Discussions

Strange behaviour in AUTO mode, 3DR Hexacopter.

Posted by Bernt Christian Egeland on March 17, 2013 at 11:33am

Hi all..

After several successfully flights with 3s lipo and standard PID settings i decided to change out my 3s with 4s 5000mAh batteries.

But something stranges happen during waypoint flight in AUTO mode.

It was set to climb 150meters in a 1km flight path. Everything started just fine, spot on and i was really happy with the result due to the wind and gust.

When the Hexa was almost at 150mtr height, it suddenly smacks the throttle to the max 100% and the copter goes to the sky like a rokcet.

i grab my RC and switch the mode from AUTO to Stab and was able to get it down without any crash.

My Gopro camera was also onboard. ;)

After i tried one more time, Set point of 100mtr .

When the copter reach 60mtr, same thing happend, it suddenly gives 100% throttle and goes like a rocket up in the sky,

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Im not able to find the root couse to this problem.   Please help.. 

The log also showing 11sat count at all times.

Can this be becouse of 4s lipo???  or is this just a coincidence?

When using 4s, i ha to change my Rate P from 0.150   to    0.110.

Regards

Ludvig

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Replies

  • Antonio Pedro Maia Brasil October 26, 2015 at 2:30pm

    hi mate!!!!

    Yes something similar happened to me. on my case it was flying nice in stabilize... also nice in alt hold.. but the moment i press loiter and started to work with satelites... the quad just started climbing like crazy. it was not a problem of satelites number or even hdop. check vibrations on z axis. in the new update you have the EKF on the main menu of the flying data. to measure the vibrations. however dont do it in the ground. it happens flying so you have to measure it flying. 

    regards!!

  • Bernt Christian Egeland March 25, 2013 at 6:54am

    Hi Guys 

     

    I agree, the problems seems to be related to vibrations.

    After i installed foam under APM board and adjusted the INS_MPU6K_FILTER to be 20, i never had this problem again.

     

    I think i will invest in new and better motors and carbon prop.

     

    @Bill

    Im using 3g GPRS for telemetry.

    https://www.youtube.com/watch?v=pV4_WlfTPq0

     

     

  • Bill Patterson March 25, 2013 at 6:25am

    Is there an error path back to the GCS using Mavlink? 

    I'm trying to think of ways that the Aircraft could communicate a problem to the Ground Station.

    Logging seems to be so port-mortem.

  • Developer
    Marco Robustini March 19, 2013 at 12:22pm

    Can you post here all the logs of this unwanted event?
    I think is not related to the number of lipo cell.

  • Mike Boland March 19, 2013 at 12:13pm

    But quite a few of the many strange runaways is happening after many successful flights and with no changes.

    Add fresh battery, start mission as usual, and it takes off, or crashes.

    This is happening more frequently now with 2.9.1 but as yet no pattern has emerged to indicate any commonality, other than running 2.9.1

  • Ajai Sehgal March 17, 2013 at 7:09pm

    Seems like there have been many instance of a runaway climb in Auto and Loiter modes that I have read on the forums (or seen personally). Is it possible that this is being caused by not setting the new tuning values as per Randy in the V2.9 / V2.9.1 release notes?

  • T3
    Richard Boyhan March 17, 2013 at 4:49pm
    The battery should make no difference. Your copter will fly a bit more aggressive with 4S and you should tune down you P value. With my quad I switch between 3S and 4S with a little change in P value. You might want to reset and reload and recalibrate again and manually enter your parameter values. There is a chance of carrying bad parameter values from old parameter saved files.
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