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Centered axle — Parallax Forums

Centered axle

TaishoTaisho Posts: 34
edited 2006-06-26 15:11 in Robotics
Can anyone point me in the right direction on how to center an axle. I am trying to build a 4-wheeled robot using BS-2 controllers but I am stuck on the wheels. When an axle is turned how can I rotate it back to center? I had thought about some mounting of an LED and photosensor but wondered if there is a better way. My research has found me info about Ackerman drives and their complexity so I know I'm picking a fight with a beast beyond my skills but I am determined to make it work.

I appreciate any nudge in the right direction.

Comments

  • Bill PlanoBill Plano Posts: 14
    edited 2006-06-26 06:18
    Tashio

    Look at this link http://www.parallax.com/detail.asp?product_id=28107, it is for a wheel encoder and may be just what you need to center your axle.

    Bill
  • TaishoTaisho Posts: 34
    edited 2006-06-26 13:51
    Thank you Bill. I think that is the right nudge in the direction I need to go. I have been stumped on how after turning the axles and completing a turn that I can realign them to center position so they both are aimed exactly forward. Thank you!!!!
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-06-26 14:15
    I don't know what the weight or torque requirements are for turning this axle, but if you use a heavy-duty servo you can center it just by sending ~1.5 ms pulse to it.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • TaishoTaisho Posts: 34
    edited 2006-06-26 14:58
    I am keeping the weight down as much as possible. Right now the beast is weighing in at a little over 5 pounds. I am using Parallax continuous rotation servos to drive it. I am trying to build a 4 wheeled bot that will have each axle capable of turning independently for maximum maneuverability. It is going to be a rather simple bot using a Ping module and infrared sensors for maneuvering as well as a Parallax PIR motion detector to occasionally stop and check for movement (expected to be a dog or cat smile.gif This is my first bot so I am playing in a realm that is entirely new to me. I don't have any experience in radio control cars or planes either so I knew nothing about servos or vehicle suspensions coming into this.

    I appreciate both of your inputs.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-06-26 15:11
    There should be plenty of servos out there which could support that weight.· Really depends on budget, since the higher the torque, the more expensive the servo.· I hope this helps.· Take care.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
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