Help Tuning the PIDs

ArduCopter Copter 4.6
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1

I need help tuning my 5-inch copter. The vehicle specs are as follows

MCU: STM32F05
GPS: M10
Mag: Q588L
Baro: DSP 310
Firmware: Arducopter V4.6
Motor KV 1750

Props: 5156 triblade
Battery 6S LiPO
Props out configuration

GW: 700g-750g

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I cannot seem to reduce the step response. Everything is still oversooting. Tried changing P and D, but the issue remains the same. There were oscillations on default pids, but I was able to fix that.

Autotuned PIDs were unflyable

How should I proceed from there? Any tips

Here are the log files

2

Im assuming that these are autotune .bins?

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Your loop times are struggling a bit, may be because of all the logging you have set and the over kill on the filters.

Update to the latest firmware…

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Do a simple hover for 1 min and postr that .bin file.

Also your notch filter config looks a bit over kill.

Do the sim[ple hover flight and lets start back there.

3

For PID tuning need to start with proper filtering first, try this

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4

You have some out of whack PID’s. I would reset to default and start over. Set the Initial Tune parameters and these after updating to current Stable firmware where you posted:
ATC_ANG_PIT/RLL_P, 9
The Rate Pitch/Roll P&I terms to .06, D-terms to .0015
PSC_ACCELZ_P, .06
PSC_ACCELZ_I,0.12
INS_ACCEL_FILTER,10

Configure for Dshot600
Disable the Notch Filter
INS_LOG_BAT_MASK_1
INS_LOG_BAT_OPT,4

Make a hover flight for a minute or so.

1 Like
5

@dkemxr
Thanks. But about dshot 600. Is there any advantage to using that since ArduPilot loop rate is only 400Hz

6

Thanks i will reset my filters and try again

7

Yea, it’s generally the most stable. And the rate it runs at is set with the servo_dshot_rate parameter. Default being ~1.4khz with a 400hz loop rate.
Dshot ESC’s

1 Like
8

Filters won’t fix a a fundamental problem. It’s the last thing to configure before it’s ready for Auto Tune.

9

@Abrew_Abraham_Alex do the things in the order @dkemxr recommends. There are many reasons why that order is correct and other orders are incorrect.

1 Like
10

Yes I will do these changes as suggested. Thanks a lot for everyone input. Will keep this thread updated

11

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Can someone review my filter settings? I haven’t done PID tuning yet

12

You only need the first harmonic and you must reduce the BW to 40 Hz when using multisource

13

Okay thank you @ amilcarlucas. I read somewhere that it’s better to have three harmonics, as I’m using a tri-blade prop. Is there any relevance in this?

14

None. Use the minimum configuration to get the job done.
And if you want a review post a link to the .bin log file.

15

Please check this log file. I was going through the PID review tool, and it seems the actual is tracking well as far as I can see, but the step response is not rising to 1 (which I believe is the ideal).

16

You only need the 1st harmonic and the BW is too high when using Multi-source. maybe you confused BW with attenuation in this regard.

This looks like it works well to me (use estimated post-filter)

Notch
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17

oh thankyou so much, changed the params as you suggested. There is some log of altitude controller there as well. Any suggetions on them will be greatly apreciated. @dkemxr

18

You are not logging RC outputs. Attitude looks good.

19

I will enable RC output and post a log. Can you please check the altitude controller perfomence. It kinda feels too noisy for PIDA > target and actual

20

Here is a log with RC Outputs. Hope this help