Started up this morning upgrading to use the new Epiphany web browser on my workhorse pi. This is the only RPi I have that’s not headless, so it’s the one I use for transferring files between Phoebe and my PC. And the update failed catastrophically. So I’m downloading the latest image and will try again. No real impact on Phoebe other than wasted time.
Up for testing today were
- refined dynamic accelerometer calibration
- tinkering with dlpf to see if 5Hz is workable
- try take-offs from near horizontal as compromised indoor demo @CamJam
Together these yielded the best behaviour yet. From a sloping takeoff platform, Phoebe shot off in the direction of the slope for a few meters, before stopping and hovering. From a horizontal platform, nigh on zero drift, but lack of accuracy in height. Just about safe enough for an indoor demo.
Phoebe’s initial drift from a non-horizontal take-off is an irritation, but I think the fix / enhancement is too large for me to try prior to the Jam. What’s required is both angular and motion correction PIDs running in parallel: the angular PID would level her up on take-off, and the motion PID would then stop any drift.
There are other cases where both PIDs are needed such as flying in a circle: she needs a fixed angle on one axis to produce centripetal force, but she needs a fixed velocity on the other axis to make her move around the circle at that level of inward tilt.
Because flying in circles uses only one of the two PIDs per axis, this could be simple to implement but the case of vertical takeoff from a slope needs a mix of both and I suspect they will conflict; vertical take off requires a 0° angle while 0m drift requires a dynamic angle.
For the CamJam though, I’ll stick with a horizontal take-off platform for safety.