26 June, 2019 at 06:39 #62738
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 !!!!30 June, 2019 at 16:38 #6276830 June, 2019 at 19:20 #62770
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?14 July, 2019 at 12:15 #62888
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?15 July, 2019 at 09:16 #62896
Do you carefully check and adjust the Center of Gravity ?15 July, 2019 at 12:07 #62897
Not realy. Where should it be?15 July, 2019 at 12:59 #62898
It should be at the center of the flight controller …15 July, 2019 at 19:54 #62901
ok thx. tomorow i wil have the right batteries and will test it again16 July, 2019 at 04:48 #62907
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.
Attachments:16 July, 2019 at 06:24 #62911
Jihlein, it’s very interesting. What is “step response” ? Can you explain ?16 July, 2019 at 15:26 #62913
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 >>
16 July, 2019 at 18:35 #62914
- This reply was modified 6 months ago by jihlein. Reason: Better explanation in subsequent post
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…
17 July, 2019 at 01:50 #62915
The tool I used for the analysis is PIDtoolbox. It has an excellent explanation of what the step response plot means.18 July, 2019 at 15:14 #62925
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 … ?
18 July, 2019 at 16:46 #62927
- This reply was modified 6 months ago by Claude.
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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