot. Through rigorous testing, I determined that a holonomic chassis, specifically one using Mecanum wheels, as well as an intake made of pneumatic tubing would be optimal for this robot.

The robot was primarily constructed using aluminum C-channels. It would eventually have pneumatic cylinder powered "wings" added to it, which increased its surface area and allowed it to plow Triballs into the goal more easily. The wings were constructed out of small aluminum L-channels and were attached to the pneumatic cylinders using a clever screw pivot joint. To help the robot drive over the barrer in the middle of the field, thick "sleds" were designed and manufactured out of PLA filament to allow the robot to remain tangent to the PVC pipe barrier and gain enough traction to effectively jump over the barrier. The robot would later be affectionately referred to as "The Jawn" by other club members, a Philadelphian slang term referring to any person, place, or thing and a playful reference to the club president's Pennsylvanian roots.

Outcomes

Illini Cornfield Clash

The Jawn saw its first competition start at the Illini Cornfield Clash tournament hosted by the University of Illinois, Urbana-Champaign on February 10, 2024. As a whole, BLRS achieved a record of 4 wins and 3 losses during the qualification round and was the 4th seed going into the elimination round. They were subsequently eliminated by Northern Kentucky University (identifier "NUKE") in the quarterfinals. Throughout these matches, The Jawn scored 27 Triballs in the goal, although its primary role was passing Triballs over the center barrier for the 24" robot to score in the goal. Judges were impressed by the robot's strafing capability, allowing it to have positional superiority over the field. After the tournament, BLRS was awarded the Design Award for extensive documentation and The Jawn's unique design.

Purdue SIGBots Slam and Jam Qualifier

After the Illini Cornfield Clash, The Jawn was scrapped for parts and was largely downgraded from its original form. It was kept as a reserve robot while the team decided to pursue a new iteration of a 15" robot that would capitalize on the descoring aspects The Jawn intended to test. At the Purdue SIGBots Slam and Jam qualifier, The Jawn once again made an appearance as a substitute robot, replacing the current 24" robot due to rule compliance concerns. In the singular match The Jawn substituted into, BLRS would go on to win the match 93-18 against the University of South Carolina (identifier "EZPZ").