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HelicopterAerial Photography and Video › IMU for stabilization
12-23-2008 06:18 PM  8 years agoPost 81
cblake144

rrNovice

Swansea, Ma USA

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future features

Hi George,

had a couple ideas for features. i remember the vision lock had park function you could activate with an rc switch. actually would be more better if you could activate it at a programed pwm from a free channel.

the other idea would be to have an output (perhaps analog) that could work with OSD,s like eagletree or http://www.gentles.ltd.uk/gentvu/index.htm this one. i use gentlted right now and have my mag heading and alt overlaid. could be very cool as an attitude indicator for fpv but im sure you already thought of that.

another cool osd if you havent already seen it

http://www.rangevideo.com/index.php...25d135c978529cf

chris

Chris Blake

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12-23-2008 08:41 PM  8 years agoPost 82
cblake144

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Swansea, Ma USA

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seen this?

http://www.xsens.com/en/products/human_motion/mtx.php

could you do all 3 axis with it? don't know the price

Chris Blake

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12-23-2008 11:09 PM  8 years agoPost 83
GeorgeM

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Europe

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Hi Chris,

I am aware of that module, and many others like it that combine accel, gyro, and mag. Price is the only issue. They ARE expensive.

BTW.. Regarding your mention for the sail winch servo:

I think it's an unfavorable use of that servo in this application.
The resolution you're likely to get is very low, since the 180 degree travel of a normal servo is spread over 3.5 turns, therefore a loss of 7 times the resolution.
For best stabilization, you firstly need accuracy, then speed.

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12-28-2008 01:38 PM  8 years agoPost 84
cblake144

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Swansea, Ma USA

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hi George,

i hear what you are saying what you are doing more than meets my requirements. I plan to stabiliz yaw with an idea i think you floated a while back. i plan to use two variable pitch props(tail rotors)on opposite sides of the yaw axis with the hh gyro.these gyros work fine as they were intended and the drift is not such a big deal as i have the compass heading overlayed on my video. i use a balloon so im just curious but have you tried your imu's on a heli to stabilze pitch and roll of the ship itself? how about a plane? I look forward to trying one of these.

Chris

Chris Blake

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12-28-2008 01:47 PM  8 years agoPost 85
cblake144

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Swansea, Ma USA

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sail servo

hi George,

would what you said about the resolution of the sail servo apply if the rol axis only moved 90 degrees for the 3.5 turns of the sail servo? my roll axis will be a circle riding inside another circle that will be in my blimp or balloon tether(tether wraps around the outer circle and exits top and bottom.) a the inner circle will be driven by a belt with a cog on the servo attached to the outer. even with a large cog i get a large gear reduction. the other way i could do it is use an expernal 10 turn pot from digikey and a fast digital servo. i like to know what you think about this.

Thanks
Chris

Chris Blake

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12-28-2008 02:35 PM  8 years agoPost 86
GeorgeM

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Europe

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>>plan to stabilize yaw with an idea i think you floated a while back<<

Gee...!!! I remember that !!!!
I think that was mentioned by others as well. Possibly, that sparked many ideas...

Back to topic.

A'normal' servo is designed to 90º max travel ( more if you have tweaked the insides of it or geared it up on your mount)

The more you extend the max travel, you'll notice sluggishness in movement, and inaccurate stopping (possibly overshooting).

If you plan to use your sail servo for the roll, I'd limit the roll range from +90º : 0 : -90º or half a complete rotation with center being what the camera sees as a normal upright image.
You leave latitude for left and right compensation to movement.

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01-20-2009 03:01 AM  8 years agoPost 87
aramsdell

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Sanford, Maine

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George, Will this work with the AP200I to keep the heli level???

I had been thinking, and tried to implement, a simple gyro / mixer circuit to keep my heli level. The problem I came across was differeing frame rate from the gyro out and from the Rx out. Caused a twitching.
The Idea was 2 gyros that were initialized on the ground. They then mixed with a rx channel for the same control, ie ail. or elev., The gyro inputs both connected to a common centered spare channel. The gain to both on a switch to turn them off or recal in the air.( needed in case of extreme angular change, move a HH gyro too far and it locks in at a diferent angle) The mixer took say aileron and mixed it with the gyro output that way I would be able to overide the gyro signal and fly around then release control to the gyro. Kinda like the AP2000i with IR sensor.
As I said it had a twitching problem. You I am sure could implement this .

Should've bought a sim. Got a bucket of used blades!

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01-20-2009 10:15 AM  8 years agoPost 88
GeorgeM

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Europe

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Hi Aramsdell,

I understand what you were trying to do, and understand why your problem happens.

I do not own an AP2000i, and therefore cannot comment whether it will work or not.

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01-20-2009 04:37 PM  8 years agoPost 89
just4fun2

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torrance

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how much if you don't use cheaper parts? $300 people will buy that now!

when will your head tracker come out? looking forward to testing it....

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01-21-2009 01:50 AM  8 years agoPost 90
aramsdell

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Sanford, Maine

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Hi George, I didn't have this attached to my AP2000i. The 'mixer' is actually just that, a V-Tail mixer. Just what is in the picture in the link below. My idea is supposed to be suitable for a mechanical mix swash or as input to a mixer such as the AP2000i that changes it to CCPM. I couldn't find my original drawing. I redrew the one in the link, really quick, and it pretty much sums up what I was trying to do.
Gyro gets a 1.5 us pulse for a false center. Initialize the gyro on the ground. If aileron then tilt heli enough to counteract torque. Gain is from none up to some % of Heading Hold. A Futaba 401 at no gain(no rate, no HH) passes it's input through I believe. When switched into HH it assumes the current angular position as it's heading.
If the gyro travel is kept low then the channel (aileron or elevator) it mixes with can override the gyro ouput enough to maneuver the heli. If a gyro like this is turned more than approx 45 degrees?? then the gyro assumes a new angle for HH. Just guessing but I think it's about = to the amount turned -45 degrees. That's like the helis tail blowing out. The gyro doesn't lock back in on the original heading. This would mean don't tip in any given direction too much! Then you would want to turn off the gain until you level the heli well.

The AP2000i works, in the air, basically the same as my circuit(is supposed to). The pilot has to fight the gain on the AP2000i . The more gain the more you must push the sticks to move the heli.n You can fly around and let go of the sticks. On a good day... which is why I started with this idea. Stray IR from a building or hillside or road or THE SUN on the horizon or cold from lots of snow can really confuse the IR sensor. Try my idea if you like and let me know what you think .

PS I'll want 2. Ha !

Al Ramsdell

http://www.maineaerialphotography.n...o_and_Mixer.jpg

Should've bought a sim. Got a bucket of used blades!

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01-21-2009 05:19 PM  8 years agoPost 91
GeorgeM

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Europe

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Hi Aramsdell,

Sadly, that system as in your sketch won't work for too long.
HH mode will slowly drift the gyro to full travel L or R.
In fact that mixer is already built in the gyro as it gets control from the channel. However you have control on the output of the gyro.
As in your sketch, you'll be fighting all stick to try to keep heli level in no time.


With IMU, the mixer is already built in. IMU does not drift. It knows where gravity is.
Still some more testing before release !!

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01-21-2009 07:34 PM  8 years agoPost 92
U.S.U.L

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Poland

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The latest option I implemented is to have an option to choose the operation of the built in mixer in either slew or direct position control.

Still some more testing before release !!
Good work my friend. We are all waiting eagerly

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01-22-2009 03:45 AM  8 years agoPost 93
aramsdell

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Sanford, Maine

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Hi George, The drift free part is where your IMU comes in. Seems like that is what you have already though so ship Two to me and I will make sure the rest of these guys hear how good it is !

I make a good tester. I did the Beta testing for the Canon G9 with the CamRemote Shutter/zoom controller for Linnar Edesi in Finland. That's a nice alternative to The BLIP switch, which I also have.

Should've bought a sim. Got a bucket of used blades!

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01-22-2009 08:58 AM  8 years agoPost 94
Flightlutions

rrApprentice

NYC

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Count me in

George,

Count me in if this will work with the 3 axis Copterworks Mount.

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01-22-2009 04:07 PM  8 years agoPost 95
GeorgeM

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Europe

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>> Count me in if this will work with the 3 axis Copterworks Mount. <<

Of Course it does !!!

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01-31-2009 08:46 PM  8 years agoPost 96
bobtitus

rrNovice

France

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Hello George,

trying to keep updated, when will you sell your system?
Shipping to France?
Thanks

Smile... tomorrow will be worse.

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02-01-2009 10:18 PM  8 years agoPost 97
GeorgeM

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Europe

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Yes. Might be shipping soon.

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02-01-2009 10:39 PM  8 years agoPost 98
GeorgeM

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Europe

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Here's a sort of cheap'n dirty demo of what it can do.. Some new features have been added to the unit. Well worth the extra wait !!!

Wish my mounts looked a little bit on the good side.... !!! That's one of my poor old 3 axis testbeds (sans le... roll and tilt )

The IMU can now also drive open loop servos without the need for feedback pots !!! The IMU is sitting on the axis that is being thrown around !!!
Noticeable is how accurately it returns to its original position after all that jazz that I'm throwing at it.....no shudder when it stops, and its stays there without drifting even after many cups of coffee..

Watch at YouTube

Enjoy...

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02-01-2009 10:40 PM  8 years agoPost 99
daytonabeach

rrElite Veteran

Oslo, Norway

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George, where?

Never argue with an idiot, he'll drag you down to his level and beat you with experience...

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02-01-2009 10:53 PM  8 years agoPost 100
bobtitus

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France

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Great job George!

Smile... tomorrow will be worse.

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HelicopterAerial Photography and Video › IMU for stabilization
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