Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: bob on November 16, 2009, 10:44:03 PM

Title: servo motor moment
Post by: bob on November 16, 2009, 10:44:03 PM

I buy the polypropylene 10 mm thickness and the size is 40 cm X 20 cm
my problem is that is weigh a lot a proximate 2 kg maybe more
now I afraid that the motor can't drag the 50 dollar robot
also the wheels are heavy a proximate the three wheels 1 kg and have diameter of 12.5 cm
are the servo motor of the 50 dollar robot can drag robot with total weigh 4 kg ?

Title: Re: servo motor moment
Post by: SmAsH on November 17, 2009, 12:10:16 AM

Why dont you try it? Testing is the best way to find something out...
Do you have the servos already?

Title: Re: servo motor moment
Post by: bob on November 17, 2009, 03:03:59 AM

no i don't have the servo
i need to buy servos because of this i ask my question

Title: Re: servo motor moment
Post by: Razor Concepts on November 17, 2009, 05:05:09 AM

Quote from: SmAsH on November 17, 2009, 12:10:16 AM

Why dont you try it? Testing is the best way to find something out...

Well.. calculating it should be the best  ;)

Title: Re: servo motor moment
Post by: SmAsH on November 18, 2009, 01:19:22 AM

Yeah, but calculating is hard!

Title: Re: servo motor moment
Post by: Antonb on November 28, 2009, 10:57:26 AM

As long as you dont need to move your robot on sloped surfaces the modified servos will work fine but remember that with so much weight you ran into other problems. The heavier your system the more inertia it will have which means that you have slow acceleration, is difficult to stop and furthermore a motor-forced stop condition may lead to your gears getting damaged. 

Title: Re: servo motor moment
Post by: Pierre on November 28, 2009, 12:24:44 PM

Quote

are the servo motor of the 50 dollar robot can drag robot with total weigh 4 kg ?

Spec sheet for HS-311 of the $50 robots and the Stall Torque is 3 kg.

You mentioned that your robot would be at 4kg.  Here is your answer.


  

Title: Re: servo motor moment
Post by: hopslink on November 28, 2009, 02:48:58 PM

I expect he will have two motors :P, besides there is slightly more to it then that...

Just a thought, but will you really need all that sheet for the 50$ 'bot. I would have thought a 10 x 20cm base would be plenty. Weight comes down to ~500g for the base, and you can make four 'bots form your sheet...

And if the wheels are that heavy there is a good chance they are far stronger than they need to be. You could probably lose some mass by drilling holes in the wheels and the base of your 'bot (but save that as a last resort because it is hard to put back...).