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#1
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slow Drive system
We're a rookie team, and so far we are working on making a tank drive system with just 1 of the cim motors on each side. gear ratio of 1:3 . Is this not gonna be enough? I'm seeing alot of other teams using two motors together, or a transmission.
Thanks, Nerdlingers |
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#2
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You will be slow, but you should have lots of power.
P.S. dual motor transmissions add weight, and complexity it is a good choice for most rookies to go with a one motor non shifting drivetrain [edit] I didnt see that you said 1:3, I automatically assumed it was 3:1. Anyways, yeah what Jimmy said Cory Last edited by Cory : 26-01-2003 at 07:07. |
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#3
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Quote:
3:1, on the other hand, would equate to approximately 1400rpm, still assuming 4200rpm. Last season, with the Atwoods, we had two gear ratios. The high speed selection was geared at 10:1, and the high torque selection was 100:1. We moved at a nice 12feet/sec, I would estimate, in high gear. It moved like a snail in low gear, but boy was it hard to stop. <edit> I'm leaving the post as it was, but I'm just acknowledging that I am dumb, and that I was thinking in terms of rpm, not teeth per gear. Thanks to M. Krass and Jon Lawton for clearing that all up for me. </edit> Last edited by FotoPlasma : 27-01-2003 at 00:39. |
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#4
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don't the cims only produce 2.2 Nm of torque at stall, and you will not reach due to your 40 Amp limit, so you will only have maybe 6 Nm of torque on either side . . . .
I'd say go slower. |
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#5
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Quote:
Last edited by Adam Y. : 26-01-2003 at 15:19. |
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#6
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For the most part, there is almost always a team that is slower and/or less powerful than you.
You shouldn't lose any sleep over it ![]() |
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#7
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Lord Nerdlinger, how big are the wheels you are planning on using?
Because the way i am seeing it assuming 4200rpm output, geared 1:3 puts you at 1400rpm on the wheels which is 23.3 rps multiply that by the circumference of your wheels. If you are using 6 inch wheels that gives you a top speed of 36.65 fps which is way too fast. I would recomend having a speed of about 10 or 12 fps. Which would mean you would have to gear it 1:10 |
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#8
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We are using the 9" neumatic wheels, with the 1 gear on the motor shaft and one w/ 3x the teeth on the wheel shafts. I thought the cim motors were 1500 rpm? so that would make the wheels only 500 rpm, right?
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#9
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I think the drill motors in high gear are ~1500 RPMs
I thought the CIMs ran it up to about 5000 or 5500 or so. Yah, reduce it more, way more. |
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#10
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Yes, the CIM motors have a max rpm of about 5500.
Using the CIM motors geared 1:3 with the 9" pnuematic wheels will give you a top speed of 55 fps, That is way too fast! I would recommend gearing 1:10 and using the 6" skyway wheels, this would give you a top speed of 11 fps, much more manageable |
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#11
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Our drive is using 2 CIM's and we have them at a 10 to 1 "gear" ratio...
We are very fast, and we have torque to back it up... |
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#12
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Whatever ratio you do decide upon, please remember to make sure that it puts out enough torque at 40 amps to move your robot.
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#13
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Quote:
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#14
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Hey. Very interesting. CIM is being sued by Motion Systems ( a New Jersey Corporation) beacuse CIM is supposedly bringing in cheap Chinese knock-offs of Motion Systems wheel chair actuators. Read all about it at http://www.levinhawes.com/1/pr/Motio...PrelimInj.pdf.
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#15
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First, the CIMs are 5500rpm, not 4200. http://www2.usfirst.org/2003comp/Specs/Chiaphua.pdf.
Second, the breakers will not let you get 120amps for a single motor. That is limited to 40. The 120 is the total number of amps the entire robot can draw. Third, you need a MUCH better reduction than 3:1. With 9" wheels, you probably want a wheel speed of approx 250rpm. This can be accomplished very easily be using the gearboxes FIRST provided with the drill motors in low. Fourth, until you get a few years under your belt and have been to a few competition to see what works on what doesn't, I wouldn't even recommend attempting a two-motor transmission. Along those same lines, when you do go to a regional, assign at least one person to go talk to other teams and see how they did their drivetrains. It should give you some good ideas for next year. |
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