Developer

APM now supports Differential Ailerons



Sometimes APM development goes fast, and sometimes it goes like molasses in winter. After being asked repeatedly (over many months - sorry) I have finally gotten support for multiple aileron channels in place. You can use this if you want to set your airframe up with differential ailerons or if you have separate servos on your ailerons and they don't move opposite directions for a given input.

 

The big delay with this change was coordinating the way we would use channels 5-8 for a variety of purposes.  Functionality is coming for flaps, camera mounts and more.

 

Here are the things to know about using the new dual aileron functionality:

  1. I have tested this on the bench, but have not flight tested it.  I do not expect any problem, but as always with new functionality exercise some caution.
  2. The functionality is in the current version of the code in the repo (trunk).
  3. You can set up the second aileron on either channel 5 or 6.  Remember that it does not matter which channel it is on your receiver.  Just take that receiver output and hook it up to 5 or 6.
  4. For that channel (5 or 6) you will need to set a new parameter.  For channel 5 it is rc_5_funct.  You can set this as a parameter through a GCS like APM Planner, or you can set it using a #define in your config file.  If you set it in your config file use #define RC_5_FUNCT RC_5_FUNCT_AILERON.  If you set it through the GCS set rc_5_funct to a value of 1.
  5. If you want to use differential aileron travel program your radio so that it works as you desire in manual mode.
  6. You will need to redo your radio calibration.   I do not know if APM Planner properly supports calibration of channels 5 and 6, but I will drop Mike O an email about it and I'm sure if it does not now, it will very soon.  The CLI procedure does work fine.
  7. You cannot set the reversing for the 2nd aileron channel with the dip switches (as there is not one available for this).  So, it is highly recommended that you disable the dip switches and set up your reversing using the parameters.  Remember that if you are working with the raw parameter values reversing is 1 or -1.

 

Views: 1025


Moderator Comment by Chris Anderson on August 21, 2011 at 4:20pm
Great news. How should people get this version of the code?

Developer Comment by Doug Weibel on August 21, 2011 at 4:29pm

It is available from the svn repository now, and a new build will be available through APM planner soon.

Comment by DaveyWaveyBunsenBurner on August 21, 2011 at 5:08pm
As someone with a bunch of Skywalkers on the ToDo list thanks!
Comment by Tom in ON on August 21, 2011 at 5:15pm

Excellent! And very timely!  Thank you.


Developer Comment by Andrew Tridgell on August 21, 2011 at 6:08pm

Hi Doug,

How does this interact with the hardware failsafe of the 328? If I switch chan8 to over 1750, will the 328 pass the extra aileron channel through to the servo? I thought it only passed through 4 channels?

 

 


Developer Comment by Doug Weibel on August 21, 2011 at 9:43pm
Hey Tridge,

Hardware manual mode will pass ch1-4 through by hardware and the 2nd aileron channel through by software, so switching into manual mode is no problem. Of course if the main processor crashes then the hardware mux cannot pass the 2nd aileron channel through. If that is really important for your mission you might look at one of the external mux boards. i think you can get one that will do 6 or 8 channels.
Comment by apocolipse on August 22, 2011 at 2:24am
I noticed in the source change log it was mentioned that the functionality could also be extended to flaps on channels 5-7. I was wondering if it would be possible to add Switch control in-> proportional control out (as flaps on real aircraft typically move slower than the input), 2-3pos switch for flaps seems to move them too quickly and a switch in -> smooth proportional curve out would be awesome

Developer Comment by Mark Colwell on August 22, 2011 at 1:17pm

Nice work!   Now  'Crow' mode is possible with flaps. Thank Doug.


Developer Comment by Doug Weibel on August 22, 2011 at 1:19pm
Crow mode - don't get carried away yet. Flap functionality exists using the set_servo commands, but I am working on improved flap functionality. I will work on flaperons after that. Crow is a combination of flaps and flaperons I suppose.

Developer Comment by Mark Colwell on August 22, 2011 at 1:39pm

Ok I will hold my horses, I need it for a Super Cub and Ventus 2.

 I will use AP 328 as Camera controller on second RC system.

 I will add external mux for full 8 Ch switching.

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