[Donny]

hello cliff:
  I have already upload my test movies to Youtube, the website is :https://www.youtube.com/watch?v=HlhBvxdkTeU
Donny

[TheOtherCliff]

The PFD tilt and jitter in that video are normal amounts.

I see that you are still running with 10 degrees of Aux Mag Orientation: Pitch.  You are using 0,10,0.  This should very probably be 0,0,0.  This orientation is relative to how the craft hovers.  If it hovers level and GPS/mag is mounted level, this needs to be 0,0,0 unless your GPS/mag is mounted with a tilt.  If mounted with a tilt, maybe you need -10 instead of 10, but I think that positive is correct.  The mount may be tilted, but it looks much less than 10 degrees.

The only time you should need Aux Mag Orientation pitch is if your quad has "race mount" motors that are mounted tilting forward, or GPS/mag mount is tilted.  In these cases the GPS/mag is not level when hovering.

I see and hear several problems.

I see and hear an oscillation at about 4Hz.  Are you running stock PIDs?  I suggest you go to stock PIDs.  Equally important is that you MUST set ESC signal protocol to PWMSync or PWM@490 for all banks that have an ESC connected.  Using PWM@50 makes it very sluggish to respond and hard to fly.  It also makes these 4Hz oscillations if you use default PIDs.  See the Output page for these settings.

I see a very slow and large movement oscillation building up.  This can be caused by the 0,10,0 previously mentioned.  Set it to 0,0,0.

I see that you are using DJI GPS/mag.  The DJI "smooths" the GPS data, which slows the information down.  This can cause a large east-west movement oscillation.  There is a patch to fix this.  Use the patched firmware.  It is 100% compatible with 16.09.  No settings changes or saving is needed.  I assume you are using LP version 16.09
https://forum.librepilot.org/index.php?topic=3012.msg21154#msg21154

You were getting some mag alarms when flying.  You should twist all your pairs/triplets of thick (high current) wires: battery to PDB, PDB to ESC, ESC to motor.

So:
- Save your settings before making changes, so you can go back if you want
- flash the patched firmware
- EKF to default values
- PIDs to default values
- Aux Mag Orientation to 0,0,0
- ESC signal protocol to PWMSync, PWM@490 (or faster, but not for example PWM@50)
- I really suggest PWMSync or PWM@490 at least for a test
- twist high current wire sets

Good luck.  Make another video and post your settings UAV file (File->ExportUAV...).

[Donny]

Hi Cliff:
  thank you for your reply.
  I will compile code and flash firmware today, and upload test movie soon.
  I just try PWM@490, this effect is very good, the frame flight is steady than pwm@50 in cf algorithm. Because EKF algorithm update cycle is 490hz? I set pwm@400 ago,but it's effect is very bad, and the store of ESC tell me to need set default parameter, so i set pwm@50. why? i don't kown.
  thank you for your advice again.
Donny

[TheOtherCliff]

490Hz is used because if you use normal servo pulses of 1.0ms to 2.0ms and you try to have 500 pulses at 2.0ms then there is no time for the pulse to be inactive since 500 times 2ms is 1.0s (the whole second is used up with "on time").  Be aware that this is the reason that it is recommended to use 1.0ms to 1.9ms; that leaves 0.1ms of "off time" when running at 500Hz.  PWMSync runs at 500Hz.
https://librepilot.atlassian.net/wiki/spaces/LPDOC/pages/12058743/ESC+Calibration

50Hz is bad because then the ESC response time is about 10 times slower than 490Hz.  You get oscillations with stock PIDs and very mushy response to sticks.

So is your problem fixed now?

[Donny]

Hi Cliff:
  I have already upload latest test movie to Youtube And the website is ]https://youtu.be/kizSoqO3fNA
  The frame's firmware has updated according to your get me at website is https://forum.librepilot.org/index.php?topic=3012.msg21154
  And the frame's servo freq has set pwm@490.
  I have some problem about the movie that test today.
  1. the PFD is tilt before i armed the flight, but when i take off it and control it by remote control and land  earth, the PFD is horizontal. take off and land position is same. why PFD change? Because mag leave earth and get good data or else?
  2.last Saturday, i test VelocityRoam mode, result is the frame lose balance and fall. I see this mode and Position hold mode difference that it can position hold and control by remote control in body coordinate. I need note what?
  And today, i also test altitude hold, but the effect is not good. the test movie website is ]https://youtu.be/TZqGLLhss9U
  Please look and tell some advice, thank you.
Donny

[TheOtherCliff]

First, for your understanding, it is not necessary to set bank 4 to PWM@490
channels 1 and 2 (ESCs 1 and 2) are on bank 1
channel 3 is on bank 2
channel 4 is on bank 3
nothing is on bank 4 that I can see

Setting bank 4 doesn't hurt though.  This is just information.

That much tilt in PFD is close to normal.  I would not like it if it was any more though.  The tilt comes because INS13 uses 3D compass and actually gets some leveling information from compass, so it is accels plus compass for INS13 versus just accels for Basic (AttiEstAlgo).

I like your string!    I have actually done that myself one time to make sure it could not fly away.    Ahh I see now that you are using it to move the quad in PositionHold to see if it returns.

Did you see that your GPS went orange during flight?  You are flying in a challenging area for fine and accurate GPS signals.  There will be GPS signal reflections from the many hard surfaces, buildings and especially if there are any metal surfaces.  Tall buildings are bad two ways.  They can block GPS sats and they can reflect signals to make then incorrect.  Your flight looked fairly reasonable considering the GPS was dropping and adding satellites.  I suggest you try flying GPS modes one time in a grass field in the country, not city, just for a test (if that can be arranged).  Also, it is good to let GPS sit with power on for 13 minutes before the first flight of the day.  It downloads the "almanac".  You have a good GPS with 6 hour memory.  The very tiny cheap GPSs don't have this memory, but almost all other ones do.

Oh, and VelocityRoam is 100 times more fun than PositionHold.  When sticks are centered, VR is exactly the same as PH.  It runs the same code.  VR is so easy to fly.  Just release the sticks to let them center, and the quad stops moving (even in the wind).  Then you have as much time as you need to figure out how to push the sticks.  Just think like Stab1/Attitude mode when you fly VelocityRoam.  Left roll means move left.  Forward pitch means move forward.  Left yaw, rotate (pirouette/compass) left.  Throttle is vertical velocity, not vertical power and is much easier to work with.

Second video said you were using AltitudeVario, not AltitudeHold.  Throttle stick center should hold altitude.  Non-center is vertical velocity.

Try VelocityRoam and move sticks like Stab1/Attitude mode. 

I never use PositionHold flight mode or AltitudeHold thrust mode; they don't give any control.  I always use VelocityRoam flight mode or AltitudeVario thrust mode; they give hold or control, you decide.

[Donny]

Hello Cliff:

  First, thank you for your reply.
  I'm in Beijing China, there is deny flight, so i need string to sure the frame is safe, of course, test also need it.
  I see gps signal change yellow from the test movie. At weekend , i will test frame in VR mode in grassland, after i will upload the test movies.

Donny