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Aerial Photography and Video > Gyro to stablize video
 
 
ben1000
Senior Heliman
Location: Gilbert, Arizona

My Posts This: Topic  Forum		Howdy...

Has anyone here tried to use a standard heli gyro to stablize a video setup?

If you attached a gyro to the servo that controlled the tilt of the camera, and mounted the servo on the tilt access of the camera, would the gyro compensate for pitch changes in the heli when you want to increase or decrease forward speed?

I'd like to be able to transition from a hover to slow forward flight without the camera tilting down with the heli. Maybe this would work.

And if it works well, perhaps you could use 2 gyros, and put the second one on the pan axis of the video camera. Perhaps this would be a cheap way of 'gyro-stablizing' your camera. If this works, the camera would stay locked on regardless of small changes in the hovering or forward flight of the camera.

What do you think?

Regards,

Ben
02-06-2002 Over year old.
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1UP
Key Veteran
Location: Claymont DE.

My Posts This: Topic  Forum		boy i never thort of that!! i use a slow servo speed and keep the heli in line. and for my big rig my wife work a sys. of it salf than of the heli.
let me know what happen after you spen the money to see if it work
james

JAMES
member of the HOT GIRLS thread?
If it's worth doing, then it's worth over doin
02-06-2002 Over year old.
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ben1000
Senior Heliman
Location: Gilbert, Arizona

My Posts This: Topic  Forum		Not that expensive

Howdy..

Considering that you can get a cheap gyro new for $60, or used for $20 (everyone's selling 'cuz they want to upgrade to HH), it shouldn't cost that much. I'm going to try it in a couple of weeks.

When you say you use a slow servo, what's the slowest you've found? I was thinking about buying one of those slowing circuits that people use for scale retracts.

Any thoughts?

B.
02-07-2002 Over year old.
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1UP
Key Veteran
Location: Claymont DE.

My Posts This: Topic  Forum		You don't need to !! just program it in the radio.. just set the rate real high
james

JAMES
member of the HOT GIRLS thread?
If it's worth doing, then it's worth over doin
02-07-2002 Over year old.
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Phil Cole
Veteran
Location: Redwood City CA

My Posts This: Topic  Forum		A standard gyro would damp the attitude changes, but not eliminate them, the same as a standard gyro does not completely hold the tail steady, just slows it down far enough for us mortals to keep up with the torque changes. E.g. if you were to pitch forward ten degrees, the gyro would pitch the platform back while you were pitching, but once the new attitude had stabilised and you're in steady forward flight, the feedback would stop, and the platform would slowly move to its inititial position relative to the main part of the heli. The gyro would smooth things out, impressing everyone with your gentle, smooth flying.

An HH gyro would do the job, provided it didn't drift too much. The GY240 would seem perfect for this application. You have to be careful to stay within the travel limit of the tilt servo (i.e. no loops) so the gyro didn't lose its hold reference. A remote gain with reset facility like the GY401/501/502/601 would allow you to re-level the camera as you get into position to start shooting.
02-07-2002 Over year old.
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ben1000
Senior Heliman
Location: Gilbert, Arizona

My Posts This: Topic  Forum		1UP

1UP -> Good suggestion, but as far as I understood, the 'rate' control on a radio doesn't actually effect how fast a servo moves, but rather changes how far the servo will throw...

For instance, if the full deflection of a servo is 100 degress, when you set the rates to 60%, the servo will only travel 60 degress.

What I need is way to slow the servo down, while still travelling all the way to 100 degrees. Is this what you had in mind?

Regards,

Ben
02-07-2002 Over year old.
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RC-CAM
Senior Heliman
Location: USA

My Posts This: Topic  Forum		Ben, the idea you have in mind will work with R/C gyros. A pair of good standard rate gyros and two FAST precision servos should do the trick. If you use heading hold, you will need to recal their level starting point during flight (a Tx toggle switch sort of thing while hovering).

This is not something that you can slap together and expect to work. The mechanical aspects will need to be carefully constructed. I think that it is best to decouple the servo from the articulated camera carriage using a belt drive, or else the gyro will sense servo motion as a yaw input. If not done properly, your carriage will motor-boat out of control (like tail wag on a heli).

Having said all that, my recommendation is for you to practice your hover to FF transitions. I believe that you will find that you will not need an elaborate gyro system to tame your pitching issue.

As far as slowing a servo down for camera work, the "PanCam" project is designed just for that application: http://www.rc-cam.com/projects.htm
02-07-2002 Over year old.
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1UP
Key Veteran
Location: Claymont DE.

My Posts This: Topic  Forum		hi mr. cr-cam !!! i love your web site i been going to it for ideals for a time now ! the pan-cam is nice work.. i see you been on since july but never tolking we love to hear what to have on your cam work
i know , i know, just got to your web site !!!
james

JAMES
member of the HOT GIRLS thread?
If it's worth doing, then it's worth over doin
02-07-2002 Over year old.
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Virtual1
Senior Heliman
Location: Waterloo, Iowa - USA

My Posts This: Topic  Forum		I've got a LONG way to go before I start installing a camera, but I have already thought a lot about it and came across the same idea, to use a pair of gyros. It would make sense to take it one step further if you have a few spare dials on your transmitter, to simply give it pan and tilt control via the dials, and attach the gyros through the servos in the same way you do the rudder. then just twist the dials a bit off center to rotate the camera to gain your center when ready to shoot. Not sure how many channels you have left available though after installing the camera... might be running too short to afford room for two more. Definitely go with heading-hold on the gyros tho. At that point, it might be better to get a 2nd receiver and transmitter, and have one person man the heli and the other man the camera control. That would make for some sweet videos if you could do some fly-by shots while panning (and maybe even zooming?) the camera, keeping a lock on the subject while going by. Definitely not a one-man-job though. A mushy (slow) servo might help there I think, so you don't have that stop-on-a-dime jerk when panning. Or get a good scale flyer manning the camera that's good at slowing down the action. ;-)

The other spiffy add-on would be a digital or mechanical no-shake on the camera, to eliminate vibration. I forget the common name for that feature, but it's really popular with camcorders. Not sure if that's available for regular cameras, something tells me a camcorder (even the newest lightweight digitals) would be a bit too much for a heli to easily lift. hehe...
02-19-2002 Over year old.
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MitchD
Senior Heliman
Location: Antioch TN USA

My Posts This: Topic  Forum		someone in virginia was building a platform that had 3 gyros on it and it worked very well,it was expensive(@15K for everything) but it did work........you could twist and move the machine all over and the cam stayed in position,very cool....
02-21-2002 Over year old.
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Rhandal
Heliman
Location: Santa Barbara, CA

My Posts This: Topic  Forum		Servo Speed

One way to control the travel speed of a servo is to remove the pot limiter on the servo itself. This will also give the servo an infinite rotation both direction. The speed of the rotation depends on how much stick you give to that servo.

I'm not going to get too technical on this but one way to do this is to remove the pot limiter and replace it with 2 resistors Another way is just remove or disable the part that rotates the pot in the servo gear. If your leaving the pot in, then you will have to center the pot and secure it. Each servo varies!

Now if you don't mind the infinite rotation which will give you a 360+ degree rotation both direction then this will work. I think that a cam mount capable of 360 degree pan/tilt/roll is cool.

remote-i
Remote Aerial Cinematography
03-12-2002 Over year old.
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RC-CAM
Senior Heliman
Location: USA

My Posts This: Topic  Forum		> The speed of the rotation depends on how much stick you
> give to that servo.

Some R/C servos that have had the continous rotation modification will try to run at full speed. Regulating speed is sometimes difficult, but using your Tx's ATV settings will help a lot.

Proportional speed is provided by the PanCam project. It offers proportional speed control without having to modify the servo for continuous rotation. It has other useful features too.
03-12-2002 Over year old.
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ELOSSAM
Veteran
Location: Es

My Posts This: Topic  Forum		Hi guys
I´m the latest one on the forum
I´m using a modified servo for 360º rotation and reducing the servo ATV to 10% right and 25 left (that helps to find the stop point) speed was also reduced a lot. Then depending on the stick amount you can do a normal travel from side to side or a fine tunning. For up&down I use an also modify servo to run 180º with a 1:2 reduction to have about 90º total travel that allows me to take vertical shots, 45º shots and a remaining to turn the camera quite up to cover the camera lens when take off or landing.
Ellosam
03-12-2002 Over year old.
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ed vega
Key Veteran
Location: nyc, queens

My Posts This: Topic  Forum		I think it will work, how are you isolating the gyro and camera unit from vibration ? -

check this out - the keyence little flying saucer has the right gyro for your project .. it's smaller and lighter, plus has three a point axis gyro .. strip it down to what you need and it'll be perfect ..


03-16-2002 Over year old.
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freestyle
Veteran
Location: Redmond WA USA

My Posts This: Topic  Forum		I have a little (tiny) bit of experience with Bergen's pan/tilt system, which uses 9202s modified for continuous rotation. Servo speed control was no problem at all - we used a second transmitter for the pan/tilt control, the Tx stick controlled the pan/tilt speed very smoothly, and it stayed centered just fine with the stick centered.

Then we tried adding gyros to the mix... With the gyro set to heading hold, the camera mount just oscillated no matter how low we set the gain. Even after tweaking the parameters inside the CSM-360 we were using, we never got the oscillations out. In theory it should work but in practice it appears that the gyro needs to be drastically retuned. My guess is that it's got to do with the reaction time of the feedback loop. The pan/tilt system responds very slowly compared to the tail rotor system. It might be do-able though, I'd like to hear from someone who has actually made it work with an HH gyro.
03-26-2002 Over year old.
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RC-CAM
Senior Heliman
Location: USA

My Posts This: Topic  Forum		> It might be do-able though, I'd like to hear from
> someone who has actually made it work with an HH gyro.

Nate, I had the same experience with a CSM360 equipped camera platform that I experimented with. I was able to tame most of the motorboating, but not enough to fully satisfy me.

Another fellow prototyped a stabilized camera mount using one of the new Futaba HH gyros with the latest SMM technology sensors. It did NOT oscillate (at least not on the bench). I don't think it was ever put in the air (the exercise was purely academic).

Your suspicians about the closed loop nature of the control system is correct -- pan and tilt systems are a tad different than a tail rotor. Nearly all of the gyro base camera platforms are using standard rate gyros. From the reports of of other RC-CAM'ers, the older mechanical ones work great and are preferred over a "better" piezo type. That does not mean that a solid state gyro won't work -- they just require MUCH more care to optimize in our application.
03-26-2002 Over year old.
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Rhandal
Heliman
Location: Santa Barbara, CA

My Posts This: Topic  Forum		Going back to regulating servo speed. We have modified many JR servos by simply removing the pot or permanently centering it and this will allow you to regulate the speed by how much stick you give. To slow it even more, you can remove travel on your radio to that servo. Again this will give you continues rotation, but it will allow you to regulate the speed depending on how much stick you give. The more stick you give, the faster the servo will rotate. It's a cheap and quick way of doing it. This works!

Rhandal
remote-i
03-29-2002 Over year old.
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rsilvers
Senior Heliman
Location: Marshfield, MA

My Posts This: Topic  Forum		What about a Canon image stablilized lens on an EOS Rebel? (for 35mm)
04-02-2002 Over year old.
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Byrun
Heliman
Location:

My Posts This: Topic  Forum		Found it.
Looks like there has been some discussion on particular topics some friends and I have been studying for the past couple of weeks.
This may get out of control!

I'm in the process of design for a self enclosed unit with a pan/tilt/roll mechanism. It would include battery, 3 servos, picovet hardware, all mounted to an aluminum platform, which in turn would have to be custom mounted to any specific application.

There are issues at present, one concerning weight, specifically, in the lowest profile design, the battery would be mounted ahead of the vertical plane of the camera/picovet hardware, along with the pan servo and chain drive. The camera would hang, (or be mounted upright), at the centre of the aircraft. That would be my Kadet.
Another concept is to shift the whole thing back from centre to compensate in that configuration, not sure if that's needed in Heli flying.

The second, is using 2 servos working in opposite direction for tilt control, which would also add a great deal of stability on the roll axis, but undesirable weight. Testing will be needed. (This could be easily added to my current design).

At present, the design concept has been (to name a few)

Lightweight (of course)

Self Contained (just bolt it on to your custom hardware mounts and go)
All accept video transmitter and reciever.

Three Axis Control (to keep photo centred in frame)

Low Profile (the smaller the better) At present this design's height is approximately 4.75" (pan configuration, bearing surfaces not remedied yet) with the camera'(s) pointing at the ground (landing position).

Low CG (majority of weight remains in the vertical plane), with heavier components closer to the centre of the aircraft (whatever it may be)

Stable (Design process is critical in order to prevent ANY resonant vibration) Without this the project is a failure, but I'm sure it can be overcome with the correct components. Some machining/foam/rubber mounts may be required.

Inexpensive (machined sufaces, servos, and gear boxes all cost money.)
By next week I will have more gizmos to play with for pan action.
32 pitch gears, 4 to 1 gear box, chain, servos (100 oz torque for my Kadet when it goes into a dive)
If anyone has any gizmos or ideas they would like to share in order to make this project a success, I would love to hear from them.
my email is
byrun@execulink.com

Love the gyro idea! I wonder if an old mechanical type would be sufficient? Maybe I should leave room for it on the mounting bracket?

http://community.webshots.com/album/34647102dqwVPs


Happy flyin'

Byrun
04-06-2002 Over year old.
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Optech
Key Veteran
Location: San Diego, CA.

My Posts This: Topic  Forum		I'm currently working on a Bergen Observer system. The servos are continuious rotation. What I did to manage servo rotation speed, was dial in 100% exponential. I also left the travel ATVs at 100%. This works very well. The rotation speed is very, very slow and precise at the first part of stick movement but if you need to slew faster simply move the stick full deflection. The amount of slew rate is proportional anywhere from stick center to full deflection. In other words, the more you move the stick from center, the faster the slew rate will get.

Mike

Viva La Airtronics!
06-01-2002 Over year old.
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