+ Reply to Thread
Results 1 to 12 of 12

Thread: Servos shaking

  1. #1

    Default Servos shaking

    Hi!

    I am using Parallax Servo Controller (PSC) USB to control 6 servos (Futaba S3001).
    Sometimes the servos start to shake.

    Is it possible that the controller doesn't send "clean" signals to the servos?

    The servos are connected to a separate power supply (5v).
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  2. #2

    Default

    Servos need to have their signals "refreshed "every 20 ms. or so . Does your code do that?
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  3. #3

    Default

    Parallax Servo Controller (PSC) USB is programmed to controll the servos.
    What I do is to send commands via RS232 that tell the controller which servo will be moved.
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  4. #4

    Default

    Oualid-

    Are the ground lines of the servos, Stamp and PSC all connected?

    peter

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Peter C. Charles

    Director, Research and Technology
    CyberBiota, Incorporated
    Peter.charles@cyberbiota.com
    http://www.cyberbiota.com
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  5. #5

    Default

    I have not used the PSC, or done a servo with a stamp (yet). My observations are based on past use in R/C:

    While 5V may work, my experience in R/C suggests this is a little on the low side. Forces tended to be higher (mostly ground based high speed cars and boats), so my opinion here may be incorrectly biased.

    More significantly, it was not unusual to have a slight "shake" depending on exactly where the servo was "pointed" at. Move the control stick a hair one way or the other, and the shake was gone. By hair, I mean just that, a hair.

    As a suggestion, try chaning the position by a few units and see what happens.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    John R.

    8 + 8 = 10
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  6. #6

    Default

    The processor used on the PSCusb requires 5 VDC which is supplied by the USB port. Servos
    require far more power than the USB port can supply.
    Therefore I use a separate power supply 5V for the servos.

    The following document shows how to connect the power supply:

    www.parallax.com/dl/docs/prod/motors/PSCusbManBv3_3.pdf

    Maybe the servos need more power, 6V.
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  7. #7

    Default

    From the PSC docs,

    The processor used on the PSC requires a supply 5 VDC. Use a separate power supply for
    your servos. In general, servos require 4-7.5 VDC. Be sure that the servo power source can
    supply ample current at the proper voltage and will not damage the servos.

    In my experience, make sure your power supply can provide at least an 1 amp when driving multiple servos.

    JJ
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  8. #8

    Default

    OK, I will check the current.

    Post Edited (Oualid) : 12/12/2005 8:47:35 AM GMT
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  9. #9
    Parallax Engineering

    Chris Savage's Avatar
    Location
    Rocklin, CA
    Posts
    12,433
    Blog Entries
    8

    Default

    Hello,

    What firmware revision does your PSC have? There is example code in the documentation to determine this.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  10. #10

    Default

    The version of the firmware is 1.4
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  11. #11
    Parallax Engineering

    Chris Savage's Avatar
    Location
    Rocklin, CA
    Posts
    12,433
    Blog Entries
    8

    Default

    Well, that's up to date...Could be power supply related...

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

  12. #12

    Default

    This is right! I changed the power supply that can deliver 5V, 2A and the servos don't shake anymore.

    Thanks for the help everyone!
    Last edited by ForumTools; 10-01-2010 at 10:36 PM. Reason: Forum Migration

+ Reply to Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts