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An ERHS Robotics club season overview

All photographs by Eagle Rockbotics

With the school year coming to a close, clubs are also beginning to finish their activities for the year. One such club is the Robotics Club, an FRC team participating through ERHS.

Image by FIRST Robotics Competition

The Competition

In January of every year, First Robotics Competition, or FRC for short, releases a new game and challenge for teams across the world to design and build a robot for this year’s game: Crescendo:

The Autonomous Phase

This year's game, Crescendo, has an autonomous phase, where robots operate independently for 15 seconds before the teleoperated phase begins. This phase will also allow robots to score additional points from the same methods available in the other phases.

The Teleoperated Phase

For the next two minutes, drivers and human players will maneuver their robots throughout their field. For this year’s game, robots will move around the field picking up “notes,” or large foam rings scattered around the field. After collecting these notes either from the floor or the “source,” a field piece operated by human players, the robots will move back to their starting zone to score into either the “speaker” or the “amp.” With an angled opening raised above the field, as well as a trapezoidal subwoofer to prevent certain shooting angles, the speaker is the main source of points throughout the game. The amp is a very different game piece than the speaker, the amp has a much smaller and lower opening with only a 3-inch recess, forcing robots to place notes into it to score. While the amp scores minimal points, every two notes scored into it allows a human player to “amp up” and greatly increase the points scored into the speaker. 

The Endgame Phase

The final element of the game, the “stage”, comes into play in the last 20 seconds of the game, the endgame phase. A triangular truss structure, the stage has a low-hanging chain that robots can climb, as well as a “trap,” a device similar to the amp that can only be reached when the chain is climbed. The final aspect of the game, the “spotlight,” has human players throw “high notes” onto the stage, spotlighting hanging robots on the chains below. 

Meet the Robot

This year’s robot, Lieutenant Craig, was a complicated one. Designed to score into both the speaker and the amp, Craig was also made to climb the stage during the endgame phase.

The drivetrain:

The main frame of the robot, the drivetrain is a key piece that holds everything together. Generally, FRC robots contain either a tank-drivetrain or a swerve-drivetrain. For Lieutenant Craig, a swerve drivetrain was used, the more complicated and agile of the two, though it can lack in raw power. Utilizing four wheel modules, a swerve drivetrain will have pivoting wheels that can allow for omnidirectional movement, as well as smooth dodging and rotation, all of which are incredibly important for traversing the field as quickly as possible. Unlike a tank-drivetrain, with two motors and three interconnected wheels on each side, which allow for the strongest straight lines, swerve uses eight motors: four to allow wheels to pivot completely independently, and four to rotate them, giving a swerve-drivetrain the mobility necessary to be the dominant drivetrain on the field.

The intake:

Before notes can be scored by the robot, they first have to be collected and held until a shooting position is found. In order to do so, the intake is capable of flipping between the shooter and a ground position, where it uses its two rows of compliant wheels to intake and discharge its notes. Rather than having motors flipping in line with the intake, it utilizes a set of free-spinning gears and chains to spin the wheels separate from the rest of the intake, greatly reducing the weight of the intake, as well as the risk that comes from extending it out of the robot.

The shooter:

The main scoring element of the robot, the shooter, was a mechanism capable of scoring into both the speaker and the amp by utilizing a wide-angled wrist pivot. Supported by two 3D-printed PLA blocks, the entire shooter is motorized and capable of pivoting into an amp-scoring position. And with an intake system similar to the ground-based one, the shooter is capable of holding onto notes before pivoting and shooting, while also maintaining enough power to shoot into the speaker. By utilizing two heavily weighted flywheels, as well as 4-inch sideways compression, the shooter can produce enough force to score notes into the raised speaker.

The elevators:

The final mechanisms of the robot, the elevators, are separate from the rest of the bot, existing purely for the endgame phase of the game. Using 3 smooth sliding box tubes, the elevators are extended by a series of coiled springs, before they are collapsed by a motorized winch system with enough torque to lift the 117-pound robot fully off the ground. Whilst the shooter does interfere with the climbing of the chain, it can be flipped back to avoid doing so, which also has the added benefit of further balancing the robot.

The Competition Season

The team competed at two different competitions this year: the Port Hueneme Regional and the LA Regional. 

Port Hueneme Regional:

The first of the two competitions, the Port Hueneme competition was to demonstrate flaws and fixes that needed to be made in the robot. Competing in a total of nine 3v3 qualification matches, the “Rockbotics” team unfortunately only placed 30th out of the 50 teams competing, not scoring high enough to qualify for the playoff matches. While this competition did not have the ideal placements, it was very important for the success of the team and robot for the rest of the season.

LA Regional:

Coming into this competition, the “Rockbotics” team came with a much more refined and ready robot, capable of scoring reliably in almost all aspects of the game. While the team did place lower than in Port Hueneme, only 34th, the competition was very successful overall: the robot was much more complicated than usual, displaying a new swerve-drivetrain, as well as a complicated CAD design. 

As a whole, this season was an incredibly beneficial experience and year for the team; countless hours of work were poured into the robot, new heights were reached, and the year was an amazing investment for the future. If you want to learn more about the “Rockbotics” team, you can find them in room S5 after school on Thursdays, or check them out at @eaglerockbotics on Instagram.

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