Tricopter build with yaw concept

[Fosch]

Please see the video and the description below

https://youtu.be/pAUj4XosrOU

I checked that there is no screw “ground issue”
I haven’t Ohm-tested the motor yet

[Kevin_Erik]

Your desyncing when not under load and the ESC’s are rebooting. Not good sign for the ESC’s. Do a visual inspection, reflow the connections and if you dont find anything new, swap the ESC 4 in 1 out.

Question: Could you do a quick install of Betaflight to confirm that this 100% isnt a dRonin issue? This would absulutly eliminate it as a possibility. I ask because my Tricopter-Mini FCF3 does the exact same thing.

[Kevin_Erik]

Here is someone with a similar issue. (Read video description)

[Kevin_Erik]

A good JB video on the subject.
https://m.youtube.com/watch?v=DWIyXmv5GIQ

[Fosch]

Sorry I can’t spend too much time right now on my hobbies…

What I don’t understand :

Why does the tail motor works fine with un-tuned parameters, and not so well after tuning ? There is obviously something coming from the firmware or the settings I apply.
(and maybe in addition an issue with the motor or the ESC that I will troubleshot later)

[Fosch]

Hi

Finally I just did a very simple test regarding the tail motor that doen’t spin in idle after tail tuning :

I switched “S” motor channel and “NW” motor channel in dRonin.
=> “NW” motor didn’t spin in idle, while “S” motor spinned properly in idle.

My conclusion is :
– The ESCs are not damaged
– A parameter of the tail tuning has an impact on the signal which is sent to the tail ESC.

If weather is fine this week-end, I will try to tune it again (4th attempt)

[jihlein]

Forgive all the questions, trying to get a mental picture of your setup…..

1)When you refer to tuning, which is causing the observed issue? On ground tail tune, airborne tail tune, or autotune?
2)Are you using a feedback wire from the servo?
3)Do you have motors spin when armed checked?
4)What ESC protocol have you selected?
5)What is the motor(s) neutral value setting? Min setting? Max setting?
6)Which flight controller?

This may be detailed elsewhere in the thread – I didn’t review the whole thread right now. 🙂

There’s a number of triflight parameters that affect the rear motor, but none of them are changed via the tailtune or autotune steps. At the moment I can’t come up with a connection between these other parameters and the rear motor not spinning, especially if the other parameters are left at their default values.

First thing I can suggest is to check is the tail servo limits, make sure the left/right tilt angles from vertical are equal at the PWM min and max settings, and they match the value in ServoMaxAngle (default is 40 degrees). If this is mismatched, it will cause the computed servo angle to be wrong, and this can cause problems, though I’ve not observed it to cause the issue you are seeing.

Next if it’s not checked, check the motors spin when armed box.

If that doesn’t resolve things, and I have a setup similar to yours, I can send you the UAV settings file from my copter to try loading and see if that helps.

[Fosch]

1)The issue comes after a “in-air Tailtune”

2)I’m using a feedback wire from the servo

3)Motors spin when armed is checked

4)ESC protocol: DSHOT600 (I tried DSHOT300 too)

5)Motor(s) setting : see attached picture please

6)MATEK F405 STD

Maybe a root cause… I changed the ServoMaxAngle to 35°. I will restart all my tuning from Zero with 40°.

Attachments:

1. 

   Output-2.jpg
   

2. 

   RC-input-1.jpg
   

3. 

   RC-input-2.jpg
   

[Fosch]

OK, I did some tests again this WE :

-The tail motor still stop spinning after arming right after an in-air tail tune (need to push throttle to start).
-The tail has some strange behavior after flips, changing the orientation of the tricopter which is not easy to handle and could lead to crashes in LOS.

In conclusion, I will probably stop this project at this point because I can’t spend hours and hours to tune it properly (if it is possible to get something clean on this build…). Quadcopters are more adapted for LOS Acro and my needs.

Anyway, thanks a lot for your help all along this build 🙂

[Kevin_Erik]

If your spending so much time trying to tune it, then thats a clue right there that you have a hardware issue. I still think you should try another ESC 4-in-1, and possibly swap out the Servo before giving up. Often a bad flight that ended in a hard landing can result in damage that goes unseen but yet is aparent the moment you throttle up.

Question, what is your min throttle set to? If its too low one or more motors may stop moving or not move when the copter is Armed. This can be further compounded if your ESC’s / Motors are not working right. Beyond that, the make of ESC your using could be part of the “why”. Never heard of this MFR before so first time i saw it I had some concerns. Stick to Aikon as their known to be very reliable while not being overly expensive.

https://www.aikon-electronics.com/index.php?id=5

Edit: Your LOS video was very impressiv! Yet i did hear a loud crack at the end of the flight as it you smacked the ground pretty hard. I’d say you were running fine up to that point where something failed or came lose resulting in a loss of control. For the type of flying your doing the Tribaby frame would be better suited to those extreme maneuvers. I would suggest to flying with the motors / props inverted as this allows the copter to Roll with the direction of Yaw instead of against it.

[LitterBug]

I’ve got a handful of baby tris, mini tris, etc… all running dRonin. One thing I will throw in here is that the more overpowered I have built my Tricopters, the more I have to DROP the P/I below the defaults before running an autotune (ie 1/2 – 1/3). Hot motors are a good indication of some serious oscillations. Throwing autotune on top of an already oscillating bird is a quick way to burn up motors.

Cheers!
LitterBug

[Author]

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