| Motor/Wheel Questions [MELTY Ant] | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Motor/Wheel Questions [MELTY Ant] Sun May 09, 2010 7:36 pm | |
| So I'm doing some more in-depth work on my antweight melty design, and I've come to the question of what wheel and motor I should use. For weight's sake, I'm aiming to use only one wheel [and therefore only one motor]. The catch is, I'd like to have weapon a tip speed around 8,000 RPM (which is a nice neighborhood for a 5"-6" diameter weapon speed), but that means the wheel needs to hit around 30,000 RPM. So, what does everyone think the best choice for a wheel [and motor] at those speeds is? Keep in mind this is an antweight bot, and I'd like to keep the wheel & motor around an ounce each if possible.
My current thoughts are to take the smallest colson available and maybe reduce its overall width on a mill, driven by a micro brushless outrunner (the kind used for miniature RC helicopters). | |
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rjw Chief Bottle Washer
People Skills : 7766 Registration date : 2009-03-31 Location : Miami
| Subject: Re: Motor/Wheel Questions [MELTY Ant] Sun May 09, 2010 9:34 pm | |
| Have you or anyone else figured out how to control a brushless in a melty?
Also, I don't know that anyone has really gotten much over 100o to 1500 rpm with much luck while translating.....
So, what do you know different? | |
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Cody 2000+ club
People Skills : 7813 Registration date : 2009-03-16
| Subject: Re: Motor/Wheel Questions [MELTY Ant] Sun May 09, 2010 10:03 pm | |
| From what i remember death by translation ate threw colsons on a thirty and MUCH lower rpms. | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Motor/Wheel Questions [MELTY Ant] Sun May 09, 2010 10:16 pm | |
| To my knowledge, there is no good reason why manipulating a brushless motor should be much more difficult than a brushed motor, except the need to take into account for hardware specifics. After all, you only need a few set pieces of input data (the robot's current rpm and three receiver signals) to produce the translational control output (throttle signal * [% angular modulation]). I'm 99% sure all this could be done by one arduino microcontroller accepting three inputs and producing one output for a standard brushless ESC to drive the robot.
However, now that I think about it, the problem concerning high-rpm translation is due to too little time to actually apply the modulation to the wheel, and should be even worse at higher speeds. That said, consider this project scrapped - there is no good way to improve translation at high speeds (in two dimensions) on MELTY bots, rendering them inferior in the lighter weight classes.
EDIT - Except maybe if it's a hovercraft. Then it might work. | |
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Cody 2000+ club
People Skills : 7813 Registration date : 2009-03-16
| Subject: Re: Motor/Wheel Questions [MELTY Ant] Sun May 09, 2010 11:03 pm | |
| - Quote :
- rendering them inferior in the lighter weight classes
cant say i agree with it at all | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Motor/Wheel Questions [MELTY Ant] Mon May 10, 2010 1:07 am | |
| - Cody Harris wrote:
-
- Quote :
- rendering them inferior in the lighter weight classes
cant say i agree with it at all Sure, they may be durable, but they can't compete for energy against even a plain-old undercutter. | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Motor/Wheel Questions [MELTY Ant] Mon May 10, 2010 11:10 am | |
| New tack I'm looking at: melty drive (at around 600 rpm), with a more standard friction-driven shell. It may end up requiring a larger battery, but could have some pluses in terms of durability. | |
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Cody 2000+ club
People Skills : 7813 Registration date : 2009-03-16
| Subject: Re: Motor/Wheel Questions [MELTY Ant] Mon May 10, 2010 12:12 pm | |
| so 1lb at 1k rpm vs maybe a 3 ounce disk at probably 4k at the most isnt even close? i dont feel like doing the math but i have to think there more then just close
most undercutters dont spin to the moon | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Motor/Wheel Questions [MELTY Ant] Mon May 10, 2010 12:16 pm | |
| - Cody Harris wrote:
- so 1lb at 1k rpm vs maybe a 3 ounce disk at probably 4k at the most isnt even close? i dont feel like doing the math but i have to think there more then just close
most undercutters dont spin to the moon 6" OD, 5.75" ID, 1" H, steel mono-tooth = 2.66 kJ at 8594 RPM. At 3000 RPM, it's 0.325 kJ. EDIT: And that's a ring. Bars are less efficient, but I've seen both discs and bars run pretty fast in more than a few ants. | |
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rjw Chief Bottle Washer
People Skills : 7766 Registration date : 2009-03-31 Location : Miami
| Subject: Re: Motor/Wheel Questions [MELTY Ant] Sun Sep 05, 2010 12:17 am | |
| some melty logic in this thread, I think...
technology can change overnight | |
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| Subject: Re: Motor/Wheel Questions [MELTY Ant] | |
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| Motor/Wheel Questions [MELTY Ant] | |
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