FIRST STEAMWORKS was the game played in the 2017 Season of First Robotics Competition (FRC)
The main scoring objectives were shooting 5" wiffle balls into a 21" cone and carrying gears across the field from a loading station to pegs on your alliance's airship. Additional points could be earned during the endgame by climbing a rope on the airship and activating a touch pad.
Spectre has dual fuel shooters that each use a BAG motor with 4:1 gearing to a belt driven axel. The axel has a centered, 6 inch diameter 75A durometer urethane rubber traction wheel from Andymark. The surface of the curved polycarbonate backplate is 4.75" away from the outer diameter of the wheel. These components are supported by two (per shooter) 1/8" aluminum plates custom designed in CAD and cut via waterjet owned by one of our outstanding sponsors, ISCO Manufacturing. Wheel speed is regulated using a hall effect sensor mounted near the surface of the wheel with a magnet embedded in the wheel. A PID loop uses feedback from this sensor to keep speeds ideal for consistent shooting.
Spectre's active gear mechanism consists of two pneumatic pistons, both controlled by the same solenoid running at at maximum of 60 PSI. These pistons are attached to two 1/8" C channel aluminum pieces taken from a spare kit drive base. Their shape allows for the gear to be held in such a way that it cannot fall forward or backward. The closing angle of the pistons is set and positions the gear at the proper height for the peg to enter one of three holes between the spokes on the lower half of the gear, leaving room for our front loading floor intake in front. Above the gear is a polycarbonate flap controlled by a servo. When the flap open it serves as a backplate to help guide the gear in at the loading station and when it is closed it prevents balls from getting stuck when loading from hoppers. The flap also prevents the gear from flying out in the event of a collision.
Spectre's climber is powered by a CIM motor with a 20:1 gear ratio that allows for a 6 second climb. The 1/2" hexagonal output shaft from the gearbox is connected to an 11" long, 1/2" wide solid aluminum hex shaft using #35 chain. The shaft is supported by two high-load bearings mounted in 1/8" aluminum brackets with a 1/4" thick aluminum structural plate on either side secured to the base frame. The shaft is wrapped with 3M DualLock Velcro, which we discovered is incredibly grippy when used with the standard loop side of hook and loop tape. Our rope has small segments of loop strips sewn on to our 1/2", strap (rope) alternating between sides to maintain flexibility. Either side of the shaft has an aluminum, cone-shaped piece to keep the rope centered.