saturation with standard mixing table hexa+

[gionag]

Must test that...
What kind of rope do you use? How much tension and how do you connects each motors ?
Thanks

[LPR]

gionag

So many questions. I just used anything I had around. At first I used nylon reinforced tape. I just slip the string under the motor mount and over the tube arm. I'm sure you could tie them to the motors but I just let it rub on the mount. All your trying to do is stop the arms from being like tuning forks.
How did you like the video?

Larry

[gionag]

yeah... i liked the video of the uglyest octo i have ever seen (i'm just joking).

anyway... tried your method and the vibration is still there... but today i've changed props... APC SF 12X3.8 seems to be better (still no balancing at all).

i'm thinking of changing frame... maybe something stronger like quadframe (aka jakub). 21.5mm carbon arms seems to be stiffer to me rather than my 16s.

now i have also a new balancer. a top flite one.. hope to fix this. in the meanwhile... someone can confirm the quality of my inflight log ?

[gionag]

ok... maybe i've found the major problem.

flying with the motor mixing table suggeste by JussiH and using balanced APC 12x3.8 the things runs much... much smoother. now i think i have only to do some pid optimization and that's all...

no more saturation on motors..

so, at last, i think the mother of all my problems were the vibrations in my frame. AQ seems to be very susceptible to this kind of problem. i think because other FC act a very strong low-pass filtering on the sensors and, as far as i understand, aq count "only" on oversampling for reducing noise.

i suggest to point it out very well on wiki. "do not fly until you have a very vibration-less frame".

at the moment.... thanks to all of you.

[JussiH]

Great to hear, congrats.

I am sure we can find a place for a general warning on vibration problems!

We are working on a "vibration troubleshooting" section for the wiki. We are a limited number of people that writes and maintains the documentation and we all have other obligations in life (specially this time of year). So sometimes stuff just gets put back in the queue....but it will be done...sometime

[gionag]

jussi.. do you think there's a way to improve filtering ?
maybe bill can clarify this aspect.. but i think we can improve versatility if some sort of low passing will be available

[LPR]

[gionag]

[LPR]

gionag

I spent way too much time messing with mixing tables but I did get my octo to fly nice. From my experience I would try something like this motor mix.

motor--------Thro-------pitch---Roll----yaw
front left----100---------34------66---- -100
front---------100---------34--------0------100
front right--100---------34----- -66--- -100
rear left-----100------ -34-------66------100
rear----------100------ -34--------0---- -100
rear right---100------ -34----- -66------100 "

If you have your vibrations under control and the mixing table is right I found that default settings will work very well except for rate D and throttle factor. I needed lower rate D to 5800 and throttle factor to .6 for my octo to perform well in position hold and missions. You can see a video of the octo flying in AQ Media Showcase.

The higher the rate D setting the slower attitude changes and the less wobble you will have.

Larry