← All projectsS.T.A.T.I.C., FTC 18996Sep 2021 to Jan 2022
FTC FREIGHT FRENZY Robot
The 2021-22 robot. It was not finished in time to compete.
FREIGHT FRENZY was the 2021-22 FIRST Tech Challenge game. Robots collect freight (boxes, some of them weighted, and balls) from the warehouse, deliver it to the shipping hubs, and spin a carousel to drop rubber ducks onto the field.
Our robot drove on mecanum wheels, picked boxes up with a two-jaw claw and turned the carousel with a wheel ringed with strips. The clips each show one mechanism by itself, so this page walks through them one at a time. We did not get the robot finished in time, so we did not compete that season.
The claw
The claw hangs from the front of the robot and closes on a box from both sides. The jaw is a perforated aluminum plate with green rubber bands stretched across it in an X, so the bands are what touch the box.
A servo sits on top of the claw. As it turns, a short linkage swings the moving jaw in against the box.
Freight is not all one weight: some boxes carry metal weights in their cells, so the same grip has to hold a light box and a heavy one.
Calculation How much more does a heavy box ask of the grip?
| Box size | 2 x 2 x 2 in, polypropylene | REV, FREIGHT FRENZY game elements |
|---|---|---|
| Light box | 0.9 oz | same page |
| Heavy box | 4.8 oz | same page |
- Heavy box: 4.8 oz x 28.35 g/oz = 136 g, and 0.136 kg x 9.81 m/s² = 1.33 N
- Light box: 0.9 oz = 26 g, 0.25 N
- Held from the sides, the box stays up only by friction at the jaws, so the jaws must supply 1.33 N of friction for a heavy box and 0.25 N for a light one
- Heavy / light: 4.8 / 0.9 = 5.3
The grip has to be set for the heavy box: that one needs 5.3 times the friction of a light box, which the same squeeze then holds with plenty to spare. That is the job of the rubber bands on the jaw.
Static hold only; lifting and driving add to it. Rounded.
With the box held, the claw lifts it clear of the floor.
The carousel spinner
The carousel is a turntable at the edge of the field loaded with rubber ducks. Turn it, and the ducks come off onto the field, where they score, in autonomous and in the end game.
Our spinner is a sprocket ringed with strips. From above, the wheel sits against the carousel's rim: the strips press on it, and spinning the wheel turns the carousel.
Turned fast, the carousel carries the ducks round until they come off it.
How the season went
Problem Not finished in time
We did not get the robot finished in time for a competition, so the team did not compete in 2021-22: our record on FIRST's event pages for that season is empty.
The clips on this page show what the robot could do: the claw gripping and lifting a box, and the spinner turning the carousel.
