Developer

TrIMUpter - GPS Position hold test with ArduIMU + GPS EM406 on Vimeo.

Hello, I have successfully tested the GPS position hold with my TrIMUpter (a VTOL tricopter).

The full stabilisation process is simply done with:
- an ArduIMU+ V2 flat,
- a triple axis magnetometer (HMC5843),
- a GPS EM406,
so this is a very cheap setup.

Below a photo of the setup used:

The TrIMUpter is stabilised by the firmware TriStab v2.1

Some features of the firmware v2.1:

- Full stabilisation process required for a multicopter,
- GPS position hold, tested with the GPS EM406, and compatible with Ublox, NMEA, and Mediatek MTK ,
- a true Heading Lock for the yaw with 2 modes: inertial heading lock or magnetic heading lock,
- self-calibration of the IMU sensors,
- self-test at the startup for valid datas from the HMC5843 triple axis magnetometer,
- the switch from the "stabilisation mode" to "the GPS position hold" is done with switch linked to the ch5,
- the Roll/Pitch PID gains can be easily tuned via the transmitter knob linked to the ch6,
- the main servo mixer is placed in one function "call_servomix()" and can be easily modified for multicopters
and also helicopters...

The firmware TriStab v2.1 can be downloaded here.

Have fun and happy dev,
Jean-Louis

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Comments

  • Developer
    Hello, here a new TrIMUpter test flight video fully stabilised with the TriStab v2.1 firmware:

    TrIMUpter v2.1 flight fully stabilised by a 9 DOF IMU + GPS from Jean-Louis Naudin on Vimeo.



    The TrIMUpter flight is very stable and cool...
    Regards, Jean-Louis
  • Truly amazing! Great job man.

    I am doing one myself, hope to discuss with you more on the hardware/software settings.
  • Developer
    Hello SID, Its easy with an oscilloscope to find the serial PPM output on a PPM receiver, I have done this successfully with the Graupner R16Scan receiver.
    You will find here a link to do it on a Futaba R607FF / R617FF (2.4Ghz). You need only to set in the TriStab source code the number of channels to 7. A friend of mine have done this successfully with my firmware.

    futaba-r607ff-sum-signal-medium.png?w=700


    If you don't have time or mean to do it, you may also use the 8 channel PPM Encorer from DIY Drones store that you may purschase here

    BR-PPME-2T.jpg

    I hope this will help you,
    Regards,
    Jean-Louis
  • Jean,
    Thanks a lot for all the details. I am seriously thinking of making one but I would need a ppm Rx. I will have to look for one. Frames are no problem. I have a friend who has a mechanical shop , will do it for me.. How about a folding frame with centre hub ?

    Regards
    SID
  • Developer
    Hello, you will find below my radio setup of my Graupner Mx16s which works well with the TrIMUpter v21:

    Stick mode: 2,
    Modulation: PPM,
    Mode: Fixed-Wing
    Tail type: normal,
    AL/Flaps: 1 Aileron
    Receiver Output: S2->Output 1, S3->Output 2, S1->Output 3, S4->Output 4, S5->Output 5
    Servos setting:
    S1 => 0% 125% 125%,
    S2 <= 0% 100% 100%,
    S3 <= 0% 100% 100%,
    S4 <= 0% 100% 100%,
    S5 => 0% 100% 100%
    Controls setting: E5 (Sw2) +100% +100%
    Dual Rate/Expo: AL 100% 0%, PR 100% 0%, DI 100% 0%



    Happy dev with the ArduIMU and Enjoy your flights with the TrIMUpter,
    Regards, Jean-Louis
  • Fantastic, you are too strong Jean-Louis, at this speed in 1 week it TrIMUpter to make a navigation in all autonomy with return to the foot of sound maitre!!!!
    Cordially
    DODY
  • In further to my previous post, a little bit of research seems to indicate that the yaw servo is there to cancel out the effects of asynchronous thrust, which varies at different engine speeds. That makes sense - sorry for the silly question. Very interesting build - well done!
  • Hi,

    Please excuse my ignorance of this topic, but why is the yaw sensor needed? Does having three degrees of control not give you three degrees of freedom for rotation? Is it present to make control easier (rather than having to undertake potentially complicated calculations), or is there some aspect of tricopters that requires additional degrees of control freedom?
  • Developer
    Here an interesting pressure sensor for altitude hold which speak I2C and which can be connected in on the I2C bus of the ArduIMU (no additional I/O consumption...). This is the Bosch MEMS pressure sensor BMP085
    More infos at: http://www.bosch-sensortec.com/content/language1/html/3477.htm
    Regards, Jean-Louis

    BST_start_BMP085_ts_rdax_80.jpg

  • Developer
    Below a photo of the two sensors that I have planned to test for the Altitude Hold in the TriStab firmware.

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