Drone flipping over
« on: September 26, 2017, 03:46:24 am »
Hi guys,

I am building my first drone and was able to get through all the configuration steps, including calibration and it arms properly.  Motors are spinning correctly (CW and CCW), propellers are mounted correctly.  I'm using a CC3D controller with a Flysky T6 transmitter / receiver.  I ensured the controller was absolutely level when I went through the accelerometer, gyro calibration process.  I did notice that even after that process the virtual image of the drone keeps moving around on the "Flight data" tab even if I keep the drone perfectly still.

When I arm the drone and push up the throttle, it immediately tips over to one side.  Is there a "basic" tuning / configuration I should be using for PID settings ?

« Last Edit: September 26, 2017, 03:51:41 am by DroneAcharya »

Re: Drone flipping over
« Reply #1 on: September 26, 2017, 04:44:51 am »
See this post for a list of things that can cause flipping.

Re: Drone flipping over
« Reply #2 on: September 30, 2017, 02:41:39 pm »
Thanks.  I went through the checklist as follows:

- FC not mounted with arrow forward (and ESC connectors on right side)
   Checked.  FC is correctly mounted.
- ESCs connected in the wrong order
   Checked.  ESC connections to FC are in correct order.
- wrong motor spin direction
   Checked.  Spin direction is correct and propellers are mounted right side up.
- wrong prop type on motors
   Checked.  Correct prop type installed.
- PIDs incorrect (try stock PIDs)
   Set PID to default.  This may have helped.
- ESC signal configured too slow for the PIDs (try PWMSync or PWM-490Hz)
   Set to PWM 490Hz.  I noticed the default on LibrePilot was set to 490Hz for 2 fields and 50Hz for the other two.  I changed all to 490Hz.  Could this have been the primary issue ?
- very bad ESC calibration
   Re-ran calibration after making the drone "very" level using decks of cards and an electronic level on top of the FC.  Might have helped.
- taking off from a hillside
   Actually put the drone on top of a tripod to get rid of "ground effects" on take off.
- moving the sticks before it is in the air
- increasing throttle slowly during takeoff (you should arm and immediately take off from level ground with a jump up to knee high)
- disabling "zero the integral when throttle is low" on stabilization page (why do newbies do this?? :) )
   Done.  May have helped

So, great suggestions.  Thanks !  And they seem to have worked - I think it was a combination of things.  The drone took of and flew for a while.  I noticed that it continuously (but slowly) yaw-ed in the counterclockwise direction during flight even though I did not use yaw at all.  Is there a way to debug the issue by downloading flight data and posting it to this forum ?  Or other thoughts on where I should look ?

Thanks again for the help so far.

Re: Drone flipping over
« Reply #3 on: October 01, 2017, 07:54:29 pm »
Yaw drift is usually caused by moving the quad during gyro init (a few seconds after power on and/or at arming time).  A human is not motionless enough.  It must be sitting on a firm unmoving surface just after plugging in the battery.

It can also be made worse by badly calibrated ESCs, mismatched motors or props, and very weak thrust.