Society of Robots - Robot Forum
General Misc => Misc => Topic started by: Admin on November 25, 2009, 01:41:55 PM
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Futaba has released an interesting new type of servo.
Its non-continuous, and you can't modify it to rotate continuously.
However, you can manually rotate it continuously forever - making you think it was continuous but not really. It has no mechanical stop, yet still acts like it does when you power it up.
I've only played around with it a little, but I see this as a good thing as the mechanical stops on my Hitec servos keep breaking. Replacement case sets are like $8 . . .
This is the one I have:
http://www.servocity.com/html/s3156_servo.html (http://www.servocity.com/html/s3156_servo.html)
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A servo with a mechanical stop acts the same way. It's the position of the wiper on the POT verse the width of the pulse (analog type) that determines where the servo stops. You could remove just the stop in a standard servo and it would not continuously rotate. You also must disconnect the pot and insert a fixed value resistor.
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So, does it still use a pot or what?
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It may not since there are several ways for a circuit to determine the servo's position. One would need to dissect it to find out.
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Its a digital servo that rotates continuously with power off, so there probably is no pot. I assume it has a built-in quadrature encoder of some type.
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Ah, i thought that may've been the case...
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Hi,
Its a digital servo that rotates continuously with power off, so there probably is no pot. I assume it has a built-in quadrature encoder of some type.
The page says: "Potentiometer Drive: Indirect Drive", so perhaps it's just a mechanical coupling with slip when the outside axle is rotated.
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Hmm... futaba used to make an indirect drive servo, the S148. I actually have a few of them but never opened them up.
S148 (http://cgi.ebay.com/FUTABA-FP-S-148-INDIRECT--SERVO_W0QQitemZ360207775830QQcmdZViewItemQQimsxZ20091115?IMSfp=TL091115168005r2275)