ASU robotics club blasts away competition

Rossum Rumblers’ designs pushed limits of VEX U robotics, earning awards for innovative engineering and attention to detail

VEX Robotics, a company that builds robot components for educational purposes, maximizes the use of their products in a competition series for students in elementary school through college. The competitions include a new challenge every year for participants to design and build robots that duke it out for the top spot and to earn additional awards.

Arizona State University’s VEX team, PYRO, is part of the Rossum Rumblers student robotics club on the Polytechnic campus and takes part in VEX U collegiate competitions. The organization hosts meetings and events at ASU’s Polytechnic campus for any ASU students interested in experimenting with robotics, including PYRO and groups interested in small combat robots, industrial robots and more.

“Our overall goal is to provide students with a way to apply the skills they learn from their classes in a more relaxed environment, which earns them experience for their professional careers,” says Kenneth Hodson, the Rossum Rumblers president and a robotics and autonomous systems graduate student in the Ira A. Fulton Schools of Engineering at ASU.

Rossum Rumblers’ PYRO team provides a competitive outlet for club members looking to achieve robotics engineering superiority against more than 300 VEX U teams from around the world. PYRO has participated in the competition series since 2014 and has earned numerous awards during the 2022–23 season for the team’s innovative designs.

From left, Rossum Rumblers PYRO team members Armando Pinedo, Brian Hou, Charles Jeffries, Kenneth Hodson, Kylie Baker and Andrew Ayerh stand in front of an arch with their robots and awards at the 2023 VEX Robotics World Championship. Photo courtesy of Charles Jeffries

PYRO’s 2022–23 VEX U awards include the Design Award, which recognizes organization and engineering skills; the CAD Engineering Challenge award, which rewards the creation of a new part for VEX robots using computer-aided design; and the Build Award, which rewards attention to detail in safety and design.

The CAD Engineering Challenge award honors PYRO’s custom-built mecanum wheels, a type of wheel enabling vehicles using them to move in any direction. The team won the Design Award for its well-documented building process and previous solidly constructed robot designs used during the season.

The Build Award was bestowed on PYRO for the design of an attention-grabbing robot named the Air Blast.

Shaking up Spin Up

The Air Blast robot competed in the 2022–23 season’s Spin Up challenge. Teams competing in Spin Up score points by using robots to launch discs into goals, similar to disc golf, in a small arena.

PYRO gained an advantage in the competition by paying attention to the rules’ wording. The rules state that teams are prohibited from using robots to touch opponents’ discs.

By using the literal interpretation of the rules, Air Blast knocked opponents’ already scored discs from the goals not by touching them, but with explosive blasts of pressurized air.

The Air Blast was inspired by a rocket launcher owned by a PYRO team member. The launcher uses compressed air to fire rockets made from paper and Styrofoam from a PVC pipe with a valve to release the air pressure.

“During robot design brainstorming, we got this launcher out and tested it on the Spin Up goals, but it did not have enough power,” Hodson says. “However, we liked the idea enough to pursue it further.”

After increasing the amount of power from the compressed air release, Air Blast used the technology to become one of PYRO’s fleet of 2022–23 robots. Because VEX robots typically use pneumatic components that require half of a liter of air, a small source of compressed air is already part of typical VEX robots’ systems.

However, given the large amount of compressed air needed to effectively blast opponents’ scored discs from goals, PYRO would need a much larger capacity tank.

To launch a burst of air at 100 pounds per square inch, the Air Blast robot has an air tank measuring five gallons, or more than 18 liters. Other than the air tank, most of the design consists of off-the-shelf VEX parts.

Brian Hou, an undergraduate robotics engineering student who led the build process of the Air Blast robot, says it was important to keep the design a secret until its debut at the World Championship.

“Keeping our game-changing idea hidden was tough,” Hou says. “We had to build the robot in complete silence because we didn’t want the other teams to catch wind of it and replicate our concept.”

Hou and his fellow PYRO team members engineered the Air Blast robot to use a ball pressure valve at high speeds to fling the game discs out of the goals and into the air. The solution resulted in robust reliability while remaining in compliance with U.S. Occupational Health and Safety Administration standards.

Charles Jeffries, a software engineering graduate student, led work on the Air Blast robot’s programming. Despite the unique design, Jeffries says programming was an easy process. The biggest challenge involved coordinating the timing of the motors that open the pressure valve for maximum release force.

“With our Air Blast robot, we had a capability to de-score that no other team had, and we had a robot the likes of which no one had ever seen before in the long history of the competition,” he says. “The most stressful part was getting it through inspection. We weren’t really sure whether the robot would be ruled legal or not. We were absolutely ecstatic when the robot was given a pass at inspection and allowed to compete.”

The other half of the robot team

The Air Blast robot’s innovative design impressed organizers enough to win the Build Award, enabling the robot to successfully reduce other teams’ scores. However, PYRO needed a way to score points as well.

Each team in Spin Up entered two robots, leaving room for one to focus on scoring. To earn points, PYRO created a robot that uses a flywheel to fling discs upward into the goal.

Unlike Air Blast, the second robot was built almost entirely from custom-made parts, including PYRO’s CAD Engineering Challenge-winning mecanum wheels.

Despite its award-winning wheels, the launcher robot had some performance problems. The drive chassis and wheels’ low ground clearance, though intentional in the design, eventually suffered from the combination of extensive upgrades and the mechanical strain of competition, resulting in the robot’s drivetrain sagging onto the ground.

The robot’s weight increased from heavy-duty modifications throughout the season, such as replacing surgical tubing on the disc launcher intake with solid rubber wheels and upgrading the disc launcher’s flywheels from aluminum to steel. The wear and tear from competition also increased stress on the robot’s structure, which didn’t have the rigidity required to prevent bending.

Ultimately, the sagging drivetrain kept the robot from driving in a straight line, reducing its performance capabilities.

“This is all an experience we’ve learned from and are working to fix for the 2023–24 season,” Hodson says.

A force of innovation

The Rossum Rumblers finished the season’s competitions with seven wins. Although PYRO didn’t win the World Championship, the Air Blast robot made the event a memorable experience for all the team’s members.

“People were glad to see a truly innovative robot, and that carried through to our matches, which often attracted the largest crowds at the event,” Jeffries says. “This culminated in an invitation to do a special interview in the grand finals arena between the matches to showcase our robot.”

Hou agrees that Air Blast gave PYRO a presence like no other at the event with its loud blasts of air.

“When any other teams would play, the bleachers would be about one third full or even less,” he says. “But when PYRO played, people had to line up to get the perfect spot to watch the match. The scene of the crowd covering their ears simultaneously at the last 15 seconds of each match has been on my mind ever since.”