What motors do you use to drive your robot?
 

I'm curious to know what other teams use as their main drive motor?

Our drive trains group wanted to use the drill motors, are these appropriate for the drive train? I had assumed they would use the big CIM motors, but they were worried about having to gear tehm down alot.

Thanks for any help

Re: What motors do you use to drive your robot?
 

Last year, team 234 used a drill and CIM geared together and then geared way down so that we were slow, but deadly powerful. We geared a transmission in as well, but we ended up not switching gears. This same setup can be geared higher to be faster, or whatever you want.

Hope this helps

Re: What motors do you use to drive your robot?
 

drill motors work fine and our team is using them again this year. It's crzy easy to do the drill motors simply because the mouting is prefabricated and the gearbox is something that has already been built. They're less of a drain overall on resources to use. Problems with the drill motors can be heat, our motors had major problems with heat because we ran one forward, one in reverse and the drill motor is not designed to go in reverse for any long periods of time. In time, one of our motors literally cooked, the back melting into a big mess of plastic and wires and all that. Heatisnks have been used before the cool the motors as have fans, though that does some to cool the motors, heatsinking is better.


The problem however with the Atwoods (the CIMS you were talkign about) is that there were not designed to run for long periods of time according to one of our mentors. They lack a cooling system, fans or even vents, for that reason. So when you run them, all the heat builds up insides of the motor and you end up setting yourself up for major problems. The other issue of gearing down is a valid one because a gear box (and a good one at that) is needed so that the drive train will not kill it self when it tries to inch forward...they spin I think at like 5000rpms or something like that when you hook them up to a battery. So you WOULD have to gear down the atwoods...and if the gear box isn't build lacking completely of movement, gears start seperating and thus, start stripping. It can be very bad.

All in all...stick with the drill motors. They're convenient and lack a lot of the problems that the Atwoods have.

Re: What motors do you use to drive your robot?
 

Typically we have used the drill motors for the drive train (like every past year) but this year we are trying something different and going with the Chipuau (Indian Outlaw, half Cherokee and Tompawa, there a one of a kind) But yes I definetly agree with the gearing down part; right know we are having to decide between two gear boxes that we might use.

Re: What motors do you use to drive your robot?
 

You might want to add Drills+CIM's.

As for your question, either one will prove to be fine. The Drills have a bit more power than the CIM's. They can be shifted using their transmission if you wish, and you already have the mounts and gearboxes if you dont want to make a chain and sprocket drive. People have voiced concerns with the integrity of the transmissions, but if you do it right, there wont be any problems. Also, the drills wont backdrive in their standard configuration, which may or may not be an advantage.

As to the CIM's, they are very easy to mount using the holes on the face. (10-24, I believe?) They still have a good amount of power, they don't overheat as often as the drills. They don't have an anti backdrive feature like the drills. They are also a bit heftier than the drills. One plus is that they spin at approximately the same speed forward and backward, unlike the drills, meaning that your robot wont drift to one side constantly.

Cory

Re: What motors do you use to drive your robot?
 

We used the Atwoods last year with our two speed transmission and they seemed to work just fine. We are probably going to end up using them again. We had them geared just right and they gave us the power to push anyone we wanted around in low gear running at 4fps. Even in high gear we were able to push a lot of the competition around at 10fps. No problems with overheating. In years past we did use the drill motors and they were effective.

Re: What motors do you use to drive your robot?
 

In past years, we have gone with just the drills (2001, 2003). In 2002 we used the drills and the CIM's with a complex and heavy chain & sprockets transmission (We didn't have a machine shop).

Last year we just used the drills, shifted them with servos, and geared them down with chain. It worked well, although we had trouble overheating during the playoffs. We fixed that by cooling them with canned air (which is freezing cold).

It is much easier to go with just the drill motors.

Re: What motors do you use to drive your robot?
 

We used the CIMs the past 2 years, but we'd used the drills the previous 4 years. This year, we're using the drills and F-Ps together.

Re: What motors do you use to drive your robot?
 

We have used the drills and CIMs the last 2 years (actually, in 2002, we used the drills, CIMs, and Fisher-Price).

A little more information to help you out:

1. The drills this year (and last) are great for rookie teams due to the pre-fabricated gearboxes that come in the kit. The drills are also the most powerful motor by about 30% - 40%.

2. The CIMs are an excellent motor for driving because they are close to the same speed in forward and reverse and since they are a big motor, they dissipate heat a lot better than the drills.

The CIM motors are excellent for driving and we have never had a problem with overheating. We have never failed a CIM motor, but have burnt both the FP and the drill. The CIM motor is very robust.

3. I would only use the F-P if you are combining it with the drill or the CIM. I would not use it by itself.

-Paul

Re: What motors do you use to drive your robot?
 

Since our team has had success with the Bosch drill motors we keep using them year after year. We keep the transmission on them (with the pins removed) so we can have low and high range shifted by a small pneumatic cylinder. Our drive train has one mounted on each side and connected to the wheels with 35 chain. The motors are mounted opposite each other and one is connected to a jack shaft before the spocket to the chain so it will run the same direction of the other motor. This solves the problem of the robot "drifting" to one side when driving. They do get hot if they're driven long (like in a parade) but they don't get a chance to heat up during a normal 2 minute competition match.

Re: What motors do you use to drive your robot?
 

Last year we had too many issues with the drill motors. This year I think we're going with the Chippewas

Re: What motors do you use to drive your robot?
 

We will use either the drills, or the CIMs. It all depends on what we use the other motors for *Wink* :yikes: :ahh:

Re: What motors do you use to drive your robot?
 

Last year was the only year (that i know of) where we used the CIM motors, and we did have a large and heavy (and poorly constructed) gearbox. This year were reverting to the tried and true drill motors.

Re: What motors do you use to drive your robot?
 

Well the past 3 years we've used the drill motors (this year is no differerent). Last year though, we tried a dill/CIM combination which worked pretty well, although they added a lot of weight :/

Re: What motors do you use to drive your robot?
 

If my calculations are correct, the Chias have more torque at 40 Amps than the drills. But the drill does have a higher stall torque and is overall a more powerful motor.

Re: What motors do you use to drive your robot?
 

It doesn't matter what motor has more torque at 40 amps, its what motor has more power at 40 amps. You can change the torque by adjusting gear ratios, but you can't change the power.

Re: What motors do you use to drive your robot?
 

The Bosch and the Chiaphua are both excellent for driving. The versatility and relative ease of use of the Bosch drill motors for drive applications is unparalleled, and many teams use them for that very reason. They are a safe choice, and a strong choice as well. As Paul Copioli pointed out, we have found the CIMs to be very good in both directions and they are fine even after long use. They are actually usually colder on the exterior after a match than anthing else we've used in recent memory, including the drills and Fisher-Prices. For Fisher-Prices and drills (which clearly aren't meant to be used nonstop and stalling for two minutes), I highly recommend some kind of compressed air cooling spray to use between matches.

Many older teams with the means to build a gearbox do so in order to get CIMs and Bosch drills running together (i.e. four-motor drive). That way they can run at relatively high speeds while maintaining the power they need in order to hold their own. Or even have a transmission in addition to the four motors. Some teams (including 217 in 2002 and 188 for the past two years) mate three motors per gearbox for a whole lot of power. Or at least power drain; by the latter third of a match, these robots tend to be out of juice. Last year we built a simple gearbox that mated the Bosch drills, CIMs, and Fisher-Price motors so that we could run at high speeds and still outpush the vast majority of our opponents. We did have some trouble with our battery voltage dropping low enough to cut out our controller in two matches (one of which being the finals in the Canadian Regional :(), but those were very extreme circumstances.

While we have used Fisher-Price motors in our drivetrain before, we don't use them by themselves. Depending on the configuration of a robot, in some cases they won't be able to even turn it, and then you'll get the distinctive toasty Fisher smoke and smell.

Re: What motors do you use to drive your robot?
 

Team 25 used a combination of Drills and CIMs in the 2003 season, and will do so again in 2004.

Re: What motors do you use to drive your robot?
 

Team 356 used the drill motors only in years 2000, 2001, and 2002.

Team 356 used both the Chips and the Drills in our 2003 drive system. They are both excellent motors to use if you pay attention to all of the mounting and cooling quirks.

Since 2003's drill motors were so happy to have a friend (the Chips) we thought we'd add another friend for the drills and the chips this year, the Fisher Prices.

It didn't occur to me to use the Globe Motors in the drive system. Hmmm. Maybe in 2005.

Re: What motors do you use to drive your robot?
 

Team 116 has a 2-motor, 2-speed gearbox that has worked well in the past, and will hopefully continue to work well for us as we use it again this year. It combines the chipuas and drill motors and the plans are in the white pages on this site for anyone interested.

Re: What motors do you use to drive your robot?
 

Be sure to watch your current draw in designing this year then. We haven't had much trouble with six motors (I don't think we ever tripped a breaker last year for example), but that depends on many factors. A robot with too many motored devices (especially those that run constantly), too much friction in its gearboxes, or too high a gear ratio to push other robots can seriously gulp current and cause your battery to run out as well. I personally wouldn't consider using the Globes for driving; they aren't particularly powerful. The gearbox they come with is nice as it is, and increases torque to something useful for non-drive applications, but the Globes just aren't powerful or reliable enough to warrant driving with IMO. Good luck in getting six motors to work well. :)

Re: What motors do you use to drive your robot?
 

I was actually joking about using eight motors (counting the globes) in a drive system. Aside from the current draw thing, there would hardly be any motors left to do anything else or any weight allowance.

On the current draw thing, up to a point, as you add motors (especially in the drive system) there is a tendency to balance the load among the motors and run each motor at a lower current draw.

Re: What motors do you use to drive your robot?
 

Oh, I figured you meant Globes instead of F-Ps (i.e. still six-motor) actually, but eight motor has been done before, sort of.

Yeah this is supposedly the case, but I think the difference is pretty negligible.

Re: What motors do you use to drive your robot?
 

does anybody know what the max watts of a CIM motor is?

Re: What motors do you use to drive your robot?
 

~320 Watts I believe.

Re: What motors do you use to drive your robot?
 

Ok, I will let everyone in on our team secret. We use the globe motors for our drivetrain, and they work great, but you have to give them... ummmm..

special treatment!

before each match we soak them in liquid hydrogen to get their core temp down to 3°K, which is almost low enough to become superconductors

but once they start to spin, the airflow over the coils causes a windchill factor of -7°K so they superconduct - we get about 4HP out of each one, and once you apply a current to it, it keeps running (because of the supercondution) until you reverse it. Therefor they actaully consume almost no power at all.

:c)