AP2000i parameter idea

[AZ ChopperCam]

Angelos... if you happen to read this I'd be very interested to hear your opinion.

I would like to see a stabilization delay adjustment on the AP2000i. Not gain delay as it already has but a delay in the control inputs it sends to the servos.

I am experiencing a wild oscillation on my Logo 24 if I go above about 55% gain. I am certain the reason for this is there is a delay between the time the AP corrects attitude and when the heli actually comes to level. If I ramp the gain up too high it gets into a harmonic oscillation that would certainly tear the heli apart. It get's really bad.

I'd wonder if there was a slight delay or phase adjustment or softening of the response near center to allow the gain to be ramped higher yet shift the control response outside of the harmonic frequency and not allow the oscillations to manifest.

I can only relate it to when I am trying to motion track an object in video post production software. If I have the motion tracker gain set too high the tracker point will begin to oscillate if the camera movement has some shake in it. If I apply 10 or 15% "jitter filter" to the tracker (that's what Autodesk Discreet calls it.. sorry if it's not the proper word) the motion of the tracker is smoothed out and tracks the object properly.

I could reduce oscillation of the tracker by reducing the gain but then the accuracy of the track suffers.

So could the same logic be applied to the AP2000i control loop to allow for higher gain values without fear of oscillation?

[MarkWebber]

DJ,

Wierd how there seem to be a select few heli's out there that will oscillate like that. I wonder what variable causes this.

Your idea seems like something Angelos could add. I might suggest posting this in their support page. I haven't seen Angelos on the forums much recently. I think they are hard at work with the new gyro which should be coming out soon.
http://www.spartan-rc.com/support/ttx.cgi[/url]

[rroback]

I've got the same issue with my maxi joker. I found that the heli can fly decent with gain from 20-30 percent, but the big issue is that if I touch the stick, to make a correction, then it has a huge wobble, until I release the stick. It's as if the ap2000 is increasing my control throw... any ideas?

Rhett

[MarkWebber]

Where do you have your rates set on the AP2000i? That might do it. I just set one up on my Trex 600 and had the pitch rate too high and the throw was way too much. Very touchy on the stick. I'm lucky I didn't drive it into the ground.

Note to self...always start with a fresh model program or you might miss something. :roll:

[Piton]

I just got back from flying today in 80 degree temps, 15mph wind, and sunny skies.

Perhaps off topic, but I've had the best luck flying vid so far with very low gain settings. Today I was using about 15% and it seemed about right. If I went higher than 30%, flying was unpleasant and "shakey".

Disclaimer:I have only flown 6 times with the AP2k

[rerazor]

My stretched Mini Joker (710mm) oscillates like crazy with anything over 30-40%. On my stretched eRaptor never had the problem. :dontknow

[MarkWebber]

I'd love to know what your tx and AP2000i settings are for those having oscillation problems. I've put one on 3 of my heli's so far and none have oscillated at any gain. There must be something behind this occurance and I'm curious to know what it might be.

[AZ ChopperCam]

ok.. check this out

I just finished a new stretched Logo 24. took it out for a test flight today. Anything over about 30% and it oscillates like mad. it has 710mm blades.

I pulled the 710's and put on 620's. Took it up and ran the gain up to 100% with no oscillations.

So that makes 4 helicopters that I've owned with 710mm blades that oscillates (Joker CX, Stretched Raptor and two Logo 24's)

Smaller bladed helicopters seem to not have the oscillation problem. I really think it's because larger ships cyclic response rate is slower and the AP is working at too fast a rate for the big ships. I think the AP control timing falls within a harmonic range that sets these bigger ships in motion. I think if we had a way to dial in a bit of delay we'd see this problem go away. I know there are some guys running gassers with the AP and I'd be curious to see how high they are able to run their gain.

I've sent an email to Spartan so we'll see if Angelos gets it and understands what I meant.

[CoastalTom]

No oscillation problem with my JR gasser running 800m NHPs and the AP2000i. I've run the gain up to 100% but usually use it at around 50%.

[MarkWebber]

Intrepid EB with 810mm V's and no issues at 100% other than, like Tommy, I usually fly lower than that.

Interesting theory, DJ. When you've switched between blades, do you notice a change in the responsiveness to your inputs? I would think it's opposite what you're suggesting. Maybe since the heli was designed for smaller blades, once you put the larger blades on it now has too much cyclic throw for the increased potential lift changes? Maybe moving the servo balls in on the links would act to slow down the cyclic response? Basically, that is what I had to do on my flybarless conversion to reduce the tendancy to oscillate.

[ssozonoff]

Hi,

I have not problems on my Maxi Joker 2 running 800's either and I have flown at 65% gain on the AP2000i.

Serge

[AZ ChopperCam]

ok here's what I've done to reduce the oscillations with the long blades.

I reduced the elev and ail travel on the AP menu down to about 20%. I then made sure that the TX travel values were at 100%.

Before this I had the AP values at about 50% and I had the TX at around 80% to reduce the travel to the proper amount. Flipping it around helped alot. I Still can't use 100% gain but I get to about 60% now with pretty good stabilization

[dreslism]

Makes sense.

You're actually stabilizing over the travel needed for your heli instead of unused travel.

I would think that this would make your stabilization smoother also since it now knows about the reduced travel and will not have to try to adjust too much like it did before?

By smoother stabilization I mean if you were shooting video and doing FF, if you gave a little right cyclic to nudge your heli, and then let go of the stick, it would not jerk back so fast since your travel is reduced now.

Let us know if notice any difference. I never dropped my travel on my ap2000i, and I think my Tx is still at 100%.

[MarkWebber]

This is exactly why you should do all adjustments in the AP2000i. Scott hit it right on the money. If you set endpoints or reduced rates in your tx, you will have reduced control but the stabilization will be able to overdrive the controls. That's why I was wondering what the tx and AP2000i settings were for those experiencing the oscillations.

[rerazor]

Checked my settings tonight and my Tx was at 100% and the APi at 50%.

I'm going to drop the Elv/Ale to 20% on the APi and try tomorrow.

I just need the altitude hold sensor now????? :dontknow :dontknow :arggg: :arggg:

[AZ ChopperCam]

I just need the altitude hold sensor now?????

yeah... you and about 100 other AP2000i fliers!

I'm at the point now where I'd pay Angelos a hefty bribe to be able to have that feature

[dreslism]

I just need the altitude hold sensor now?????

yeah... you and about 100 other AP2000i fliers!

I'm at the point now where I'd pay Angelos a hefty bribe to be able to have that feature

Sweet. You pay the bribe, and we'll back you that it is absolutely needed.

Sounds win win to me! :D

[rerazor]

I think from checking the swash movement at 20% that I might need to make it higher. It just doesn't look like the swash is moving that much and that has me a little concern. Maybe I will try a quick test hop in the morning and see how responsive it is and adjust accordingly.

[MarkWebber]

Depending on the heli, you don't generally need as much as they normally call for. That's for the 3D guys. When I switched my R50 to flybarless, the scale guys told me to go with 7 or 8 degrees cyclic and the swash barely moves at that setting.

[rerazor]

20% Ali/elv. settings resulted in no oscillation at 100% gain. I guess I will adjust the travel a little higher until I get oscillation at 100% gain.