Gyro Stabilization of a Camera

tigershark35

Hi.
I have a project that I want to gyro stabilize (at least on a heading - I will have a pan tilt on it) a camera.· I have read a lot on the net and here that I can use Model Helicopter gyros to do this. I could not really discern if I needed a "heading hold" gyro or other type. Anyone doing this. The robot or robotic camera will be suspended from a wire and I want the body not to spin or move while I move the tilt pan unit on the bottom.· Any help will be appreciated.·

JG

Tricky Nekro

You want to pan and tilt a camera right...

Why you need a gyro to stabilize your camera...

Is it mounted on something it rotates... If Yes then you need a Gyro...



If you have already a Stamp try this one from Analog Devices... (ADIS16250) It has a digital (binary) output so you don't need a ADC...



Provas, Greece

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bennettdan

You might try using one of these http://www.parallax.com/detail.asp?product_id=28017
to read your position then tell the pan and tilt table to move opposite of the move you read, that way your cam should stay close to the original position it started at compared to level ground. Example if you tilt 3 degrees to the left on say a hill then your cam can till 3 degrees to the right to stay level.

tigershark35

Thanks.

I was planning on having a separate servo for the "heading" hold and two servos that will operate the pan tilt. Since this will be suspended from a wire for the application, it is subject to some spin and I wanted to keep the body of the 'bot from turning. I would have the body with the gyro turning against the connection point of the tether to always hold one direction. One question is that I have seen two types of gyros, a "heading hold" and another and I wanted to know the difference.

Thanks again for the posts.

bennettdan

A heading hold if not mistaken is used on a helicoter that trims the speed of the rear tail rotor speed causing the heli to fly straight. this might not work for you·the gyro connects between the reciever and the servo to make correction not just total standalone control. Look for some gyros at towerhobbies.com and then look at the manuals on the gyros. You will have to have a sensativity adjustment output from the stamp to adjust its position and also it has a manual input from the reciever or stamp that lets you operate the servo directly. I still dont understand why you will need three servos for the pan and tilt though.

Post Edited (bennettdan) : 6/15/2006 2:30:30 AM GMT

tigershark35

Ok, thanks. I may have to try several things.·

Jim

bennettdan

Jim
I edited my post to you

Briefmark

Check SparkFun Electronics, http://www.sparkfun.com/commerce/product_info.php?products_id=393
·for their rate gyros.· These units produce a voltage dependant upon the angular rate at which they are rotated.·

Fred

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RinksCustoms

Just a quick correction to the helicopter posting, a gyro inline with a servo will usually only stabalize one axis, and on a copter with a tail motor his statement is true, but if it's the type with some kind of drive from the main rotors, then the gyro for the tail will control the pitch of the tail blades (a servo position instead of a motor speed).

And gyros for the most part will only stabilize direction alittle bit, if your looking to have the camera "lock" on a fixed position on say the ground, you will have to make use of the Parallax compass, and or the three axis accelerometer. Man, that's a cool idea, i'll have to try that sometime soon...

RinksCustoms

oh, BTW, why would you suspend the camera from a wire, if your using a helicopter this will create a pendulum effect, not to mention the twisting of the cable (and Camera).

tigershark35

Hi
I am not suspending from a helicopter. It would be from a wire on the side of a building or else where from a pretty much fixed point for inspection purposes. The unit would be subject to wind and proably spin. The gyro would be for spin. A reel and traverse mechanism at the top could be progammed to damp some swing in one dimenision - L and R.

JG

tigershark35

Hi
I am not suspending from a helicopter. It would be from a wire on the side of a building or else where from a pretty much fixed point for inspection purposes. The unit would be subject to wind and proably spin. The gyro would be for spin. A reel and traverse mechanism at the top could be progammed to damp some swing in one dimenision - L and R.

JG

bennettdan

I think using a pulley on your camera pedalum then run the wire through the pulley and attach one side to the frame then the other wind up on your winch setup that way it will be stable and not spin around. Bigger pulley the less spin.

RinksCustoms

oh, sorry, i see now, and please correct me if i'm wrong... you wish to use an existing wire attached to the building stretching across to another. If this is the case there are a few ways to stabilize the camera, Mechanically would be the easiest, but you could use an accelerometer in the bottom of your camera case to give a consistent baseline of movement to scale and integrate (modify the PWM) of the varous servos controlling your pan & tilt. The Mechanical solution would be to simply create a three ring (three axis) gyro and add counterweights to the bottom of the camera so that the camera stays oriented, the downside to the mechanical method is that your lubricant will get more viscous with lower temperatures, in any case, I hope i was of some use to you.

Other than R&D'ing this myself, i couldn't tell you what would really work best... Good luck.