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Inconsistent Servo Speed — Parallax Forums

Inconsistent Servo Speed

Jonathan MorrisonJonathan Morrison Posts: 23
edited 2005-07-21 01:01 in Robotics
I have a BOE-BOT that has 2 servos on it. I run one servo at freqout - 650 and one at freqout - 850, however, the bot always veers to the left a little. Is there a way to fine tune the servos so they are in sync - or do I need to adjust the freqout code to do 657 instead of 650, etc.? Or have I missed something by assuming that 750 == center, 650 == full speed left and 850 == full speed right? Thanks.

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-07-17 06:05
    Jonathan,

    ·· Sometimes one servo will run slightly faster than another.· In these cases you may have to make adjustments to the code, and/or to the values sent to the servos to compensate for this.·

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • AmaralAmaral Posts: 176
    edited 2005-07-18 22:50
    Did you tune-up your servo before mounting into a boe bot ? This question may be silly but sometimes we are so excited to put the Bot Together that we skip these things?
  • Jonathan MorrisonJonathan Morrison Posts: 23
    edited 2005-07-18 23:06
    Yeah - I manually tuned it so that both servos were still at freqout = 750. Is there any other tuning to do? Thanks.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-07-19 15:11
    Jonathan,

    ·· On page 129 of the Robotics Manual V2.2, it explains how to tune the servo values to compensate for a BOE-Bot that veers when moving in what should be a straight line.· I have had to do this myself.· Basically it's good to write down the values you end up with so they can be integrated into code you write later.

    ·· For example, on one of my BOE-Bots, to go forward I am supposed to use the values 850 on P13 and 650 on P12.· But I have to use 840 and 650 instead, because my bot veers right a little.· It took several tries to get the exact number, but now that I have it, whenever I have code to go forward, instead of using 850 and 650 I use 840 and 650.· I hope this helps you.


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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com


    Post Edited (Chris Savage (Parallax)) : 7/19/2005 10:59:23 PM GMT
  • Jonathan MorrisonJonathan Morrison Posts: 23
    edited 2005-07-19 21:03
    Awesome. That works perfect - thanks!
  • MacGeek117MacGeek117 Posts: 747
    edited 2005-07-21 01:01
    freqout = 750, I thought it was PULSOUT 12, 750.
    bugg

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