### Author Topic: less than .07 degrees  (Read 5746 times)

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#### SupremeRulerG

• Beginner
• Posts: 1
##### less than .07 degrees
« on: May 07, 2006, 07:48:32 AM »
hi, I'm doing my thesis right now, and one of the requirements is to move a camera very precisely, down to the very last .07 degrees!!! yep! that's right --.07degrees thats two decimal places

Can someone suggest what motor I should use? servo or stepper? I'm currently considering using a stepper motor which has 1.8 deg per step, then, I'll just use gears to reduce the movement upto .07 deg.  But is that possible?
can I really control it that precisely with a stepper motor?

lastly, can a servo motor be controlled to stop at a very precise position like for example...120.07 degrees?

• Supreme Robot
• Posts: 11,703
##### Re: less than .07 degrees
« Reply #1 on: May 07, 2006, 06:56:25 PM »
Servos have an accuracy of about one or two degrees.

As for steppers, accuracy varies widely. You probably wont be able to find one any more accurate than a servo.

I think to have two decimal placess accuracy however is very unreasonable for a camera. Cameras are very good for robots, you shouldnt need accuracy like that . . . I think you should find another way to solve your sensing problem.

Why do you need such high accuracy?

Your only solution is a highly geared down stepper motor, cant think of anything else. Probably use a planetary or worm gear.

• Robot Overlord
• Posts: 293
##### Re: less than .07 degrees
« Reply #2 on: March 10, 2007, 11:25:44 PM »
Hi,
I don't know the topic of your research so I can't give you an specific answer. But you sould look for astro navigation telescope motor if you want a high precision. Or you could build something like this: http://www.mistisoftware.com/astronomy/Equipment_Drives.htm
A.I.(yes those are my initials)

#### Brandon121233

• Contest Winner
• Supreme Robot
• Posts: 320
• "Genius is %1 inspiration and %99 perspiration"
##### Re: less than .07 degrees
« Reply #3 on: March 14, 2007, 05:27:10 PM »
why dont you just use a servo with a large gear that is indexed to the precision that you need then just use an encoder to count the clicks you need for a specific degree http://www.societyofrobots.com/sensors_encoder.shtml
Hell, there are no rules here—we're
trying to accomplish something.

—Thomas Edison