pic: 4 motor Gearbox CAD

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[GBIT]

How would you work that in to a crab drive?

Is that for one pod?

or,

a central unit that turns all four?

[Lil' Lavery]

Originally Posted by GBIT

How would you work that in to a crab drive?

Is that for one pod?

or,

a central unit that turns all four?

More than likely a single unit that powers all the modules in a co-axial swerve system. Other modules would be used for steering the wheels.

Originally Posted by Lil' Lavery

More than likely a single unit that powers all the modules in a co-axial swerve system. Other modules would be used for steering the wheels.

Exactly.

[GBIT]

ok that is what i figured but i didn't want to assume it.

[Tottanka]

Wouldn't it be easier and better to have 2 gears, with 2 CIMs in each. Each Gearbox controls a pair of wheels?
If im wrong, what do you think are the advantages of a 4 CIMs-in-one-gear?

[Greg Needel]

Originally Posted by Tottanka

Wouldn't it be easier and better to have 2 gears, with 2 CIMs in each. Each Gearbox controls a pair of wheels?
If im wrong, what do you think are the advantages of a 4 CIMs-in-one-gear?

The advantage is all in the power distrubution. If you have all four cims in one gearbox, each wheel is taking an equal amount of power when the weight is centralized. If one wheel looses traction (due to a shift in the center of mass) the full power of the drive will still be used (assuming no wheel slipping).

If you had 2 gear boxes on each side if one side of the robot looses traction you effectively loose half your power. Now considering the real world, the odds of your robot loosing complete traction on one side and still being able to drive would be an accomplishment in itself.

Ultimately having a centralized drive does give some advantages for serviceability, and maybe even weight, but I would still prefer 2 serrate gearboxes

My reason for preferring this is all resource and weight driven. If my team actually lets me build ones of these (which I doubt will happen...), then I want to save on machining costs and weight as much as possible. That's the real motive behind this.

[SgtMillhouse648]

Originally Posted by Tottanka

Wouldn't it be easier and better to have 2 gears, with 2 CIMs in each. Each Gearbox controls a pair of wheels?
If im wrong, what do you think are the advantages of a 4 CIMs-in-one-gear?

648 did the two gearbox setup this year, and had some power to spare, however , no reduction was made through gears. The twin small CIMs came up through the mounting plate with a small pulley on each. Then a timing belt serpentined throughout the pair and one other pulley gave power to each of the individual crab modules. This pulley gave power to a pair of bevel gears, then went through a final reduction through a chain drive to the wheels, giving us a final reduction of 9:1. To be honest however, I was incredibly impressed by the setup on the 118 bot. how many motors did you guys use in that one, If I remember right, you had two small CIMS, to big CIMs, and the FPs? One thing eluded me however, why did you use two pots to tell the angle of the wheels? It seems to me it would have been quicker and easier to use something like this Miniature Absolute Magnetic
Shaft Encoder After the season was over, we wanted to see just how powerful the swerve drive was, so one of the biggest/strongest kids on the team tried to shove the robot around, and the robot ended up pushing him backwards without a problem.
Thanks
Malhon

[Pavan Dave]

Looks nice. It reminds me of the V6. So you arreee thinking about making a drive system with a central power house! Good luck.

[robostangs548]

Looks pretty powerfull, but heavy.... Looks good though. Nice cad, and sick gear box. Nice It would definitally put up a fight against the new AndyMark Super Shifters, (those look sweet, but i can already feel them "shifting" the money out of our teams bank account, if you know what I mean.) Nice, I would love to see it in action!

[pakratt1991]

hmmm
comment...

you're amazing!!!



for no reason you design a massive 4 motor gear box....
it is just so simply... first-like

[Dan Petrovic]

Originally Posted by pakratt1991

hmmm
comment...

you're amazing!!!



for no reason you design a massive 4 motor gear box....
it is just so simply... first-like

Well, there's always a reason to CAD something like this. It's so if the team decides to use something like this, they don't have to take the time during build season to design it.

[AndyB]

Originally Posted by InfernoX14

Well, there's always a reason to CAD something like this. It's so if the team decides to use something like this, they don't have to take the time during build season to design it.

Good point, in that case, I should probably get back to work on my 4 CIM, 2 Minibike, 2 Globe, 2 Fischer Price, and 18 servo gearbox. Wait, you say 118 beat me to it? sheesh.

[Alan Anderson]

Originally Posted by InfernoX14

...if the team decides to use something like this, they don't have to take the time during build season to design it.

Be sure to check the rules before you use existing plans for a custom assembly. The 2007 manual contained this surprising nugget:

Originally Posted by 8.3.3 Fabrication Schedule

...completing detailed dimensioned drawings of parts, and any actual fabrication of any hardware items intended to go on the actual competition ROBOT is prohibited outside of the approved fabrication periods.