Replies to This Discussion

ModeratorPermalink Reply by John Church on December 13, 2011 at 8:31am

Hi,

I am sure that your issue is with vibration. The vibes are causing the IMU to think it's tilted. Either try to straighten that motor shaft or replace it and you should be good. If the shaft is good, are you trying to run crashed props? Either way, eliminate the vibes and you should be good.

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DeveloperPermalink Reply by jasonshort on December 13, 2011 at 12:43pm

You may need to recalibrate your ESCs after a bad crash. I've had them loose calibration like that many times.

Also check for increased vibration due to bent motor shafts, prop adaptors.

Also, make sure you have soldered the low pas filter pads on the IMU as per instructions in the wiki.

Jason

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Permalink Reply by Marc Puig Pasarrius on December 13, 2011 at 12:56pm

Connect it to the APM Planner and check if the sensors are responding ok. This seems a hardware problem, it happens to me a lot of times after a hard crash: a gyro looses contact to the board and then AC gets crazy. Then I have to reflow the board with a heat gun and an infrared thermometer to control the temperature limit.

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Permalink Reply by jjohow on December 13, 2011 at 6:17pm

Thanks for the quick response,

I removed the props,  and balanced the motors. Now there is hardly any vibration in the system. (I did fly before with really bad props and vibration, but I never had problems.)

Anyway - What else I did until now:

1.calibrated ESCs (I hope I did?! - Full throttle up (Ch3), power on, beep-beep, Di-da-di-da-di, throttle down, disconnect)

2. flashed new firmware.

3. checked sensor response in APM Planner. I can see the data produced by the sensors, but if what I see is cool?! I don't know. Looks alright. (what is a healthy gyro datastream?)

4. with no props I checked the copter response in STABILIZE mode. I reacts strange...e.g. when I tilt it around 45 degrees, one Motor does even stop. :(

--------------------

what I will do: Check all my Soldering (oh F**K!)

Thank you very much, guys! I'm really desperate.

Joerg

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Permalink Reply by Marc Puig Pasarrius on December 14, 2011 at 1:12am

To check if the gyros are ok you can watch the artificial horizon on the APM Planner, if it reacts according to the board movements then gyros are ok.

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Permalink Reply by jjohow on December 14, 2011 at 2:02am

Thanks for your help again!

The artifical horizon reachts totally normal. But I noticed, that right after connecting the APM to the missionplanner the compass drifts a little. Is this normal and beacause its all starting up and there is no gps lock? The drifting becomes really slow after about 30 seconds. When I move the copter, it stops. I dont know if it wqs there before.
I took the props of, balanced the motors and tested it with almost no vibration. At full throttle and with stabilize mode on when I tilt the copter hard to one side (about 45 deg.)the motors seem to react normally. But is it normal that the corresponding motor totally stops?! I really don't get whats wrong.

:(

Thanks again.

Joerg

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Permalink Reply by Marc Puig Pasarrius on December 14, 2011 at 2:10am

The compass drift is normal, it starts pointing to the north and then it moves to the correct heading. The motors usually stop when you tilt the copter at low throttle, so the behaviour you've commented is not normal. Have you calibrated your radio?

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Permalink Reply by jjohow on December 14, 2011 at 2:35am

Hi Marc,

I am happy it does not seem to be a problem with the compass or the gyros.
You mean the calibration in the mission planner? Yes - I did it over and over again.
I tilted the copter 45 deg. at full throttle and one motor stopped and sometimes it didn't come back on (!!!) - only when I tilted it hard the other way it came on. The motors seemed to not spin at 100% when I gave full throttle - or maybe I was mistaken because the props where off. (battery was full btw.)
Man... this really gives me a hard time. I think I'm gonna disassemble the whole thing and check my soldering. Or any other suggestions?!

Thank you so much.


Greets from Berlin.

Joerg

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Permalink Reply by Marc Puig Pasarrius on December 14, 2011 at 3:10am

Can you attach a flight log? For example the one recorded in the youtube video. Have you tweaked the default PID's?

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ModeratorPermalink Reply by John Church on December 14, 2011 at 8:00am

" Have you tweaked the default PID's? "

Good call. Take a look, jjohow, and make sure you don't have a decimal in the wrong place or something on any of your PID parameters.

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Permalink Reply by Gareth Rens on December 14, 2011 at 11:49am

Also check the soldering on the actual motors. I had an issue (after a crash) where there was a dry joint on the one motor wire and had a similarish problem.

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Permalink Reply by Gareth Rens on December 14, 2011 at 12:01pm

Although watching the video, it looks like hardware problem to me. If it was software, re-loading the firmware should of sorted out the problem...

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