Tuning frusration

I’m trying to get my F550 Hex airworthy but it doesn’t behave well enough to let it off the leash.

Been doing some tune on a string - chain in my case - and trying to make sense of what is going on, out of the box settings clearly don’t work on a hex, well they don’t on mine.

Decide to go back to basics - I set up first to do pitch - I’ll repeat this for roll.

Using ‘extended tuning’ screen set small P value for Pitch / Roll and Yaw - set to 0.1, set I and D values to zero

Set stabilize mode.

Arm and try to ‘level’ hexacopter and it seems to be massively over reacting and I don’t mean slowly, it ramps motors almost OK at first and then without warning almost digitally - and spins like a top - the only way to stop it is to disarm. It’s a good job it’s tied down :exclamation: :exclamation: :exclamation:

Decide to read some more but if you go to this page :-


The description makes total sense - the only problem is that NONE of the parameters listed exist in the parameter list shown by Mission Planner or APM Planner 2, the code described also doesn’t exist in Arducopter.

It’s damn hard for a newcomer to Pixhawk to get into this given the amount of conflicting information, simply sorting through what is relevant or not, identifying which parameter to change, by how much, or which not to touch. How much PX4 is appropriate, if it isn’t where are the ‘similar’ Pixhawk pages?

And which config software to use - because they don’t play nice together on the same PC.

After much twisted string and stress I now have a flying hexacopter, just a few quirks to tune out now but I have no clue what to tweak to fix the biggest quirk.

Biggest issue is a major altitude loss when yawing, either motors doing the yawing aren’t going fast enough or the ones not yawing go too slow. I’m reasonably sure that increasing P on Yaw will increase the speed of the yaw motors but how do I stop the controller reducing the speed of the others too much ?? -

Admittedly I was 300g overweight but I was assessing capacity / behaviour / hover points - the DJI E300 system proved well able to lift 1.3kg - hover at approx 70% - my ultimate fly weight will be around 850g with the 8000mah battery and 650g with the 4500mah.

So how do I set the balance between motor speed increase and decrease so that I don’t lose or gain altitude when yawing ??

Looking at the logs the non yaw motors seem to do the inverse of the yaw motors - is there any way to tune or scale this ‘inversion’ ?

Are you sure you’re not inadvertently moving the throttle too when you move the yaw stick?

I’ve put a fairly large EXPO on the yaw because I do have a tendency to do this but in the opposite way - I tend to add or remove yaw when I push the throttle up and down.

I need to be real gentle on the yaw until I get issues with it resolved - the copter loses significant height so it is clearly dropping the non yaw motor speed far too much, it does yaw but it drops like a stone. you can be in Alt Hold and solid as a rock, put too much yaw in and it drops, not even alt hold can deal with it.