pic: Lightweight 8 CIM Shifting Swerve Drive Chassis

[Bryce2471]

Very nice! Is that weight with all fasteners, etc? Do you have any pictures of the module itself?

It includes everything you see in the picture. I've still been too lazy to find CAD for small snap rings because their weight is negligible, but I think I've got everything else accounted for. I'll post a close up of the module soon.

Looks great, but does it really need two CIMS on each model?

No.

But I it would be nice! In some games, extreme amounts of drive power and maneuverability is desirable enough that a drive train like this would make sense. Although, I'll admit that it's unnecessary in most cases.

Looks awesome, but isn't "lightweight 8-CIM drive" an oxymoron?

Kind of ;D
I guess this calls for the picture to be renamed...

[asid61]

Two cims or a cim/minicim combo per module is the new metagame. You need those to go higher than 18fps, and it's useful for lower speeds.
In any case, what were you going to use them for, it not for drive? With the abundancy of motors these days, there's no point in not doing it...

[Tyler2517]

Originally Posted by asid61

Two cims or a cim/minicim combo per module is the new metagame. You need those to go higher than 18fps, and it's useful for lower speeds.
In any case, what were you going to use them for, it not for drive? With the abundancy of motors these days, there's no point in not doing it...

There is a point of over kill and i think this might reach it...

[Electronica1]

Now you just need a pto for each module. Might as well get as much use as possible out of all those motors.

[Dunngeon]

Originally Posted by Tyler2517

There is a point of over kill and i think this might reach it...

I think it might barely reach it, just a tiny bit.......

Originally Posted by asid61

In any case, what were you going to use them for, it not for drive? With the abundancy of motors these days, there's no point in not doing it...

Except the loss of all 40amp circuits, that's kinda a big deal.


All in all though, this lightweight packaging is a pretty sweet deal. I've really liked the iterations I've seen in the last few days. Too bad we won't see this module at Bunnybot

[asid61]

Originally Posted by Dunngeon

I think it might barely reach it, just a tiny bit.......



Except the loss of all 40amp circuits, that's kinda a big deal.


All in all though, this lightweight packaging is a pretty sweet deal. I've really liked the iterations I've seen in the last few days. Too bad we won't see this module at Bunnybot

True, you can't exactly just add more circuits. Even so, I still don't see the need for every motor we're allotted. It really does depend on the game, but a lot can be done with pneumatics (254's robot this year had tons and tons of pneumatic cylinders and locks instead of just motors) if you are short on motors.

Also, 1 2/3 cims per module is just a tiny bit more powerful than a 6-cim drive. If you want acceleration in a swerve drive, you can either have a multiple of 3 modules or you can go cim/minicim. I prefer the latter for a multitude of reasons. Think of it: not only can you snake and translate, but you can do it at 20fps and save momentum. The possiblities are amazing!

Now a PTO for this would be the next step... Maybe #25 chains under the chassis, to use the turning motors to climb or something?

[Bryce2471]

Originally Posted by Dunngeon

I think it might barely reach it, just a tiny bit.......

I actually agree, in most cases. For most games I would prefer the 5.4 lb, single speed, single motor module I posted earlier. If the situaltion comes again where mobility is almost everything, this would be awesome.

All in all though, this lightweight packaging is a pretty sweet deal. I've really liked the iterations I've seen in the last few days. Too bad we won't see this module at Bunnybot

Thank you! I wish we could field this at bunnybot as well...
Unfortunately, the money and resources to do that just aren't there this year.

Originally Posted by asid61

True, you can't exactly just add more circuits. Even so, I still don't see the need for every motor we're allotted. It really does depend on the game, but a lot can be done with pneumatics (254's robot this year had tons and tons of pneumatic cylinders and locks instead of just motors) if you are short on motors.

Good point. I think their robot only used four small motors outside of their drive base. That's few enough that they could have used this drive.

Also, 1 2/3 cims per module is just a tiny bit more powerful than a 6-cim drive. If you want acceleration in a swerve drive, you can either have a multiple of 3 modules or you can go cim/minicim. I prefer the latter for a multitude of reasons. Think of it: not only can you snake and translate, but you can do it at 20fps and save momentum. The possiblities are amazing.

or you could do this:

[asid61]

Originally Posted by Bryce2471

or you could do this:

Not if you want a full-featured swerve. The cim in the middle will limit what kind of snake turns you can make. Each wheel in the swerve has to be able to rotate and speed up fully independently.
For crab drive, you can indeed chain them together.

[Bryce2471]

Originally Posted by asid61

Not if you want a full-featured swerve. The cim in the middle will limit what kind of snake turns you can make. Each wheel in the swerve has to be able to rotate and speed up fully independently.
For crab drive, you can indeed chain them together.

With good code, a rectangular robot, and 6 CIMs of torque; I think you would be able to do any swerve movement with a little scrubbing.

[Ether]

Originally Posted by Bryce2471

With good code, a rectangular robot, and 6 CIMs of torque; I think you would be able to do any swerve movement with a little scrubbing.

What makes you think that?

[Bryce2471]

Originally Posted by Ether

What makes you think that?

Each wheel is independently steered, and if you had a 6 CIM 4WD tank that was 21" by 35", it would be able to turn in place without too much trouble.

This drive would be able to turn in place or translate without any scrubbing. It wouldn't have any resistance until it turned while driving. I think this relatively small disadvantage would be outweighed by the advantage in a pushing and driving straight.

[Ether]

Originally Posted by Bryce2471

This drive would be able to turn in place or translate without any scrubbing. It wouldn't have any resistance until it turned while driving. I think this relatively small disadvantage would be outweighed by the advantage in a pushing and driving straight.

It sounds like you just moved the goalposts. But perhaps I am misunderstanding. Are you still saying that it "would be able to do any swerve movement with a little scrubbing" ?

[Bryce2471]

Originally Posted by Ether

It sounds like you just moved the goalposts. But perhaps I am misunderstanding. Are you still saying that it "would be able to do any swerve movement with a little scrubbing"

Yes my intent was to support that claim. The only time scrubbing would be involved is when translating arbitrarily, and rorating at the same time. I believe that in that case, the 6 CIMs would be able to power though the scrubbing, given the gear ratio and width/length of the drive base.

Obviously, this is an opinion, and you can be sure without testing.