Does anyone know what might cause the plane (Skywalker 2014 with pixhawk, 3dr gps/compass) to always fly to the right of the waypoints? This results in my planned flight lines being alternately too close, then too far, apart (see attached .jpg). This happens every flight, regardless of wind speed or direction; flying crosswind, or parallel. First flight line starts NE corner.
What does your cross track error show? Is it think it’s centered on track?
The cross-track error always shows 1/2 to 2/3 of a gradation to the right of center.
I’ve checked aileron and rudder trim – plane flies straight/no side-slip in manual, and I used TRIM_AUTO to transfer these trim values to auto mode.
The wind is from the south. For E->W lines, the plane banks left, and yaws left about 10-15 degrees into the crosswind – as expected. BUT For W->E lines, the plane is still banking left! It compensates by yawing 30 degrees right to maintain the desired heading. That makes no sense to me.
Hi mapper905,
This information might help you:
plane.ardupilot.com/wiki/navigation-tuning/
Note: This is more a plane software question, moved to the right subforum.
Have you tuned the Yaw yet? Could it be related to torque? Does the same thing occur in a descent with throttle off?
Build a plan with a climb and descent and see if it changes. If so, tuning the yaw should solve the problem.
I’m having the exact same issue, my Skywalker with AP 3.03 flies to its right of every waypoint about 8 or 10 meters.
Where is the cross track error located? Is it a parameter or something that is logged?
[quote=“pdonovan”]I’m having the exact same issue, my Skywalker with AP 3.03 flies to its right of every waypoint about 8 or 10 meters.
Where is the cross track error located? Is it a parameter or something that is logged?[/quote]
Upper left hand corner of the HUD.
I have the same problem.
Using Arduplane 3.0.1 and MP 1.2.99 we first had several good testflights and a mapping mission with accurate results.
upload.droneshare.com/view/bmyvoby
Then during another long flight in an area 600km north of the original place, the above described problem occured. The flighpath was always 30-40m right (starboard) of the planned flightline.
We did not changed any params between the two flights.
I experienced this too today. It was only about 5m offset, but it was consistently right of coarse the entire lawnmower mission. Just like the examples above, it is always to the right, irregardless of the direction of the wind.
I’ve never seen this behavior before.
APM 3.03
Remo,
The reason is your roll is offset from the demanded roll during auto which indicates your RC calibration is not correct.
Paul
[quote=“Remo Peduzzi”]I have the same problem.
Using Arduplane 3.0.1 and MP 1.2.99 we first had several good testflights and a mapping mission with accurate results.
upload.droneshare.com/view/bmyvoby
Then during another long flight in an area 600km north of the original place, the above described problem occured. The flighpath was always 30-40m right (starboard) of the planned flightline.
We did not changed any params between the two flights.
[quote=“priseborough”]Remo,
The reason is your roll is offset from the demanded roll during auto which indicates your RC calibration is not correct.
Paul quote]
Paul,
Could you take a look at Mapper905’s case? He was the original poster and stated that he used autotrim.
Thank you
Could it be related to magnetic declination? 600km is a big distance, declination could be different on that place, depending on the direction of your trip.
This is definately caused by the torque of the big prop on the 2014 Skywalker. This causes the plane to fly in a constant left bank of about 5-10 degrees. The is in combination with right rudder, causing the plane to fly in a slip. This is confirmed by positive lateral acceleration “ay”. If I bring the throttle to idle I see ay get close to zero, and at max throttle ay is around 380 units.
I turned on the Sideslip Controller YAW2SRV_INT and YAW2SRV_SLIP. This helped a lot, but I still have some Sideslip occurring with throttle.
My Skywalker 2014 with a 9 x 6 prop and APM 3.03 is still flying to its right of waypoints. On auto-takeoff it slowly veers right of its initial course too.
Where do I find “ay” in my logs (I’m not using telemetry)? And what exactly is the cross track error?
I will try enabling YAW2SRV_INT and YAW2SRV_SLIP.
YAW2SRV_INT and YAW2SRV_SLIP are now both 1. Skywalker still flies somewhat to the right of waypoints, but it’s somewhat improved. NAVL1_PERIOD is 20.
That L1 could be a lot tighter. I’m using 12.
[quote=“iskess”]This is definately caused by the torque of the big prop on the 2014 Skywalker. This causes the plane to fly in a constant left bank of about 5-10 degrees. The is in combination with right rudder, causing the plane to fly in a slip. This is confirmed by positive lateral acceleration “ay”. If I bring the throttle to idle I see ay get close to zero, and at max throttle ay is around 380 units.
I turned on the Sideslip Controller YAW2SRV_INT and YAW2SRV_SLIP. This helped a lot, but I still have some Sideslip occurring with throttle.[/quote]
My plane is flying very straight now with the sideslip controller on.
If this were my thread i could mark it solved.
As Paul indicates, the plane is definitely flying side-slipped – left wing down, right rudder to compensate. Paul suggested re-trimming. I’ve neutralized the rudder trim and added so much right aileron trim that in manual the plane flies circles to the RIGHT. I used auto trim to pass those settings to the autopilot, but in auto mode the plane is STILL banked left, flying right of flight lines! Trim doesn’t solve the problem.
Iam: I did turn on the side slip controller – no effect I could see. I keep wondering if it’s tuning, but doesn’t the tuning simply affect how fast the plane stabilizes – for a long flight line, shouldn’t it eventually settle onto the programmed line, even if my tuning is not optimal?
Paul: Maybe a dumb question, but the autopilot knows where the intended flight line is — what’s preventing the autopilot from flying the flight line?
Pdonovan: Did you ever resolve your issue?
Thanks to anybody who can shed some light!
One last comment about proper trimming – since the original post, I DID see some improvement, which may be from adjustments to aileron trim. I’m now down to 5-10 meters of cross track error, always to the right, but I seem to have hit a wall there–I think I’ve obtained all the benefit from that adjustment possible.
Tuning is very important. The “I” acts like auto trim and makes corrections over time. Have you tried autotune?