Replies to This Discussion

3D RoboticsPermalink Reply by Chris Anderson on June 28, 2012 at 3:51pm

Maybe your ESC/BEC can't handle the current and it's browning out? You need a pretty beefy BEC to handle APM + four servos.

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Permalink Reply by Adam Haggerty on June 28, 2012 at 3:56pm

its the castle 10amp, its good

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Permalink Reply by Adam Haggerty on June 28, 2012 at 3:57pm

also if it helps, i can recreate this every time i boot up

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3D RoboticsPermalink Reply by Chris Anderson on June 28, 2012 at 4:00pm

Probably something to do with your EZUHF > ppm sum out setup. I've never tried that. 

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Permalink Reply by Adam Haggerty on June 28, 2012 at 4:10pm

I think the ppm sum is being truncated so it doesn't read above chan4 after a bit.  I've heard of this happening when the apm reads a null value (it will use the last known value).

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Permalink Reply by Michael Pursifull on June 28, 2012 at 8:36pm

What did you configure 5-7 as? Do you mean they are not responding to RC tx inputs? Do you see those channels respond in the TX calibration page, or in the "status" page from Mission Planner? 

Are these also control surfaces, or are they camera servos, or something else? 

What version of code are you running? Did you calibrate the TX in Mission Planner? What mode are you in when this happens?

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Permalink Reply by Adam Haggerty on June 29, 2012 at 7:04am

Good questions, ask all you want if it helps I just want this thing to work.

First off all servos are micro servos (9g).  What I mean is, for the first 10 seconds, the control surfaces move correctly to my stick inputs, then 5,7 freeze and hold their last known position.  So if I hold aileron hard left, after 10 seconds the channel 7 aileron stays in that position from then on.  The channel 1 aileron continues to respond.

1) What did I configure 5-7?  On my futaba 5,6 are right flaps, left flaps respectively.  Channel 7 is aileron 2, which gets it's signal from the aileron differential program in the futaba (sends reverse of channel 1(ail1)).

2) In mission planner when plugged/powered by usb, when I configure Tx throws (firmware tab>apm setup button), all inputs seem to respond fine.  Roll left and right are correct, etc etc.

3) I haven't checked anything in the status page.  If this would be helpful I will do so.

4) Like stated, all 6 servos (throttle is channel 3) on channels 1,2,4,5,6,7 are control surface servos.  I am running a skywalker with a 4 servo wing (2 independent flaps, 2 independent ailerons).  The tail has rud/ele servos also.

5) I have only ran updates through the mission planner.  When I start the program it updates itself, then I loaded the arduplane firmware yesterday.  I'm looking at it now and it says under firmware tab, arduplane v2.4

6) The mode I believe is stabilize, but I will try manual as well today.

I hope this helps, let me know if you want me to test anything else.

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Permalink Reply by Michael Pursifull on June 29, 2012 at 9:16am

#1 - I mean, what did you configure on the APM to tell it to do with these channels? I suspect this is the issue. You told the TX what you wanted done with these channels, but not the APM.....

#2 - good, that is the second step, after the TX.... the TX has to work, the APM has to see the TX inputs. But now we go back to #1, the APM has to know what you expect done with these signals, when we are not in manual mode. Try it, as you said in #6, in manual mode, and everything should more normally.

#3 - you'll see on "status" that the channels in are changing. But we haven't told APM what to do with these inputs yet. The default setup on an ArudPlane is for a four channel plane. Ailerons - ch1, elevator - ch2, throttle - ch3, rudder - ch4. There are easily configured options for differential ailerons, and for flaps. For everything else, you are off the map, in your own special place. 

#4 - that sounds like fun. Err...but why so refined control? Do you maybe want differential ailerons rather than independent ailerons? Why independent flaps? 

Have a close look at:

http://code.google.com/p/ardupilot-mega/wiki/MultipleAilerons

http://code.google.com/p/ardupilot-mega/wiki/Flaps

Here is the index to the functions for each aux channel (5-7)

k_none = 0, ///< disabled
k_manual = 1, ///< manual, just pass-thru the RC in signal
k_flap = 2, ///< flap
k_flap_auto = 3, ///< flap automated
k_aileron = 4, ///< aileron
k_flaperon = 5, ///< flaperon (flaps and aileron combined, needs two independent servos one for each wing)
k_mount_yaw = 6, ///< mount yaw (pan)
k_mount_pitch = 7, ///< mount pitch (tilt)
k_mount_roll = 8, ///< mount roll
k_mount_open = 9, ///< mount open (deploy) / close (retract)
k_cam_trigger = 10, ///< camera trigger
k_egg_drop = 11, ///< egg drop

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Permalink Reply by Adam Haggerty on June 29, 2012 at 11:18am

Thank you so much, I haven't tested this yet, but it sounds like exactly my problem.  I had assumed it was a ppm sum issue.  In answer to your question... the reason I set up individual channels for flaps and ailerons is because... well basically because yes, I want differential ailerons for smoother rolling and as far as flaps go... well basically because I installed the flap servos symmetrically.... so if I send both servos the same channel output (y harness) their direction of travel will be reversed.  Maybe I should flip one servo around and just pair them on the same output?

Obviously I'm no expert at programming or functionality of the apm, but it makes sense now.  Only thing that I'm unsure of is the following:

In the aileron/dif aileron setup you linked, it mentions inputting receiver ail output to channel 5 or 6 input on the APM.  The problem is... I'm sending the ppm sum (on a single servo channel) to the APM... so there is no way for me to swap around input/output numbers.  Ail2 is on channel 7 (because futaba requires chan7 for the differential aileron programming).  So I'm stuck with channel 7 output needing to arrive at the channel 5/6 input.... and no way to change it around.

Does that make any sense?

And by the way.... you are great thanks so much for your time!  I was pulling my hair out trying to figure out what was wrong.  I'll test it in the next 30 minutes and let you know if manual mode works!

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Permalink Reply by Michael Pursifull on June 29, 2012 at 11:23am

yes, it makes sense. However, you can change which channel the futaba uses for differential ailerons. I don't know of any other solution when using ppm sum, sorry. Maybe someone else does. 

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Permalink Reply by Adam Haggerty on June 29, 2012 at 11:37am

Ok I'll try to set aileron2 to channel 6.  Testing the manual mode now.  Is it standard to combine flaps to a single output and just invert servo mounting direction?

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Permalink Reply by Michael Pursifull on June 29, 2012 at 11:58am

It is customary to use one channel for flaps. Otherwise, they become ailerons. You always want them to move in sync. There are a few ways to reverse one of the servos, even without flipping it around. 

You could use one of these: http://www.graysonhobby.com/catalog/servoreverseryharness-p-1216.html

Or one of these, with a standard y connector: http://www.google.com/search?client=safari&rls=en&q=reverse...

Or you can mod the servo (analog) like this: http://www.youtube.com/watch?v=EK_FdRTenl0

See also http://www.rcgroups.com/forums/showthread.php?t=1250731

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