After flight my quad tried to fly away even though motors were shut down

Posted by Edgar Scott on December 28, 2012 at 1:09pm

After a great flight all motors shut down.

I turned off myTx before my Quad batter disconnect, I know it went into FailSafe

I know why it may have done that but if the chopper is stopped and on the ground it should not take off again.  Lucky I grabbed it and brought it back but really I think 

A solution could be to always check that the throttle is > 10% before it ever tries to engage RTL to prevent it from taking off and smacking someone in the head like mine almost did if they forget to unplug their battery after a flight.  I don't want to see someone get hurt from a rouge flying quad.

Ed,

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Replies

  • Developer
    Randy December 28, 2012 at 11:29pm

    We reworked both throttle failsafe and battery failsafe for 2.9 and the first thing we did was fix this issue so now if your throttle was zero before the failsafe was engaged then it'll instantly disarm the motors instead of going into RTL.

     

    If you want to see how it's done you can check out radio.pde's read_radio and set_throttle_and_failsafe functions but in summary there is a short moment, as we receive the new radio frame, in which we know both what the previous throttle was and what the new throttle is.  In that moment we can check if the pilot had his/her throttle at zero before the throttle failsafe was engaged.

     

    2.9 is in testing at the moment and you can follow progress by looking at the end of the 2.8.1 release thread.  There's one important issue that needs to be fixed which is the new inertial nav alt-hold doesn't work well on the APM1 most likely because the noise characteristics of the APM1's accelerometers and baro are different from the APM2 ... hopefully it'll be resolved in the next few days.

  • Gil December 28, 2012 at 3:10pm

    I understand your problem, my Quad took by him self inside my garage, 10 minutes after i shutdown the transmitter and i did not disconected the Lipos on it, result... 2 broken props, luck me i wasn´t near it...   Gil

  • Thomas the Nerd December 28, 2012 at 2:12pm

    This is why there is an ARM/DISARM function. The copter doesn't understand your intentions (yet).

    I've had a related problem: I tried using the "ARM" button in the Mission Planner, and the controller was off. When I turned the controller on, the motors were already armed and the vehicle went full-throttle. Luckily, it was tied to my test stand so it didn't crash into the ceiling.

  • Developer
    Bill Bonney December 28, 2012 at 1:30pm
    In ArduPlane the RTL fail safe does not engage unless the plane reports a movement of 10m/s. Though even with this you can get a false positive if the GPS is indoors. There is a big long thread about fail safe started by Monroe... Check that for more info on this.
  • 3D Robotics
    Chris Anderson December 28, 2012 at 1:29pm

    How can it check to see if the throttle is >10% if there's no RC input at all (because the Tx is turned off)? Instead, a better approach might be to not engage failsafe if the quad is on the ground (that's not always easy to detect 100%, but worth considering).  

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