Figure 1: RHSS Robotics (Team 1285) Final Robot
The 2014 FRC Game was released by FIRST in collaboration with NASA on January 3rd 2014. This leaves teams 6 weeks to design, manufacture, program, and iterate their design; the robot is than locked away and cannot be worked on until competition. The game is released with a set of rules and documents as well as a brief game animation depicting the major rules.
Video 1: 2014 Game Animation
During the year of 2014 I helped mentor two teams under the same robotics club (RHSS Robotics) the teams were 1241 and 1285. Both teams decided through initial brainstorming that the robot would require these constraints:
• Efficient, fast and agile drivetrain running at 16 ft/s.
• An intake system that should be able to intake the game piece while the robot is at max speed.
• A shooting device that can score the game piece from the autonomous start line, as well as being able to score in the low goal.
• The shooter must be able to shoot over the truss and the robot must be able to pass the game piece to another robot.
• The robot must be able to acquire the ball from the human loading station.
From these criteria the students worked on initial prototypes using wood planks and any objects they could find in the schools machine shop. A design review was than conducted and these were the most efficient results:
• A catapult shooter utilizing elastic bands and a disengaging feature to fire the game piece.
• The intake system would need to be inside the robots perimeter when the game piece is being fired.
• The intake system would be powered by pneumatics because of its binary location.
• A catching mechanism was ruled out as it requires a large amount of coordination and does not reward the alliance with a sufficient amount of points
There was than another brainstorming session to decide the best way to achieve these constraints and this is what the team came up with.
Video 2: 2014 Robot Reveal Video
Figure 2: Rendering of Final Design
Figure 3: Drivetrain Design Featuring Gates Belt Components
The drivetrain features a 6 wheel setup with the center wheels being .125in lower than the outer wheels to allow an easy pivot. The drive gearboxes feature all aluminum gears to minimize weight as the competition only allows the Robot to weigh 120 pounds. The electrical system was also laid out in CAD to ensure the shortest distance between wires and an easier way to troubleshoot problems.
The drive also features two optical encoders to sense speed and distance as well as gyroscope to read angular deviation. The design also incorporates an onboard pneumatic compressor.
Figure 4: Initial Catapult Design
The catapult features a potentiometer to sense the angle of the catapult. This design also features a concave design so the game piece will sit perfectly in the catapult and have a large area of contact.
Figure 5: Ball Intake Device
The intake uses two 12V Banebots motors and an off-the-shell planetary gearbox to maximize simplicity. The walls of the intake feature a very unique lighting pattern that incorporates the teams name and the possibility to add another roller wheel.
After the initial design were completed we began to manufacture the parts using the schools in house machine shop. The facility includes multiple manual Lathes and Mills, as well as a CNC Router Table and two CNC Mills.
Figure 6: Manufacturing of Components Utilizing a CNC Router
Figure 7: Manufactured Intake Arms
Figure 8: Assembly of Catapult
Figure 9: Finial Assembled Drivetrains Beginning to be Wired
Figure 10: Manufactured Dog Clutch
Figure 11: Catapult Gearbox Being Assembled, Design Features a Worm Gear Ratio
Figure 12: Robot Being Assembled
Figure 13: Modification of Catapult Shifter, Entire Motor Now Disengages to Fire Catapult
One of the main "cool factors" of the robot was the release of the catauplt. a pnumatic piston is actually attached to the motor and the entire motor pivtos to releas the motor from the gearbox and allow the catapult to fire.
Figure 14: RHSS Robotics (Tean 1241) Final Robot
Video 3: Match VIdeo of RHSS Robotics (Team 1285) at the 2014 FRC World Championship
The season was a huge success, the team won multiple finalists awards as well as a Regional Championship. The team also won the General Motors Industrial Design award for how the catapult is fired using a pivoting motor.
