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Author Topic: New home made servo from scrap my story  (Read 4776 times)

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Offline JhdgkssTopic starter

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New home made servo from scrap my story
« on: May 09, 2007, 01:48:54 PM »
hi there first of all hi to every one i am new hear.

I have been trying to build my self a biped robot but i am  alarmed by the cost of servos especially ones that are powerfully up to the job well i should say the final cost after buying the huge number needed for such a project, also i have found that servos do not model real muscles that well (please ref to the Lucy robot).

so what i have done is obtained an old PC CD ROM removed one of the motors and attached it to a piece of m5 threaded bar via a home made coupling and a set of grub screws. then made a small block out of aluminium that is threaded m5 all the way through of which is threaded on to the m5 rod ( making a worm screw)

So as the motor turns it turns the threaded rod which moves the Alu block down its shaft. this block pushes against a spring which in turn presses against the joint making it move. On the joint there is a pot to provide feed back. the main reason for the spring is that it makes it possible for the limb to sense when it hits something.

so far i have tested the straight lifting capability of the device at 300g lifting just straight from the Alu block vertically at a speed of 40mm/sec using a 7.6v battery. the Assembly is roughly about 60mm long and 20mm in diameter. the best thing is you can use and motor as it is all directly driven. And the whole thing took about 1hour to make with the aid of a pillar drill

has anyone else tried this??
« Last Edit: May 09, 2007, 01:55:57 PM by Jhdgkss »

Offline dunk

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Re: New home made servo from scrap my story
« Reply #1 on: May 09, 2007, 02:43:12 PM »
kind of like this but with a stepper motor right?
[url][http://www.xrobots.co.uk/modules/news/article.php?storyid=8/url]

dunk.

Offline JonHylands

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Re: New home made servo from scrap my story
« Reply #2 on: May 09, 2007, 05:12:43 PM »
Sounds like a simple series elastic actuator...

Check out http://www.yobotics.com

- Jon

Offline JhdgkssTopic starter

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Re: New home made servo from scrap my story
« Reply #3 on: May 09, 2007, 11:17:38 PM »
hi there yhanks for the reply.

Yes its isvery similar to the links you both posted but it is alot smaller

Offline JhdgkssTopic starter

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Re: New home made servo from scrap my story
« Reply #4 on: May 12, 2007, 01:26:42 PM »
HAs any one else tried to do replace servos with a cheap more effective alternative to noise expensive servos

Offline blackbeard

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Re: New home made servo from scrap my story
« Reply #5 on: December 15, 2009, 08:19:20 PM »
yep i've used those cdrom linear actuatorish things. since almost all cd roms have the same bits it's pretty easy to rig up. try collecting burnt out servos and just using the boards (assuming that's not what's burnt out)
"sure, you can test your combat robot on kittens... But all your going to do is make kitten juice"

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Next step: Give them vaginas

 


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