BOB 319 - 2017 Offseason Robot

319’s been working on a gearbot for the offseason. Here’s what we’ve come up with:](


Drivetrain - 8x 775pro single speed (12/14/16 fps) OR 4x cim dual speed (6 and 14 fps)

Gear mechanism - 1x BAG for collecting, 1x BAG for moving

Climber - 2x 775pro on a 1.25" velcro drum

*Dimensions * - 27"x29.5"x15" @ ~70lbs (before bumpers and battery)

The goal was to learn custom gearbox design, current profiling, CAM, and CNC machining while determining if we like 775pro drivetrains.
We’ll be running the bot at offseasons in NE between now and kickoff 2018 and releasing documentation around November.

I would switch the gear reduction on the hanger to a chain, just in case. In the worst case, your entire robot’s weight is being supported by two gear teeth (momentarily). Chain spreads this load out over multiple teeth, which is nicer.

Then again, between the multiple motors driving the hanger, and the very light weight of the robot, this likely isn’t a huge issue. Just something that’s burned me before. :slight_smile:

What are those tabs on the rear portion of the bumper rails for?

Also, are you direct driving your gear mechanism off of the Versa Planetary output shaft? It probably won’t actually be an issue of any sort, but it’s still a design choice I wouldn’t be thrilled with, personally. Given that you’re supporting the far end of the VP shaft, you’re avoiding overloading the output shaft during normal operation, which is good. However, since this is a mechanism that deploys beyond the bumper zone, the shock loading could be unpredictable in a collision (with either another robot or the field border). Given that it doesn’t seem like you have any real packaging or weight concerns (nor is backlash a significant concern in this application), it seems easy enough to rotate the gear mechanism off of a shaft separate from the VP output shaft with a 1:1 gear/chain/belt ratio in order to protect the VP output shaft.

Hella slick bot, Ty! You and the team should be proud. I’m pretty stoked to see this thing compete, especially with those beastly 775 transmissions. If this is any indicator, I can’t want to see what 319 comes up with in 2018.

Yet another amazing robot from you guys! I can’t wait to see it in action!

Agreed. The chain reduction would be more optimal, but we’ve been running this exact climber on our comp bot all season and haven’t had issues.

Those used to be the pivot point for our fuel collector on the competition robot. We’re re-purposing the competition drivetrain with all fuel capabilities removed.

Yep. We’ve been running the same gear collector on the back of our competition robot all year, but your points still stand. It doesn’t actually ever extend outside the bumper zone (artifact of our fuel system taking up as much space as possible), but that doesn’t completely protect it from impacts. Main point is that the gear mechanism already exists so we won’t really have time to change that one.

Cool robot!!! What are those light blue extended semicircles (wording stolen from 2012 game manual) with the holes in them mounted to each side of your bumper rails?

Also, what is the round thing in between all four motors on your drive gearboxes? Looks like maybe an encoder?

To quote one of my CAD students, “Can I get an Onshape link?” No but actually, any plans to release the CAD?

Best of luck competing with this robot at offseason events!

The semicircles used to be the pivot points for our fuel collector. The chassis is re-purposed from our comp bot.

The round thing is where we hope to place our greyhill encoders, they fit perfectly in CAD so we’re gonna print up some mounts and see if we can make it work.

Sure. Here’s a link. We’re hoping to release more documentation and a whitepaper of our findings around November.

I made an unauthorized CAW for this

Will you be using this bot at summer heat?

Yep. We likely won’t have the 775 pinions in time to run the 775pro gearboxes, so we’ll be running the 2-speed version.

Everything else should be there though.

Bring both of them. We are looking to backfill a spot.

What do you need for pinions? We might have some.

You should take riot crews advice and bring both robots. This event only has two 40 KPA shooters, 2648 and 133.

8x WCP-0002

I’ll take a look tonight. If they are pressed onto the RS775 pro motor, would that work for you?

Nada. Sorry Ty.