Team Mean Machine 2471 2019 Reveal


#21

As always a very nice bot.
Hope to see you at PNW Champs.


#22

Interesting swerve design. Any plans for Auto, or are you guys switching to driver control because of the drivetrain switch?


#23

We have updated MeanLib to accommodate omnidirectional drivetrains, and we will be using it to create autonomous modes. Hopefully we will have material for an update video later on in the season.


#24

As always, and impressive machine. Looking forward to seeing you in a couple of weeks in Oregon City.


#25

Holy Cow!!! Kudos to you guys.


#26

Looks really good! Can’t wait to play with you at Clackamas Academy!


#27

Is that a redline with the red line removed? Looks to silver-ey to be a 775pro :thinking:


#28

I believe those are the AndyMark 775-125. It is a motor that can be doubled up on a motor controller.


#29

Always love the robots Team Mean Machine! Very glad to see another swerve robot, and your execution with them looks great! Just curious, are the swerve skids there to break the force of hitting the ramp, or to keep the robot from bottoming out?
Best of luck from My Favorite Team :slight_smile:


#30

Beautiful machine! Can’t wait to see it on the field.


#31

The skis are primarily for smoothly traversing the cargo depot. The rear skis serve the dual purpose of holding the bumpers above the hab level when we climb.

Also, for anyone curious about the name:
εpsilon was voted on by the team on bag night, as is tradition. It was admittedly chosen because it sounds cool, but it is also a subtle space reference in that ε0 is the permittivity constant of a vacuum.


#32

Beautiful machine! Good luck this season.


#33

Could you post a picture by chance of one of these? Really curious to see how the module is all the way down to 4lbs with the drive and steering motor included. Also could you say what size and kind of wheel you are using as well as which bevel gears?

Great looking robot and from what it sounds like great swerve!


Swerve Wheels
#34

Sure thing! I’ll take a picture of a spare module at shop tonight if I can remember.

Edit:
I found some pictures of a practice bot module on my phone:



#35

The wheel is 3" in diameter 3d printed, and the gears are 1.25module 15 and 45 tooth from khk gears.
The modules have been doing well so far, but we won’t truely know their durability until much later in the season. I posted a very similar design on here quite a while ago, if you want to look at the CAD.


#36

That’s looking like a really clean module. Any continuous fibers or just the stranded fibers in Onyx?

Edit: also, that looks like it took forever to print on a Markforged. Do you know the printing time for one of those modules?


#37

Some follow up now that we can see some pictures:

How are you fixing the nitrile to the printed wheel?
What bearing are you using for the rotation of the module?
When you say it weighs 4lbs, is that including absolutely everything we see in the picture?
What gear ratio are you running for both the speed and steering?
Is it a belt or gear stage going from the VP output shaft to the module for the steering?
Did you have to modify the KHK bevel gears at all besides broaching them?
It looks like the black encoder visible on the top of the plate is for your steering positioning, do you have an encoder for speed?
What is going with the wheel shaft in the second picture? It looks like it is exposed or something on the bottom of the printed part of the module.

Looks like an interesting module, wish I could see it up close.


#38

Currently riveting, but we are worried about repeatedly drilling them out, so we’re changing them to bolts.

It is a custom slew bearing. The inner race of it can be seen on the wheel cover:

It’s geared for 15fps free speed now, but we will probably change that to 12.
The steering ratio is about 100:1

Belt.

The small one only required broaching. The large one had to be opened for a bearing bore, and we did some additional weight reduction.

That is the drive speed encoder. The steering encoder is a magnepot that is visible in the scale photo.

The wheel shaft is exposed on the bottom, so it can be removed without disassembly.

The feeling is mutual. I wish I could see your robot up close!

Thanks! The only continuous fiber is in the small steering pulley, but I doubt that it’s necessary.

Forever is not far off :wink:
I don’t actually know, but I can ask someone who is on our Eiger account. I do know that most of it was printed with normal infill and turbo mode, and we used three separate printers, and it was still a very long process to make 10.


#39

Any lubrication on your custom slew bearing?

Thanks for sharing this design! I have my printers back online, so this is definitely my first summer project after the garden is up and running.


#40

We put some white lithium grease in the bearing for a lack of any better ideas.

That’s great to hear! Let me know how it goes.