2018 - Dennis
FIRST Power Up
Dennis participated in Power Up, the 2018 FRC game. During Power Up, two alliances competed to manipulate large yellow cubes, with two main ways to score points. Robots could either place cubes into the opening on their driver station wall, immediately earning points, or use the cubes to weigh down large seesaws/scales, which generated points each second for the alliance that they leaned toward. At the end of the game, robots earned points by latching onto a bar in the center of the field and lifting off of the ground.
Robot overview
A CAD of Dennis may be found here.
Because an elevator mechanism for accessing the central scale would be quite complex, 4311 opted to focus entirely on the lower goals. To accomplish this, Dennis was designed with a pair of "arms." The arms rotated up and down, and could open and shut like a pair of pliers, allowing Dennis to grasp cubes. To facilitate picking up and ejecting cubes, the arms were equipped with wheels that could draw the cubes in or push them out.
Strengths:
The robot's arms were able to firmly grip and manipulate the cubes. The arms were especially adept at moving cubes into the driver station wall, allowing 4311 to specialize in that area during matches.
The robot had multiple autonomous routines that could be performed in various situations, allowing 4311 to collaborate effectively alliance members, no matter their robots' autonomous programming.
Dennis could give people hugs.
Weaknesses:
The driver camera was mounted in a poor location, directly behind the arms. When the arms were raised, driver vision was completely obscured, and controlling the robot became much more difficult. The driver camera should have been mounted in a location that always gave a good view of the area around the robot.
Though Dennis made heavy use of pneumatics, requiring multiple pistons to move the heavy arms, only two air tanks were installed on the robot. This was not enough to meet the pneumatics system's needs, and robot performance suffered due to drops in air pressure. Ideally, Dennis should have been fitted with three or four tanks.
Arm subsystem
Dennis made use of a pair of arms that were mounted to a rotating hex axle. To left the arms up and down, a large piston attached to the front of the robot was actuated, causing the arms to swivel. To allow the arms to open and close, three additional pistons spanned the two arms, fixed at each end. When they extended, the arms spread apart. Finally, to suck the cubes in/out, a CIM motor was attached to a gearbox on each arm, which drove two wheels connected by standard belts.
