Need some extra brainpower to figure out this tricopter...

[RedTwenty]

Hello

I have a love/hate relationship going on with my Talon Tricopter.

I've got it flying, tuned in etc. etc. and it seems to not have a problem until...
After a bit of hovering I move off slowly for some out and back type circuits (in the fairly tight area I have been testing in behind the house). All seems well and then suddenly it is as if motor 2 dies momentarily. Of course it tries to stabilize itself (I have tried this with self-leveling and and off) but it over-corrects wildly and drops to the deck before I can regain control.
I have tried replacing the KK2.1 control board and also replacing the motor and ESC on arm 2 with no change.

The daft thing is it never used to do this. On the first KK2.1 I had it flew fine but I broke it after a crash and had to replace the board and the tail portion. Could I be unlucky enough to have 2 dud KK2's?
That said, I do have the problem with the 2 newer KK2.1's that only M1 has the 5v pin connected so I have had to solder a jumper underneath the board between M1 and M4 to get power to the tail servo - could this be causing a drain on the M1 output when I start maneuvers that is knocking out the KK2 somehow?

I am running a very soft tune with Roll/Pitch at P=30 I=20 and Yaw at P=40 I=30

A few specs to complete the picture:
Controller = KK2.1 upgraded to Steveis latest beginner version (but have also tried V1.6)
Motors = NTM Propdrive 28-26 1000kv
Props = SF 9 x 4.7
ESC = Turnigy Plush 25A with basic changes made (Nixx, low voltage cutoff, mid timing)

Going a bit insane here trying to figure it out so would appreciate any thoughts from the community...

Cheers,
Mike
Red20RC

 

[xuzme720]

Yes, it's possible. See, the KK2's are designed that way with an intentional split power buss. M1-and all left side input ports are all joined together on the power pins and also provide power to the KK2. M2-M8 are the second buss. You can power the servo by leaving one of your other ESC power leads (M2 or M3)hooked up. It doesn't matter which port you use since those are all connected together but separate from the M1 buss. I wouldn't try to join them as I'm just not sure what effect that can have on the board.

 

[RedTwenty]

Ahhhhh... I didn't realise M2-M8 were joined as a second buss. Hang on (goes into workshop with multimeter)...

Well I never!

Okay, so I am probably causing some surge or fluctuation in the board by connecting the two buss' (or is that "busses/bussi"?) together, which is giving this error.

I'll have a fiddle and let you know...

Thanks for the help

Mike

 

[RedTwenty]

Bah! I thought that had done the trick but after a few minutes - wobble, wobble smack!

Now I have to consider that I have done some permanent damage to the board with my shenanigans. Oh well, I don't like the setup I have anyway so I think I'll get some new motors and ESC's in (and another KK board) and start again...

 

[xuzme720]

Before you bin the board, try giving it a re-flash after doing a factory reset. It might be some shenanigans going on in the firmware... not something you did...

 

[RedTwenty]

Anything is worth a go (and if it works I'll have a couple of spare KK2.1's laying around - hmmmm)!

That said, my Deadcat SK450 went in from about 100ft up today whilst I was flying FPV. It was the first time I'd ever flown it that far or that long so I put it down to a radio problem but that wobble when I lost control looked very familiar...

Now, that frame is running totally different motors and ESC's but both are running KK2.1's with the 1.12S1 Begginer firmware from Steveis and FRSky Futaba compatible FASST radio.

I'm going ot play around with the tri and also do a LOT of flying around low and slow with the quad to see if it does it again. I'm also going to reset and reflash both - probably with the new V1.14S1 firmware.

Fingers crossed

PS - incidentally, the quad hit thigh length thick Australian grass and didn't have a scratch on it. In fact I brought it back to the field, plugged the same battery back in and flew the rest of the charge out!

 

[Craftydan]

Red,

Not sure it's your issue but I was having glitching in one of my multirotors like that.

One boom -- and *always* the same boom -- would stutter for a fraction of a second and drop 4-5 inches, and the board would catch and bring it back. It would happen randomly through the flight -- once every 1-3 minutes.

It started after I swapped out the ESCs . . . and the previous ESCs had ferrites on the signal leads. I had a spare one lying around, so I put it on the signal lead and the issue went away. I've got no reason to believe the ESCs are inherently bad or that all of that brand need one, but the tolerance of an ESC to noise will depend on the signal filtering it has built in. If the onboard filtering is not enough for where it lives in the airframe, that's an easy way to clean it up.

 

[RedTwenty]

Just an update on this one...

I went ahead and replaced the motors, ESCs and KK2.1.

The motors I went up a little in KV but stuck with the NTM propdrive. The ESC's I changed for Multistar 30A and flashed them with SimonK. The KK2.1 I flashed straight away with the latest V1.4 pro.

I've set it up (and just realised I didn't adjust ANY of the gain settings or self level settings ) and flown out an entire battery taking it up and down at walking pace. The thing is now totally solid. No glitches or anything. In fact, it was so stable I could hover it in front of my nose and push it around with a finger!

I could probably get to like this frame after all...

 

[xuzme720]

Now you know what all the hype is about! Way to go and I'm glad you stuck it out! So, is it love/love now?

 

[RedTwenty]

I've been using the most recent beginner firmware up until now but this latest build is miles ahead of anything else I've used. To be that stable without any tuning on a tricopter frame is pretty special.

I just updated my deadcat quad as well so looking forward to trying it out...

 

[RedTwenty]

I just put a longer post in the other thread on the KK2.1 Steveis firmware but basically this new build is awesome! The quad is so stable it is scary.