Highlander: Roll servo (help please)

[brs]

I've spent a couple of hours in flight working on the autopilot calibrations. The pitch servo was a no brainer but the roll servo has kept me occupied more than I would like.

The problem is getting rid of the overshoot while in TRK (and any others) mode. After talking to Mark (or was that Mike) at Dynon I started over with my calibrations going from a 'roll sensitivity' of 5 up past 20 in one step increments. I finally settled on 19 which seems to (almost) be the sweet spot. However I still have an unacceptable amount of hunting. If I poke the rudder occasionally it settles down but then starts up again.

I've checked for play in the system (though I want to do this again and double check) and have calibrated the compass. I'm not sure what to try next any ideas?

 

[davedubb]

We've seen this problem before on custom installations when the servo mounting bracket was allowed to flex. This causes induced oscillation in the system.

 

[Dynon]

A few questions: Are you using the Autopilot In-flight tuning guide? This is the number one thing to do if you're not already. It has a methodical method for going through the settings to dial things in.

Also, what is your roll gain setting? Have you adjusted that at all?

Finally, is there any meaningful "slop" in the linkages between the servo and the control surfaces (ie, can you move the servo arm without moving the control surfaces?)

 

[bobemery]

Hi
I have had the same problem.  The compass heading rolls past the actual heading when wings inclined, which the AP tries to chase.  Tried all sensitivity adjustments, just cant get it right. Zenith Zodiac 601 with D100
Any suggestions?

 

[Dynon]

Hi Bob - if you use TRK mode instead of HDG, does that change anything?

 

[wombat]

Not exactly on topic, but I am very interested as to how you installed the roll servo in the Highlander. I am planning an installation of Pitch and Roll servos in my Highlander. There doesn't appear to be a great deal of first hand information available.

Thanks for any help you could provide.