i think you misunderstood. I didn't mean putting a drill and a atwood together on a single drive train, i meant having each seperate wheel controlled by a seperate (singular) motor.

That's us, except we went with the Fisher Price because they were smaller and coupled better (easier i guess) with the drills. We're building our own transmissions for the first time and lemme tell you, it's a BLAST!! Hopefully it'll work out...we'll see at San Jose!

lauren

They don't fight each other if you gear them to the same rpm. The efficiency doesn't drop that much as long as you gear for the "sweet spot" in each of the motor curves.

As for programming goes, it's no different. You could run both speed controllers off of one pwm and the programming is no different than it is for one motor.

Same here.

(watch for pics to be uploaded soon)

Harrison,
What do you use to switch from low to high gear...servos or pneumatics...or something else??

From the specs I saved, the Chiapua motors had just slightly less power (less than 10% differential) and a lot more torque. At stall, the Chiapua had 315 oz-in of torque. The 2002 drill motor was 650. mN-m at stall, which is about 92 oz-in. I'd expect 3 times the torque with all the copper and magnets in that big motor!

And don't be fooled by the torque specs with the drill gearbox...I'm talking the motor only.

If you gear two different motors to have the same output speed, the one with more power will also have more torque. This does not necessarily mean the drill motor is a better choice because with both motors geared to the same speed the Chalupa motor will probably have a lower effective mass and accelerate faster.

Using Drill and atwood motors
 

For those of you using both the drill motors and the atwoods, I am wondering how you are planning on programming the motors. I ran into a few problems, we want to beable to use drill motors on the front and atwoods on the back, and basically moniter the wheels so one doesnt spin faster than the other. Basically we made a speed-o-meter and if one is spinning faster than the other, they correct themselves. Heres the problem, we wanted to use the pulsin command to moniter our hall effect senors, but as it turns out, pulsin isnt supported. Sigh.. what to do. Any one have suggestions? am i going about this the wrong way? please respond
thanks
J.D.

Actually, it isnt that hard. Look at 60. Relatively simple drive, worked great with independently powered wheels.

Cory

drills
 

our team is using just the two drill motors and we can get across the field in about 6 seconds but we still have a ton of power

I like this year's drills much more than previous years, they do feel almost as smooth as the atwoods (for driving) and are very backdrivable as well. Given good traction, they can also be very very pushy/powerful, and are extremely responsive (from what i've seen driving our chasis around).

its all about the gearing, this year were using 2 chips(atwood) and drills. We having been using this combo from last year and they have worked extremely well if geared correctly. This year we had to redesign our gear box because they chaged the motors and our gearing is simple and comes out to be 11:1 from the chips to the drills. we havent really given it a shot on the the carpet yet. Thouhg its working well.

we are using the 2 drills and it takes us 5 secs. at 1/3 speed to get up the ramp, at full we will fly over it. Our robot also puts up a big fight in a pullin contest with a 200 lbs person on our team. Anyone jus locking into either low or high?

Jon

I always liked the Atwoods, with proper gearing they can work wonders. The only reason I dont like the drills is that there tranny is mostly plastic. I dunno I just like simple parts that do simple tasks and work time after time. And the atwoods are very easy to mount, and they can take a huge beating and still work.

The Chiaphua is more powerful than the drill.
We accidently wired our combiner backwards and as soon as you put any substantial voltage to it, the chip would over power the drill. The breaker would trip every 1/2 second causing the robot to run in spurts...

Moral of the story: Never trust your sparkE's... I mean, the Chip is more powerful...