Home Forums Everything about the Tricopter LR BETAFLIGHT 4.0.3 and KAKUTF4V2

This topic contains 63 replies, has 10 voices, and was last updated by  Kevin_Erik 1 week ago.

Viewing 15 posts - 16 through 30 (of 64 total)
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  • #62738

    Claude
    Participant

    when I started with multirotors with a small quadcopter (I will post the story soon), I tried some firmwares and finally moved back to Betaflight, with the feeling to be “back home”.
    And Betaflight can handle Tricopter perfectly, in my opinion.

    Last weekend I assembled and tested the bicopter, but I’m not a fan of it. I will sell it now and concentrate back on my Tricopter LR.

    The next step is to mount a french very perfomant FC, the YupiF7 (from the french Team CopperYu).
    When satisfied Under Betaflight, I will migrate the YupiF7 to Inav to use it’s dedicated GPS ….

    Whooooooo, what an exciting project !!!!

    #62768

    Claude
    Participant

    Finally, my DIFF output 🙂

    Attachments:
    1. DIFF02.txt
    #62770

    theluxembourgishguy
    Participant

    Nice one!
    If you have wired up your electronics in the same way as in David’s video, I suggest you enable current metering (Onboard ADC), especially for long range flights I find that very useful!
    Have you had any luck with experimenting with the PIDs?

    #62888

    Sascha
    Participant

    Hi Claude and the rest!

    Thank you for the diff, it works nearly perfectly! (I’ll explain my issues later)
    I was following David’s Tricopter builds for a year or so and wanted to build one for a long time. But quads are easier to begin with.
    So a friend and I looked for a long range build and now there was the release of the LR!

    So I bought one with the complete electronics and startet to build and set it up with dRonin.
    After autotuning it, I wanted to try it out aaaand was disappointed… weird hard tail wiggles when I give some throttle and nearly unflyable.
    So I came here to the forum for some tuning tips and saw this post. I thought ‘why not try betaflight?’. And today I was testflying it and it’s really good!

    I have only one issue: the yaw axis is not properly tuned BUT I don’t have the right batteries atm. only a 2200mah 3s, the 5200mah are on their way to me.

    Now is it possible that the tune will be better with the added weight?
    Plus on a 1500mah 4s my tail rotor gets really hot and it twitches around… any fixes for that?

    #62896

    Claude
    Participant

    Do you carefully check and adjust the Center of Gravity ?

    #62897

    Sascha
    Participant

    Not realy. Where should it be?

    #62898

    Claude
    Participant

    It should be at the center of the flight controller …

    #62901

    Sascha
    Participant

    ok thx. tomorow i wil have the right batteries and will test it again

    #62907

    jihlein
    Participant

    The TriLR is an interesting airframe. It’s light, has large props (low disk loading), and what seems to be a powerful tail. These attributes lead to dynamics that I believe are quite different from some of the other tricopters we’ve worked with. This is evidenced by the issues dRonin has with the autotune, my V4 autotunes very well (after zeroing the computed yaw D), but my TriLR does not autotune well at all.

    So I finally got around to trying BetaFlight 4.0.4. I threw together a custom target file so the servo is on the LED pad, LEDs on the M4 pad. No need for resource mapping and the LEDs work, at least my logic analyzer trace looks to be correct. Using Claude’s PID values, it handles real nice, better than I’ve gotten it with either dRonin or iNav. The figure below is the step response, computed from one of the blackbox toolsets. Roll and pitch are believable given the PID values, the yaw looks strange to me. Need to think about that one a bit, and experiment some. I’d expect the rise time to be faster given yaw P = 100. Not sure if this is an artifact of the toolset, or if it’s real.

    Anyway, as already said, this is an excellent starting point. I’ve also attached my hex file for those interested. If you’ve been using the stock KakuteF4V2 hex file, you will have to set your resources back to the default values. My wiring is different from the BetaFlight “standard”, I swap motors 1 and 3 with the resource command.

    #62911

    Claude
    Participant

    Jihlein, it’s very interesting. What is “step response” ? Can you explain ?

    #62913

    jihlein
    Participant

    Claude, in simple terms, the step response is a measure of how well the controller is doing.

    << Rest removed in favor of explanation here: https://rcexplorer.se/forums/topic/betaflight-4-0-3-and-kakutf4v2/page/2/#post-62915 >>

    • This reply was modified 1 month, 1 week ago by  jihlein. Reason: Better explanation in subsequent post
    #62914

    Kevin_Erik
    Moderator

    From my experience(s) with Plasmatree, the Yaw is the most difficult thing to tune for. To be blunt, it’s better to Dial-in your Roll / Pitch first while your Yaw is still held back. This will help prevent oscillations (on ground and in air), while allowing you to see the Roll / Pitch values cleanly. Granted as you raise Yaw P and I, your bound to see Roll and Pitch start to misbehave. That’s when you know your at the edge of what you should see for Yaw. Going beyond this point is possible but it very time consuming for what amounts to small gains in performance.

    Here is a “Yaw” Plasmatree GIF i made some time ago. This combines the Logs from several flights so the changes / interactions can be seen. Notice how crisp the Roll and Pitch are…

    #62915

    jihlein
    Participant

    The tool I used for the analysis is PIDtoolbox. It has an excellent explanation of what the step response plot means.

    https://github.com/bw1129/PIDtoolbox/wiki/PIDtoolbox-user-guide#5-step-response-tool

    #62925

    Claude
    Participant

    Waooh, very interesting…. but too advanced for me.

    If my tricopter has a clean behaviour for my flight , motors noise regular, motors / ESCs stay cold, it’s ok for me 🙂

    Jihlein, eventually the curve for YAW is normal for a tricopter … ? As the Yaw is not based on motors speed only (as it is for a quad), but it depends of the servo too. It’s an additional parameter for YAW, with tricopters … ?

    • This reply was modified 1 month ago by  Claude.
    #62927

    jihlein
    Participant

    No, it’s still controlled by the yaw PID, it’s just that rather than sending yaw commands to vary motor rpm as would be done in a quad, the mixer sends the yaw commands to the servo.

    Does that answer your question?

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