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Inconsistent servo moves using basic stamp — Parallax Forums

Inconsistent servo moves using basic stamp

AlanogAlanog Posts: 1
edited 2014-02-08 11:27 in BASIC Stamp
I built a two servo walking robot from scratch but one of the servos does not always turn the same distance right or left and tends to "creep" round with successive moves. Does this indicate a problem with the servo and if so how can this be verified?

Comments

  • ercoerco Posts: 20,257
    edited 2014-02-05 13:14
    Sounds interesting, please post a Youtube video link, or at least some photos so we can help. Are these standard or continuous rotation servos?

    Most standard servos are very consistent, provided they have not been abused and missing internal gear teeth. CR servos require centering and can drift occasionally.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2014-02-06 12:12
    Some standard servos can appear to drift if you're overdriving them. You should be waiting at least 20 ms in between pulses.
  • trookstrooks Posts: 228
    edited 2014-02-08 11:27
    Might I suggest writing a simple program to move straight ahead for as long a distance as is available to you.

    Once you see how far and which direction the bot veers off course adjust your code to correct and then keep running the same straight course _without_ changing batteries. If you get the same results I got you will find that as the batteries get low the servos will behave differently from how they did with fresh batteries.

    Since I don't need movable bots to test my coding I set the bugger up on a small box and marked the wheels with chalk to verify that my code made them move in the right direction. I could then plug in a P/S and manually manipulate the sensors to verify that my code caused the correct response from the wheels. With the money I saved on batteries I was able to continue having beer and cigarettes.
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