Parameters related to battery chemistry

  1. I’ll set 50hz and see what I get.

  2. Dshot doesn’t generate RCOUT data.

The copter does fly pretty well with these “out of range” PID’s.

I wish I’d gotten better efficiency from using BLHeli32 and Dshot-600. But I’m pleased with the simplicity and responsiveness.

In logs there is RCOUT represented as PWM even if you are using DSHOT

Here’s the new FFT charts with FFT_MINHZ set to 50.

It was weird - the copter flew great - but when I armed it, the copter wobbled on it’s legs until the RPM came up a bit.

I think I’m going to bring MOT_SPIN_ARM up a little bit.

My plots of RCOU are all 0.

I must be doing something wrong.

That FFT is excellent, in-flight FTT and HNOTCH working as planned!

Sometimes Yaw RAT p and I can contribute to that arming shake, I’ll check more.
(working solely on mobile phone at the moment)

Check output 9 10 11 12

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Yep - of course, because they’re on Aux ports. Brilliant!

Arming shake gone with higher MOT_SPIN_ARM. Still below the default - but too fast now to tell which way the props are spinning.

Initially I’d probably drop the yaw accel max to about 20000 and see if you can lower the arm spin successfully. This won’t noticeably affect flight.

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See the other discussion on accel and gyro filters…
INS_ACCEL_FILTER should be left at 10 as you had it.
I incorrectly assumed it should be set to the very old default of 20.

Thanks @xfacta -

Is this the discussion you’re referring to?

I obviously have a lot to learn still about control loops and filters. The concepts aren’t difficult - but the information about them is pretty sparse. Seems like most of my learning occurs during troubleshooting sessions such as this. It makes me feel guilty that I haven’t done my homework first.

Hi Joseph,

I watched this video

After I made the filter post on the forum. This video is really great and adds a lot of knowledge about the filters.

Hi Joseph.
If you have time it would be good to set
AUTOTUNE_AGGR,0.05
INS_ACCEL_FILTER,10
and I’ll be very interested to the differences another Autotune makes

As soon as it stops raining I’ll do exactly this.

Reading the notes on AUTOTUNE_AGGR it does seem like setting it to 0.05 is the better choice than where it is now - 0.1.

This copter is neither large - and pilot responsiveness would be a good thing.

Late last week I reset INS_ACCEL_FILTER back to 10. I did a little test flight in my yard checking out the “snappiness” of the latest tune. I like it.

One issue however was when rapid changes for and aft in pitch, the copter would oscillate perceptibly in it’s transition. The stick movements were aggressive - so might not be apparent in normal operation.

I’ll be looking to eliminate these oscillations in subsequent tunes.

Good evening @xfacta -

I did an autotune today with AUTOTUNE_AGGR=0.05

The results were a wee bit of an eye opener.

The copter completed autotune quickly and easily.

The resulting PIDs however were so “mushy” that the on a subsequent test flight the copter got into an unrecoverable roll oscillation that the copter crashed. Fortunately, no lasting damage.

Here are the PID’s before and after:

Pretty amazing - don’t you think?

Here’s what MavExplorer had to say after I put the copter back together and did another cautious flight:

I’m thinking that tomorrow I’ll re-set the PIDs back to what I had - and autotune again with the AUTOTUNE_AGGR parameter set to 0.075 - the mid-point of it’s range between 0.1 and 0.05.

Interesting stuff. Suggestions?

Thanks!

Looks fairly common for low (.05) Autotune aggression to me. We see this reported often enough with some reported crashes. Those resulting Rate P&I’s are suited to a high thrust/weight mini quad.

yeah, that was bad.
You could put PIDs back to previous values of course.
.075 I have used many times before without problems.

I’m curious about why you suggested I try 0.05 a try.

Based on the discussion about Accel and Gyro filters, it was suggested 0.05 was good with low vibration/noise levels. 0.1 Autotune aggressiveness was to cope with the presence of undue noise.
It’s possible I’ve misinterpreted what had been said, and I’m sorry it caused you extra work and expense.

Remember to check the noise levels under the RATE category on the log file.

The RATE.Rout, Pout, Yout, and Aout. These should ideally be below 0.1 in the log if I understand correctly. If not, the gyro and rate filters probably needs to be lowered.