Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: jcoliverors on July 19, 2011, 06:41:31 AM

Title: Servo or gearmotor
Post by: jcoliverors on July 19, 2011, 06:41:31 AM

Hello,
      I wanted to know if someone can help me decide between a servo and a gearmotor.  I am basically trying to rotate an aluminum tube (about 1-2lbs).  Using the robot arm calculator, I see that I will need at least 125 oz-in of torque.  However I do not know whether it would be better to get a servo or a gearmotor.

Title: Re: Servo or gearmotor
Post by: waltr on July 19, 2011, 09:59:14 AM

Have you searched and read on the many threads that have asked a very similar question?

A servo (RC Hobby servo) contains a Gearmotor plus position feed-back circuits. If you require the Arm to move to a set position with a simple signal then a hobby servo is what you want. Hobby servo's are available in many sizes and output torques however they do get expensive in the larger sizes.

To use a plain gearmotor you will need to supply a position feed-back signal so the controller knows when to stop and to apply current to hold the Arm in the desired position. So this gearmotor and position control feed-back is really a servo (look up 'servo' in Wikipedia) but you must design and build the feed-back and control portion.