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signed signal value of climb rate: negative but climbs up

Posted by Hans-Jochen Kelle on May 25, 2014 at 4:14am

Hi everyone,

my copter is flying stable in Loiter, then suddenly starts climbing. I can only stop this by changing (at 50 feet or so) to stabilize mode. Wind 10..15knots.

Data flash log says, climb rate goes negative, baro_alt rises (i see it climbing, and signal values rise), and inertia_alt goes up about half the baro altitude.

GPS seems to change some satelites, no errors, no Nlon HDop is OK.

Can anyone help me:

1) when the sign of the climbing rate is negative, I sink = is that right?

2) how does the APM calculate IAlt and IClimb?

3) does anyone know about feedback from Motor/Prop noise via the IMU sensors to the controller, causing an undesired climb rate?

Thanks for any help!

Greetings, Hans-Jochen

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Replies

  • Dennis Okeefe November 7, 2014 at 6:59am
    with this being open source we should be able to get to the code and look at it. i don't know where to go to start - do you?
    dennis
    • Hans-Jochen Kelle > Dennis Okeefe November 8, 2014 at 12:43pm

      Hi Dennis,

      I think there is a chance of changing the software, but we need a discussion of the architectural design.

      Designing a filter for altitude estimation will say, how many different signal sources do I have, how do they depend on each other? Can I use data from an implemented EKF, or do I have to build this first? What about the time slices and the CPU capacity?

      Have a look in the "drones-discuss" forum, and find out what chance our idea has (just being heard!).

      I think, for the winter I will change my apm1.0 to 2.6 with a separate gps-compass combo. Maybe this solves already some of the actual problems?

      Kind regards, Hans-Jochen

  • Dennis Okeefe November 6, 2014 at 6:05pm

    did you ever get an answer to how IALT and ICLIMB are determined?

    dennis

    • Hans-Jochen Kelle > Dennis Okeefe November 6, 2014 at 10:14pm

      Hi Dennis,

      sadly I got no answer, but I thought about starting a thread about altitude calculation.

      The last time I had the APM in the air, I had a dozends of stable flights.But there is always a kind of drift in the altitude, e,g, starting loiter at 5 Meter ends up ten minutes later by touching the ground (sonar not activated).

      Anyone welcome building an "altitude estimator", connecting the sensors and other inputs. I have done things like this in my daily work when developing software functions on speed and mass of vehicles, so I would like to share this experience with the forum users.

      I have already written down some notes on that issue, I think there should be no problem to discuss, review and integrate them on a new SW step.

      Greetings, Hans-Jochen

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