this is a better pic of the swerve module Winnovation uses. Our drivetrain consists of four of these modules. The front two powered by two cims through an andymark gen2 and the back two the same way.
All of the modules are steered together by one fischer price motor.
maneuverable, and lotsa traction
You’re the only other team I’ve seen do welded tube construction wheels. I thought we were alone with that because everyong else seems to hog them out of a billet.
Wow… those are beautiful. Are those wheels driven throught a screw gear or am I not understanding how the motor drives those wheels?
It is done by changing the axis of rotation with a set of miter gears.
Nice setup, saw you guys on the MWR webcast, good looking robot.
I like how you used snap-rings instead of collars. That has to save a lot weight.
these are faster to make and are also most likely lighter and stronger in the places the force is applied.
its really easy to just waterjet the sideplates and weld them on, these wheels are 1.75" wide
I LOVE SNAP RINGS!!! lol also the custom 7068 hex axles…not overkill at all…
Yes, I loved your guy’s setup when you brought over the spare module to compare to ours at MWR. It is a real slick setup, not to far from ours. Great job on the wheels, and I absolutely love the sprockets you guys use to steer. That is an amazing setup on that. Hawging out the middle of hte sprocket also has to save a ton of weight, and I liked the slotted holes in the sprocket (if I remember right) to fine tune each wheel’s tracking before you went out onto the floor.
Hey, I like it. They look great! Swerve drives are for me as a rookie pretty impressive just because of their advantages. I’ll probably test my cad abilities during the off-season by designing one myself… I’ll see but it’s a nice piece of metal!
Same reason we do wheels out tube and plate welded together.
How easy is it to hold the plates and tube concentric while rounding?
If it is just standard Al tube, how thick are the walls and how true to round is the outer surface?
We cut a relief pocket in the plate so that it over hangs the tube and tube literally snaps into the plate. This gives us wheels as close to concentric as possible to make. I’ll dig up some pictures and grab a few of the evolution of the design when I’m at the shop today so you can see what I mean.
Pictures now up.
We just used 4" o.d. 1/8th wall tube, and waterjetted the sideplates, due to the nature of a waterjet it puts a slight taper on things so when i had it make a
3.75 o.d. disc it pressed right into the side of the tube and held itself there solidly while it was welded.
they’re as concentric as you’ll ever need for wheels.
How are you keying the wheel to the axle. I’m planning on using that type of wheel next year and just looking to compare ideas
how is the lower plate supported? I know it used as a bearing surface, but it is sandwiched between plates or riding on small ball casters. I have always wondered how this work with swerve modules, I understand the rest of it but the lower support plate is the only gap in my limited knowledge of drive systems(I don’t go into the kinematics…yet).
The lower plate isn’t necessarily a support plate, just a bearing surface like you said. Due to the nature of friction, it does a little support, but mainly it just rubs against flat plastic patches (lubed up to reduce friction) on the frame to aid in steering the modules. The face of the contact between the plastic and the plate is purely vertical. No horizontal contact is made between the plate and the frame. It is welded, in the corners, to the square tube that makes up the vertical body of the module.
the bottom disc is simply supported by 4 tangential pieces of UMHW (ultra high molecular weight) plastic, that we keep white lithium grease on all the time to keep it slick. Rollers are more efficient but take longer to install and are heavier
With such an effective drivetrain, it’s no wonder you guys went undefeated at Colorado. I love the way you guys keep the robot chassis facing forward through the match, but still have the swerve function to put you back into position. That’s very innovative.
Keep up the hard work and military-like competing guys.
That module looks very simular to our initial idea, except we were putting the motor/transy inside the module itself.
It’s very nice looking =D
That’s what we did last year, we had a cim mounted vertically through a dewalt on each of the modules. This coaxial design made maintenance much easier (though it has gone through 3 regionals and hasn’t broken once). Here is a pic of our underbelly, http://www.chiefdelphi.com/media/photos/28596. I guess we don’t have a closeup of the module from last year.
This guy weighs in at 2lbs 14oz and i coulda taken a couple more ounces out of the steel sprockets. Lighter than last years