For the FIRST Stronghold challenge, the team endeavored to design, build, program, and operate a robot that would shoot balls through the high goals of the tower while traversing the lower profile obstacles. The robot was maneuverable enough to open the drawbridge and hold it down for an alliance member to pass through. It wsa also designed with a central tower that featured arms that could hook the climbing bar and lift the robot to achieve the climbing bonus at the end of the match.
One important manipulator would be the intake. In order to pick up the balls, to shoot them, wheels and plastic tubing were used as a conveyor belt. Pnuematics were used to open the intake system to pick up balls to shoot them and closed to push the balls into the low goals.
The conveyor intake was controlled with pneumatic actuators that would raise the intake when it was time to pick up a ball. Rotating rollers were connected with pneumatic tubing to create a conveyor belt that advanced the ball towards a curved ramp and up to engage the shooter mechanism.
A tank drive and six pnuematic wheels allowed us to easily get over the different terrains. Dual motor transmissions, driven by four CIM motors ran the six wheels with belts. After losing traction at competition, we designed tentioners to keep the belts tight.
Controlled by two 775 motors, the flywheel spun at a high rate of speed to propel the “boulders” into the air. The flywheel was placed to compress the balls slightly against the ribbed, curved backstop, which would help control and accelerate the ball.
Within the climbing tower, we attached the RoboRio, PDB, VRM, and PCB to a perf board and placed it inside of the tower. Strategically placed holes on the sides of the tower allowed wires to easily run from the power distribution board to the talons, located on the sidewalls of the intake.
Using the Igus slew rings for “shoulders,” the climbing mechanism used pivoting arms that would grasp the climbing bar and retract down rails from Bishop Wisecarver. As the arms retracted, the robot would rise, climbing the tower.
We used LabView to control the robot and manipulators. The vision processing was programmed using GRIP, then ported to LabView.
The code from the 2016 robot can be found in our GIT repository. Source code can be found here.
A camera mounted on the top of the backstop coordinated with a motor that would rotate the lazy susan mounted flywheel and backstop. As the camera continued to maintain focus on the target, the flywheel would accelerate to an appropriate angular velocity to launch the boulder into the target.