It is an off the shelf hall effect joystick (HF | Fingertip Proportional | Joysticks | APEM) with a custom 3d printed handle. We really liked the feel of the bottom of a CH flight stick, but hated the analog circuitry and associated trim wheels for potentiometers. This is a nice compromise.
I was fairly certain we had put the most effort into joysticks in FRC until I saw 971’s controller for this year…
Oops, that was a typo, we subtracted 0.05" from our belt C-Cs
Were your drive gearbox shafts custom sized? Our (7013’s) WCP SS gearboxes showed 3/4" of backlash on a 6" wheel. Most of this from an undersized hex shaft mating loosely with its gear. I imagine it might rear its head over the long distances in a 3 or 4 cube auto.
We mount our drive encoders directly to one of the wheel shafts, so this doesn’t effect the accuracy of our odometry. There is a similar amount of backlash in our drive (much of which comes from the dog itself, to ensure smooth shifting).
What size do you mill your bearing holes for 1.125" and .875" OD in your drive gearboxes?
I believe it’s 1.12480011222338483848828474828111838474 and .87480002837474928282919474749238. But you can round too.
Such precision. Much floating point.
I love machining in fantasy land.
I target -.0005 to -.00025. Won’t really go lower than -.0005, but occasionally they come out to nominal and we loctite them in.
+/- 0.005" tolerance
Don’t do this. This is way too tight on one end and way too loose on the other. See Cory’s post.
It was a joke in response to the 27 decimal place accuracy in the dimensions provided in R.C.'s post.
Should have added ‘/s’, I guess.
But I agree, that tolerance would be way too much.
With the blue nitrile wheel setup you switched to, did you use a COTs wheel with the tread or did you make the wheel? Also, did you just pop rivet the tread onto the wheel?
We used WCP wheels and riveted the tread.
Hmmm O(10-37 inches) resolution on the larger hole. That’s less than a thousandth of a Planck length. There are some particle physicists out there who would pay a LOT for that mill, or even some of the extraneous data it can generate.
Not to revive a dead thread or anything, but I’ve got a question about your elevator encoder. How accurate was measuring the drum position as a means of knowing your elevator position? Did the strings wrap exactly the same way every time? And if not, was it negligible, or did you have some method of solving that problem?
Another question, how did you rivet your tread as to not leave a “tail” that sticks out, or a small tread gap in the circumference of the wheel? It seems like an art I’ve never been able to master.
Guess and check. Rivet one end then pull the other taut. Cut it a little long. Then pull taut again and cut a 2nd time to length.
It was accurate enough to get close enough to our raised elevator setpoints, even with added error due to weird wrapping. Maybe +/- .5". The only setpoint that needed a high level of precision was at the bottom of travel for doing the exchange. We had a limit switch there so it was pretty easy to make sure we made it. We also reset the position buffer of the encoder on the Talon when we hit that limit switch in an effort to mitigate the effects of variable wrap on the spool.
What solenoid and manifold do you guys use and why those ones compared to others? Did you test multiple variations and saw this was the best combination?
Standard SMC stuff that everyone uses now.