pic: 1625's swerve module (better pic)

[Peter Matteson]

Originally Posted by Aren_Hill

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

Same reason we do wheels out tube and plate welded together.

[AdamHeard]

Originally Posted by Peter Matteson

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?

[Peter Matteson]

Originally Posted by AdamHeard

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.
Pete

Edit:
http://www.chiefdelphi.com/media/photos/31104?
http://www.chiefdelphi.com/media/photos/31105?
http://www.chiefdelphi.com/media/photos/31102?
http://www.chiefdelphi.com/media/photos/31103

Pictures now up.
End Edit

[Aren_Hill]

Originally Posted by AdamHeard

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 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.

[sdcantrell56]

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

[A_Reed]

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).

[hillale]

Originally Posted by A_Reed

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.

[Un Luchador]

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.

[Jimmy Cao]

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

[hillale]

Originally Posted by Lostmage333

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.

[Aren_Hill]

This guy weighs in at 2lbs 14oz and i coulda taken a couple more ounces out of the steel sprockets. Lighter than last years

[lukevanoort]

Originally Posted by Aren_Hill

i coulda taken a couple more ounces out of the steel sprockets. Lighter than last years

Have you thought about going to aluminum drive sprockets to save a touch more weight?

Originally Posted by Aren_Hill

This guy module weighs in at 2lbs 14oz

Is there a girl module?

[Aren_Hill]

Yes i have but during the season i was too busy to find a supplier or someone to have them made.

[Elgin Clock]

Aren, do you have a white paper on this, or at least a picture of the other side of this assembly showing the bevel gears?

I got to see this up close at IRI, & was very impressed.
Not only did it perform great on the field, but it was relatively lightweight for what it consists of.

I'm trying to convince my teammates to experiment with as many drive trains as possible over the summer with our upcoming test chassis, & want to show them this one as a great example of swerve assembly.

Originally Posted by Aren_Hill

This guy module weighs in at 2lbs 14oz and i coulda taken a couple more ounces out of the steel sprockets. Lighter than last years

Hm, you should switch to Kevlar belting and aluminum pulleys. Then this setup would be truly frighteningly light. Out of curiosity, how many teeth does your steering sprocket have? I'm currently designing a bottom support crab, so I can finally post one that doesn't get hit with the "you're not supporting it right" complaint.