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Today I did a lot of testing and tuning with the new unreleased beta version of ArduCopter code, known as "2.9.2ß" (V3 i think for the official exit), quad with APM V2.5 and U-Blox GPS by 3DRobotics.
The inertial control developed by Leonard and Randy, with the support of Jason, is finally giving the results that for over a year all we are waiting.
To be perfectly sure I've repeated this test at least 10 times in three different flight, with the same great performance.
As you can see from this image and video the max radius in Loiter is now not over one meter in windless/gusty winds and max two meters in strong crosswind, near the position hold performance of the best commercial product, DJI Wookong-M.
We are trying to improve the waypoint navigation but now we're here, the next release will be really a milestone.
We still have to solve a few problems related to the inertial control x/y/z, but I am sure that the excellent results achieved so far are to mean that we are on the right track.
I attach the telemetry log.
DJI, here we come...


Ciao!

Marco
-= AC Dev Team =-

EDIT: in my video you can see the version "3" of the code, nothing secret of course, is the current master branch on GitHub called at the moment "2.9.1b-DEV".
Jason Short on the dev list has proposed to move version from 2.9.1 to 3.x for the massive changes inside the code (ap_hal, PX4 support and other), and following its proposal I have appointed as such in my videos, that's all.

2013-04-14%2014-04-46.tlog

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Comments

  • Moderator

    @Marco: Yes, but there are more APM's with cheap MTK than expensive U-Blox, fact, no matter how you look at it or what you compare it to. U-Blox is an upgrade, standard APM2.5 comes with MTK so you have to make sure it works 100% on lowest common denominator.

  • Developer

    Theo: The main problem with using inertia alone for positioning, is that the error rate builds. The position will be fine for a couple of seconds and then the error rate will start to increase rapidly. Making inertia positioning stable for longer periods of time is something even highly specialized and very expensive full-scale aircraft systems struggle with.

  • Within reason again...

  • @marco, agreed however that would also mean then we could of position hold indoors? with no GPS plugged in....

  • Developer

    @Graham: to compare the performance of the new inav controller with other commercial products must have a gps to their height, DJI and Mikrokopter use U-Blox chipset in their GPS, not a cheap MTK.
    @Theo: in theory yes, but it is obvious that the wind could still translate to the quad, the inertial controller can not do everything alone.

  • Moderator

    Yes, there are many more APM's flying with MTK GPS's than Ublox, there will be a lot of disappointment if the new changes are optimised only for the Ublox.

  • Marco would i be correct in assuming that in theory we will be able to have position hold without gps....??? within reason....

  • Developer

    @Robert: yes, the inertial controller were capable of holding the copter "completely" motionless, with the obvious limits of MPU6000.
    On average U-Blox GPS here in Italy has an error of about 3 meters, no further, I have done tests about half an hour.
    In fact without the inertial control that is the radius that I always had with version 2.9.1.
    It's obvious that the error of the GPS remains but the inertial discriminates against excessive movement, the result is what you see in the log.
    It would be interesting to try now with MTK.

  • Moderator

    It's going to have to be ArduCopter v3.0!

  • great news, one more step to perfection...

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