Jello and Altitude

Posted by Jeff Treadway on April 19, 2015 at 7:09pm

 Hi Everyone,

While flying this evening I sent a different camera up instead of GoPro. The SJ4000 is very similar in size and weight and fits snugly in the GoPro cradle on the gimbal. However-really bad jello, waves of it. I noticed a constant slight vibration when Iris sitting on landing pad. I held my hand on top and could feel it. Come home and get GoPro . Go back to fly, can still feel vibration by resting my hand on Iris, but no jello while flying. Is the jello and vibration something I can smooth out by calibration ? I did have the gimbal off for a few days but I'm sure I put it on correctly. The tilt works from the radio.

Also, while in loiter mode at a steady hover, when I try to go forward-loses altitude. When I go to the left also. When I go to the right and backwards it holds the altitude. This is while leaving left stick at 50%.

If I try standard mode it keeps coming backwards. If I trim it to not come back towards me, how will my trimming affect loiter mode when I switch back ?

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Replies

  • Todd Harper April 20, 2015 at 5:33am

    Nick,

       The loss of altitude is not uncommon. Most, if not all, types of aircraft experience this. In order to keep the craft in flight at a constant altitude, the force of lift must balance the force due to gravity (weight of the craft). This force of lift is generated by the airflow around the craft. Now while this is general outline it does pertain to the IRIS+ as well.

    I would suggest you try PosHold mode and see if that is more to your liking: http://copter.ardupilot.com/wiki/flying-arducopter/flight-modes/pos...

    Also take look through the rest of the APM Copter page. It holds a wealth of knowledge and will help you to understand the IRIS+ a bit more. http://copter.ardupilot.com/

    Jeff,

      In order to get some smoother footage from your gimbal a few simple steps need to be address before digging into the gimble setting themselves.

    Are all the props balanced? This is one of the main problem areas when it comes to the jello effect.

    Are you seeing high vibrations? You can check on that here: http://copter.ardupilot.com/wiki/ac_measuringvibration/

    Is the gimbal and its suspension set-up correctly? Sometimes changing the suspension (damper) balls can improve the footage.

    Are you using any type of filter on you SJ4000 or GoPro? Using a Neutral Density filter will greatly help smooth out your footage.

    Todd H.

     

    • Jeff Treadway > Todd Harper April 20, 2015 at 6:25am

      Todd,

      Thanks for the informitive reply.

      Not currently using ny filters-ordered and on the way

      I alos emailed 3DR for their thoughts.

      I will look into calibrating the gimbal

      Props seem to be fine and I did ESC and Accelrometer calibrations.

      It may t be that the SJ4000 is just an inferior camera for a drone.

      Thanks,

      Jeff

    • Nick > Todd Harper April 20, 2015 at 6:07am
      Yeah i understand the loss of altitude is not uncommon, due to the angle of the craft, speed at which you are flying, and gravity. I use LTR and it works nicely, just thought the GPS in Iris+ when in LTR mode, would adjust the altitude as needed. Just like it helps flying.

      I will check out thevlink you posted, thank you ☺.
  • Nick April 19, 2015 at 7:32pm
    I notice the loss in altitude when going forward as well. Kind of hard to do a clean shot, when you always have to correct the altitude. I always leave it in LTR, so i thought Iris+ was smart enough to maintain the altitude when flying. I like handling it manually vs using mission planner.

    Almost thinking about selling the Iris+ and upgrading to the Solo, or Inspire 1.

    3DR support is slow. Still waiting, going on 5 business days. Only to have 1 reply saying, they are transfering my question over to one of the technicians. I just asked how to calibrate the altitude, because the controller reading is off. Their manuals suck, and the website has nothing for trouble shooting. Just a few setup videos. Leaving us to find out the solutions on our own, via forums like this.
    • Jeff Treadway > Nick April 19, 2015 at 7:49pm

      I also noticed the altitude read out on the radio to be a few meters short of accurate. I bought an altimiter that works well to verify my settings. 20 meters in geo fence = 67 ft on altimiter. Radio readout says 17-18 meters. Since I have the altimiter I don't worry too much about the radio, it doesn't any higher than I set it for.

      But I don't understand why it should lose altitude going forward.

      I don't think iI would buy a Solo until they are out for a while. The Iris can be finicky-but it's tolerable.

      I bet there is a setting to adjust gimbal so not so sensitive to smooth out jello on my other camera.

      3DR support on the phone is pretty good.

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