I write the robot code. The team builds the mechanism, I make it move under software. Our stack is WPILib command-based Java, NetworkTables for telemetry, and PhotonVision for AprilTag pose estimation.
The most rewarding subsystem to date has been the shooter, we tuned a state-space controller with an LQR cost function and a Kalman filter for the flywheel RPM estimate. It hits its setpoint in under 250ms and stays there through impact disturbances.
Beyond competition matches, this is where I learned to read other people’s code, write unit tests that actually run, and own a system end-to-end with a deadline that doesn’t move.