pic: OmniSwerve chassis Bottom View and Concept Discussion

[Dan_Karol]

Maybe i'm missing something, but how does it turn?

If all pods are ganged together then you have no control over what your heading is or you have no ability to strafe.

[GeeTwo]

TL;DR Trying to wrap my brain around what this does and why you'd want to do it.

If all the wheels steer in unison, you have crab drive - with the inherent [crab] inability to rotate the chassis (not good for a triangular chassis in most conceivable games) and the additional [omni] weakness of being highly vulnerable to cross-drive forces. I don't see any way to get anything faster than geared speed in this scenario, either.

If only the wheel near the steering motor is steered, I can imagine a scenario where you can get up some extra speed, though I haven't done the math to convince myself it's viable. If this is the case, why are the two non-steered wheels built up so they appear to be swerve modules?

Or is something else going on (e.g. one of the wheels steers counter to the other two, or something even more arcane)?

Edit:

Originally Posted by asid61

How are you getting above max speed?

Originally Posted by Scott Kozutsky

drive straight to max speed, turn left at 90 degrees and accelerate in that direction to max speed. Because of the omni wheels, you actually (ideally) don't lose your forward momentum after turning and, as such, move in both directions at your maximum geared speed, hypotenuse of that vector triangle is 1.414 times the side length.

Maximum speed is achieved when the drag/frictional forces are equal to the drive forces, and the drive forces are applied. Once you turn the drive in another direction, you'll begin to slow in the direction you are moving. You may be able to achieve a bit better maximum velocity, but after accounting for the longer distance traveled, I don't see how you can achieve a higher net speed.

Edit2: That is, at maximum speed, saying you don't lose forward momentum, even ideally, is not valid. Maximum speed is inherently the result of significant loss of forward momentum due to friction.

[Scott Kozutsky]

Originally Posted by Dan_Karol

Maybe i'm missing something, but how does it turn?

If all pods are ganged together then you have no control over what your heading is or you have no ability to strafe.

The way I have it is they all point in the same direction. You can tank turn in any orientation by simply driving one side forward and one side back. Only the pivots are chained together not the actual drive.

The reason you can't turn in conventional crab is because the drive is all chained together and because the wheel scrub from trying to tank turn is too significant.

here's a crude vector diagram of my 3 wheeled swerve rotating.
http://imgur.com/0HMYj0g

If they were traction wheels the steering would be awful (non existent) because the wheels would oppose the lateral forces exerted on them. With omni wheels this does not happen so it should be able to turn quite nicely.