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Are servos choppy? — Parallax Forums

Are servos choppy?

lardomlardom Posts: 1,659
edited 2013-01-18 22:03 in Robotics
I tested servo control with a mini breadboard potentiometer using code I found in the OBEX. I couldn't get the servo to move smoothly and wondered if there was a problem with the pot, the code or the servo. Is that the way servos normally move?

Comments

  • TtailspinTtailspin Posts: 1,326
    edited 2013-01-15 07:49
    Could be a power supply problem, or the servo is not getting a signal within the 20ms window.

    Would need to look at the code, and your breadboard set up. :)


    -Tommy
  • lardomlardom Posts: 1,659
    edited 2013-01-15 08:09
    @Ttailspin, what you said is encouraging. As long as I know servos are capable of fine control I'll find the reason that mine was so sloppy. I have more experience with steppers but they are not the best motor for every job. I'll work on it some more. Thanks.
  • ercoerco Posts: 20,255
    edited 2013-01-15 10:18
    Smooth motion is definitely possible. Servo quality and age (worn out pot or motor brushes) are just two of many factors. I found that my robot arm (which used 3x $2 Ebay China 9-g servos) operated more smoothly at lower voltage (3.6V was smoother than 5V). Smooth motion is critical for any kind of arm accuracy: http://www.youtube.com/watch?v=kF6TwbIT384&feature=player_detailpage#t=35s
  • lardomlardom Posts: 1,659
    edited 2013-01-15 10:39
    I want to build a robot arm just like every other normal person in this forum! This was a good day because after weeks of fiddling I got my steppers to travel in an arc with a ramp-up and a ramp-down without that little 'hook' at the end so I'm kind of pumped. I ordered some stuff from Parallax today including a compass and a tail-ball so I'll be OK for the rest of the day. I'm going to daydream of putting an arm on my robot...
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-01-18 20:10
    Larry, Do you have a QuickStart board? If so, try out my QuickStart servo tester.

    You should be able to get smooth motion from a servo. In post #9 of my 32 servo demo, I show how you can use an algorithm to give a servo a pendulum type of motion.

    Sorry for the late response, I've been busy (working on a robot) over the last few days and I haven't been checking the forum much.
  • lardomlardom Posts: 1,659
    edited 2013-01-18 21:20
    Thanks Duane. Yes, I have a Quickstart and a Demo Board.
    I saw the video of your hexapod and I thought "It looks alive!" You know your stuff.
  • ercoerco Posts: 20,255
    edited 2013-01-18 22:03
    Duane Degn wrote: »
    I've been busy (working on a robot) over the last few days and I haven't been checking the forum much.

    What are you up to, Duane? Something sweet for Expo? :)
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