I've now added support to my Cleanflight Blackbox firmware for recording the barometer, magnetometer, and VBat information on flight controllers that support it. You can see the barometer and vbat displayed in the bottom left corner of this video!
Posted by thenickdude |
Nov 23, 2014 @ 05:32 AM | 2,502 Views
My FPV setup is back in action today, so I was able to capture some datalogs at higher airspeeds. Here's what speed wobbles look like in super-slow motion, recorded by the flight data recorder I'm developing for the Naze32:
You can see how the P and D terms conspire to have the quadcopter continuously overshoot its roll target, causing severe oscillations in the roll axis. I think I can solve this by reducing my P term on the roll axis.
This is the Blackbox flight data recorder for the Naze32 I'm currently developing in order to investigate uncommanded yaw control problems with my quad at high speeds. However, since I was limited to LOS flying today (which limits my top speed), this was a problem-free flight! The current time in the video is in the centre, marked by the vertical red band.
The Blackbox is a patch for Baseflight which causes it to send RC commands, gyros, PID intermediate calculations and motor commands to an onboard OpenLog serial logger connected to the Naze32's main serial port at 115200 baud. This data is captured on every single FC loop (here at 415Hz), so basically everything about the FC's behaviour is losslessly captured, and any quirks with the craft can be identified and solved!
The recorded datarate is about 8.25KB/s, which allows for essentially unlimited recordings on an 8GB microSD card (that's 30MB/hour).
The Blackbox software isn't complete yet, but I hope to make it available for testing soon.
It looks like YouTube hasn't been kind to the colours I chose for the graph, here's a still screenshot:
The couple of gaps in this log are due to the FC sending data a little bit faster than the OpenLog could keep up with. I'm working on improving that: I've reduced my data rate by 15% by improving the compression applied to it, and I'll investigate using a faster microSD card (currently I'm using a 8GB no-name Class 4 card).
The OpenLog is tiny, at 15x19mm. I wrapped it with electrical tape and attached it to the frame with the microSD card slot pointing outward using double-sided foam mounting tape: