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roll servo-divergent oscillation
- Thread starter Johnkerr
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Have you tried the alternate roll control mode bank mode? Per the 5.3 release notes:
Improved: An alternate set of autopilot control algorithms which may improve roll performance in some aircraft. To try this mode simply set TRN RT LMT to 0. The autopilot will more directly control bank angle instead of targeting a specific turn rate. The maximum bank angle that the autopilot allows continues is still limited by the BANK LIMIT parameter. In this mode, set the BANK ANGLE LIMIT to the maximum value you want the autopilot to use in a turn.
Improved: An alternate set of autopilot control algorithms which may improve roll performance in some aircraft. To try this mode simply set TRN RT LMT to 0. The autopilot will more directly control bank angle instead of targeting a specific turn rate. The maximum bank angle that the autopilot allows continues is still limited by the BANK LIMIT parameter. In this mode, set the BANK ANGLE LIMIT to the maximum value you want the autopilot to use in a turn.
Recalibrated EDC twice, with sensitivity setting at 10 heading varied 20 degrees left AND right. after stabilized hand flying and reengaging A/P the heading control degenerated again to the 20 degree swings.
With sensitivity setting at 25 heading about 10 degrees left and right.
It might be of some interest in the analysis that the A/P is installed in an RV9.
With sensitivity setting at 25 heading about 10 degrees left and right.
It might be of some interest in the analysis that the A/P is installed in an RV9.
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Do you have a GPS hooked up? If so, does it do it in all modes (HDG, TRK, NAV) , or only heading mode?
When flying by hand, is your magnetic heading on your EFIS correct at all headings and stable?
Also, did you try the flight with your turn rate limit set at zero, as mentioned above?
When flying by hand, is your magnetic heading on your EFIS correct at all headings and stable?
Also, did you try the flight with your turn rate limit set at zero, as mentioned above?
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What kind of aircraft is this? And when in 0 degree (roll control) mode, what is your bank angle limit set to?
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And, as asked before, does it work any differently in TRK and NAV modes than HDG mode?
Thought I'd chime in for what it's worth. I have a relatively new (March 2010) installation of D10A, HS34, and two servos all with the 5.3 software in an RV8A. The elevator moves less than 1 degree with the control stick locked neutral. I get the best response from both heading and alt hold with the sensitivities maxed out. Alt holds within about 10 feet comfortably in both smooth and rough air. But it does lose about 20 feet or so during the first 30 or 40 degrees of a long turn then gets it back. Hdg holds very well in smooth air but has some trouble in chop especially heading north and south where it (displayed heading) wanders plus or minus 5 degrees while the nose essentially stays straight. The autopilot slowly tracks towards the displayed heading, but since it wanders, everything averages out pretty well near the north or south heading. I have a vacuum driven HSI set up just underneath the D10A so I can see this happening clearly. The heading does not wander appreciably when you're pointed east/west even in rough air. I wish I could find someone who could give me a clue as to what I might do to fix this rather insignificant but infuriating problem. Or is this just as good as it gets? The Magnetometer is 4 inches in front of the aft bulkhead (where the static ports are on the RV8), and is aligned within one degree of the EFIS. There are two steel rudder cables within about a foot of the EDC10 but a compass moved around by hand shows no reaction. There are no power wires within 2 feet. The mag inclination and intensity are correct and I think the ground calibration is as good as it can be. What specific tests can I perform to verify an adequate installation. Is there an engineer willing to talk with me on the phone about this? Thanks in advance...Jack L.
By the way, GPSS works great in that the AP stays on track even with the heading wandering quietly all the time. I fly in AP comfortably IFR enroute but I don't think any heading/track mode is ready for WAAS/ILS final approach accuracy yet.
By the way, GPSS works great in that the AP stays on track even with the heading wandering quietly all the time. I fly in AP comfortably IFR enroute but I don't think any heading/track mode is ready for WAAS/ILS final approach accuracy yet.
The newly upgraded D10A is installed in a RV9. As answered in the previous post have been unable to sort out the solution to TRK and NAV, HDG is the only option showing in AP menus or HSI. Something I'm not getting and a different problem making troubleshooting the divergence more troublesome.
bank angle limit is set at 35 degrees but since setting turn rate to 0 the wallowing has stayed 10 degrees left or right. Have not been aware of Jack's North South East West anomaly but all of my test flights have been on north/south tracks. My EDC setup sounds similar to Jacks and has been calibrated 3 time in the past 72 hours with no change in flight characteristics.
bank angle limit is set at 35 degrees but since setting turn rate to 0 the wallowing has stayed 10 degrees left or right. Have not been aware of Jack's North South East West anomaly but all of my test flights have been on north/south tracks. My EDC setup sounds similar to Jacks and has been calibrated 3 time in the past 72 hours with no change in flight characteristics.
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For both of you - are you seeing any roll servo slips during the wallowing? As a reminder, you can tell if the servo is slipping if the mode indicator in the lower left highlights in yellow.
JackL: It sounds like your compass calibration may not be ideal - have you recalibrated AFTER putting in the correct inclination and intensity values? Those are only used during cal, so if you had an old cal from before intensity was used, and just added that value recently, your calibration may not be as good as it can be. Or, it could be that your EDC might be misbehaving. We could try swapping it if you run out of troubleshooting options on your end.
JackL: It sounds like your compass calibration may not be ideal - have you recalibrated AFTER putting in the correct inclination and intensity values? Those are only used during cal, so if you had an old cal from before intensity was used, and just added that value recently, your calibration may not be as good as it can be. Or, it could be that your EDC might be misbehaving. We could try swapping it if you run out of troubleshooting options on your end.
Thanks for that... To answer, first, I see servo slips fairly often in both alt and hdg/gts in choppy air with both servos set to 100% especially if there has been a serious jolt or something where a large correction order is sent. Second, I just redid the calibration prior to the last flight I made before writing that input. So I don't think I can do it any better. Taxiing straight ahead on the ground, my GPS track on the GNS 430, pretty much matches the heading on the D10A, and both even return the same runway heading going down centerline as published on the airport diagram detail on NACO charts. It's different in the air but very difficult to determine what is actually causing the heading disparaties. Today I was out in bumpy air heading south hand flying the airplane and I could lock the D10 heading fine. But when you turn on AP, heading wanders...today about 10 degrees. I may have been wrong yesterday. AP could be doing all the dirt. I'll keep trying to nail it down and keep you informed. Could be the magnetometer for that matter. Lets see what happens...Jack L
Sorry to be uncertain.
Sorry to be uncertain.
in test flights this weekend 2 areas of improvement were noted. E/W HDG's appeared to be more stable than N/S. Setting bank angle limit to 25 degrees while not eliminating the searching did reduce the oscillation.
an area of concern is that in dutch roll holding heading on target graphic seems to "run down hill". rolling left yields higher numbers, rolling right yields lower numbers before the actual turn is initiated. The remote compass has been calibrated numerous times. Intallation is in RV9 just ahead of bulkhead behind cargo bulkhead and was oriented utilizing digital level.
an area of concern is that in dutch roll holding heading on target graphic seems to "run down hill". rolling left yields higher numbers, rolling right yields lower numbers before the actual turn is initiated. The remote compass has been calibrated numerous times. Intallation is in RV9 just ahead of bulkhead behind cargo bulkhead and was oriented utilizing digital level.
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Let's focus on getting your GPS talking first to see if that flies normally. That will help us figure out if it's a heading-based issue.
gps problem apparently resolved; blue wire carries nessary data not the violet wire as shown in provided documentation.
test flight last week, successfully held numerous trk settings for approx 30 minutes then efis showed err/err and red DSAB flag appeared. Could not enter AP page "efis not bus master".
test flight last week, successfully held numerous trk settings for approx 30 minutes then efis showed err/err and red DSAB flag appeared. Could not enter AP page "efis not bus master".
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What is the full complement of Dynon products in your aircraft?
followed jakes suggestion to disconnected the disconnect wire. related are not did obtain off/off indication and flew with similar results. 30 minutes good lock. then as attempted hdg mode heading generally south course started to diverge turn to left noticed heading ribbon holding steady a/p locked up and could not reaccess. efis not master.
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Give us call when you have a chance at 425-402-0433 so we can help you a bit more personally.
jakej
Well-Known Member
DS
John has his EFIS 'locking up' as well - I have since discovered he has an internal battery AND keep alive connected. He will change that and report back the results.
Jake J
John has his EFIS 'locking up' as well - I have since discovered he has an internal battery AND keep alive connected. He will change that and report back the results.
Jake J