MECHANICAL ENGINEER
Dynamic Feeder (FIRST Team 4201)
About the Project
This dynamic pneumatic feeder was designed for the 2015 FIRST Robotics game Recycle Rush, in which our robot had to make stacks of totes to get points, with taller stacks earning more points. This feeder was designed following our first competition at the Los Angeles Region, where our team finished as semi-finalists. As the driver during the competition, I noticed that a large amount of time was wasted aligning the robot to pick up the totes.To fix this issue for the next regional, I designed a dynamic feeder system to help with tote alignment
Design
The modified feeder consisted of a VEX BAG motor sandwiched between two aluminum plates, spaced 2 inches apart. These plates attached directly around the 2x1 extrusions that made up our robot's frame. I used bevel gears to connect the wheel to the motor. The feeder rotated around a shoulder screw supported by bushings. The feeders were actuated by a pneumatic piston. To choose a proper piston, I calculated the required torque needed to actuate the feeder and used a spreadsheet made by an FRC mentor to select a piston with the bore and stroke length that fit our needs.
Once I had a piston selected, I did a piston analysis using constrained 2D sketches in Inventor to determine the distance the piston's mounting point should be from the pivot point of the feeder. After fixing a position to mount the piston onto the frame, I used the stroke length, angle of rotation, and start and end positions of the piston (I chose to have it both start and end in the same position) to calculate the exact distance from the pivot point I would need to attach the clevis of the piston. With this distance, I was able to CAD up the model for the feeder plates, truss it out, program it in MasterCam, and mill it on the CNC mill.
Results
After assembling the feeders and attaching them to our robot, our efficiency improved dramatically. The new feeders were a large part of our team becoming finalists at the Ventura Regional, and qualifying for the FIRST championship. A video of the new feeders in action can be seen below. Notice how much faster the robot is able to create stacks, since it can pick up totes at a wide range of angles as opposed to having to line up perfectly like in the first video.
Images
Video
