Hexa flying strangely, log analysis, please

ArduCopter
1

FC = Holybro Pixhawk4

No. 48 log - before parameter change, before re-executing compass calibration.

No. 49 log - After changing the parameter, re-run compass calibration.

https://mega.nz/folder/K0dxCQjA#BI_-DAeOQOGOwnCCRj_ylg

First of all, the second flight was much better than the first.
But the underlying problem doesn’t seem to have been resolved.
I heard that the internal compass was not good, so I made up for it.
But nothing definitively improves.
What equipment is this a problem? Or am I doing the parameter tuning wrong?

The difference between the first and second parameters is
1 = Moved posxy_p value from 1 to 1.2.
2 = Compass Calibration was rerun.

I don’t know what the problem is now.

I can’t fly long.
It can fly in about 5 minutes.
My battery capacity is very small

So even autotune is not possible.

A) If this is an equipment problem, what should I fix?
If it gets better after Compass Calibration, is it a way to use RTK?

B) If it is a PID problem, what parameter can be modified to what extent?

Hexa’s symptom is that even among the Loiters, it does not stand still and flows little by little.

If i release the Pit or Rll while moving (When i release my hand from the remote controller stick), the Hexa will automatically brake. and stagger

I think I’ve already spent 3 weeks on this problem.

Never been like this before

too difficult

2

I see in other posts you’ve got U8 Lite motors and Flame ESCs

Compass 2 , internal, is badly affected by throttle.
Set COMPASS_USE2,0
and these, some are important, some are just to get back to a known state:
ATC_INPUT_TC,0.2
ATC_RAT_PIT_FLTD,10
ATC_RAT_PIT_FLTT,10
ATC_RAT_RLL_FLTD,10
ATC_RAT_RLL_FLTT,10
ATC_RAT_YAW_FLTT,10
INS_GYRO_FILTER,20
BATT_ARM_VOLT,36.90
BATT_CRT_VOLT,35.00
BATT_LOW_VOLT,36.00
BATT_FS_CRT_ACT,1
BATT_FS_LOW_ACT,2
INS_LOG_BAT_MASK,1
INS_HNTCH_ENABLE,1
PSC_POSXY_P,1
PSC_POSZ_P,1
PSC_VELXY_D,0.5
PSC_VELXY_I,1
PSC_VELXY_P,2
LOIT_ACC_MAX,600
LOIT_BRK_ACCEL,300
LOIT_BRK_DELAY,0.3
LOIT_BRK_JERK,300
MOT_THST_EXPO,0.4
MOT_PWM_MIN,1100
MOT_PWM_MAX,1940

Now, some minor attitude control adjustment. Pitch was performing better than roll, so let’s make them the same as a starting point.
ATC_ANG_RLL_P,6
ATC_RAT_RLL_P,0.15
ATC_RAT_RLL_I,0.15
ATC_RAT_RLL_D,0.007
ATC_RAT_PIT_P,0.15
ATC_RAT_PIT_I,0.15
ATC_RAT_PIT_D,0.007

Now just hover and do some gentle movements for over a minute. Hopefully some of the oscillations are better. If oscillations are worse land immediately and I’ve got another set of ATC PIDs that should work.
Let’s see the .bin log file from that test flight.

EDIT: You can copy all those params from here, paste into notepad and save as a .param file, then simply “Load From File” in MissionPlanner to save trying to find them all and type in the correct digits.

1 Like
4

https://mega.nz/folder/PoFHUQCL#Gmsjf-whQ6H7WpYGGJX8lA

I flew today

first log = mode2 flight

second log = mode1 flight

brake faster than before
Brakes are very smooth

other than that I don’t know

Still staggering as if drunk

I also attach my parameters and flight video.

Thank you

5

I’m checking that log and planning the next steps

7

I got a new log today.

Please check once.

https://mega.nz/folder/Dp8m3BKL#cMS0DKNzQKuFyCqXDLMunw

8

You can definitely add this in before the next flight
INS_HNTCH_MODE,1
INS_HNTCH_REF,0.27
INS_HNTCH_FREQ,64
INS_HNTCH_BW,32
INS_HNTCH_ATT,40
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,2

Any reason that you dont put in the battery voltage and failsafe settings? Or the MOT_PWM settings?

9

I would try lowering the Angle P’s and raising the Rate PIDs
ATC_ANG_PIT_P,5.0
ATC_ANG_RLL_P,5.0
ATC_RAT_PIT_D,0.023
ATC_RAT_PIT_I,0.25
ATC_RAT_PIT_P,0.35
ATC_RAT_RLL_D,0.023
ATC_RAT_RLL_I,0.25
ATC_RAT_RLL_P,0.35
…and refer back to the tuning guide to work out the order to change them from then onward.
I would set up transmitter tuning.

These large craft with U8 motors and T-Motor ESCs seem to be always difficult to tune, and I think almost always the props are too big.

EDIT: the ATC_ANG P values may be able to go even lower, say down to 3.5 or 3.0

11

You said 0.15 for p the other day

I flew it up to 0.175

0.35 is a fairly large value.
is it okay?

The reason I didn’t set up the battery was because I thought it wouldn’t affect the performance of the flight much.
Am I wrong?

thank you

12

The missing battery settings dont directly affect tuning until the battery dies. What usually happens is the battery failsafe settings are ignored “because I am only testing” and then the testing goes on for longer and longer. Eventually you get excited when tuning is successful and start flying around more, having forgotten to set the battery failsafe…

14

The pid of the log I gave is p and i are 0.175.

Is it correct to increase it to 0.35?

thank you

15

Did you get a chance to try those PIDs?
Also please change LOG_BITMASK to 196607 before you do your next flight
This enables PID logging and Fast Attitude

16

sorry for late reply

Flight has improved a lot

But Yaw is a bit disappointing

Visually, it looks good.
I wish the aircraft had a little more force to level it.
(It still shakes a bit when hovering and stopping while moving)

I will link the B log and parameters in the evening based on my country.

17

https://mega.nz/folder/6sdBDQxY#nmKgE9o5zH7NAYYWN56G4Q

Hello Shawn

The report was late.

This is the most recent flight image, the most recent parameters, and the most recent binary.

I was so busy this week that I forgot to send this

sorry

and thank you

18

Please retest with these params when you get a chance

ATC_ANG_PIT_P,5.0
ATC_ANG_RLL_P,5.0
ATC_RAT_PIT_D,0.023
ATC_RAT_PIT_I,0.25
ATC_RAT_PIT_P,0.35
ATC_RAT_RLL_D,0.023
ATC_RAT_RLL_I,0.25
ATC_RAT_RLL_P,0.35
LOG_BITMASK,196607
INS_HNTCH_REF,0.27
INS_HNTCH_FREQ,64
INS_HNTCH_BW,32
INS_HNTCH_ATT,40
INS_LOG_BAT_OPT,2

19

The fluctuations in values ​​are quite large.

Existing values ​​or data messed up that much?

I think it was pretty good when I saw it with my own eyes or when I was actually flying.

This is my misunderstanding, can applying this value make my Hexa fly better?

20

Hello Shawn
It’s been a while since I flew a Hexa.

And there was a problem.

This is not what I remember.

In my memory, it had a more stable flight, but on the 24th of September, it flew like it was about to crash.

The last parameter you gave has not been applied yet.
(I think it’s stable enough)

Will it be ok if I apply the last parameter you gave me?

  • This has a very unstable attitude towards the wind.