New DJI550/NazaM - oscillation

[edwar64896]

Hi all.

New F550/NAZA-M machine - First time user and first time poster.
Machine seems to be flying fine - no toilet bowls to worry about.

There seems to be a slight oscillation in the hover.
The battery is placed on the top plate of the F550 with the electronics
on the lower deck.

Do we think that the oscillation is to do with a CG issue?
Should I be mounting the battery at a lower point on the fuselage?

Very happy with it so far, but just a bit pissed that I bought a NAZA-M
and only just found out about the Naza V2 release - #ohwellthatslife

Hints and suggestions would be much appreciated.

many thanks,

mark.

 

[bnt276]

Hey Mark. Oscillation in a hover is typically too high a gain setting for your input... whether it be roll, pitch or yaw.
The idea is when it is oscillating, put the gain down 5% until it disappears. You do this for each channel if it is evident in each input.
What I found is if you use rudder and it oscillates when turning, then lower the yaw gain. In the other end of the spectrum -
if when you yaw the quad and it feels sloppy like it wants to tip then gain is too low... turn it up until it oscillates... then down a little.

Do this for each channel until you get a good happy medium.
If you have a camera on, it's a good indicator of slight oscillations that you cant see from a distance. So, in your video if you notice a slight oscillation,
back off the gains just slightly.

Good luck!

 

[edwar64896]

many thanks for this. I have set up the remote gain tweakage for X1 channel and will be testing gains.
I'm currently battling a battery issue - I have 3 x 4S 5200mAH 20C LiPo batteries but for some reason I am getting a massive voltage drop in the climb.
This is tripping the Naza Voltage protection really quickly and causing the craft to descend under battery failsafe.
I'm balance charging all the batteries at the moment but I fear I'm probably going to have to get some new ones.
The batteries I am using are all currently in production use in my field recording gear - which doesn't really draw much current at all - not breaking a sweat even after a couple of days usage in the bag. The multicopter seems to draw a lot more current and is definitely taxing one or more of the cells.

I'll have to fix the battery issue first then go back to tweaking the gains - when I can get some decent flight time out of it!

thx mate - your advice is much appreciated.

m

 

[PeteDee]

I don't doubt you have a voltage drop in the climb, what does it weigh with 3 x 4s 5200 battery packs, that would be around 1.5kg on its own?

 

[bnt276]

Hey ed,

Are you using the voltage monitor in the assistant software?
A lot of people do not use that feature as I have heard it may not be accurate and also a bit confusing to set up.
People are just turning off this feature and relying on a cheap voltage alarm and timing their flights with a countdown timer on their radio.

I would try that first before deciding your batteries are kaput.
And if you are lugging a lot of weight then absolutely could be a cause.

 

[edwar64896]

the batteries are pretty heavy - I have ordered some lighter 3S LiPo's that start at 45C with a peak of 90C. The ones I was currently using were 20C and unbalanced.
While this was fine for working with my sound gear - not so with the multirotor. I have set about balancing up the 20C's anyway, but will be waiting for the 3S LiPo's to arrive before flying again.

I have been using a 9XR with frSky DJT Telemetry TX/RX. I'm using a voltage tester on the craft and seeing voltage drops from about 13.5 down to below 9 in the climb. This is definitely tripping the Naza M voltage sensor and dropping the craft down to the deck where it remains with a little red flashing LED. I can reset for another few seconds in the air, but it's really no fun playing bouncy helicopter. I'd really like a good 10 minute flight out of it.

We'll see how we go with the new nano-tech batteries at the end of the week.

Worst comes to worst, I can pull out the NazaM voltage sensor setting and just fly without it. The telemetry back-channel gives me a good reading on the voltage anyway. If I'm below safety levels on the craft - I'll land it.

m

 

[edwar64896]

Also - on my last quick flight - I managed to play around with remote gain control - setting up X1 to control attitude pitch/roll gains. Currently got them set to 40% with external control via X1. Managed to get the craft tuned nicely just below the oscillation point on X1. I'll leave this setting turned on for now, but when I'm happy with it I'll lock in the gain setting. Love the way you can tune it remotely!

 

[bnt276]

Nice. I like it too. I could do it on my old GAUI 330X but just gain on one channel.
NAZA setup for external control is pretty decent. I have my gimbal set up on my AUX 3 knob on
my DX8. It's great for high altitude snapshots and even video (even when using the GOPRO for you FPV camera)

I think the only time you will have to re visit you gains is when you make major changes like prop sizes or big weight changes.

b

 

[OneStopRC]

What size props?

 

[fahrvergnuugen]

Are you using the voltage monitor in the assistant software?
A lot of people do not use that feature as I have heard it may not be accurate and also a bit confusing to set up.
People are just turning off this feature and relying on a cheap voltage alarm and timing their flights with a countdown timer on their radio.

This is exactly what I ended up doing and I'm much happier with the alarm than using the naza's built in voltage protection. I might try and tune it again some other time, but for now the $1.50 i spent on the alarm does exactly what I want.