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My new octocopter frame

Posted by Peter Koch on March 13, 2011 at 2:30pm

This is the new folding frame Project I am working on.

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Can anyone tell me if it´s possible to control the eight counter rotating motors with ACM.

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Comments

  • Peter Koch April 12, 2011 at 5:48am

    @Denny

    it is not a problem to get it working you just need a software that can control 8 motors seperatly.

     

    @I.S.

    At a normal quad configuration you have two CW and two CCW motors for example yaw left - you speed up the CW motors an slow down the CCW motors now on a X8 configuration with splitted servo signals to two ESC´s on each arm you almost have no tuning moment as the counter rotating configuration will compensate any turning moment so you definitely need a software which can control 8 motors separately. So for the example yaw left function on a X8 config you have to slow down all 4 CW motors and speed up all 4 CCW motors on each arm of the quad.

  • I.S. April 12, 2011 at 3:54am

    @Peter

    puting the other motor upside down will  counter rotate the other motor thus getting yaw functionality.

  • Denny Rowland April 12, 2011 at 3:42am

    Looks like Bros. Olson got it working OK

    http://vimeo.com/9435221



  • Peter Koch April 12, 2011 at 3:20am

    Splitting the servo signal to two ESC´s is not only inefficient its more unusable as of the counter rotating motors you have no tuning moment and therefore you will have no yaw function.

  • DaveyWaveyBunsenBurner April 12, 2011 at 2:06am

    @Robin

     

    Apparently that is a problem, but a number of quads, and Tri copters use this arrangement. The Draganfly for example. Although I've heard the prop wash is an issue, a massive number of small/toy RC helicopters use this arrangement, so I'm not so sure its a big problem as they tend to be small and need stability. Jani mentioned a while back that unless you have a copter board specifically configured for this arrangement, simply splitting the servo signal to two ESCs per arm will work but is inefficient.

  • Robin Behrens April 12, 2011 at 1:53am
    I was just wondering if any one else has experimented with this kind of engine placement. I would have imagined that the prop wash from the top motor would have diminshed the efficency of the bottom motors prop. any thoughts? 
  • Denny Rowland April 5, 2011 at 9:33pm

    Jani

    What we need from you is a super stable mode where you can switch to the the 4x gyro output i.e. 110 deg/sec from the Invensense and use that instead of the normal 500 deg/sec. This will give you much less latency in the stabilisation. less noise at higher gain settings. Instead of 2 mv/deg/sec it would be more like 8 mv/deg/sec. at the point of initial movement. The ADC would like that?

  • Denny Rowland April 5, 2011 at 8:38pm

    There was a world shortage of the 40 Amp. a few months ago and having tried alternatives such as HiModel Pro which did not work as well, I took these as a safeguard instead. New video of the MK-2 is underway, but here's the Mk-1  http://vimeo.com/21241710

    It's quite big. 36" between motors. Mk-2 is Lighter, Faster and has more bells and whistles.

  • I.S. April 5, 2011 at 10:57am

    @Denny

    Aren't ESCs a little bit oversized? The official product page, says 37A peak current, so instead of the 60Amp Plush, the much cheapier 40Amp Plush should be sufficient and still stands up to 6S LiPo.

     

    That's a quite beefy quad. It would be nice to see any fotos and/or vdos of it.

     

  • Denny Rowland April 5, 2011 at 10:07am

    I can definitely recommend the Pulso X 2826/12 760kv with 14x4.7 props, that is what is used on my Flying Camera Mount. With 5s batteries each motor can lift a max. of almost 3 Kg. 60Amp. Plush ESC's

     

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