Re: GPS assist and Heli
« Reply #30 on: November 20, 2017, 04:48:05 pm »
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Fly a quad in Attitude mode for a long time in a straight line using forward pitch stick (like flying 2km FPV).  After a while, you must add more and more pitch to keep it flying forward.
In my opinion this situation do not cause any issues.

I'm just saying that there should be an option to allow it to heading only or 3D mag with the new INS13 ... if there is not currently an option.

If I understand Basic AttiEstAlgo...

I know that most advanced FPV fliers don't use Attitude mode, but beginners do.  This would also be an issue when hovering in a constant wind for a long time (with the same compass heading).  You need more and more stick to counteract the wind.  That's not right.

It seems to me that needing more and more stick (or a similar issue that comes from flying continuous coordinated circles) is wrong (I know it's hard to fight this issue) ... and that always needing the same amount of stick to get the same bank angle is right.  And if my understanding is correct, then an INS13 with a 3D mag will be better at doing this correctly than an INS13 with a heading only mag.

f5soh

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Re: GPS assist and Heli
« Reply #31 on: November 20, 2017, 05:13:26 pm »
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This would also be an issue when hovering in a constant wind for a long time (with the same compass heading).  You need more and more stick to counteract the wind.  That's not right.
Flying in a constant wind changes nothing to the Attitude estimation, simply need bank angle or more bank angle than expected if moving for a multirotor. There is no issue here.
Put your quad in a car and go to the highway, run at stabilized speed for 10km. Is the Attitude (complementary) wrong after a while ?

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It seems to me that needing more and more stick (or a similar issue that comes from flying continuous coordinated circles) is wrong (I know it's hard to fight this issue) ...
You can easily reproduce the issue with complementary, attach your quad to a 3m rope and do turns around you for some time.
A carousel for kids can be used as well.

karla

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Re: GPS assist and Heli
« Reply #32 on: November 21, 2017, 07:10:42 am »
Maybe you are trying to arm while the flightmode switch is one GPS/GPSAssisted mode ?
You must choose one flightmode with only primary stabilization for arming.

Nope, I use mode stab5 and stab4 got the GPS assist.
Any other possible reason?

f5soh

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Re: GPS assist and Heli
« Reply #33 on: November 21, 2017, 08:56:34 am »
Maybe remove CruizeControl in Stab4

You should do testing in this order:
- basic AltitudeVario
- PosHold
- VelocityRoam and others modes
- GpsAssist

GPSAssist is the latest step and can be properly enabled Heli at end.

karla

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Re: GPS assist and Heli
« Reply #34 on: November 21, 2017, 09:04:20 am »
Thanks.
I will try it in that order.
I have tried with all possible combinations for the thrust setting on stab4
- no change, same error.
Will take me a while to get to GPS assist it seems :) so no hurry

Re: GPS assist and Heli
« Reply #35 on: November 21, 2017, 10:42:02 am »
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This would also be an issue when hovering in a constant wind for a long time (with the same compass heading).  You need more and more stick to counteract the wind.  That's not right.
Flying in a constant wind changes nothing to the Attitude estimation, simply need bank angle or more bank angle than expected if moving for a multirotor. There is no issue here.
Put your quad in a car and go to the highway, run at stabilized speed for 10km. Is the Attitude (complementary) wrong after a while ?

Attitude mode: Hovering in wind in one place at same heading is exactly the same as flying in a straight line for the same length of time, so it is not just FPV that has this issue.  Hovering in the wind would need more and more stick the same way as a long straight flight with no turns.  This is also the same issue as using transmitter trims (instead of Rotate Virtual) to adjust level Attitude mode hover.

This of course assumes I am correct about how Attitude mode works.

f5soh

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Re: GPS assist and Heli
« Reply #36 on: November 21, 2017, 06:19:15 pm »
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Hovering in the wind would need more and more stick the same way as a long straight flight with no turns.
Still no issue.

Why more and more stick input ?
What's the limit ?
There is a point where you cannot counteract the wind due to a limited attitude response ?

Re: GPS assist and Heli
« Reply #37 on: November 22, 2017, 05:10:11 am »
Maybe asking a question will help.  If you only use Attitude mode, can you use transmitter trims to stop/reduce the drift or do you need to keep adjusting the trims?

f5soh

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Re: GPS assist and Heli
« Reply #38 on: November 22, 2017, 07:22:20 am »
There is already plenty of questions before.
Can you explain why there is a issue flying in a straight line and no issue flying circles using complementary ?

Re: GPS assist and Heli
« Reply #39 on: November 22, 2017, 08:33:44 am »
(Attitude mode) They are both problems.  It sounded like you agree there is a problem when flying in circles, but not that there is a problem when flying for a long time in a straight line, which is the same as hovering in the wind, which is the same as using transmitter trims to stop drift.

In my opinion this situation do not cause any issues.

karla

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Re: GPS assist and Heli
« Reply #40 on: November 22, 2017, 01:26:36 pm »
You should do testing in this order:
- basic AltitudeVario
- PosHold
- VelocityRoam and others modes
- GpsAssist

Today basic AltitudeVario completed reasonably well.

It was very gusty winds today and a heli is really sensitive in vertical stab with sudden gusts gives a strong lift on the rotor. So, it was not ideal, but I think it kept altitude reasonably well. Did some adjustments on the Stabilization-Altitude page, but it had limited impact. What had more impact was to adjust the combination of throttle and pitch curves on the transmitter around where hover takes place. Also checked the barometers, they seem okay and fluctuate in less than 1 meter. Next time I will redo it to make sure.

karla

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Re: GPS assist and Heli
« Reply #41 on: November 22, 2017, 02:53:54 pm »
Did some adjustments on the Stabilization-Altitude page, but it had limited impact.
What had more impact was to adjust the combination of throttle and pitch curves on the transmitter around where hover takes place.

I have a suspicion here:
the FC in AltitudeVario/AltitudeHold is trying to correct altitude just by altering the thrust, and not by changing the collective pitch of the heli.

This would be logical, its a mode to be set for the thrust.
Also, since both throttle- and collective pitch curves are defined in the transmitter (in my case), there would be no way for the FC to know what pitch to change into, since the pilot is not changing the sticks.

Can anyone confirm if this is how it works?
« Last Edit: November 22, 2017, 03:15:51 pm by karla »

Re: GPS assist and Heli
« Reply #42 on: November 22, 2017, 06:37:22 pm »
It's my understanding that that is a current deficiency in LP...  The FC will only control throttle or collective, but not both.

It would be fairly simple to add a curve and have the thrust channel control both throttle and collective, but no one has done this...  Sorry.

Do you have open cell foam covering the baro sensor?  That is needed to keep air gusts from affecting baro sensor readings too much.

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Re: GPS assist and Heli
« Reply #43 on: November 22, 2017, 07:55:40 pm »
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(Attitude mode) They are both problems.  It sounded like you agree there is a problem when flying in circles, but not that there is a problem when flying for a long time in a straight line, which is the same as hovering in the wind, which is the same as using transmitter trims to stop drift.

Yes, there is a issue with attitude estimation using complementary when flying in circles.
Flying in a straight line should not cause issue with complementary, if there is a issue in this situation it should be great if you can explain why.

Re: GPS assist and Heli
« Reply #44 on: November 23, 2017, 02:05:36 am »
Do you agree that there is a problem with using transmitter trims to correct drift in Attitude mode (even when Attitude is the only mode you use)?  I know that changing trims for Attitude mode will mess up Rate mode but that is not what I am talking about.