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Old Mar 07, 2014, 11:18 AM
I win again!! - mother gravity
Flying Pitcher's Avatar
Greenland, Qaasuitsup
Joined Apr 2013
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Idea
4axis gyro! collective controller.

hey, umm, is there a way to use an additional gyro to control collective if wind makes it go up...? i know 3axis controls pitch, roll, rudder...is there a way to run another gyro to control collective....?

i know it's kinda difficult, cos it'll have to run all three servos...any thoughts..? oh, and i know there are these fancy barometric control devices that control aLtitude. i'm wondering more if there's a way to run an additional gyro to make it work the "simple??" way?
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Old Mar 07, 2014, 11:47 AM
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Kauai
Joined Jan 2011
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Quads use Baro for altitude hold,most quad flight controllers can be setup for helis(at least some list heli settings).Gps altitude hold can vary +\-100 feet or more so not accurate enough.
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Old Mar 07, 2014, 11:50 AM
Cranky old fart
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Germantown, WI.
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I don't think you have thought this through. Just what would this additional gyro measure, that it could compensate? A 3 axis gyro already measures pitch, roll and yaw. There is no 4th axis. Accelerometers measure change in attitude, barometers measure change in altitude, magnetometers measure change in heading and GPS measures position. Without those "fancy barometric control devices" you have nothing to measure.
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Last edited by Balr14; Mar 07, 2014 at 11:56 AM.
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Old Mar 07, 2014, 03:54 PM
I win again!! - mother gravity
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Greenland, Qaasuitsup
Joined Apr 2013
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ok. i probably meant 3axis gyro with accelerometer on collective. by "4-th"axis, i meant it could modify or trim throttle.
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Old Mar 07, 2014, 10:16 PM
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It sounds reasonable. It would have to have an extra accelerometer I suppose, or maybe combine existing accelerometers. It's probably been done, but I've never heard of it.
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Old Mar 08, 2014, 10:30 AM
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United States, NJ, Manville
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I think you have to read what Barl said again....Maybe he confused you with the attitude thing.....I think the better way to say that a Accelerometer measures a given enertia on an object....A barometer measures air pressure which changes when altitude changes.....
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Old Mar 08, 2014, 11:19 AM
I win again!! - mother gravity
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Greenland, Qaasuitsup
Joined Apr 2013
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well, i'm not talking about total altitude hold, but rather keep those spikes from happening during gusts of wind where the accelerometer just trims collective a little to keep it from jumping up and down..

for example, 3axis gyro doesn't keep the bird completely steady in the wind, it still slides sorta around unless you probably put gps control or something fancy....3 axis gyro just keeps the bird manageable during windy conditions, i thought maybe it can be done with collective control as well
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Old Mar 08, 2014, 11:32 AM
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Quote:
Originally Posted by Flying Pitcher View Post
well, i'm not talking about total altitude hold, but rather keep those spikes from happening during gusts of wind where the accelerometer just trims collective a little to keep it from jumping up and down..
That's what I thought you meant also. There is probably a reason it is not done, probably issues with dampening collective or it's not really necessary.
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Old Mar 08, 2014, 11:43 AM
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Denver, CO
Joined Dec 2005
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A regular gyro needs rotation, so its out. An accelerometer would eventually get confused by having to track the motion, and by g-forces. So something else is needed.
A barometer, laser altimeter, optical devices, sonar, and GPS are things I know have been used. Sometimes a combination of devices, since each has its drawbacks.
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Old Mar 08, 2014, 12:20 PM
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United States, NJ, Manville
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Accelerometers and Gyros do not detect changes in altitude....GPS alone does nothing and needs feedback from satellites to measure altitude change.....A Barometer detects changes in air pressure which happens when an object changes altitude......The Naza H uses all 4 sensors...You can use 3 excluding GPS and still keep altitude.....They make chips with both Accelerometers and Gyros on the same chip so why not use that chip and a Barometer to be more accurate ?...
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Old Mar 08, 2014, 01:20 PM
I win again!! - mother gravity
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Greenland, Qaasuitsup
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alright i guess it's not gonna workwell, just thought i came up with something ingenious
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Old Mar 08, 2014, 02:03 PM
Cranky old fart
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Germantown, WI.
Joined Oct 2007
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Try the DJI Naza H. Or, buy a mulitWii flight controller board.
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Old Mar 08, 2014, 03:55 PM
I win again!! - mother gravity
Flying Pitcher's Avatar
Greenland, Qaasuitsup
Joined Apr 2013
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hehe, gotta love them prices. Balr, that stuff is really neat, but i don't want to put something like $400 "ghiga-maghiga" on a $300 heli

i'd rather put a little monkey on the heli to control collective than that
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Old Mar 08, 2014, 03:58 PM
Cranky old fart
Balr14's Avatar
Germantown, WI.
Joined Oct 2007
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A multiwii board with everything but GPS sells for about $50. But, it requires some fair mount of effort to use it. What you want has been done with these boards.
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Old Mar 09, 2014, 12:00 AM
postcounts are meaningless
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Joined Feb 2014
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Just took a drive to Astoria OR (right at the mouth of the columbia river and pacific ocean).
As we started down the hill into town, the Garmin said we 427 feet above sea level. I'm thinkin' that's about 200 feet too high, but not 100% sure. On the way home, at the top of the same hill, it said we were 42 feet BELOW sea level.
Gotta go with Kauaiguy
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