Solar Falcon first attempt with ArduPilot and Nunchuck Acc

my first ground test with APv1 was full of problems. till last summer i am working on my hand made airframe. finished the plane and solar wing is connected and tested. system works well, i tested it for 55mins until my radio battery drained.
system: 35 mhz 6 ch radio (because im planning to use 900mhz x-bees for telemetry and 2.4ghz video downlink), solar wing with ailerons, planned to use APv1 on throttle and rudder. stabilization on ailerons and elevator with a hand made system consisting of a Nunchuck accelerometer connected to another Arduino clone and a working software adapted from the work of Andrea Salvatore. first attempt with a Diecimila which worked well but clumsy and heavy. next try was with a Funnel IO which is very small but connections too weak, especially battery connector disconnects often. last try was with an old Ardupilot BetaV3 board used as an Arduino clone which proved as the best alternative.
Apv1 connected, throttle on input1 rudder on input2 ctrl on ch5. APv1 software uploaded flawlessly by Arduino IDE.
when ESC connected everything looks fine. power led is on, Mux led is ok when engaged via ch5, rudder moves when toggled, GPS lock led is solid within seconds.
problem issues:
1- when AP is engaged via ch5 rudder moves and throttle is on for a few turns and then spinner stops. when disengaged, problem persists, spinner stops after few turns although stick at full throttle position... possible cause: not enough power for brushless motor?.. although the solar panels are connected to support battery with 1.2Amps... not a problem when AP board was not in the system...
2- loss of signal simulated by shutting off the radio. Mux led and status led is blinking. AP moves rudder and tries to apply some throttle, spinner is on for a few turns and stops. the elevator moves down immediately (that is weird because it is not connected to AP)... possible cause: rf intervention to receiver which has lost signal... thank god the plane is not in the air...
any suggestions and help will be appreciated... i can provide some pics and video...

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Comment by dincer hepguler on May 1, 2009 at 7:17am
Chris,
actually my throttle from Tx ch3 going to AP in1, esc coming out from out1 as in your diagram... i think this is the correct wiring.. in2 and out2 connected to rudder... yes, the throttle power isnt enough even when the AP disengaged via ch5, mux off... the spinner turns for a few seconds then stops in both case, even when the mux off and throttle stick at full throttle position... i know its weird but something with the AP board limits thrttle power... no probs with the servos though... they work well...
Comment by Reto on May 1, 2009 at 7:37am
Hi Dincer. Did you make a test with your 35mhz Rx and ESC alone directly connected? Does it work flawlessly? This to check if the problem could be on the side of ESC. Remember that many ESCs do auto throttle stick calibration on the fly during power up to adapt to different Rx brands. I wonder if it could be that, I'm not sure. Maybe if you have another ESC brand laying around you could try that out with your setting.
Another potential source of problem is current capacity of your BEC (probably Bec included in ESC). Most have limited current output (1-3A). If you have servos + 2 Ardu boards + Rx + Xbee it's drawing to much?
You could see if its the last problem, when connecting your ESC directly to Rx (not through Ardu board) and leaving the rest as now. If it's shutting down the brushless after few spins, then the problem could lie in the BEC drawing too much.
Comment by dincer hepguler on May 1, 2009 at 7:52am
thx Reto,
i will check with the ESC now... i have some extra esc lying around and will test with some other... all my escs are with bec (no external) and need to check the settings... the settings calibration is really pain and i hate the procedure and dont know the basics as well... i will check this aspect now... thx again for the suggestion...
Comment by dincer hepguler on May 1, 2009 at 8:23am
thx Reto,
i diagnosed the problem with ESC... the settings have been changed somehow and throttle doesnt work as before even when the AP is removed from the system. will try to make the calibration again.. the calibration procedure with the throttle stick is a pain as i told before and i hate it. will try the other Turnigy ESC which has a seperate calibration device for the purpose.. Now, do you have a suggestion too for my other problem stated in the post.. while simulating the signal loss, i shut off my radio, Ap engages in and moves the rudder for RTL i think but elevator moves down immediately although it is not connected to AP... a possible rf intervention???
Comment by Reto on May 1, 2009 at 8:51am
Dincer, I think it's good if check the ESC/BEC. As to the elevator, since it is not connected to AP but only to Rx, when you turn off the Tx, the Rx has no signal data to feed the right pulse to the servo anymore. If it goes down on your Rx, in my mind it could be an indication of a Rx failsafe function. If the Rx has no failsafe function, it's impossible to predict the servo behavior when signal is lost. If on the contrary it has a failsafe, it is at the moment set for having the elevator down! You may check this by trying to push on the servo arm when in such down position and listen to the servo reaction. If you feel there's a resistance to keep the arm in position and the servo is working, then it means the Rx is feed exactly this down position continuously to the servo. In that case you only have to find out how to program the failsafe to have it as you'd like. This depends on Rx and I cannot be of any help. I hope the elevator problem is something like that. You may also try to use another Rx channel with the elevator to check if the behavior is similar.

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