Sorry it’s been a bit quiet here – I’ve been working on lots of little bits, none of which individually were worth a blog, but the whole is worth more that the sum of its parts…

  • a complete recalibration of the accelerometer as carefully as possible across 3 axes against temperature
  • some code tidying to sharpen up transition between velocity PID targets – I’d softened these out previously to stop mid-flight reboots due to power surges, the down side being that during a soft transition between state, there’s prolonged acceleration, and that acceleration skews the angles leading to drift – without the softening, acceleration is a short burst, and the angles remain more accurate as a result
  • some tidy up of other commented out bit of code that had historical value that now has depreciated to zero
  • a general spit and polish.

And as a result, I’ve just had a perfect flight.

Flight Track

Flight Track

The units of the graph are meters.  Phoebe drifted only around by 0.25m and self correct according to the plot, and what’s critical is that matches my perception of the flight.

Sadly, because it was just a test flight, I wasn’t rigged up for video – I’ll try and get one done later this week.

On the plus side, I’ll be updating the code on GitHub shortly.  Be aware though that the code is now dependent of VERY accurate accelerometer calibration – use it as is at your own peril.  I’ll blog again how to do the best possible calibration.

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