1.8: Serious Failsave Issue

[jevermeister]

Hi,
I mentioned this more than once in the past and now I have some new infos.

As you might knwo, I ahd some problems with the failsafe feature since v1.8.

The effect is as follows:
If I turn of my TX (loosing contact) the failsafe starts and starts to land. After the waiting time the motors shutting down. Since 1.8 the motors are try<ing to rearm in cycles, one can see that in the GUI, the throttle is alternating between zero and some value.

This only happens if you loose conenction if throttle < minthrottle and you use the armi/disarm feature via Aux1/aux2.

I tried some fixes but I am not satisfied. The problem is, that the values for all channels are alternating between failsave values and real values, even the Aux1/aux2. So the copter is really trying to arm for milisecond.

I think this is a serious problem.


Nils

[Hamburger]

I think this is a serious problem.

only if failsafe kicks in
yes it is. who knows about failsafe and arm via aux1/aux2 implementation details?
Hamburger

[jevermeister]

Hi,
I think I found the reason.

Code: Select all

      } else if (activate[BOXARM] > 0) {
        if ((rcOptions & activate[BOXARM]) && okToArm) armed = 1;      //only rearm if failsafe
        else if (armed) armed = 0;
        rcDelayCommand = 0;
      } 
.
.
.
.
    rcOptions = (rcData[AUX1]<1300)   + (1300<rcData[AUX1] && rcData[AUX1]<1700)*2  + (rcData[AUX1]>1700)*4
               +(rcData[AUX2]<1300)*8 + (1300<rcData[AUX2] && rcData[AUX2]<1700)*16 + (rcData[AUX2]>1700)*32;

rcoptions is a few lines later in the code, so if the failsave disarms the copter, the throttle is zero and

Code: Select all

rcOptions & activate[BOXARM]) && okToArm)

rearms it.

Solution one

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      } else if (activate[BOXARM] > 0) {
        if ((rcOptions & activate[BOXARM]) && okToArm && failsafe_warn < 2) armed = 1;      //only rearm if failsafe   

Failsafe_warn is a variable I introduced to show the actual failsafe level. This is used for the buzzer alarm frequency

or put the whole stick input thingy into a if failsafe not active statement.

I have to test it this evening wehen I am home from work and training. I keep you guys updated!

Nils

[jevermeister]

I found the solution, i already coded and tested it, i tried to commit it into my branch, but server eror again


Nils

[Alexinparis]

thank you for this code digging.
I think it's also possible to avoid this effect with the existing variable:

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        if ((rcOptions & activate[BOXARM]) && okToArm && (failsafeCnt <= 5*FAILSAVE_DELAY)) armed = 1;

[oyibox]

me too i'm facing a serious problem with Fail safe.

i've kinda 3 fails safe : within the multiwii code, within the quadrino FC and within the Rx/Tx.

i've made a test by shutting off my Tx and...absolutely nothing happened ;(props remain turning at the same speed until i switch back on the Tx.

don't know from where to start, please any help ?

[jevermeister]

thank you for this code digging.
I think it's also possible to avoid this effect with the existing variable:

Code: Select all

        if ((rcOptions & activate[BOXARM]) && okToArm && (failsafeCnt <= 5*FAILSAVE_DELAY)) armed = 1;

Alex, your welcome.
I think this solution is more elegant :

Code: Select all

        if (failsafeCnt > 5*(FAILSAVE_DELAY+FAILSAVE_OFF_DELAY)) {          // Turn OFF motors after specified Time (in 0.1sec)
          armed = 0;
          okToArm = 0;                                    //This will prevent the copter to automatically rearm if failsafe shuts it down and prevents to restart accidentely by just reconnect to the tx - you will have to switch off first to rearm

        }

This resets the switch. And also it prevents form starting the copter unwanted just by getting contact again after the failsafe turned it off, i think this is a safety feature we should use.

Nils