Dynamic notch filter on IMU_APPS based on Motor RPM

LucaVertiq

We chatted at AUVSI about getting dynamic notch filtering working. Right now I have all the basic stuff implemented, but am running into two issues.

The first issue is that even in a sandbox I'm having trouble creating an appropriate notch filter. I've looked at how PX4 and Ardupilot do it, but I'm not seeing as much attenuation as I'd expect. Seeing as you wrote the filter library, I was wondering if you had any notch filters already written. My filter knowledge is rather lacking.

The second issue is that ESC telemetry is only reported across the 'mavlink_onboard' topic at 10hz. I think I'd rather have it be a bit faster.

I was wondering if you had any insight into either of these. Here's the repo I've been working off of:
https://github.com/vertiq-luca/qrb5165-imu-server/tree/feature/rpm_filter
It's just mavlink rpm data feeding a low pass filter for now until I can get my notch filter to work, but it does appear to be filtering!

Best,

Luca

LucaVertiq

@Moderator bump?

LucaVertiq

@Moderator So I was able to get the notch filter working, but I'm still wondering if there's a way to get the mavlink onboard to publish faster than 10hz.

They dynamic notch filter as really improved the VIO on my vehicle which is very prone to vibrations.

Eric Katzfey

@LucaVertiq You could add the command mavlink stream -u 14556 -s ESC_STATUS -r 20, for example, to the file /usr/bin/voxl-px4-start to increase the rate to 20hz.

LucaVertiq

@Eric-Katzfey That worked perfectly! Thank you. I put all the dynamic notch stuff on my github. I know James mentioned he wanted to implement it.

James Strawson

@LucaVertiq Great work!! I'm going to be OOO for a while but as we discussed before I'm happy to review it when I'm back and integrate into the SDK.