I'm working on altering some elements of the Arducopter code to add support for 4-servo, 90 degree CCPM and could use some help from developers with experience with the code base.

It seems that the only files that need changing are in AP_MotorsHeli (.cpp and the header file) but perhaps I'm wrong in that assumption. I've tried some preliminary changes but upon uploading it to the APM through the Arduino IDE I noticed no alteration in the behavior of the system.

I suppose the problem can be broken down into two parts: re-purposing one of the auxiliary channels (presumably either channel 6 or 7) to drive the fourth servo, and altering the CCPM to apply roll and pitch discretely to the two pairs of servos.

You can view the alterations I've made over at my Github repository. Please bear in mind that these changes don't preserve the regular 3-servo CCPM setup; I wasn't expecting to have this work integrated into the official release.

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Can you boot it up, connect to MP, turn on the live tuning window and display your Ch8 input, and Ch8 output, and see if there's anything happening there?

Also make sure you're using the correct version.  I hope we can focus the testing on AC3.1-rc7 because that's the latest and (hopefully) greatest and we don't yet have confirmation that it works ok for trad helis.

Randy, I've actually been using rc7 on this heli with the PX4.  So far it's looking OK on the bench.

Now if I could ever get the darned thing airborne....  :(

There's only so many levels of comment indenting you can use, like 5 or 6.  That's why you can't reply anymore.

I have no idea at this time what the problem with Ch8 could be.  I haven't had any time to put into that.

I use Tortoise GIT which is a GUI on top of GIT that I like a lot.  Basically to update, you have to set up your GIT to point at the main repository as an Upstream Remote, and then pull from that.

Re why no output on ch8, maybe the H_RSC_MODE parameter is set to 0?

Randy, I believe he did.  He said he tried both modes.

I don't quite understand the question.

Typically we don't send a "throttle" signal through the APM.  But we use Ch8 to turn the motor on and off through the APM.

did anyone get any further with his ?

We have a large helicopter with a 4 servo 90 degree squashplate setup and would like to use Arducopter with it, does anyone know if there has been any progress on supporting this, either in 2.x or 3.x?

If it is not supported out of the box we will likely try to add support ourselves using ChristopherBonner's code so would be interested to hear what the best way of doing this is.

As far as I know, 4-servo support hasn't been added.

Wondering if the 4-servo setup ever got added? Sorry to revive an old thread, but I'm working on retrofitting a Sniper A800 for pixhawk, and am struggling with servo setup.



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