Altitude Hold severe jitter
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@Delta558 said in Altitude Hold severe jitter:
The quoted response was slightly misleading, in it's entirity what I said when asked was that I will have a look at the autopilot settings and see if there is something in there which is causing it. However, you have to be aware that the autopilot in the sim uses trim for control, and I will not be altering the trim settings in any way as it works and you are able to trim precisely with it at all speeds. As the altitude hold is there as a 'cheat', I will not prioritise that over fundamental flight dynamics for those who fly the aircraft as it is intended to be flown.
So let's hope it's something in the autopilot settings!
While I hear you that the plane doesn't have it IRL, the sim version does and was added as a highly desired convienenance, all the AP's (or most?) Use trim in MSFS successfully, so trying to blame it on that is a head scratcher.
It seems like an easy fix, maybe you're trying to hold too precise of an altitude or you just need to apply smoothing to the AP trim commands to even it out, but I know the community would appreciate it if.you could fix it, especially with the turbo arrow sales probably highly dependant on the state of the standard arrow when the turbo goes live.
I personally love the Arrow you have built, but the pitch thing is really bad, I wanted the turbo more than anything but AP is very useful if I need to do something real quick like pick up the baby, and the turbo will be even more of a cross country machine.
Edit: and yes I do want to agree JF arrow trims absolutely beautiful and it's a real treat to fly on my control loaded setup, I've spent considerable hours tuning the control loader for this airframe, aside from the horrendous cross wind takeoff roll problem sometimes I just like to do touch and gos and enjoy the flight dynamics.
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The following recommended changes to the AI.CFG file will smooth out the Heading Hold and Altitude Hold...
headingPID = 1.0, 0.01, 1.0, 0.2, 1.0
verticalSpeedPID = 1.0, 0.05, 0.2, 300.0,1000.0 -
Thank you RetiredMan. Unfortunately those changes did not sort out the jitters for me. I'm curious what those changes do but I'll mess with that later.
Anyway, it did lead me to look into it more. I found this page and pulled up the AP debug in the sim.
Long story short I made a change that has removed the jitters. I'll post the whole section, but it's the same as the G36, with a change from
pitchPID = 2.0, 0.1, 5.0, 1.0, 100.0 to
pitchPID = 2.0, 0.1, 2.0, 1.0, 100.0[STICKANDRUDDER]
rudderGroundPID = 0.015, 0.001, 0.001, 1.0, 1.0 ; Pk,Ik,Dk,I boundary, D boundary
throttleGroundPID = 1.0,0.10,10.0,10.0,20.0
brakeDifferentialPID = 0.0, 0.0,0.0,0.0, 0.0
throttleDifferentialPID = 0.0 ,0.0,0.0,0.0,0.0
throttlePID = 20.0,0.50,20.0,20.0,500.0
pitchPID = 2.0, 0.1, 2.0, 1.0, 100.0
rollPID = 1.2, 0.1, 0.6, 8.0, 100.0
headingPID = 2.0, 0.01, 1.2, 0.2, 1.0
verticalSpeedPID = 0.5, 0.01, 0.35, 300.0,1000.0
nav_ex1PID = 3.5, 0.1, 10.0, 0.035, 50.0
nav_yawPID = 0.015, 0.005, 0.001, 1.0, 360
glideSlopePID = 4.12, 0.05, 4.5, 2.0, 60.0
flightLevelPID = 100.0, 1.0, 10.0, 100.0, 1000.0 -
So after lots of testing and trial and error, I've got a pretty descent AP now. No swaying, no jittering, not overshooting the turns... not too badly anyway ;)
ai.cfg
[STICKANDRUDDER]
rudderGroundPID = 0.015, 0.001, 0.001, 1.0, 1.0 ; Pk,Ik,Dk,I boundary, D boundary
throttleGroundPID = 1.0,0.10,10.0,10.0,20.0
brakeDifferentialPID = 1.0, 0.001,10.0,1.0, 5.0
throttleDifferentialPID = 15.0 ,0.001,25.0,10.0,40.0
throttlePID = 20.0,0.50,20.0,20.0,500.0
pitchPID = 2.0, 0.1, 2.0, 1.0, 100.0
rollPID = 2.4, 0.3, 1.1, 8.0, 100.0
headingPID = 1.0, 0.01, 1.0, 0.2, 1.0
verticalSpeedPID = 1.0, 0.05, 0.2, 300.0,1000.0
nav_ex1PID = 4.50, 0.1, 10.0, 0.03, 50.0
nav_yawPID = 0.015, 0.01, 0.001, 1.0, 360
glideSlopePID = 4.12, 0.05, 4.5, 2.0, 60.0
flightLevelPID = 100.0, 1.0, 10.0, 100.0, 1000.0systems.cfg
[AUTOPILOT]
autopilot_available = 1
flight_director_available = 1
default_vertical_speed = 700.0
autothrottle_available = 0
pitch_takeoff_ga = 8.0
max_pitch = 15.0
max_pitch_acceleration = 0.5
max_pitch_velocity_lo_alt = 1.0
max_pitch_velocity_hi_alt = 0.8
max_pitch_velocity_lo_alt_breakpoint = 4000.0
max_pitch_velocity_hi_alt_breakpoint = 8000.0
max_bank = 20.0
max_bank_acceleration = 5
max_bank_velocity = 10
max_throttle_rate = 0.1
yaw_damper_gain = 1.5
pitch_use_trim = 1
altimeter_indicator = 2
default_pitch_mode = 0
default_bank_mode = 3
alt_mode_slot_index = 2
max_IAS_ref=185
min_IAS_ref=60 -
@weptburrito So far so good here, tried a few different cruise speeds at 7,000 MSL and looking significantly better. Do all the ai.cfg changes only change when computer is flying? any chance it can affect hand flight?
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@sluflyer06 to the best of my knowledge no, it shouldn’t affect hand flight. Just AP and I assume AI “copilot” flight is tied in there also.
I did do a test flight with the AI flying just to see what would happen. I was quite surprised it landed the plane. A little rough, but it was ok.
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@weptburrito said in Altitude Hold severe jitter:
@sluflyer06 to the best of my knowledge no, it shouldn’t affect hand flight. Just AP and I assume AI “copilot” flight is tied in there also.
I did do a test flight with the AI flying just to see what would happen. I was quite surprised it landed the plane. A little rough, but it was ok.
Thanks for posting this, your solution will be the necessary one for anyone wanting to fix the AP as JF has said they will not being looking into it, so it is what it is.
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@sluflyer06 said in Altitude Hold severe jitter:
JF has said they will not being looking into it, so it is what it is.
Not the case, if you'd actually read my post further up this thread in its entirety.
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@Delta558 said in Altitude Hold severe jitter:
@sluflyer06 said in Altitude Hold severe jitter:
JF has said they will not being looking into it, so it is what it is.
Not the case, if you'd actually read my post further up this thread in its entirety.
The response to my ticket from JF from a developer on your team said this issue is not being considered.
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@sluflyer06 and my original post in this thread stated that that was a miscommunication - Basically, if AP then yes but if base flight dynamics then no. As it appears to be AP, it will be looked at and dealt with.
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@Delta558 said in Altitude Hold severe jitter:
@sluflyer06 and my original post in this thread stated that that was a miscommunication - Basically, if AP then yes but if base flight dynamics then no. As it appears to be AP, it will be looked at and dealt with.
I mean I got the response just this morning, so after your post.
Thank you for your email.
If this is at the same time as using the built in ALT hold function, we are aware of this but at this time we will not be going back over this at this time as the real aircraft does not have one in it and the aircraft is just as capable of flying without the ALT hold by correctly trimming.
Kind regards -
@sluflyer06 Aah, right - okay, well there is work going on in the background (yaw, engine) and the AP section will be looked at as part of all that. No idea of timing, unfortunately - real world job at the moment has been throwing all sorts of obstacles in the way but I'm hoping to get most of these issues sorted so that the Turbo can benefit from a more smooth release.
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@Delta558 said in Altitude Hold severe jitter:
@sluflyer06 Aah, right - okay, well there is work going on in the background (yaw, engine) and the AP section will be looked at as part of all that. No idea of timing, unfortunately - real world job at the moment has been throwing all sorts of obstacles in the way but I'm hoping to get most of these issues sorted so that the Turbo can benefit from a more smooth release.
Ah ok cool, I mean, aircraft is good overall, the posted values do sort the AP behavior. Excited for the turbo IV.
your signature made me think you worked for Just Flight..no?
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@sluflyer06 yes, but that's not full time. 'Real world' involves shifts and can be quite demanding, the flight dynamics has to fit in around it and family.
