5205 Full Metal Jackets: 2019 Robot Reveal - Trixie

#1

Introducing Trixie

5205 2019 Robot Reveal

Capable of hatch/cargo on all levels. Passively powered suction cups, we just ram into the hatch panel and then open up valves to let it go.

8 Drive Pods, each independently suspended, each driven by a 8:1 gearbox and NEO, on 4" VEX omni wheels.

It makes for a super zippy robot.

Here is video of the underbelly showing the Drive Pods:

Some initial testing of the final drive design

Also able to climb to level 3 hab, but we really just like watching her drive.

Coming in at 124.8lbs, we hope. Not sure our scale is totally calibrated.

Competing at FIM - Lakeview and Jackson

6 Likes
#2

this is one of the coolest drivetrains i’ve ever seen.

4 Likes
#3

CAD release of our 2019 Robot. Includes a 8 drive pod omni design, elevator and intake.

#4

I loved watching 5205 this year, congrats on the first banner! After running it for a season, how do you guys feel about the drivetrain?

#5

The drive train held up well over the entire season. Never had any failure with the planetary gearboxes and chain during competition. We had a couple masterlinks pop off during practice runs so we checked the masterlinks every few matches as PM. We did notice at Worlds that 2 of our drive pods were pulling 2X more current that the rest so we did eventually change them out. But not sure if that was a gearbox or motor issue.

We actually re-geared our drive train for States and Worlds so it would be a little faster. We changed it to be 6:1 on 4" omnis on the outside corners and 8:1 on 4" omnis on the inside diamond. We tried going all 6:1 and the inside drive pods heated up a little too quickly.

It didn’t push as well as we had hoped. We were traction limited. The rubber on the omnis do not have as good as a COF as normal traction wheels. The good news was that we didn’t get pushed around as badly as when we had mecanums on last year.

We never had enough out of bag time to get Field Centric Driving to work. So our driving skills never improved dramatically over the course of the season.

All in all, pretty happy with the season considering this was a highly experimental drive train that we didn’t not start developing until January.

1 Like
#6

Why this drivetrain design over a conventional tank drive or even a more common FRC omni directional drive (swerve, H, X, mecanum, etc.)

Looks p cool.

#7

Mecanum rollers have a really high attack angle. So gearing forward for high speed makes strafing stall out the motors a little too much. So the compromise is that you gear higher, reduce forward speed. Also, mecanum requires all wheels on the ground to maintain traction. In a pushing contest, the second one of your wheels lift off the ground, you will get pushed incredibly easily.

Swerve is great, but you need multiple off-seasons to get it right and we were just not ready to use our design yet. Maybe next year.

X or H drive is essentially what we have with more redundancy. With 8 wheels on the ground, even if a few lift off, we still maintain decent traction.

Conventional tank I always thought didn’t provide enough design experience for our team. And didn’t differentiate us from any other KOP team. So I wanted to make sure our team was always doing a little more.