You put your right prop on..

your right prop off.
on, off, on, off
and smash into a wall.
You do the hokey cokey and you turn around.
That’s what it’s all about!

Why do all my crashes break a right hand, ACW / CCW rotating prop?  I have so many spare lefts it’s getting embarrassing!

Though it wouldn’t help that sometime (I think yesterday) I fitted 10″ instead of my normal 11″ props to Phoebe’s left hand side.  Oopsy – it least that explains the increasing negative (ACW) rotation, eventually leading to the left wall collision.

On the plus side, with the correct props fitted on the left hand side, I got stability matching the take-off angle with the attitude only PIDs (i.e. completely as expected), and zero-drift once the motion PIDs were included too (again, completely as expected).  In other words, absolutely perfect…

…except for the fact she kept climbing; nevertheless still worth videoing.  Two reasons why I didn’t video the flights – they’re called Jacob and Milly; I’m the parent in charge until mid-afternoon so my time for test flights today is very limited!

So back to the Z-axis velocity PIDs, it seems.  I wonder whether the dlpf of 3 (44Hz, 4.9ms lag) could be the cause – either too high or too low – I can speculate on the cause of either way, so I’ll try both dlpf 4 (20Hz, 8.3ms lag) and dlpf 2 (90Hz and 3.0ms lag).


3 thoughts on “You put your right prop on..

  1. it might be a fundamental bug in the rotation matrices or there´s possibly one (or an odd number of) extra/less negative sign in the code if the pattern keeps repeating itself –ie. right crash into wall. did you try auditing the code line by line (last option…), make sure the right hand rule applies to all axes and 3-2-1 rotations are applied?

    • Nah, the crash into the wall on the left was because I’d put the wrong props on the left (smaller) – mea culpa! (Though I have at some point in the past got wrong every one of the possible causes you’ve listed!)

      Fairly confident in right-hand-rule code – I only recently double checked / corrected it, and since then, all problem diagnostics have clearly been RHR correct. Likewise 3.2.1 rotations.

      Problem now is raw accelerometer readings are drifting linearly even when just sitting stationary on the floor. Doesn’t bode well 🙁

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