Mechanical Design

Isometric View

Dimensioned Chassis Sketches

Note: All units are in mm

Frame

The chassis plates and walls were lasercut from 3/16" duron sheets and fastened together using cutouts designed to fit 3.5x20mm bolts and nuts. 

Actuation System

A two-gear rack and pinion system creates tension on four extensional springs; relevant parts are labeled in the 2D side view diagram below. The springs  connect from the L-brackets to the left of the push gear to the opposing mounts on the gear rack. The gear rack is mounted to a ball bearing carriage that glides on a metal guide rail. Initially, both the push and pull gears are in the "slip" condition--that is to say, their teeth are rotated away from the gear rack such that the rack can slide back and forth without interference from the gear teeth. When the load command is received from the on-board microcontrollers, the push gear is rotated by its servo to move the gear rack towards the pull gear. The pull gear is then rotated by its servo to engage its teeth with the rack. The push gear servo then resets the push gear by rotating it back to its original position, disengaging its teeth from the rack. When the fire command is received, the pull servo rotates the pull gear counter-clockwise until it reaches slip condition, causing the tension in the springs to be released and making the hammer fire the loaded puck. After this sequence, the pull servo resets to its initial position to ready itself for another load command. 

Note: All units are in mm

Drive Train

A metal shaft connects two DC motors to couplers, which in turn connect to the wheels. The shafts pass through two pillow blocks each to prevent torques that could cause the motors to experience a side load.

Scoop

A servo mounted to the second floor of the robot attaches to a duron scoop. This allows the robot to hold a puck in place while moving so it can align to the other field and fire.