I need help on one more rpm notch filter parameter - INS_HNTCH_FREQ
The wiki says use the rpm at hover from a test flight.
So for my copter this is perhaps 3200 a number below the ranger of hover rpm.
But the range on this parameter is 10 to 495. (according to the parameter list doc)
Looking at the parameters from an old copter I built a year or two ago - I had set this parameter to 30. So I’m wondering what to use in my current case.
Thanks for the help!
Based on your other posts, it seems the link below is what you need (not the page you captured). My rule of thumb is hover freq / 2 (and typically not less than 20Hz).
https://ardupilot.org/copter/docs/common-esc-telem-based-notch.html
Units matter. You are looking for the frequency in Hz, which is RPM / 60.
Good catch on the wiki page. Thanks!
If my hover rpm is 3200 at it’s lowest, then half is 1600. That’s still outside the parameter limits.
I’m pretty sure I have my settings like number of poles set correctly - my hover rpm matches what eCalc predicts.
Here’s the page you suggest:
I thought the warning was really interesting - it says to use one quarter the freq for the bandwidth parameter - and explains why. I’ll do that.
I just have to figure out to get from my measured rpm of 3200 down to a value in range of INS_HNTCH_FREQ.
Thanks Yuri!
I edited as you were replying. RPM / 60
Ah - of course - rpm is in “minutes” - hz is in “seconds”.
You would be better off using the Filter Review Tool and testing it with estimated parameters. I don’t think many are still using Mission Planner for Notch Filter review.
Filter Review Tool - this is the first I’ve heard of it. Thanks for mentioning it.
Easy enough to use - I uploaded my BIN file and it did the rest.
Now the hard part - how to interpret the results it presents.
Any chance there’s some documentation on that?
If you have the time and interest - here’s the BIN file from the test flight - I’d be very interested to know anyone’s thoughts - to help me learn how to use this tool.
It’s been around for awhile now along with some other Web Tools. Start with this Blog and associated video:
Filter Review Tool
There’s an ever growing subset of tools that make things easier.
Don’t ignore the ones under development. They are reasonably complete but less thoroughly tested (or have features that are still rough around the edges).
@jstroup1986 this is all documented and automated by the ArduPilot methodic configurator.
You would save your time, and ours if you would start using it.
It looks pretty good as configured. For some reason it’s not picking up the 1st mode X as best it can with a frequency of 55. 60 does it. And with that FC you can use Multi-Source with the same bandwidth. There is a 3rd harmonic but it’s down in the mud and as you configured it not worth adding a notch for. This is what I see as best by using estimated values:
And you need 1 for the reference. Actually, this is the reason the result with 55Hz was showing as I mentioned. You can leave it at 55 with the right reference value.
I’ve taken a look at your configurator - it’s obvious that its comprehensive.
I’ll try to devote some more time to looking into using it.
For now - I follow the ArduPilot wiki. One way to save time of the DEVs is to improve the wiki.
The tool adds to the wiki and references the wiki as well, it does not replace it.
Of course. But the wiki is the ArduPilot “front door”.
In fact, the reason I didn’t know about the Filter Review Tool is because it’s not mentioned in the wiki’s sections on notch filters. It’s only mentioned in the section about troubleshooting.
Have you considered making a video that illustrates using your tool?
I’m all about using proper tools to achieve goals. And the only reason I haven’t spent time with your tool is because I’m not familiar with it, and I couldn’t justify the time to learn it.
If others are in the same situation, a video may help people decide to use your tool.
It is actually.
Measuring Vibe with batch sampler
One could argue that it’s no longer Advanced Configuration and Analyses where it’s linked.
I see it now - kinda buried down at the bottom.
The wiki is still focused on the FFT tool.
Maybe this page needs an update. I might not be the only one who missed this reference.
BTW - I’ve taken a look at Peter Hall’s PID review tool - a good companion to the Filter review tool.
This tool may still be in development - but for people to use it, it will need proper placement in the wiki too.
By it’s very definition, the wiki is user editable. Make the changes you want to see.
