Quickly ascending with no control; Altitude Hold activated ?

Quickly ascending with no control; Altitude Hold activated ?

Postby pajarito » Fri Sep 21, 2018 6:37 pm

I have just built a multiwii quadcopter.

The configuration is this:

MultiWii 2.4
FM Receiver with ONLY 4 channels
1000kv motors
10A ESCs
Arduino UNO main board,
GY-86 board for accelerometers+gyro+magnetometer+barometric sensor connected via I2C
GPS CRIUS connected via I2C
Bluetooth link connected via serial port
I covered barometric sensor (MS5611 inside GY-86) with foam to prevent barometric readings being altered by winds, propellers, ...
The foam is also inside a white pvc enclosure fixed with a nylon screw.
The GY-86 is plugged through pins at one side to be connected to Arduino UNO

Arduino with receiver, Bluetooth and GY-86:
20180918_224553-control.jpg
stack control


I firstly tested the quadcopter with a MPU6050 IMU (not GY-86). No problems except one ESC was not calibrated and at first it was a litle bit difficult to control.
So, I calibrated all ESCs

I then replaced the MPU6040 with Gy-86 and added CRIUS GPS
Testing it I experienced a smooth flying, but after about 2 or 3 minutes, the quadcopter suddenly ascended very quickly !! at about 20 or 30 meters !! without given any order to do that.
Trying to get it down it was impossible. Throttle stick was not responding. It would have been a good idea to disarm the motors so that it would fall, but due to the nerves it did not occur to me at that moment. So pulling the elevator lever all the way down I crashed it against the top of a tree. The crash was very strong, but fortunately it broke very little and I could repair it right away.

So, I read this thread
http://www.multiwii.com/forum/viewtopic.php?f=8&t=7928&hilit=baro
About possible barometric sensor influences by wind and so on...

But the issue is that I dind't activated baro mode, nor any other mode.
And I could not have done it because my rc transmitter only have 4 channels. I would have needed at least one more channel (for AUX).

So, the question is: What the hell happened? Is there any clear way to fix it? Any ideas or suggestions?
Did something activated strangely the baro mode ...? What can I do to search what it could be the problem?
I think it is not wise to fly it again until the problem is identified...
Thank you in advance,
pajarito
 
Posts: 4
Joined: Fri Sep 21, 2018 4:24 pm

Re: Quickly ascending with no control; Altitude Hold activat

Postby PatrikE » Mon Sep 24, 2018 6:24 pm

Hi and welcome.

Hard to say what happened.
But initial guess is some failsafe glitch.
Maybe starting a RTH in failsafe.
First climb then fly home.
PatrikE
 
Posts: 1944
Joined: Tue Apr 12, 2011 6:35 pm
Location: Sweden

Re: Quickly ascending with no control; Altitude Hold activat

Postby pajarito » Tue Sep 25, 2018 7:32 pm

Thank you PatrikE

These are the code lines in my config.h:

Code: Select all
    //#define FAILSAFE                                // uncomment  to activate the failsafe function
    #define FAILSAFE_DELAY     10                     // Guard time for failsafe activation after signal lost. 1 step = 0.1sec - 1sec in example
    #define FAILSAFE_OFF_DELAY 200                    // Time for Landing before motors stop in 0.1sec. 1 step = 0.1sec - 20sec in example
    #define FAILSAFE_THROTTLE  (MINTHROTTLE + 200)    // (*) Throttle level used for landing - may be relative to MINTHROTTLE - as in this case
   
    #define FAILSAFE_DETECT_TRESHOLD  985


So, as we can see in the first line of this piece of config.h code, I have FAILSAFE function disabled... Seeing this it seems to me more mysterious...
If it was a failsafe glitch ... How could the failsafe function was activated?

I will try to make other tests... maybe using other receiver with more channels and with 2,4Ghz...
But very carefully, just in case the problem persists...
Jorge
pajarito
 
Posts: 4
Joined: Fri Sep 21, 2018 4:24 pm

Re: Quickly ascending with no control; Altitude Hold activat

Postby pajarito » Tue Jan 08, 2019 12:38 pm

I changed the receiver for another one, NOT FM, but AFHDS...

Looks like it fixed it up: The problem did not appear again...

THANK YOU!
pajarito
 
Posts: 4
Joined: Fri Sep 21, 2018 4:24 pm


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