Re: Ulesses Accersoies
 

The torque motors was donated to FIRST. That's why they were in the kit. As far as the optical sensor goes, we were going to use it (actually had it hooked up and all) to automate part of our robot function but it ended up that we really didn't want it (we needed to time delay it). So the sensor had a use and probably will in the future. However, it will not be used by most teams.

Matt

The drill motors is a completely fine motor. In fact, it's probably one of the better 12 volt drill motors you can buy. It's just the fact that we tend to put them under much higher loads then they were ever expected to preform. If you're having significant problems with the drill motors overheating, there probably is a problem with the drive train and not the motor itself. Usually it's not the motor's fault.

Matt

With the optic sensor in 99 a team at nationals (##??) used it to detect the floppies and the wheels would move out of the way. Sorta, im not sure really maybe someone rembers more than i do i was only an 8th grader amazed by the robots back then and i rember it winning an award.

Andrew

Heatsinks
 

I have seen the heat problem resolved on a few teams using a finned heatsink that works pretty well. It was contoured to match the outside can of the motor, while your at it add a small muffin fan to pass air through the fins and you are all set.
I don't know if it is legal but you can use a thermal grease to transfer the heat even better.

(Computer processors use the same thing and they get so hot you can't touch them.)

A note on the torque
 

Early in the competitions this year, my team experimented with using the torque motors to give more control to our robot. What instead happened was a robot that no one on our team could handle and after our first competition those motors were removed and all we had left were the drill motors. Those worked perfectly fine and we could easily control our bot once again. Yeah! As for getting better/faster motors: Keep in mind that not all teams might have the money to do something like this. Our team barely had the money as is and we're not rookies. I think it best to stay with what we have.

Laurel Noel

If I were King...
 

I would like to have more Mabuchi or Johnson motors (like the drill motors and the Fisher-Price motors but without the transmisions).

The next size up from the drill motor size would be perfect. Basically, the problem with the drill and the FP motors is that for the power we are pumping into them, these motors are too small.

If we had a 200-300 Watt motor (peak mechanical power, not electrical power) in the size motor that is one step up from the drill motors, we could drive them hard like we do and still have enough surface area to dissipate the heat we are generating.

I know that many teams would have trouble dealing with the high RPM's and relatively low torques that a motor like this one provides without the associated transmissions FIRST includes with the drill and FP motors, but many teams would be able to use them to great advantage.

Any thoughts on this idea?

Joe J.

Motor discussion
 

Has anybody looked at automotive cooling fan motors? They are permanent magnet, flange mount, 300 watts (roughly) large diameter, and relatively low speed due to many poles.

I had some specs on them years ago, but don't know where to look now.

We built our motor mounts out of aluminium and we put some heat sink grease between the motor and its mount. The only times we had heat problems is when we drove the robot for about an hour in the sun.

... and the sun can really be brutal in B-field! :cool: (I grew up there... I know!)

we just mounted some muffin fans above the motors to see if that will help with the heat for the extended demos.

This weekend we were runing the robot alot at our local mall. We ran if for about 2 hours straight and we had no poblems with heat. Since our drivetrian didnt have much strain on it i dont think it was a good test, but we never had any problems with our drivetrain, save a busted tranny from a nasty fall. But otherwise it was good, even when we ground our wheels down by pushing files into the wheels while running fullspeed. We just made nice aluminum motor mounts what alot of air can pass through. That probably helped.


Andrew

our motors had a lot of load on them becuase we ran at a gear ratio of 2:1 which I have been told isn't that good.

here comes my rant,

first of all there is no need for mag motors in first for many reasons;
1. there is no current controller for the motors and the few that people are currently using cost $750+ per controller. and 2 victors wont work although it has been stated that they will.
2. the cost of the motors is way to much for frist to pay ($350 for motor + $650 for controll*2 per team*750 teams) big number in excess of 1.5 million dollars!!!
3. the whole 24v deal, and exides are not fitting in robots ie new battery needed (later)
4. current draw, although this isnt touched upon much in first, big motors draw tons of current, mag motors 500+ amps at stall, yes you read that correct. this would kill the exide in less than 50 seconds thus the need for a new battery (later)
5. weight is also a problem at close to twelve pounds a piece the two would be 1/5 of the total weight allowed.
6. power, there is no need for a motor that produces 3890 inch ounces of torque @ 4000rpm, this geared down to the 400 rpm drill is aproximately 20 times more powerfull

end of mag motor rant we wont see it

we also wont see the new ifi system because of the lack of pwm inputs and out puts, currently we are allowed 8 limit switches and the new system would not allow for this.

i doubt we will see the battle hardened victors because to my knowledge they are not making them in the 12v model.

i wish we could use car fan motors but we probably wont because of internal modifications that need to be made plus the need to over volt them for there full potential.

we need new battery's, the current exides are heavy ineffeciet and do not produce a high enough current draw. the technology is out there to have a Nicad or NiMhd pack that would weigh half as much be larger in capacity and supply more current. charging would also be faster. although because of costs these options may not be available. the best bet would be to use hawker batterys which are more efficient (sp?) and allow higher current draw.
this year our battery dropped to 11-12 when we were only charging the tanks with the compressor.

drills, our team has had problems with drills in the past. allthough hard to harness there is a tremendous amount of power available. with the proper gear ratio a combiner box and even possibly a duel speed transmission we should be able to propel 150lbs bots easily. this years task really taxed the drills with the slope of the bridge and weight of the goals.

the best bet may be going with a dewalt drill motor althought they are a little harder to mount. the only problem is the cost.

along the line of motors i think first should have a few more options but limit what we are allowed to use. example we could use 4 drills but could not use van doors or have 15 motors avialable and we are only able to use 10.

i over all believe we have enough power people are seeing motors elce where and like i are getting gealous. like posted previosly i enjoy the challenge of having to make do with what we have.

i hope they change the game up someway in the future, what annoys me are the teams that keep the same design from year to year with no changes. this gives them the ability to cut out almost a week of design time.

well this is the end of my rant, cant wait to see the new challenge

tyler forbes
team 151

If it works, why fix it? The Bobcats have used the extendo arm type robot for many years (97,98,99,2001) and this design has served us well. Why would we want to redesign our robot when we have something that works extremely well?

Re: Ulesses Accersoies
 

Although our team didn't use the light sensor (or any sensors, because we ran out of time), the light sensor is probably more useful to detect when your robot is in a certain position... for example when an arm is fully extended. You can use colored electrical tape, which when passes by the optical sensor, could be programmed to stop. There is also the magnetic sensor that could be used for a similar purpose. I don't think the optical sensor was placed in the kit with the idea of detecting parts of the field, although that would be cool if you could get it to work that way.

Patrick