pic: Off season teaser 1

[Peyton Yeung]

In all this project was initially started as a swerve project but to reduce weight and cost of a traditional swerve/crab drive it took some designs from a car (ackerman steering). It isn't a true swerve/crab drive nor is it a true ackerman steering drive but somewhat of a hybrid for the sake of using less funds and weight.

[MichaelBick]

There are a couple of problems with this design:

1) Compwiztobe is right; the miter gears will lock

2) If you try to turn this assembly, the wheels will try turn in opposite directions (think of a 2 wheel drive turning) and something will have to brake or slip.

3) (i'm assuming you are going to use two of these modules) When all the wheels are collinear, the robot will fall over. If you add casters though, you can fix this problem, but that defeats the point of make two wheel modules in the first place.

4) You won't be able to turn, because unlike regular swerve, you do not have the 4 modules to form a x with the "turn' chain. You could potentially add caster, but again, that defeats the point of making modules with two wheels.

Sorry for being so negative. On the bright side, this is the dedication that makes teams win. Nice job trying to reduce the price, weight, and complication of arguable the best drive train in first.

[MichaelBick]

Sorry, I didn't realize what the pink sprockets were there for, so you can disregard comments 2 and 3. Just another comment, you will be limited in your strafing, specifically in strafes exactly left and right, or near those angles. This is countered though, by your easily achieved Ackerman steering, that needs very little programming. After my little revelation, I have realized that this is actually a rather viable drive train, once comment 1 has been fixed, to allow teams with very little resources and time, to achieve a drive train that acts like 6 wheels swerve, without the ability to strafe perpendicular the the robot, and to turn on the spot, like swerve and 6 wheel. With improvements, this could become something a lot like octocanum, giveing close to the best of both worlds.

[EricH]

With the miter gears, I wouldn't be surprised in the least if the bottom one was free-spinning. It's set up so that that's all you'd need to do to keep the gears from locking up. Then you just have one gear acting as a spacer.

[Peyton Yeung]

Originally Posted by MICHAELABICK

There are a couple of problems with this design:

1) Compwiztobe is right; the miter gears will lock

2) If you try to turn this assembly, the wheels will try turn in opposite directions (think of a 2 wheel drive turning) and something will have to brake or slip.

3) (i'm assuming you are going to use two of these modules) When all the wheels are collinear, the robot will fall over. If you add casters though, you can fix this problem, but that defeats the point of make two wheel modules in the first place.

4) You won't be able to turn, because unlike regular swerve, you do not have the 4 modules to form a x with the "turn' chain. You could potentially add caster, but again, that defeats the point of making modules with two wheels.

Sorry for being so negative. On the bright side, this is the dedication that makes teams win. Nice job trying to reduce the price, weight, and complication of arguable the best drive train in first.

1. Like EricH said, the bottom one is a spacer.

2. The wheels turn together so they always face the same direction.

3. There is no possible way for all 4 wheels to be on the same line.

4. Isn't it possible to turn a four wheel drive bot by giving a positive value to 1 set of wheels and a negative value to the other set of wheels?
The fronts are linked together and the backs are linked together.

[MattC9]

Awwwww I was looking for the new ball drive.

But it looks really good! I would also like to see how it interfaces with the frame and such.

[MichaelBick]

1. Like EricH said, the bottom one is a spacer.

2. The wheels turn together so they always face the same direction.

3. There is no possible way for all 4 wheels to be on the same line.

4. Isn't it possible to turn a four wheel drive bot by giving a positive value to 1 set of wheels and a negative value to the other set of wheels?
The fronts are linked together and the backs are linked together.

Like I said, disregard 2 and 3. For number 4, if you look at the CAD, the supershifter will be connected to both wheels. This means that you cannot power each side individually, so you cannot turn like a 6 wheel.

[EricH]

Originally Posted by MICHAELABICK

Like I said, disregard 2 and 3. For number 4, if you look at the CAD, the supershifter will be connected to both wheels. This means that you cannot power each side individually, so you cannot turn like a 6 wheel.

If you have 2 of these, each side is powered independently. If they're front and back, as stated, then it's a wide-oriented 4WD. Turns quite well, actually--maybe better than a 6WD.

There just haven't exactly been all that many wide-oriented robots the last few years--2009 had quite a few, though.

[CNettles11]

I hate to revive old threads but, this is a steering solution that will work, and this is how.

[Ninja_Bait]

On that last diagram, the bottom arrow is reversed, right? Or does this have mecanum wheels capable of that kind of translation?

[CNettles11]

That was definitely me slipping up, I should fix that.

[MichaelBick]

but you still cannot turn on a dime

Originally Posted by MICHAELABICK

but you still cannot turn on a dime

If you have your code set up so as that you can align all wheels straightly, you can turn with a skid-steer system. I wonder if that's even more possible with a 6 wheel drop center swerve...

[MichaelBick]

Not with this setup, as left and right wheels are driven together.

[RogerR]

Originally Posted by MICHAELABICK

Not with this setup, as left and right wheels are driven together.

Per an earlier post:

Originally Posted by EricH

If you have 2 of these, each side is powered independently. If they're front and back, as stated, then it's a wide-oriented 4WD. Turns quite well, actually--maybe better than a six wheel drive

If the pair of wheels in each of these assemblies is aligned (i.e. They're perpendicular to how the original picture shows them) it will allow the robot to function as a four wheel tank drive, which can turn just fine.