pic: Don't do this. It's a bad idea.

Yup. I got bored.

Not a suspension.

What’s going on in those wheels? Looks like a lot of linkages.

Looks like a psuedo suspension. The wheels look to be able to tilt up/down which would help a little in covering uneven terrain. One problem is that the pivot for the suspension is in a different plane than the U-Joint so there would be a tendency to try and stretch the U Joint unless it has something like a slip-yoke.

Looks like a possible crab module, with 2 wheels spread apart for stability, a differential in the center for better turning and U-joints for smooth suspension. Maybe next years surface will be very bumpy.:rolleyes:

Looks like the robot version of an automotive Independent Rear Suspension (IRS).

That’s a really neat project to do when you’re bored! nice

I think a rough terrain game is inevitable… and would be very cool. There seems to be a lot of teams that perfect their preferred drive train in the off season and spend the time during build season focusing on game play. Making a bumpy playing field could help, er, level the playing field for newer teams… like mine!

Okay, I’m going to try and describe this. It’s a swerve module with a differential connecting both wheels, and flex couplings to allow for some sort of suspension.

I can’t possibly imagine its use in FRC.

Coaxial swerve modules with a suspension and differential aren’t normal. But on Winnovation they are.

Winnovation: Not even once.

I can’t figure out why you have four Bevel gears (forming a box, differential?) connected to the left wheel… couldn’t you achieve the same by extending the shaft from the right wheel directly to drive the left wheel?


Actually the box results in the two turning in opposite directions.

The differential is used in the drive axle of cars, read about it

RIGHT, but you wouldn’t want them to turn oppositely, correct?

This has me scratching-my-head… :wink:

Actually, Michael, lemiant didn’t have a chance to read squirrel’s link yet. I would suggest reading that link, then figuring out the drive system.

Short version: If both can go the same way at the same speed, both go the same way at the same speed. But if one of them can’t keep that speed up, then it doesn’t have to due to the way the differential is set up.

Wouldn’t this work better with constant velocity joints (rather than universal joints)?

And are you using the universal joint as two of the members in a four-bar linkage that holds up the wheel? If so, isn’t it just going to deflect to the maximum? (Or am I missing a spring somewhere?)

This would be a fun stock design to keep around…just to tempt people when FIRST decides to give us some real obstacles.

Here’s an animation of how a differential operates for those confused.

Here’s a much better explanation…but then, I do like old stuff

So, where’s the “slippage” provided in this setup?


Why not choose pneumatic tires over the suspension? I don think you would get much “play” before the bevel gear bottoms out.

There is no “slip”* in a differential. The nature of how the gears mesh is what allows the shafts to turn at differing rates. The differential itself has no control over the situation, its just along for the ride.

*(unless we start talking limited slip differentials and lockers etc)

In the differential gearing. Two of the 4 gears in the inner box are connected to the wheels; the other two are idlers. The relative speed of the wheels doesn’t really matter to the idlers; they’ll move as fast as they need to.

Hint: Think of this setup as 2 gearboxes. The inner box is the 4 in the middle of the “axle”; the outer is the bevel at the top and the large gear it meshes with.