pic: Fischer Price motor are very powerful

[dan 322]

Originally Posted by Joe3

We've done even better with this. We have two f-p motors powering our arm, with a 16:1 reduction outside of the stock gearbox reduction, and during different points in testing we

1. buckled arm
2. tore gearbox mounting point out of chassis
3. snapped a solid 44 tooth (35 chain) sproket.

Beware of the power.

We also use two FP motors, but only a 10:1 Reduction. We also had a vandoor motor with them until weight became a problem.

[Peter Matteson]

Originally Posted by dan 322

We also use two FP motors, but only a 10:1 Reduction. We also had a vandoor motor with them until weight became a problem.

We use the FP's through the drill transmission and then reduce another 32.5 times for our use. It will viewable tommorrow at the UTC NE Regional.

[Joe Johnson]

I agree with those who discussed being too aggressive in lightening efforts.


In my opinion, this is a better example of a not leaving enough meat on the bone than the power of the F-P motors.

Actually power had nothing to do with this failure, I suppose it was torque that killed it not torque X speed (i.e. power).

Joe J.

[dlavery]

You mean it's not SUPPOSED to look like that??!?

Actually, the first time I looked at this image, I thought that Team 322 had manufactured an elliptical gear to tailor the delivered torque to certain angles of inclination of their arm (similar to high-end/competition bicycle cranks and chain wheels). I saw the kink in the lower portion of the ellipse and thought "wow - they bent their chain gear; too bad after all that work to cut the custom gear shape."

Then I realized that it really did start out as a round chain gear, and modified that reaction to "WOW!!!" Lessons learned: 1 - even more respect for the F-P motors. 2 - gotta go double-check strength calculations for lightening gears. 3 - elliptical gears could be very useful; something to remember for next year.

-dave

[dan 322]

Originally Posted by Joe Johnson

I agree with those who discussed being too aggressive in lightening efforts.


In my opinion, this is a better example of a not leaving enough meat on the bone than the power of the F-P motors.

Actually power had nothing to do with this failure, I suppose it was torque that killed it not torque X speed (i.e. power).

Joe J.

Yep, the sprocket was supposed to see only torque from the Window motors (very weak), but because we were still learning with the arm we hung incorrectly. This put the torque of 2 FP's reduced 10:1 on the sprocket. Unfortunately when you try to do a lot of tasks (big ball, hang, climb, push) with your robot, weight becomes a big issue REAL FAST. This requires the team to lose a little bit of robustness. This is what it's all about though, making the simple parts to replace the weak link. We replaced the sprocket within 5 minutes and had time to eat before our next match. We have learned a lot over the last 5 years. We also ripped off an robot finger trying hang incorrectly and blew out our trick wheels when the bot fell. It was awesome, our arm was still on the bar. I think we should have gotten 50 pts. for it.

[BoyWithCape195]

Oh course Fisher price motors are powerful *opens gear box and gazes at big gears!* They also are made to move up to arund 150 pounds, so if its moving your arm...that alot of power for not so much weight.