Drivetrain help

[Gearheads1]

So if we were to substitute a tough box for the CIMPle Box we'd be closer to OK?

[Ether]

Originally Posted by Gearheads1

So if we were to substitute a tough box for the CIMPle Box we'd be closer to OK?

Yes. Standard toughbox is 12.75:1.

Originally Posted by Gearheads1

drop center, about 1/8" being directly driven by a CIMPle Box with 2 cims on each side, front and rear tires chained up ...I'm wondering if the gearing may be our primary problem that we could correct by not direct driving and using a smaller give on the CIMPle Box. We currently have 26 tooth gears on each of the wheels.

I just re-read the above. Are you saying that the center wheels are direct-driven and the front&back wheels have a gear reduction?? If so, that's not a good idea.

[EricH]

I'd go with removing some traction at one end of the robot, too--I've seen one of the Toughbox's closer relatives, the 2006 KOP gearbox, have trouble turning a 6WD drop-center when all 6 wheels (6", in that case) were pneumatic. Replacing one end with lower-traction kit wheels worked in that case.

[Ether]

Originally Posted by EricH

...trouble turning a 6WD drop-center when all 6 wheels (6", in that case) were pneumatic...

How much was the center dropped?

[EricH]

Originally Posted by Ether

How much was the center dropped?

Can't remember--I want to say it was in the 1/8 range, but it's been 6 years. Might have been more. It turned with the 6 pneumatics... but it bounced all over the place when it did.

As shipped (6 pneumatics): http://www.chiefdelphi.com/media/photos/23376
After Arizona Day 1, where the change was made (4 pneumatics, 2 KOP on the front): http://www.chiefdelphi.com/media/photos/24202 (far right robot, the wheel in the air that's visible)

[Gearheads1]

We checked the motor direction by unplugging the PWMs and checking them one at a time on each side to ensure they were going in the same direction.

[Ether]

Originally Posted by Gearheads1

We checked the motor direction by unplugging the PWMs and checking them one at a time on each side to ensure they were going in the same direction.

Can't argue with that :-)

[Chris is me]

Originally Posted by Gearheads1

So if we were to substitute a tough box for the CIMPle Box we'd be closer to OK?

Yes, that's the fastest and simplest way to get close to the right ballpark. It'll still be a pretty fast drive with pretty high power demands, but it'll move.

You can purchase a modification for the Toughbox to bring the ratio down to ~15:1. AndyMark currently lists it as out of stock, so your best bet would be to install stock Toughboxes and plan for this mod to get better performance. If you or any teams nearby could machine the part from AM's drawings, that'd work too.

I'll let a real engineer explain the math behind drive gearing - but it's a valuable lesson to learn.

[Hawiian Cadder]

If you could modify one of the worm gear boxes from andymark to use two cims it would put you near the perfect ratio, It may also be similar in the required mounting method to your current gearboxes.

[Gearheads1]

Installing toughboxes made a world of difference. Thanks to all who responded.