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2 questions.......
#1
Hello,
2 questions:

1- when doing a full throttle punch, upon lowering throttle to zero, the aircraft rolls ever so slightly to the right, just enough to be noticeable, is this a symptom of not enough I gain ?

2- Had a crash last night, not hard, but landed on a gravel road, aircraft now has shaken video at high throttle, I'm guessing due to vibration, I can hear ossalations during punch out, so there was definitely some damage, closer inspection revealed one of the motor bells had 2 small scratches in it, as well as the top of the shaft was ground up a bit, is this enough to cause vibration at high rpm ?

I have replaced the motor bell with a spare and will test fly tonight.

Thank you
Danny Z
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#2
Sorry, almost forgot, KISS FC, KISS esc and lumenier 2206 2350 motors on an Alien frame
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#3
To your first question:
I believe the root of the problem are something else, I gain is only a "fix" not the cause.
1. COG is off centre, possibly to the right in your case
2. propellers/motors/ESCs on the right didn't match the performance eon the left, possibly a bashed propeller, or hardware issue with motor or ESC.

But yes raising I gain is meant to "fix" this issue.
There is now a feature in Betaflight called "anti gravity" that can relief this sort of problem Smile



Second question.

Yes it could, air gaps are so tight these days, a little change of shape on the bell is enough to make magnets scratching against the stator... in fact the gap tightness is so extreme these days, I even had a couple of motors came scratching out of the box...
Don't be a LOS'er, be an FPV'er :)  My Gear - Facebook - Instagram - Twitter
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#4
My first thought was to maybe increase your TPA. Not having used KISS myself, I didn't remember even seeing a TPA setting in the tutorials I've watched Wink I guess it is in the advanced settings GUI. If that doesn't work KISS recommends "I" increases in 0.05 increments.

Here is the article I found.
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#5
Thank you very much Oscar,
I am hoping to get out after work this afternoon, either way I will report back my findings, Thanks for getting me in the right direction !!


Danny Z
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#6
Drone of Prey,
Thank you for the article, I will be reading that as soon as I get home !!!!!!!

Thank you
Danny Z
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#7
Just to cover all the bases, as I don't know your familiarity with quads:

Does your quad also slightly roll when in a hover? It might be a persistent roll that you just do not notice during normal flight. You could check your RC commands in the GUI. Depending on your transmitter and your receiver connection, this could be the problem, especially if your rates are high and expo low. You could try setting a small deadband to your inputs.

Also, double check that you have not bumped the trim switches. Make sure the trim for roll is centered.

I use a FlySky FS-i6, and I had trouble once when the stick calibration went funny. I spent a while trying to figure out what was wrong with my quad before I realised that the transmitter was the problem. The signal was off by only about 3 or 4 microseconds, but that was enough to make the quad roll in flight. I only noticed it when coming in for a landing and trying to hover.
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#8
You could also try to reduce the influence of TPA on i-term. This is on the PID page, at the bottom of the PID table IIRC.

Regarding 2nd question, did you check that bearings are still ok? Also be especially careful when changing the bell, don't let it "snap on", the magnetic pull is strong enough to crush bearings.
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#9
(02-Jun-2017, 06:41 PM)Drross Wrote: Also, double check that you have not bumped the trim switches. Make sure the trim for roll is centered.

Confused  This is a mistake I made in the early days of flying... my first quad had just a touch of trim on the yaw access... I wondered why I favored left turns  ROFL  then I realized... "oh... because it's easier when I am already turning that way"... 

Anyway... not saying this is what is causing your issue... but in case it is, I just want you to know that someone else did it too!  Big Grin if not I am happy to eat humble pie and embarrass myself :p
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
[-] The following 1 user Likes Carl.Vegas's post:
  • fftunes
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#10
@Carl, it's actually quite common to have drift on kiss FC after 1st try - it has a small deadband by default from 1500-1502 which makes it a bit difficult to center channels correctly. Means, if you set tx channel mid to 1500 like you would expect to be normal, you end up with left roll / pitch forward / yaw left drift... Smile For kiss FC, 1501 is center.
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#11
That would drive me nuts fftunes! I think you just sold me against building a KISS quad... That is basically a defective set up. If they cant fix it then they are wrong. I might be judging a little to harshly because I am a quality guy but if you have a systematic defect like that you JUST DONT SHIP!... Doh

Then again, I am happy with my betaflight F3/F4 based FCs so far ♥ do its not like I am missing out on much.
carl.vegas
Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein,  Slightly modified Vortex 250 
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#12
Well i'd call it a bit of "design flaw", nothing serious. I was happy with my kiss FCs, i still think they feel more reliable on the sticks. But i would think twice about buying one now since they don't come with onboard flash memory for logging which has become important to me...
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#13
hello,
Sorry, work has been in my way , I have not had a chance to get back out, I will try to get out tomorrow, thank you all for the support and ideas.

I will post an update as soon as I can get to the field !!!

thanks

Danny
[-] The following 1 user Likes DannyZ's post:
  • Carl.Vegas
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#14
Ok,
Got out this past weekend, here is where I am at:

I replaced the motor bell on motor 1 and replaced motor 4 with a new motor, full throttle punch or rapid horizontal acceleration will bring out ossolations, BUT, not as bad as before, so some headway is being made.

I also replaced the props and prop nuts

One thing I did, please let me know if this is B.S. or not :

I removed my props, and connected to the KISS gui.
I went to the outputs tab and ran the motors up one at a time, when I ran up motor 3, the graph that shows the gyro axis response displayed quite a bit of activity (lots of peaks and valley's, like a heart beat

The other 3 motors showed basically a "flatline"

Could this "test" possibly show that motor 3 is generating some form of vibration

The only caveat to my theory, is this:

I have just built a 3rd Alien, and as of now, there is new fc, esc firmware available, so I upgraded all 3 Aliens to the latest.

I did fly my newest machine with stock pid's and it flew great !

My 1st machine, 3 months old, with new firmware and rolled back to stock pid's also flew great

So machine #2, which is the one giving me the ossolations, has NOT yet been flown with the new fc and esc firmware, BUT, I did run the motor "test" again, and after flashing the new fc and esc firmware, motor 3 does NOT show any funky "heartbeat" stuff on the gyro graph........thoughts ????? Or am I way off the reservation with my trouble shooting ?

I know the proof will be when I fly it, but I have been so busy with work and the rain here in the North East has been relentless, i wanted to respond with what i have tried

Everyone has been so helpful, I did not want people to think I am not very grateful for the assistance !!

Danny Z
[-] The following 1 user Likes DannyZ's post:
  • fftunes
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#15
Maybe the newer firmware improved filtering that much. Smile

Some day i'll have to check my kiss quads again.
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