Quadcopter Back Right Dipping

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Arducoper ACM
What steps will reproduce the problem?
1. Power quadcopter
2. Try to fly

What is the expected output? What do you see instead?

Level flight is expected but instead the back right arm is dipping at a 5 
degree angle.  

What version of the product are you using? On what operating system?

Latest version of the software using Windows 7.

Please provide any additional information below.

We have tried switching out the ESC and the motor for the propellor but no 
matter what it dips durring flight and thus we can not stay level at one 
location.

Original issue reported on code.google.com by MRP2...@gmail.com on 7 Jan 2012 at 10:32

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I have observed a similar issue with my new quadcopter. I also replaced the ESC 
and motor with no change. I have observed the following symptoms. After radio 
and motor calibration, the right back motor does not start spinning with the 
other three motors when the throttle is advanced from dead stop. (This is in 
flight mode)The right back motor starts spinning after continuing to advance 
the throttle. I have checked the motor RPM and it appears to run slower than 
the other three motors for the same throttle setting. Perhaps their needs to be 
an ESC calibration curve for each motor within the autopilot?

While trouble shooting the problem, I used the terminal CLI mode to run the 
motors test to check for proper mixing of the R/C commands. When I used any 
joystick command that required the right back motor it would not spin. My next 
step is to put a scope on multiple PWM signals to see if there is a problem 
with the APM output. I have tested each ESC individually with the R/C receiver 
and they work as expected. 

Original comment by tomk5ry@gmail.com on 13 Jan 2012 at 5:21

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It's pretty unlikely that these are ACM software issues.

It's more likely that it's something to do with how you've mounted your APM (is 
it perfectly flat?) or possibly your radio (do trim resolve the issue)?

-Randy

Original comment by rmackay...@gmail.com on 14 Jan 2012 at 12:15

• Added labels: ACM, Quad

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right back motor does not start spinning with the other three motors when the 
throttle is advanced from dead stop 
You have a bad bearing.

Original comment by jasonshort on 14 Jan 2012 at 12:17

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@ rmack... While watching the wireless telemetry data I can see that the gryo 
knows that it is hovering at an angle. It doesn't matter if the board was 
mounted lopsided because the software should be trying to level out the  copter 
which in our case it was not trying to level out. 

So my props don't start spinning at different times but they use to. I have 
tried replacing the motor and the esc and this has not resolved my problem. 

As for the radio issue how can I test that? 

Thanks for your help

Original comment by MRP2...@gmail.com on 14 Jan 2012 at 1:33

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@MRP2189,
   Presumably if you adjust the trim on your radio you can get the copter to be level?  If 'yes' then this indicates that the radio (or mounting of the APM) could be the problem.
   Try using the CLI, test, radio.  You should see values streaming by, the first three columns are roll, pitch and yaw respectively (in particular they show what the APM thinks you want the angle to be multiplied by 100.  So if you see 500 that means the APM thinks you want it to lean at 5degrees).  So when your transmitter sticks are in the middle you should see zero for all three of those.
    Of course you've run the level command either through the AP MissionPlanner set-up screen or through the CLI?

Original comment by rmackay...@gmail.com on 14 Jan 2012 at 2:22

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So I was able to make it level during flight by adjusting the default settings 
on the radio. The problem is when ever it takes off it still favors the back 
right which is weird. Also when the Quadcopter is in the air it wobbles a lot 
could this be caused by the same issue or is that something else? 

Also thanks for the idea on the radio I wouldn't have thought of that. 

Original comment by MRP2...@gmail.com on 16 Jan 2012 at 3:47

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@MRP2189,
     Wobbling is much more likely to be that your not on a standard frame so you need to modify your Roll and Pitch PI values for Stabilize's using the APMissionPlanner.  Try making them 20% lower.
     Looks like this particular issue is fixed so I'm going to close it.  hope that's ok!

Original comment by rmackay...@gmail.com on 16 Jan 2012 at 12:00

• Changed state: Invalid