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Stablilize Mode Question

Posted by Lowell on December 30, 2014 at 5:39pm

Hello all, I'm wondering if failsafe settings in APM (low voltage, low throttle, low mAh, etc.) still take affect when flying in Stabilize mode. For example, if I have set  RTL on low voltage, my control inputs will be overridden while the copter completes landing sequence, correct? If true, are the failsafes the only possible way to lose manual control while in STAB mode? Is there anyway to cancel an RTL sequence once initiated? Thanks

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Replies

  • Bill Kiskin January 3, 2015 at 2:22pm

    Howdy,

    I was test hovering in my garage when the quad started ascending slowly into the ceiling and all radio inputs were disabled.  The quad rose and the GPS antenna hit the ceiling first, the quad tilted and the first of 3 props that broke struck the ceiling, then it fell 8 ft onto an arm and broke the motor off.

    Later in analyzing the log I did see the flight go from Stabilize to RTL to Land.  It felt like I lost radio contact, but something else might have triggrered that.

    In the logs, is there any way to read them to see if Failsafe was tripped, and for what reason?

    Thanks,

    Bill

    • Lowell > Bill Kiskin January 3, 2015 at 2:57pm

      Bill, I had a similar crash which is why I asked the original question. In APM I had set the low voltage failsafe to RTL, and set the RTL height to 15 meters. I was using an old battery pack that didn't hold a charge very well and when volts dipped below the threshold the quad automatically rose up, hit a tree branch above it, broke a prop and sent the whole mess crashing down on my back deck. 

      I have since lowered the RTL altitude to 2 meters and bought a new battery. 

      The logs should show you what happened. For example, with my crash I could graph the "CURR", "VOLT" parameter and see the battery power decline below the preset threshold, and the RTL command kick in at that moment.

      • Bill Kiskin > Lowell January 5, 2015 at 5:27pm

        Hey Lowell,

        So I cleared all the junk logs and just armed the quad and spun it up. judt to create a log.

        Then I graphed it, but I don't think I really know what I am doing or looking at.  You mentioned graphing the "CURR", "VOLT" values, so I did what I thought was that.   The problem I see is that the VOLT line is completely flat, and at 0, as you can see in the image I took of my graph.

        Is that what you were suggesting, or have I missed the mark.  I expected to see the VOLT be something other than the flat line ;(

        Thanks for checking this out!@@

        Cheers,

        Bill

        Screen Shot 2015-01-05 at 7.17.52 PM.png

        https://storage.ning.com/topology/rest/1.0/file/get/3702681530?profile=original
        • Alan D > Bill Kiskin January 6, 2015 at 8:32am

          Have you got a power module? Is it configured in the APM setup?

          Without both the APM cannot log voltage and current info.

          • Stuart Brookes > Alan D January 6, 2015 at 11:36am

            try graphing volts on its own, or using the right hand axis by selecting volt with right mousebutton rather than left....on that scale battery voltage  may look flat

            • Bill Kiskin > Stuart Brookes January 19, 2015 at 4:09pm

              Thanks to you for the help!  I did reckon that it was the weak battery - the voltage dropped after about 3 mins of hovering and that was the culprit.

              Problem solved, and thanks again...

              Cheers,

              Bill

            • Bill Kiskin > Stuart Brookes January 6, 2015 at 12:07pm

              OK, Stuart, I will try that, thank you...

              Is "using the right hand axis by selecting volt with right mousebutton" similar to clicking the "Graph data to the right" button, or is that something different?

              Cheers,

              Bill

              • Stuart Brookes > Bill Kiskin January 6, 2015 at 12:13pm

                same result but different method. either find data in table and graph data ti right axis, or use the tree on the right and right click in the relevant check box 

          • Bill Kiskin > Alan D January 6, 2015 at 10:39am

            Hi,

            I have a power module, and I believe it is configured as I recall that step.  Funny thing, I am getting data points for CURR but VOLT is a flat line.

            I will re-check this evening and confirm. 

            To verify from looking at the screenshot, am I setting up the graph correctly?

            Thanks,

            Bill 

      • Bill Kiskin > Lowell January 5, 2015 at 1:10pm

        Hi Lowell,

        Thanks for replying!

        It's beginning to look more like that than the loss of the radio link.  Since then I constructed a stand comprised of a couple of vertical standoffs, to which I have tethered the quad safely with four lines so that there is approx 6" vertical movement.  I plan to run telemetry to the ground station during the hover test and visually monitor the Flight Data, and then analyze the logs.  I plan on waiting until the RTL kicks in and then flick out of Stabilize, then back into Stablilize to attempt to regain control and see how that goes.

        My batts are also less than optimal, slightly puffed, and probably "tired", so the same issue as yours may have happened to me...

        Cheers,

        Bill

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