Team 610 pre-season drivetrain

[Mr. Lim]

We typically run only 12 Gauge wire to our motors. We try and standardize on two gauges: 12 and 18. Very generally (there are always special cases) motors will get 12 gauge, and everything else that requires a circuit run from the PDB will get 18 gauge. It's pretty simple for our students to follow, and for them to explain during inspections.

This is the first time we've used Talons, and are very curious about their linearity, and how they'll behave with our software PID control.

Once it's driving we'll likely post a video, but I doubt it'll be much more interesting than any other FRC drivetrain doing laps.

The brownouts from our 2013 robot were traced back to a faulty 12v->5v DC-DC converter for the radios. We didn't catch this until we were on Einstein when the field support crew informed us that our radio (not cRIO as we originally thought) was losing power. We replaced it at some point on Einstein as we were placing the robot on the field for a match - I don't remember during which match. After that, the brownouts ceased.

Our drivetrain choices are driven by game strategy requirements. I wouldn't rule out a multi-speed gearbox in the future, but there would need to be very good reasons. We optimized last year for multiple 36ft start-stop sprint between the feeder station and pyramid, and for getting around defenders. Optimizing for, say, Overdrive in 2008 was a different matter completely. I don't think our team has ruled out anything, but we always try and find the simplest and most reliable solution to achieve the objectives that our Strategy team sets. Being able to build something that's maintenance free is also a big deal.

If the drivetrain strategic objectives were the same as last year, I think it's safe to say we'd stick with the single speed. In fact, we might've gone down to 4 CIMs, as the 6 CIM decision was somewhat a product of our power-takeoff climbing time requirements.

The weight distribution is definitely biased for just a drivetrain, however I don't lose any sleep over it. We developed this drivetrain with the intent that we hope to actually use a similar design on a full FRC robot someday. There's room if we need an open front for an intake, and the top-half of a robot is usually weight biased as well. We actually didn't know which end of our drivetrain would be the front of our robot until close to week 3 last year - and this gave our programmers fits! We intend on testing this drivetrain at full competition weight at some point, so ballast will be going on, and the weight distribution will be adjusted at that point.

[ErvinI]

Originally Posted by Mr. Lim

Once it's driving we'll likely post a video, but I doubt it'll be much more interesting than any other FRC drivetrain doing laps.

Some dubstep will make the video more awesome.

What are you expecting that is different with Talons regarding PID control? I believe that you guys mentioned that you were using CAN last year. I'm not too familiar with it, but if I recall correctly it does some of the framing for you regarding PID control. I guess that part will be different.

However, we used PID control last year for our drivetrain running 4 Talons. Proved to be accurate within 3 inches over a 100 inch drive if the count-to-inch conversion was accurate, and that was with little tuning on the drivetrain ("Test mode" only works for one motor at a time, and we relied upon it for rapid tuning). For FRC purposes, I can't imagine that non-linearity is that significant between, for example, a Talon or a Jaguar running CAN.

[Ether]

Originally Posted by Mr. Lim

This is the first time we've used Talons, and are very curious about their linearity

Originally Posted by ErvinI

I can't imagine that non-linearity is that significant between, for example, a Talon or a Jaguar...

If it helps, there is actual test data available here:

http://www.chiefdelphi.com/media/papers/2720