Hi,

I'm a first time APM user in Multicopter, but not arduplane. I'm having an strange problem here, I made almost all the hardware configurations required (but not compassmot) when I start the motors (without propellers) even if I keep the throttle at minimum it keeps going up and accelerating, I used acro or stabilize mode and the result is the same, doesn't matter the position of the throtlle, as soon as I let the stick in the place, it will go up... and if I change position it goes to the original throttle again.

What I'm doing wrong?

Thanks

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Sounds as though your ESCs are programmed for 'soft-start.'
I've not had this issue before, not much help there. What ESCs are you using?

Its not the ESCs, they work perfectly on YS-X6 and they're Blue Series 40A with SimonK software, so no possible soft-start. Anyway, when I connect the ESC directly to Futaba they work as they should. 

Please see the video below to understand whats happening. 

http://www.youtube.com/watch?v=8MDeLUGh-Lc

 

I had something very similar happen to me at one point. For whatever reason my radio calibration had been wiped out and I had to redo it. Never did find out how I lost calibration. You might make sure the APM is recognizing your radio inputs on the radio calibration page.

Hi Tom,

Its not that, the radio calibration is ok and its recognizing the correct values.

As I said, if I connect the escs directly to futaba throttle channel, it works. 

 

The ESCs working when directly corrected to the Futaba receiver don't prove the calibration is correct. It shows the problem lies in the APM, not the transmitter. In Mission Planner in the radio calibration section the red lines on the green bars should be where they are supposed to be.

Another thing you can do is run another test as you did in the video, and have a look at the log the APM generates during the test. Under the CTUN category there are recordings for throttle in and throttle out. They should be the same value. If not there are other values in the log that could shed light on what's happening.

Um....Silly question maybe, but on that Futaba (which is the same model I have) you wouldn't maybe have some weird throttle curve set, would you?

I've never yet understood why people find it easier to post a video than they do to post logs :(

Hi, sorry for the delay. Here are the rlog and tlog with the "problem" (I don't know its a problem yet, its just strange) 

https://www.dropbox.com/s/uleqrh6a72esvxx/2013-08-19%2011-47-12.rlog

https://www.dropbox.com/s/e50ccvk29st44mb/2013-08-19%2011-47-12.tlog

Please take a look and tell me whats wrong... 

Dataflash log would be better...

With the disclaimer I'm still new to this, I'd say nothing looks too strange. Your throttle calibration (Channel 3) looks OK. Under the CTUN logging your throttle in matches your throttle out throughout.

In the smaller of the two logs, the first one you list, there is no record of a full throttle command. The values are generally in the 100s to 200s, pretty low. The highest throttle I saw was about 400 (that's 40%).

The second log shows a bit of runup to a full throttle and a couple of later brief peaks. But since the throttle in matches the throttle out, these look deliberate on your part:

So I'm wondering something. Did you do this without props on the motors? I ask because someone else recently mentioned a similar problem, testing without props. I am curious if there are certain combinations of motors/ESCs/ESC timings that cause motors to speed up with no load, rather than hold a steady speed. A way for you to test this would be to install the props upside down so the craft is forced to the ground if the motors get away from you. I would bet that with a bit of a load on them the motors will hold a more steady speed.

Hi you are testing without any load on your motors,try putting your props back on but instead of putting them on where they should be move them around one position at a time for each prop,and put props on upside down.now get some clamps and fix the quad to the table or bench so it cant move.then repeat the same procedure as you did in the video.by putting the props on upside down you are pushing air up through the quad rather than down so the quad can't possibly take off,you can then do another re-callibration of your radio but this time it will be as it should be with props on.don't know if this method will give you a better indication of the issue through mission planner.

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