Park testing

It’s a lovely day here at the edge of the Cotswold; bright sunshine and absolutely no wind.  So I went to the park.

First flight was perfect – wow I thought, wish I’d brought my camera.

Second flight drifted by 10m and I was glad I hadn’t bothered.

After numerous flights trying to work out what on earth was causing the drift, lots of watching take-off for common features revealed the truth:  take-off from non-horizontal ground means there is some lateral power applied by the blades, leading to the drift.  As the take-off tilt is corrected, the drift stops accelerating, but still continues at constant speed due to momentum.  Hence the overall drift across the flight.

By having pre-flight Euler angle checks, Phoebe knows immediately she’d not on a flat surface, so the problem is all due to how fast she can compensate and get herself level using the mix of the DLPF and complementary filters along with the absolute angle PID.  Now I know I’ve mentioned these loads of times; the difference here is that I now have a greater understanding of how they are interacting.  And with that in mind, I could watch a take-off carefully, looking at the take-off angle, watch how long into the flight it took for Phoebe to correct that angle, and therefore how much drift speed she gained until she levelled out.

And as a result, I have a much better set of default configuration figures for DLPF, complementary filters and absolute angle PID gains – not perfect perhaps, but possibly good enough that if there is wind on another day, I can rely on these default to then start looking at the horizontal drift kill testing using the horizontal velocity PID.  And that is a big step forwards because once that’s sorted, it’s on to phase 2 and a remote control


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