Re: Using custom mixes
« Reply #30 on: January 24, 2016, 06:10:46 pm »
The solution: 
Select "Curve 2" to be linear from -1 to +1, was ok. But Accessory1 center position has to be 1000 (so the behaviour is the same as for throttle).
Thank you for reading.

Brunosanta

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Re: Using custom mixes
« Reply #31 on: April 04, 2016, 01:46:04 pm »
Hey guys, reading the wiki and checking the calculations, I understand we would need a mix change to one side or another talking Pitch or roll in two cases: one if the quad is unbalanced or only two motors tipped forward, and your PIDs are set low for a aerial photography, and second if your board isn't placed dead center on the frame. Then I have one big question myself, why do I have 127 as a mix when I understand it should be a maximum of 100 per cent? am I crazy on that one?
Everybody is only optimistic on the social networks.. being real is hard nowadays

12many

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Re: Using custom mixes
« Reply #32 on: April 05, 2016, 09:05:02 am »
...
A problem is that simple measuring doesn't handle asymmetrically distributed mass (e.g. heavy camera in front and heavy battery in back, but no added mass left-right).
...

Just a random idea, add the concept of moment of inertial (which I think you're referring to), probably in the PID and not the mixer.  To keep it simple probably a simple X to Y ratio would be sufficient for most needs.  It might be a good thing to neutralize this effect (not that it's really causing problems) since most vehicles have, as you say, heavy components mounted mid forward axis but little to nothing on the lateral axis.  Then experimentally find a good (probably fairly low) baseline default.  Just thinking out loud...


12many

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Re: Using custom mixes
« Reply #33 on: June 13, 2016, 02:14:53 am »
    More complex frames like Hexacopter or Octocopter do not use the same logic like your online mixercalc but this one: http://wiki.paparazziuav.org/wiki/RotorcraftMixing

I just wanted to mention that the python script referenced on the paparazziuav page is scaled to +/-256 bu default but LibrePilot GCS uses +/-127, so people  trying to use the script should replace the mm.print_xml() line with mm.print_xml(scale=127).  Or you can just divide it's output by two.

Also, the easiest way to edit custom mixer settings is:  On the System page go to Settings / SystemSettings and change AirframeType to Custom.  This will enable editing of the mixer table  on the Configuration page.

Anyone, please correct me if you think the above is incorrect.

It took me a little while to figure this stuff out, so I hope this helps...
« Last Edit: June 13, 2016, 03:41:08 am by 12many »

12many

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Re: Using custom mixes
« Reply #34 on: June 13, 2016, 03:33:40 am »
I expect to be playing around with several new multi-copter frame configurations and am wondering if people might be interested if I added a motor mixing calculator to GCS?

Right now I'm thinking of hanging a new page off of the custom vehicle type page.  It would contain a table where the user could input X,Y,Direction & see entered rotors graphically depicted on the page as well as the calculated yaw, pitch, roll, etc values displayed.  Then allow the user to push the calculated values into the existing custom page's mixing table.   Basically it would be more or less a port of the paparazziuav.org RotorcraftMixing perl script, just tailored to GCS.  Sort of like https://www.iforce2d.net/mixercalc/ but not so funky.

I know such an enhancement isn't exactly a highly requested feature.  Would such a pull request be accepted?  If no, that's OK, but I'd probably not bother unless you guys think it might help others.

Re: Using custom mixes
« Reply #35 on: June 25, 2016, 07:24:24 pm »
I think it sounds like a good idea.

Maybe a "custom multicopter" configuration so the code could be made to know that it is actually a multicopter.  Currently the "custom" configuration does a few things differently than any of the multicopter configurations.

Define the center as the center of mass and it can even handle the different thrust levels required when a multicopter is not perfectly balanced.

12many

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Re: Using custom mixes
« Reply #36 on: June 25, 2016, 09:55:13 pm »
Yeah, I've learned that 'custom mix' is pretty raw and not exactly a great UX, at least not right now.  Which is ok, what I'm doing isn't exactly mainstream.

What I (personally) like about my implementing a 'custom multi' page is that it will be a fairly isolated, seldom-used corner of GCS so my development 'efforts' :-[ won't effect mainstream users while I get up to speed.  I.e. I won't be crashing people's vehicles due to FC bugs.

@TheOtherCliff - side question:  I'm mulling over evaluating a counter-rotating coaxial prop configuration.  From what you know about mixing do you expect any issues with defining two motors at the same XY location but with opposite rotation direction?

Such a custom multi page would also be a good place to experiment with coaxial upper/lower prop throttle bias to find highest efficiency, which is on my to-do list.

Re: Using custom mixes
« Reply #37 on: June 27, 2016, 09:42:01 pm »
The way the mixer handles it, there wouldn't be a problem with it.  The mixer says: given these 4 transmitter controls, what does this particular motor do?

The other side of the question is whether a GUI would have a problem with it.  It could, but it would be simple to handle it.  For instance the GUI could be designed to use "angle and distance from the center".  Angle would be undefined in this case, so it would have to take that into account.

I created a tracking issue to implement this.  Of course it still needs someone who wants to do the work.

12many

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Re: Using custom mixes
« Reply #38 on: June 27, 2016, 09:54:05 pm »
I would really like to contribute to this.  Wish I could devote more time and had more (any) Qt experience.  Not sure I'd be much of a help.  12-2am time slot?  May become a much higher priority in a few weeks depending how things develop.

Re: Using custom mixes
« Reply #39 on: August 10, 2016, 11:00:50 pm »
How do i put this info into Libre Pilot so my quad will fly like a sports car instead of a school bus

mmix 0 1 -1 0.778 -1
mmix 1 1 -1 -0.788 1
mmix 2 1 1 0.778 1
mmix 3 1 1 -0.788 -1

f5soh

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Re: Using custom mixes
« Reply #40 on: August 10, 2016, 11:11:33 pm »
For school bus or sport you should take a look at Stabilization tab and adjust Rates.

https://librepilot.atlassian.net/wiki/display/LPDOC/Advanced+tuning