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Courtesy of FRC Team 254: The Cheesy Poofs
FRC Team 254 is widely regarded as one of the most dominant and prestigious teams in FRC history. Their competition robot is fully souped-up for efficient and reliable play.
This robot runs on a West Coast Drivebase (WCD) that is fitted with pneumatic wheels. Team 254 has found that the simplicity, reliability and power of the WCD has served them well. Considering the complexity of the other subsystems in the robot: a rotating indexer, a turret, a flywheel, the "Wheel of Fortune" mechanism, and a climb, due consideration must be given to the allocation of motors. Team 254 decided to incorporate a pneumatics to allow their drivebase gearbox to shift between powering the drivebase or diverting power to the climber. The gearbox also features a separate set of pneumatics, to allow for gear shifting in the drivebase to enable the robot to push through defense on low gear and sprint across the field on high gear.
The over bumper intake is optimized to lift up to 3 balls simultaneously. High speed front rollers on the intake grab balls off the ground while lower speed upper rollers prevent ball jams.
Balls are fed into a rotating indexer that is fitted with a central drum that rotates 3" long brushes to spin the balls. The flexible brushes prevent the mechanism from jamming and propel the balls into position for ejection by the double vertical flywheel.
To increase shooting speed and flexibility, the flywheel is mounted on top of a turret that is positioned directly over the indexer. The flywheel can be rotated to launch the balls from any orientation. This setup overcomes the more limited maneuverability of the WCD. Further, the flywheel is fitted with an adjustable hood that enables shooting release angles from 45° to 70° above horizontal. A limelight camera at the top of the flywheel tracks retro-reflective tape on the goal and aids in goal scoring. This allows for the robot to shoot into the Ports from many positions on the field.
The climber for the end game is constructed of 2 sets of telescoping lifts. Springs and pneumatics deploy the climber, while a drive gearbox pull the robot up. A friction brake in the drive gearbox brakes and holds the robot once the climb is done.
The "Wheel of Fortune" is a mechanism to manipulate the Control Panel. A pneumatic moves a motorized wheel into position to spin the Control Panel. While pneumatics can be finicky, once mastered, it has wide applicability.
As can be seen, this robot was designed to complete every task without partner/alliance support. The goal was to win the FIRST Championship. Unfortunately COVID-19 interrupted the best laid plans with competition cancellations.
Check out the team's technical binder to better understand the design thinking undergirding their bot. An in depth interview about this robot was featured in Behind the Bumper by FUN Robotics Network.
Compare this design against 2 simpler versions in Ref 1 and Ref 17. Another full feature solution albeit with more limited budget can be found at Ref 11.
* Further explanation of mechanisms in FRC Handbook Volume 1.