MicroArduCopter, 3" props, Omnibus Nano, Success!

Yes, like this:

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Hi Wicked !,hope you are well,could you please give a link to the gps you are using from mRo please and many thanks

with this compass 5 cm plastic standoffs are enough to have interference around 15% on the compass mot test

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This, but it’s discontinued:
https://store.mrobotics.io/product-p/mro-ugps-samm8q-01.htm

The new one is better… But it a little bigger.
https://store.mrobotics.io/product-p/mro10038.htm

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Thank you No 1,will get one ordered today,and also started playing with the harmonic filters

on my 3 "quad with optical flow I connected the lidar VL53L1X and the test seems to provide a correct reading but in flight it seems not to work well and the behavior of the quad is better with only the optical flow. I followed the wiki instructions. I get bad lidar health only with the quad resting on the ground and the sonar range value at 0. if I manually raise the quad the height seems correct.in the log I get only 0.3 actually the quad has reached 15 meters … I don’t understand.

I fear there is some problem with u-blox GPS on V4.1.0-dev, at least with the cheap BN-880.
With V4.0.4-rc2 on my 3 inch copter with OmnibusNanoV6 I have a good stable Loiter with BN-880.
With V4.1.0-dev and same HW, same parameter in Loiter the copter moves in circle similar to toilet bowling but is not a Compass problem.

I attach two plots from logs of the two situations.

V4.1.0-dev

V4.0.4-rc2

Maybe this problem could be related to the switch to 230400 baud for u-blox GPS with this PR. On V4.0.4-rc2 the same GPS is configured to 115200.
I will try 4.1.0-dev without this PR an I will see.

Sorry if latest post of mine is a little bit OT.

Anyway I would like to know if someone is using latest master on OmnibusNanoV6 and u-blox based GPS (at 230400 baud) and if it’s all OK or there are some problems.

yes, with the GPS’s I mentioned above. No problems.

Isn’t there a parameter for the baud? Have you tried lowering it? I wouldn’t be surprised if the bn880 isn’t quite to spec.
And otherwise, post in the main 4.0 section… Sounds like this could be more of a general issue w/ that GPS, and maybe others have seen it.

Thanks

No, after the PR I linked above u-blox GPS are automatically set to 230400 baud

You are right I will do it.

Yesterday I rebuilt V4.1.0-dev from master and did another test with same HW settings and params configuration described above and I have no problems of position control with GPS in Loiter even if the BN-880 was set to 230400 baud.
I don’t know what happened in the test posted above with bad GPS position control. Whatever it was seems to have disappeared.
I will do other test and if I will see problems I will post it in the main 4.0 section of the forum.

Moving on to another topic, I would like to know, from those who use OmnibusNanoV6, if you have problems with logs in flash memory.
I always see logs with problems, missing messages, missing flight parts.
Is it the same for you too?

Here’s one I prepared earlier:

I finally got to fly this today and it works really, really well - all my logging problems are gone

@anbello that fix is in my small copter branch as well

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Thanks, I will try it immediately :slight_smile:

Well done @andyp1per finally I see logs on my omnibus as they should be!
All tings in place and no errors when reading. All OK also from command line tools mav*.py

The only things I see missing are initial MSG like in this SD log from Pixracer (not so important, only to signal):

So the FRAM takes a while to initialize, we don’t write out any pages for 2s to cope with this but in 2s you could get enough log messages to fill the buffer and so the early messages will be lost. You could try increasing the log buffer - that might sort it.

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I have fast sampling working on the MPU6000: https://github.com/ArduPilot/ardupilot/pull/14423

That’s great!
I’ll try it soon. Might be rained out for today, but should have periods of clear weather tomorrow.

One of my omnibus copters is using 3018 props w/ 8000kv motors, and is definitely pushing the limits w/out fast sampling.

Great. I see it is also in small copter branch, will try soon.

@andyp1per I tested it on a 3 inch quadcopter with revo-mini.

Here are some results with INS_GYRO_RATE=0 (normal 1KHz sampling)

Similar of what I already seen (without PR 14423) with PkAvg around 330Hz and BwAvg around 150Hz.

Then I set INS_GYRO_RATE=1 (2KHz sampling) and I see something I don’t understand completely

It seems to me to see more noise passing in the post-filter FFT and more “spread” of PkAvg and BwAvg with BwAvg frequently near PkAvg.

I have a doubt regarding FFT_MINHZ and FFT_MAXHZ, must they be set to see the fundamental only or also the harmonics?

In the above tests I set them in this way:
FFT_MINHZ = 180
FFT_MAXHZ = 480

Is it OK or have I to set FFT_MAXHZ near 700Hz (in the case with INS_GYRO_RATE=1) ?