FRC 95, The Grasshoppers, Build Thread

[JamesCH95]

A close-up of the shooter.



It's a bit... different... than most shooters we've seen before. We've setup the first 'booster' stage (3/4 of the length) to ramp up in speed as it feeds into the 'firing' stage, which spins considerably faster. Prototype testing has been quite promising.

[JamesCH95]

A few pictures from today:

The shooter is nominally populated with belts and rollers and stuck on the robot!



How he'll be able to fit under the low bar.



Wiring is about 70% there, enough for a power-up test!



We're currently trying to get code on the Athena (we refuse to call it the "Roborio"), which always seems to have some growing pains. We'll get there...

[Caleb Sykes]

Originally Posted by JamesCH95

Mini-cim shoulder drive setup. We're gearing 108:1 with the versa planetary (if memory serves) with an additional 16:34 sprocket reduction. Should be able to flip Kovaka back on his wheels if things go sideways... err.. upside down.

Make sure you take into account the load guides for the versaplanetary. This gearing ratio is either just barely scraping by or it is outside of recommended loading.

[vigneshv]

Are you planning to intake from both sides? Is there any significant advantage, that your team saw, to that strategy (if you are indeed capable of intaking from both sides)?

[JamesCH95]

Originally Posted by Caleb Sykes

Make sure you take into account the load guides for the versaplanetary. This gearing ratio is either just barely scraping by or it is outside of recommended loading.

We did use the guide. We are right on the edge of what is advisable for the versaplanetary with a mini-cim. During normal operation we will be nowhere near the stall limit of the mini-Cim. Flipping the whole robot back over will only be a 22amp draw (from JVN) design call.

Though your point is well-taken. The versaplanetary guide is to be taken quite seriously!

[cadandcookies]

Originally Posted by JamesCH95

We're currently trying to get code on the Athena (we refuse to call it the "Roborio")

A team after my own heart.

[Akash Rastogi]

Man, I love 95's robots. You guys always put out something beautiful and unique.

[Kevin Leonard]

I love seeing this thread every year. 95 is always evolving and improving. Good luck in 2016!

[JamesCH95]

Originally Posted by cadandcookies

A team after my own heart.

Originally Posted by Akash Rastogi

Man, I love 95's robots. You guys always put out something beautiful and unique.

Thanks! That means a lot to us. It is something that our founding mentors believed in strongly.

Originally Posted by Kevin Leonard

I love seeing this thread every year. 95 is always evolving and improving. Good luck in 2016!

Thank you! It is what we strive for, at least in baby steps. And good luck to the Rocketeers!

[Andrew Schreiber]

RE the dual lock on the electronics - you sure that'll hold everything tight when crossing defenses?

Looks good again this year man.

[JamesCH95]

Originally Posted by Andrew Schreiber

RE the dual lock on the electronics - you sure that'll hold everything tight when crossing defenses?

Looks good again this year man.

We are not sure yet, definitely going to test it thoroughly. We do have some contingency plans if it doesn't work though. The wiring is secured in a few key locations aside from the Velcro.

And thanks!

[hkuperstein]

Wow, that's a really creative design in a game with many similarly designed low bar bots. We'll be seeing you guys at Granite State, good luck!

[JamesCH95]

Started our drive-train burn-in only to have the burn-in go a little too literal for us...

Side plate off to investigate:



Yeah... had some rubbing chain tensioners...



Milled them down, reassembled, and tried out some defenses.

Moat

Low Bar

Did some crossing exercises, everything looked good, until...



Weirdest chain failure I've seen, and the only one I've ever had on a 95 robot. Master-link was good, fractures are on opposite sides of the chain loop, tensioners were installed and slack(ish), and our nominal FoS is around 4 or 5. Bizarre...

[JamesCH95]

The shooter is now wired up and functional!

Here is the firing stage of the shooter spooling up to full-speed. It is powered by 2x RS775Pros with 1:1 versa planetary transmissions. All belts are designed 'perfect' center to center. Shafts are 1/4in steel D-shafts supported by bearings rated to ~50krpm.

Kovaka firing stage spool-up

Here is a test shot with the booster stage feeding the firing stage.

Kovaka test shot

Two of three subsystems down... only the shoulder to go...

[Ken Streeter]

Sweet!