Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: keyboard1333 on October 03, 2012, 06:52:25 PM

Title: Choosing motors for an arduino robot to compete in robocup jnr
Post by: keyboard1333 on October 03, 2012, 06:52:25 PM
Hey Guys!
Me and a friend recently started plans to build a robot using an Arduino Uno to compete in the Australian Robocup Junior Soccer competion.

A friend who has competed in previous years, used 200rpm 12v 1.2A motors.
Do you think that that is enough power to move a robot weighing a couple of kilos rather quickly?
(Like half a meter a second)
If not, what are the specs for the kind of motor that we want?
Thanks, keyboard1333
Title: Re: Choosing motors for an arduino robot to compete in robocup jnr
Post by: newInRobotics on October 04, 2012, 03:03:34 AM
You didn't mention wheel diameter  :)
Title: Re: Choosing motors for an arduino robot to compete in robocup jnr
Post by: keyboard1333 on October 04, 2012, 04:07:01 AM
Between 1 & 2 inches.
Title: Re: Choosing motors for an arduino robot to compete in robocup jnr
Post by: newInRobotics on October 04, 2012, 06:06:52 AM
Then max velocity achievable (without taking friction into consideration) will be between ~0.27 m/s to ~0.53 m/s. It's clear that 1" wheels don't really cut it, hence let's go with 2" wheels.

To have acceleration of 0.25 m/s2 (to be able to reach 0.5 m/s velocity in 2 seconds) each motor has to be capable of at least 63.5 mN*m torque.

You probably don't want to run motors at 100% duty cycle all the time, so to be on a safe side lets say that You want to achieve aforementioned results while running motors at 75% duty cycle. So, max motor RPM has to be at least ~252 RPM and stall torque has to be at least ~85 mN*m.

For what You want, something like 300 RPM 12V 0.39 N*m motor (http://www.virtualvillage.co.uk/pair-of-12v-300rpm-gear-motors-003604-001.html?utm_source=googlebase&utm_medium=shcomp&utm_campaign=google_shopping_feed) would be more that enough. Of course if plan on using 12V. What voltage are You planning to use?