Virtuall flybar for AP applications?

[Angelos]

from everything I read about using gyro for stability, they actually think older rates gyro are better because they almost act like they have histerisis built in. the key is low gain on newer gyro. it is almost too sensitive I guess. sounds like a fun project.

Yes rate mode works best because the frybar is in effect gyro wheel mechanically mixed with the swash. All you do is replace the mechanical gyro with an electronic one. Using heading hold gyro will not give the same feel.

Weather was crappy here today so I'll try to get in the air tomorrow.

I am also waiting for some decent weather to test fly my latest project but has been around 30MHP winds all week. It is forecasted 7MHP for tomorrow early morning and I might get my chance. After several months of work, countless late nights and hundreds of hours of simulation it will go in the air for the first time.

-Angelos

[MarkWebber]

I am also waiting for some decent weather to test fly my latest project but has been around 30MHP winds all week. It is forecasted 7MHP for tomorrow early morning and I might get my chance. After several months of work, countless late nights and hundreds of hours of simulation it will go in the air for the first time.

Secret projects? Ah Ha! :shock: Gonna share? I did! :wink:

[MarkWebber]

Got 2 quick flights on it(won't quit raining for more than a few minutes).

First flight oscillations were a bit much. I dropped the gyro gain a bit but it was still oscillating. Rain started again :roll:

Just flew it again with gain cut back and some delay on the gyros. Oscillation is almost nonexistant now. I just started to get to the blade tracking when the rain started again. :roll:

Considering the blade tracking and intense vibe in the tx :oops: it did fly very well. I think I've got a bit much cyclic pitch on it. It's very lively. With the IR stabilization on it I think it would help dampen that. :oops: Cyclic response is nearly instant. I'm surprised more skilled 3D guys haven't done this already. I would think maneuvers would become more crisp.

Hopefully the weather this week will allow for some dialing in of the gyros and I'll get the stabilization going. Getting past the first flight gitters would help, too :D

[GGoodrum]

Yeah, Angelos, spill it! :D I'm guessing it is the inertial sensors for the AP-2000i.

Mark, what do you have the 401 gain set to right now? Can you get it low enough that it will be stable in an AP/AV configuration? I agree, the 3D guys will love the "crisp" cyclics, but that's kinda the opposite of what we are looking for, right? :)

-- Gary

[Angelos]

Mark,
If you notice on a stock (flybar equipped) Raptor, the swashplate travels up/down much larger distance that ball link of the blade grip. The mechanical mixer is made to scale down the pilots controls. Just like collective the pitch/roll will also be more sensitive and very likely this is why you need to lower the gyro gain so much. I suggest that you make the servo arms shorter to reduce the overall control.Increasing the delay on the GY401 should also help since cyclic response and the swash servos are slower than the tail counterparts.

-Angelos

[MarkWebber]

Flight 3 with 75% delay and 0% gain was much better. I was just thinking the same thing about the servo arms. Makes perfect sense. You can get a twitchy tail when the throw is too long.

In any case, even with my setup being off, it was still flying well. I got the tracking close and was about to try a few rolls when the rotten rain started up again. I'm thinking of offering my services in drought regions. Every time I take the heli out it rains again. :roll:

[GGoodrum]

He's still not spilling, is he... :D

Makes sense, regarding the throws, etc. I know on the Logos, using the V-Stab system, you need to move the balls on the servo arms in to the closest hole.

-- Gary

[MarkWebber]

I'm going to move the ail.and ele. to the inner holes. On the 3rd hole out, the servo can't be moving more that 15 degrees and that's with 10 degrees on the cyclic pitch throws. Doesn't take much movement to generate an oscillation with my current setup.

At least I know it's only going to get better! :D

[Angelos]

Yeah, Angelos, spill it!
He's still not spilling, is he...

The problem with spreading the news too soon is that you get hundreds of emails asking when they can buy it. However after today’s tremendous success I am too excited to keep it secret any more. Over the last few months I’ve been developing a competition grade tail gyro. The first flight turned out much better than we expected but my limited piloting skills did not allow me to push the gyro to its limits. I can do some basic stuff like flips, rolls, fast backwards flight and it performed flawlessly. It is amazing how the helicopter physics simulation matched the real life flight characteristics. Anyhow, in the next few weeks I will ask some experts to test fly it but I am confident we have achieved what we were aiming for.

Video: Solid tail in full pitch climb with Raptor 50. (3.1MB) http://www.spartan-rc.com/pub/rr_posts/Spartan_Gyro_Test_070114_1.wmv


http://www.spartan-rc.com/pub/rr_posts/spartan-gyro.jpg

[GGoodrum]

Very cool. :) What's the target price?

We need to get you electrified... ;)

[MarkWebber]

Bummer...would have been cooler to have 'em on my flybarless conversion rather than the 401s. Oh well, maybe I'll have some gently used 401s for sale shortly :D

[Angelos]

Very cool. Smile What's the target price?

It has to be competitive so we are aiming at 106-110 GBP (+VAT charged in Europe only).

-Angelos

[GJestico]

Heres a good way to test gyros , This will show the immediate difference between a 401 and 611 for example:

Go real (real) high into a stall turn and on the way down after some speed has been gathered directly vertical do a one turn slow piro. See if the piro ratation speed is consistent with the wind and against it.
Do piro flips and see if the piro rotation speed is consistent as power is pumped and released throughout the flip.

Greg

[Angelos]

Greg, you are absolutely right. To generalise, we are looking for constant angular velocity throughout a full turn…
1. With strong horizontal wind speed. (like fast flight)
2. With rapidly changing collective. (chaos/ piro flips)

We have a radio telemetry module linked to laptop and we can observe live data from helicopter as it spins. Even better our gyro can provide the angular velocity data when another gyro is in control… thus we can compare how ours is performing compared to the big names.

[MarkWebber]

thus we can compare how ours is performing compared to the big names

Ya gotta love that :D

[askman]

sounds like a cool gyro and project.


I have a question. I've seen several dual axis tilt sensors with accuracy of sub 1 degree with range of 60/-60 degree in the market. I would think it would make excellent heli levelling sensor. may be cost prohibitive right now, but probably not for long? :)

[Angelos]

Askman,
There is not major difference between the tilt sensors that I have seen and accelerometers. They are accelerometers in effect but they perform the cosine calculation on the sensor and give you a linear signal proportional to angle. However they are still susceptible to dynamic accelerations and thus they will also pick the movement of the helicopter, not just its angle.

-Angelos

[MarkWebber]

Here's how it looks so far. Don't pick apart the wiring. I'm waiting for a crimp tool and connector ends to show up.

I really like the look of the head w/o a flybar. :D

[MarkWebber]

Duplicate

[GGoodrum]

Mark, I love the head too, very simple! :)

Ugh, we need to get you electrified as well... :D


Angelos, this new little widget is very cool, but it now begs the question, can you combine this with the AP-2000i, or maybe an appreviated version with just the eCCPM mixer to do a V-Stab competitor? :) Also, will you use some form of this for the inertial sensor for the AP-2000i?

-- Gary

[Tonystott]

I can just see it now... Angelos releases the ultimate black box:- incorporating virtual fly-bar, head holding tail servo, flight stabilisation and altitude holding!

and it might not be so far-fetched at all :noteworthy

[GGoodrum]

I can just see it now... Angelos releases the ultimate black box:- incorporating virtual fly-bar, head holding tail servo, flight stabilisation and altitude holding!

and it might not be so far-fetched at all :noteworthy

Yep, that's where I was going as well! :D

[Angelos]

Angelos, this new little widget is very cool, but it now begs the question, can you combine this with the AP-2000i, or maybe an appreviated version with just the eCCPM mixer to do a V-Stab competitor? Smile Also, will you use some form of this for the inertial sensor for the AP-2000i?

This is definitely where this is heading. Also, I have made some provisions to use the gyro for a variety of other tasks which will be very interesting to the AP operators.

I can just see it now... Angelos releases the ultimate black box:- incorporating virtual fly-bar, head holding tail servo, flight stabilisation and altitude holding!

The ultimate RC black box is probably a natural evolution in the industry like other markets. Take mobile phones for example… they now come with mp3 player, digital camera etc. However in this hobby people like pick and match the best gyro with the best governor and the best flybar-less mixer. To be successful we need to be the ones who combine the best devices on the same box. So far I feel we have done a great job with the AP-2000i and the gyro will be no exception.

The possibility of interconnecting stand alone devices is also very interesting. For example the gyro has a communications port and when we develop a governor it will also have one. Thus the two devices can exchange information between them. The gyro can inform the governor when extra engine power will be needed for the tail rotor and the governor inform the gyro about changes in throttle (from TX curve or locally computed) which would result to changes in torque. So the gyro will be ready to compensate for these.

-Angelos

[MarkWebber]

Ugh, we need to get you electrified as well...

That's where I think I'm heading. Bergen E-Magnum, I should think...are you listening, Chris? :wink:

Besides, what better heli to chop up to try things out than my rappy? :D

[oscillator]

Hey Angelos,

for those of us playing with flybarless AP rigs now, what gyros would you recommend for pitch and roll? Of couse I'd love to use your gyros/black box if you want to send me some. :mrgreen: Oh, and get those AP2000i's in the mail to Webber so he can send me mine. :wink:

Mark Webber,

any more test flights after reducing the mechanical "gain"? I've seen some people keep the washout block and arms as a further mechanical reduction from the swash to the blades. Not as clean as reducing the servo arms, but if the inner hole is still too much gain it might be worth a try.