A little help for robot new design

[j03yYunG]

Hi,

I'm looking to build a robot that will weigh about 120lbs and travel about 10mph.

Its going to sit on four 8" diameter wheels. I did some calculations, and I'm going to need at least a 420 RPM motor with about 4 lb*ft of torque. I've been looking all over the internet for 2 or 4 12v or 24v DC motor that will power this thing. I don't want the operating and stall current too high either. Can someone help me please. Any websites or motor lists will be helpful. Thanks.

ps: I'm not sure if my calculations are 100% correct. I used p = f*v (assuming 12lb force will be enough to push the 120lb robot). Then t = p/w (t=torque, p = power, w = angular velocity). 

[ed1380]

cordless drill motor.  good quality ones w/ standard planetary gearbox can do almost 500 in/lb

[j03yYunG]

cordless drill motor.  good quality ones w/ standard planetary gearbox can do almost 500 in/lb

any specify one you would recommend? links or website please? thanks

[ed1380]

http://www.robotmarketplace.com/products/motors_main.html

or you could get some cheapo 18v drill for  about $20-25, but it wont be as powerful and made in china quality

[j03yYunG]

http://www.robotmarketplace.com/products/motors_main.html

or you could get some cheapo 18v drill for  about $20-25, but it wont be as powerful and made in china quality

I was looking at these motors and some of them need to much amps to operate. Like this one...
http://www.robotmarketplace.com/products/BP389010-00.html

68 amps to run it.. jesss..

[ed1380]

o yeah. that motor with no gearbox will move your robot. 

look into the gearbox motors. they'll be geared down(lower rpm) like you need and will use less power and more torque. 12v will do. maybe even less.

[j03yYunG]

o yeah. that motor with no gearbox will move your robot. 

look into the gearbox motors. they'll be geared down(lower rpm) like you need and will use less power and more torque. 12v will do. maybe even less.

I was acutally looking at these ones...

http://www.robotmarketplace.com/products/0-BHG20.html

But the site says its only for robots 12-15 lbs... I'm afraid the shaft will break if its on a 120lb robot. Is there anything I get do to use these motors in a bigger body? Oh and with these motors... how much do you think the rated torque is with the stall torque being 355 oz-in? There isn't any data sheets... 

[Admin]

ps: I'm not sure if my calculations are 100% correct

use this:
http://www.societyofrobots.com/RMF_calculator.shtml