pic: Mean Machine's 2018 CAD Release

pnw
2471
teammeanmachine

#1



Here is the CAD for our 2018 robot “Atlas” if you have any questions leave a comment or you can email use at team2471@gmail.com

CAD download
https://team2471.files.wordpress.com/2018/05/atlas-cad.zip


#2

Awesome robot. Thanks!


#3

It’s about time :stuck_out_tongue:

xoxo <3


#4

Thanks for the CAD!

Also 600th post :stuck_out_tongue:


#5

I could be missing something, but what is the cylinder on the winch shaft for? and how did you actuate the disc brake? Also, I didn’t see any pulleys/sprockets for the drive train? What was the set-up for the power transfer to the outer wheels? Thanks for the great CAD to dig through!


#6

Very cool, any details on the layup of the lifter forks? I was hoping to do something similar but I never got around to it.


#7

Trevor,

If you add the cad files to grabcad.com, you can submit the link to TBA, so the CAD is always linked to the team’s page TBA page for 2018.


#8

Great robot this year! Always fun to see what you guys come up with.

Did you current limit or slow down your drive gearboxes any? Anything you would change with them?


#9

Are those custom omni wheels?


#10

Aw yes, it’s here! I saw your reveal video and your update videos, and now I’m so happy the CAD is released!


#11

Yes they are.


#12

The Cylinder on the winch shaft is there because the gearbox running the elevator is 2 speed ( low for climbing and high for the rest of the match)

We used cable pulled by a 2 inch stroke pneumatic that we mounted to the belly pan, but we never put it in the cadd

On the drive train we used #25 chain with tooth sprocket

The Forks are made out of a peace 0.4 carbon reinforced with Kevlar and had denim layer that our carbon sponsor had left over from a project

We used amp limiting that limits each motor to 25 amps

Yes, we had a hard time finding inch omni wheels that fit what we wanted, so we used the andymark roller replacement kits and made our own


#13

This is a great looking robot that appears to be very well thought out. Thank you for sharing the CAD. :slight_smile:


#14

If you could post native Inventor files my team and I would really appreciate it. Even if they’re a bit broken.


#15

Hoo boy, I can’t wait to take a look at this!:smiley:


#16

Is that the only software you use to help protect the drive motors? Do you have any ramp rates to limit the current draw when starting from 0 velocity? Also how did you come to choose 25 amps as your limit?

I’m impressed you were able to limit 6 motors to 25 amps each and still get such great driving characteristics from them. Most other 775 drive teams (including 88, my team) have used 8 total to further lower the current per motor.


#17

Rotacaster in La has 125mm Omnis with a 1.125 bearing bore and 85A rollers.

1/4" plate worked well as hubs.


#18

Did you do any welding on your bumper supports for the drive train? It looks like there isn’t enough gusseting otherwise, or I could just be mistaking.


#19

There is a 0.125 inch carbon gusset that holds the bumper supports, they also where the plates that held the wings and you can only see them in the whole assembly as they aren’t in the drive train sub assembly.


#20

The flat 25 amps was the only limit in place to protect the motors. We built an off season robot with a 775pro drive drain, and I believe we decided on 25amps with some (non exaustive) testing on it. We also had voltage limits and ramp rates that would scale based on the height of our elevator, but they were to improve placent control and keep is from falling over.

I’m impressed you were able to limit 6 motors to 25 amps each and still get such great driving characteristics from them. Most other 775 drive teams (including 88, my team) have used 8 total to further lower the current per motor.

We used 8 775s on our off season bot, but we didn’t really have room for 8 this time, and we felt that the extra motors were somewhat unnecessary based on some other minor testing. (It could do a burn out with two kids standing on it)