Society of Robots - Robot Forum

General Misc => Misc => Topic started by: j03yYunG on January 31, 2008, 08:38:46 PM

Title: A little help for robot new design
Post by: j03yYunG on January 31, 2008, 08:38:46 PM
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).  :D
Title: Re: A little help for robot new design
Post by: ed1380 on January 31, 2008, 09:20:37 PM
cordless drill motor.  good quality ones w/ standard planetary gearbox can do almost 500 in/lb
Title: Re: A little help for robot new design
Post by: j03yYunG on January 31, 2008, 11:37:50 PM
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
Title: Re: A little help for robot new design
Post by: ed1380 on January 31, 2008, 11:44:33 PM
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
Title: Re: A little help for robot new design
Post by: j03yYunG on January 31, 2008, 11:55:24 PM
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..
Title: Re: A little help for robot new design
Post by: ed1380 on February 01, 2008, 12:29:53 AM
o yeah. that motor with no gearbox will move your robot.  :o

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.
Title: Re: A little help for robot new design
Post by: j03yYunG on February 01, 2008, 12:39:09 AM
o yeah. that motor with no gearbox will move your robot.  :o

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...  :(
Title: Re: A little help for robot new design
Post by: Admin on February 17, 2008, 01:11:02 PM
Quote
ps: I'm not sure if my calculations are 100% correct
use this:
http://www.societyofrobots.com/RMF_calculator.shtml