I received a new prebuilt Arducopter last week from Udrones and I am having some problems getting ti to fly with the stability that I am expecting.

I am partially there, but I need some help.  I have been pouring over all the information I can find, but some nagging issues seem eluding me, I can't seem to find the answers.

The Arducopter arrived with the standard blue motors, 20 Map ESC's The 2.5 MP, a Sonar sensor, The 3DR Radio kit and everything wired, and set up from Udrones.  I installed my radio receiver (Spectrum AR8000), installed, installed the Mission Planner, did the update, got it working on the USB port and got it working with the Radio (FT232 driver).

Here's the problem I have. In Flying mode "stabilize", initially I have a lot of drift, It flew exactly like a Heli that just has conventional gyro stabilization, which now I understand is what it is supposed to do, but It had a lot of bias, and even with no wind, would move pretty aggressively rather than stay in one spot. So I set up my other flight modes, position and loiter.

Positon hold seemed to be better but it still tried to wander and needed constant control of throttle to keep it at a particular altitude. Ok, so I guess that is somewhat normal except that I would expect it to hold its location better than it does. So then I tried the Loiter mode. In Loiter mode, it immediately begins climbing, and only if I drop the throttle to 0 does the climb stop. 

In testing that mode, I have learned to put the throttle back up to mid stick and then switch back to stabilize quickly.  

Then I found that in stabilized mode, by adjusting the trims for pitch and roll, I could get the Arducopter to remain fairly stable although I have to be very active on the throttle stick to maintain altitude. 

I ran the level routine with my ArduCopter completely level, with the trims back to neutral and tried a test flight again, and I still had to adjust my trims to get it to hover in in spot. 

I think I can deal with that, and will have to learn about adjusting the PIDS to get the stability I want.

1. Which brings me to this question: can I save my entire configuration before I start attempting to find tune the PIDS, so I can revert back to factory by reloading the configuration without having to re-install?

I started to try and figure out why it wants to climb when I switch to Loiter mode;  I wonder if the Sonar/GPS/BARO  combination is somehow needing to be tweaked, or if there is a faulty hardware, or setting. In the Mission Planner, under Advanced Params..

2. I notice that AHRS_BARO_USE is disabled "0"   Is that right?

3. the next parameter: AHRS_GPS_GAIN is set to 0, is that right?

Should those be enabled and set?

It seems to me that these settings might be relevant, but I am new to all this.

As a test, I have disable the Sonar, and I want to try a test flight to see how this affects the altitude stabilization, but unfortunately the winds right now are gusting beyond 20 MPH, so not a good time to test fly.

Here is the config that I have right now, does this look right for default PIDS for a new aducopter 2.5? the loiter Rate P seems higher than Pitch/Roll P values, but what do I know, none of these are messed with, are they correct starting points?

If someone could help me understand this, thanks in advance!


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Glad you're using the uBlox. As for the parameters, you should leave them at the defaults. Don't load another param file, as that might have been optimized for an earlier version of the software. 

Ok, sounds like a good plan..


Some questions about failsafe

When in the failsafe setup screen, there are two checkbox's one is labeled:

"throttle failsafe"

the other is labeled: 

"throttle failsafe action"


By default "throttle failsafe" was unchecked and 'throttle failsafe action" was checked.

I set up failsafe for my radio so that channel three goes below 975 if the transmitter is turned off.

I want that condition to trigger RTL.  I think i have done that right. but:

I don't understand the labels for the options in the failsafe setup screen, how are they to be used? I would also like to have a switch on the transmitter like my landing gear switch to trigger RTL.  

Not knowing what I am doing, I have checked the "throttle fail safe" hoping that is correct, but what the heck is "throttle failsafe action" ???

Yesterday altitude hold and loiter were mantaining altitude pretty well, this is after a lot of troubleshooting and trying different things because the original behavior was that as soon as I went to loiter or altitude hold, it would start climbing. I had set up "of_loiter" as the mode rather than "loiter" for loiter mode.. I test flew it after correcting that, I thought I had found the problem because it flew properly and didn't try to climb when activating either loiter or altitude hold  But I forgot, I did something else as well..

Once again, I fooled myself. one of the other things that I did was to disable the sonar sensor.  Today, I took it for a test flight after re-enabling the sonar and it went back to the previous behavior. I landed, went to the MP ad disabled the sonar again from the GUI. 

test flew it again and it held altitude pretty steady again. 

So it is pretty apparent that the sonar has something to do with it. Are there any tweaks specific the sonar sensor that could fix this?


it is prob a case that your sonar is getting noise from EMI, check out this post


sonar EMI

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