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-   -   DIY Gyro Stabalizer (https://www.dvinfo.net/forum/open-dv-discussion/140525-diy-gyro-stabalizer.html)

Craig Stay December 30th, 2008 10:53 AM

DIY Gyro Stabalizer
 
I saw some thread about Gyro Stabilizers. I'm not sure how they work professionally but if i had to guess would be the way id like to make one.

Take a battery powering two electric motors with a spinning two 9 inch wheels or so and place them perpendicular to each other. Spin them as fast as possible and if this works like a bicycle wheel when it would stabilize the camera allot. build an enclosure and mount it to the bottom of a camera. would this work?

Bob Hart December 30th, 2008 11:11 AM

I tried that quite a few years ago with car heater fan motors which had oilite bearings and I fitted large wheels. Didn't work. Smaller flywheels with higher rpm and anti-friction bearings is better. The fan motors dopped about 30% of their rpm from added friction when pushed off axis. The wheels have to be balanced to the motors after assembly and re-balanced if dismantled.

Your flywheels or gyros have to be in same-axis pairs with opposing rotations otherwise if you have only the one, when you attempt to force it off-axis it will haul you off in another direction.

The Kenlabs gyros look a bit like a gas cylinder which they are. Two opposing flywheels on the same axis in each cylinder. They apparently take about 20 minutes to spool up to final rpm. Ideally the gyros should be in a vacuum to be rid of air friction altogether.

I understand this causes issues with the electric motors, maybe heat dissipation and arcing so they fill them with the lightest non-flammable gas, helium, instead.

One pair will get you stabilisation on two axes. You need another pair at 90 degrees to get a third axis. According to other websites, where you want to retain some practical agility with the camera, the second gyro pair should be inclined at about 11 degrees back from the 90 degrees.

They are not cheap.

I have been looking at small, scale-aircraft brushless DC motors to make a gyro dampener, not a fully stable rig to take in light aircraft. These motors require a controller/power supply to make them work. These motors co-exist quite amicably with radio-control receivers so should not be too much of a problem with the full-size light aircraft systems.

The first thing a licenced aircraft maintenance engineer is going to say to you when you want to climb into his plane with your home-made is "you're not going to go anywhere near my compass with that thing are you." He will be even more agitated if the airframe includes tubular steel construction. If your motors magnetise the airframe, a particularly arduous and dark art known as de-gaussing has to be undertaken.

Small-appliance Makita motors have rpm but also put out a pretty savage magnetic field, like deviate an aircraft compass 15 degrees at two feet. Then there is the issue of RFI suppression. This motors have commutators and brushes.

AC induction motors are about the best. That what the Kenlabs gyros use. The brushless DC motors have some EMF but are more benign than the Makita appliance motors.

Paul Cascio December 30th, 2008 11:25 AM

Bob, do I understand correctly that you need four spinning wheels, 2 in the horizontal plane and two in the vertical?

Bob Hart December 30th, 2008 11:33 AM

Paul.

That's correct. As I understand it, the two gyro wheels face each other in the centre and the motors are at the ends of the "gas cylinder, but I could be wrong. I don't know if the two motors are geared together for sync. The Kenlabs motors are synchronised with AC and that may be enough. Geartrains. no matter how simple, add friction

Stills shooters generally only use one gyro (pair) when going airbourne, if they use one at all. One gyro lengthwise along the optical axis will dampen yaw and pitch movments if you are facing directly ahead. Roll movements (dutches) are not dampened. These do not matter so much as they are less un-natural to the eye.

This clip is a test with a purely passive stabliser like a mini steadycam. It was also a dead-end, steady but very squiirrely and uncontrollable when deliberate moves were attempted.

http://www.youtube.com/watch?v=cdMgD...e=channel_page

Giroud Francois December 30th, 2008 12:32 PM

you can easily build a gyro from an electric motor.
take a motor , about 2 inches diameter with roller bearing a both end of the axis.
dismantle the motor, get rid of all the inside, just keep the axis. (usually 1/4" diam.)
then you need to find a piece of steel you can fit on the axis and do some machining to get it perfectly round and balanced. reassemble the motor case.
then you just need to connect the axis of this gyro to another motor.
4000 to 5000 rpm is the minimum to get serious gyro effect.
old printer got a lot of these motors with very precise roller bearing.


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