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HelicopterMain Discussion › Future rotor head control.
08-31-2009 06:43 AM  8 years agoPost 1
IYKIST

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London united kingdom

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I saw these today on youtube
A piezo motor servo
http://www.youtube.com/watch?v=BS3i...feature=related
and a spherical motor to work directly on the swash
http://www.youtube.com/watch?v=_O68...feature=channel

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08-31-2009 03:45 PM  8 years agoPost 2
Jlerch

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Parrish, Florida

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What on odd time in history we live in. I first heard about ultrasonic motors a few years ago, and I still don't profess I understand how they work, but its freaky.

James Lerch - Tampa Bay FL

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08-31-2009 06:11 PM  8 years agoPost 3
hanzuki

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London, Ontario-canada

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They vibrate really fast, thats how they work lol. But I wonder how they work under varying loads over a single movement being that for very brief moment there is no contact between the slide and the motor mechanism?

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09-02-2009 05:29 AM  8 years agoPost 4
Portblock

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Van Nuys, CA

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putting vibrating motors on a vibrating heli, is that like a drunk guy walking durring an earthquake? He walk straight?

The voices in my head can beat up the voices in your head.

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09-02-2009 07:29 AM  8 years agoPost 5
Taipan

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Sydney, Australia

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Portblock, we need Mythbusters to cover that!

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09-02-2009 09:04 AM  8 years agoPost 6
Yug

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UK. Herts

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Piezo motors use eigenmmode resonance. The technology is real close to what we need The principles of operation have been well established for many years and it's more a matter of throwing $$$ for development and use in our application.

We don't need servos or swashes as the piezo motors can directly operate the blade grips and be contained within the hub itself, or even the blades but I can't be bothered to get into that now. do a search.

Vegetable rights and Peace

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09-02-2009 10:13 AM  8 years agoPost 7
Sonic88

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Murfreesboro, TN

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That may be it Yug, it's more likely magic though.

Procrastinators of the world unite ... tomorrow.
AMA #: 912822

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09-02-2009 11:25 AM  8 years agoPost 8
xcell90

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Michigan

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Maybe I am missing some thing but did YUG forget the rotor head turns 1800RPM + ?

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09-02-2009 01:54 PM  8 years agoPost 9
Yug

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UK. Herts

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Maybe I am missing some thing but did YUG forget the rotor head turns 1800RPM
The piezo motors driving the grips will need to be relatively fast and powerful although they only need to move the grips by +/-25 degrees. I've looked into many mechanisms to drive the grips and a piezo drive seems to offer the best opportunity to achieve what is required. However, a substantial R&D investment would be necessary given currently available piezo technology (ie, Pi-line motors) is not quite there yet.
Incorporating piezo 'bender' technology into the blade itself is also a very attractive proposition whereby taking this to the nth degree, could control not only the pitch but actively control the aerodynamic profile for optimising on efficiency and performance. Crashes would be understandably more expensive though which places the idea of driving the grips in more favour.
One of the key points however, is that we can do away with all the head mechanics and servos although we would also require a controller and inductive power coupler but these can be relatively light weight and small. Many helis now use Vbar or similar, so it's just a case of replacing these existing items with new.
Hopefully, piezo drive for the TBs could also be implemented so we have NO MORE heavy servos.

Vegetable rights and Peace

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09-02-2009 05:37 PM  8 years agoPost 10
Jlerch

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Parrish, Florida

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Nice reply Yug, and how nice indeed it would be to get rid of all the rods and levers.

Something like this could almost be an aftermarket item. Pair of blade grips, controller, and a rotary power coupler.

Do the ultrasonic motors slip much?
If forced to slip, are they damaged?
Do we need a position encoder, or can the position be deciphered based on the resonance and the crystal shape?

James Lerch - Tampa Bay FL

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09-02-2009 11:53 PM  8 years agoPost 11
Yug

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UK. Herts

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Given these 'ere motors rely on friction, they can slip so a method of positional detection is required to provide feedback. They are successfully being employed for positioning in CNC type machines and other high precision movers. There are a number of topoligies in which piezos can work. One I like is the crawler, where you have 3 elements comprising 2 grippers and an extender.

There's some good info here.... http://www.physikinstrumente.com/

Vegetable rights and Peace

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