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Gyroscope based stabilizer
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zcream



Joined: 11 Jan 2009
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Gyroscope based stabilizer

I have an object that is 1-2 kgs. I can mount it with a 1/2-inch or 3/8-inch tripod thread. How do I go about using a gyroscope to keep its orientation in a vibrating environment ?
Actually, how would I even buy a gyroscope for such a purpose ?
Cheers!

Post Sun Jan 11, 2009 12:29 pm 
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Valen
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buy a helicopter camera stabiliser.
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Post Sun Jan 11, 2009 2:01 pm 
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zcream



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Costs about 2500/- USD for the standard camera versions.

Post Sun Jan 11, 2009 6:16 pm 
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Glen
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better start saving ;-P
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Post Sun Jan 11, 2009 6:31 pm 
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WiperMotor



Joined: 04 Sep 2006
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what about two heli gyros?

Post Sun Jan 11, 2009 9:10 pm 
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zcream



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Heli gyros

Please correct if I am wrong. A heli gyro prevents vibration from the tail from reaching the cockpit or the payload i,e, camera. So, I have a DC source that allows the gyros to be stable (power the motors inside the gyro) then I can use 2 gyros parallel to each other and the payload between them for stabilization.

Does this make sense or am I missing something ?

Post Sun Jan 11, 2009 10:34 pm 
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WiperMotor



Joined: 04 Sep 2006
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yeah your sort of on the right track

The heli gyro is responsable for counteracting the main blades by ajusting the pitch of the tail rotor, the faster the mainblades go the more the gyro counteracts

Gyros don't have motors in them anymore, thats 20 year old technology, new gyros have different inner workings now, they can be powered directly off the reciever.

What are you trying to achieve here? camera stabilization?

Post Sun Jan 11, 2009 10:45 pm 
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zcream



Joined: 11 Jan 2009
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Pretty much yes. Camera stabilization. However, the pro options are way out of price range. I can buy 6-10 cameras for the price of a Kenyon (thats the pro camera stabilizer).
Problem is that the compensation by any solid state devices has to be to ensure that camera is "suspended" and free of vibration. I think the heli gyros are limited in the sense that they compensate for tail vibration..Not sure if they can be adapted to compensate for any other kind of vibration or jerky movement.

Post Sun Jan 11, 2009 11:57 pm 
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Knightrous
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Considered looking at a mechanical approach?

http://www.cs.cmu.edu/~johnny/steadycam/
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Post Mon Jan 12, 2009 12:01 am 
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zcream



Joined: 11 Jan 2009
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Looked at that

Tried that by dismantling a tripod. tried a few other DIY designs. ATM, I really believe the best solution is either a gyro-based or a 2-axis or 3-axis based gimbal design.
Not sure how to start if I am going to do it myself..
Interesting problem though..

Post Mon Jan 12, 2009 12:07 am 
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Nick
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After looking at the Kenyon site, they sure look mechanical to me. The screw on pod simply has to have a large spinning mass in it and there may not be much else except a motor and power. I saw one photo where the were two pods mouted at 90 deg to each other and I would bet there is no intelligence in this 2 azis stabiliser.

When we talk about heli gyros, we are talking just about the sensors that are used for steering. They might 'stabilise' a heli, but only by counteracting external forces to keep the heli steering straight - they don't reduce vibration in the way the kenyon units do.

I would look at using two brushless motors rotating in opposite directions. they would need some kind of speed matching and the flywheels that provide the stabilisation would need to be very well balanced. Using a pair of outrunner motors with an extra weight on the rotating case would save space.

Post Mon Jan 12, 2009 12:22 am 
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Nick
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Just investigated those stabilisers - you get two brushless motors spinning @ 22,000 rpm with flywheels made of tungsten, all sealed in a maintenance-free helium filled pod - the price doesn't seem so unreasonable now Rolling Eyes

It looks like a home brew would require some lathe work and a very good balancing rig; even a slight balance problem @ 22K rpm will shake thing apart. If you want to go one up on the pros, make the flywheel from deplete uranium Laughing

Post Mon Jan 12, 2009 12:54 am 
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Valen
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if they are rotating in opposite directions they cancel out the gyroscopic effect.
IE no net stabilisation.

3x large spinning masses at 90 degrees will help remove any vibration in rotation however it wont do anything for motion along an axis, ie blade thump.

The high grade stabilisers are full 6 axis inertial measurement units mounted on a the inertial frame itself, I believe they are something like $14000 just for the IMU itself.

You can either throw a lot of smarts at it, IE a multi khz IMU system with high speed precision actuators to cancel out the shake. Or throw alot of mass at it on some fancy shocks, This isn't an easy project.

That's assuming your trying to make a decent camera shot off a helicopter.
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Post Mon Jan 12, 2009 1:05 am 
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zcream



Joined: 11 Jan 2009
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Using toy gyroscopes ??

This place http://www.gyroscope.com/ has got a decent gyroscope.
The gyroscope http://www.gyroscope.com/d.asp?product=SUPER2
Gimball add-on http://www.gyroscope.com/d.asp?product=GIMBALS

I just need to understand enough about gyroscopes now to combine them into a stabilizer.
Have to say that I did not know that gyroscopic stabilizers were that expensive.

Post Mon Jan 12, 2009 2:07 am 
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Nick
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Those gyroscopes are far too low powered - the lower speed and 112 gram weight isn't going to stabilise anything much except the gyro itself. If you think that's getting a bit expensive, give up now Smile

Post Mon Jan 12, 2009 10:06 am 
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