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Old Jul 12, 2012, 09:30 PM
Dreamer
Australia, TAS, Memana
Joined Aug 2004
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Probably also heavily influenced by the frequency of the vibration and the rigidity of the frame, and therefore sympathetic vibrations/flexing that is induced .... etc. May not be a flexing frame as such, but more a specific torsional rigidity that amplifies vibration and or forces already present ..........

I am flying the crappest flexy nylon type frame (not dji), and a board that doesn't like vibration, plus 1800kV motors and badly balanced 6x3, 3 blade propellers .... yet the quad flies great without having to lower the gains.
Seems the vibration is not amplifying, and/ or not at a frequency that is bothering the board.

Anyway ... wandered off topic ....sorry
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Old Jul 12, 2012, 10:47 PM
Enjoying the sunshine
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Australia, NSW, Sydney
Joined Feb 2011
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Personally I don't care who makes my frames (normally myself).
Banging on about a brand is just annoying.

So can anyone that had 9 minutes to spare tell me what that final video showed the source of the problem with that wayward Quad-X?
Apologies for bone laziness but I'm coding...
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Old Jul 13, 2012, 12:14 AM
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dji frame works for people with crappy low torque motors. such as dji motors. the frame is garbage and a bust thus why the price is going down to liquidate the inevtory for there new frames. all the people confused are just vitcums
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Old Jul 13, 2012, 12:21 AM
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Australia, QLD, Brisbane
Joined Nov 2011
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Originally Posted by Percalotor View Post
dji frame works for people with crappy low torque motors. such as dji motors. the frame is garbage and a bust thus why the price is going down to liquidate the inevtory for there new frames. all the people confused are just vitcums
Why are we still talking about frames?

I would like to know if the KK2 firmware has a LPF in it to dampen motor/prop vibrations, if so what's the cut off frequency?
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Old Jul 13, 2012, 12:49 AM
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Originally Posted by Erknie View Post
Why are we still talking about frames?

I would like to know if the KK2 firmware has a LPF in it to dampen motor/prop vibrations, if so what's the cut off frequency?
cuz it would be a bad choice for kk2 so ye dont buy it lol
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Old Jul 13, 2012, 02:13 AM
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Indonesia, Jakarta Capital Region, Djakarta
Joined Apr 2007
473 Posts
Lol i am such a newbie that i asked a stupid question didnt mean to start a brand war. Apologize.

Quote:
Originally Posted by Erknie View Post
Did you try the test with the piece if string in the video on the first post of this thread to work out if it's P or I wobble?
Yeah i did that but it doesnt seems to look like P nor I gain wobbles.

Quote:
Originally Posted by rolin View Post
Any success?
Have you seen my video? Does it look like your problem with the wobbles?
Yup it is simillar, it does wobbles at slow interval but really annoying. Look a lot different than PI wobble this one is like 3-4 seconds interval wobble. Otherwise a stable platform and i can see it hovers really well.

Later i tried using 2 x 2S 6000mah battery in series for 4S total and the wobble is gone Wow what a stable hover i can almost hands-free i am not sure whether the weight of the battery, the higher voltage, or the higher headspeed that helps, since 2 2S 6000mah also weight a lot for the frame.

I will try 2 x 3S 2200mah in paralel too see if the additional weight that helps.



UPDATE: tried 2 x 3S 2200 Pack in paralel. Wobble is still there although now a minor. I'll post a video soon. I guess the weight does helps.
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Old Jul 13, 2012, 03:55 AM
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Joined Jul 2012
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Reverse one or more motors

Another newbie question: Am I right there is no way to reverse one or more motors direction in software on this thing? I soldered all motor connections and now it looks like I'll have to redo three motors x 2 wires.
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Old Jul 13, 2012, 04:12 AM
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United Kingdom
Joined Nov 2008
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Originally Posted by mashi View Post
Another newbie question: Am I right there is no way to reverse one or more motors direction in software on this thing? I soldered all motor connections and now it looks like I'll have to redo three motors x 2 wires.
no !
FC does not send any direction info, just speed ....
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Old Jul 13, 2012, 04:19 AM
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Joined May 2010
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Originally Posted by Trulsen View Post
Now the only issue I have is that motor not starting correctly. I am flying X6 and than it is motor 3 not working properly. Have to give it som left aileron when taking off than in the air it works like a charm :-) Also tried to reflash that ESC with correct firmware and calibrated throttle once more without any improvements. Was thinking about to try it on another motor just to check if it actually is the board, ESC or motor trouble.


The ESC on this motor went up in smoke. Good it happened on the ground :-)
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Old Jul 13, 2012, 04:28 AM
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Slovenia, Ljubljana
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Originally Posted by blade strike View Post
$45 for a DJI f550 and $34 for a FS450, imho that's not very much! Why would you want a clone at those prices?
I have q450 frame from HK...DJI clone. For 13 is the best price and it is very good frame with PCB. So why would I buy original.
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Old Jul 13, 2012, 06:22 AM
Westland Michigan.
Joined Jan 2012
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I received notification. KK2 back in stock.
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Old Jul 13, 2012, 06:34 AM
Tri-Quad-Hexa-Octo-copters!!
United States, TX, San Antonio
Joined Feb 2007
14,591 Posts
R,
Yep. What you have discovered is that changing the weight of a multicopter changes the hover motor/prop RPM which changes that particular multicopter build's vibration frequency and amplitude. Your adding the weight of the Lipos and mounted very tightly to the arms also has a damping effect on the transmitted vibrations. All frames vibrate at different frequencies. If those vibration frequencies are in the resonant ranges of the gyros and particularly the accelerometers,then the data the FCB uses from them can be corrupted by that noise. Some frames and designs use materials that tend to amplify these vibration frequencies and cause higher amplitude harmonics. Multicopter FCBs that have accelerometers are particularly susceptible to the noise these vibrations cause in the the data the FCB uses from the sensors and therefore has to filter the noise to maintain proper level. Gyro only FCBs not so much. Note that the DJI and Sheng Tian modules have the IMUs suspended and weighted to provide the sensors an environment that is somewhat less susceptible to frame vibrations. Therefore those modules are less susceptible to the vibrations some of those plastic type frames tend to modulate. Note that there have been several changes to the plastics in those types of frames since they were introduced and also in the variety of the clone types being sold by various Vendors. YMMV
Cheers,
Jim
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Quote:
Originally Posted by rizky_p View Post
Lol i am such a newbie that i asked a stupid question didnt mean to start a brand war. Apologize.

Yeah i did that but it doesnt seems to look like P nor I gain wobbles.

Yup it is simillar, it does wobbles at slow interval but really annoying. Look a lot different than PI wobble this one is like 3-4 seconds interval wobble. Otherwise a stable platform and i can see it hovers really well.

Later i tried using 2 x 2S 6000mah battery in series for 4S total and the wobble is gone Wow what a stable hover i can almost hands-free i am not sure whether the weight of the battery, the higher voltage, or the higher headspeed that helps, since 2 2S 6000mah also weight a lot for the frame.

I will try 2 x 3S 2200mah in paralel too see if the additional weight that helps.



UPDATE: tried 2 x 3S 2200 Pack in paralel. Wobble is still there although now a minor. I'll post a video soon. I guess the weight does helps.
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Last edited by jesolins; Jul 13, 2012 at 06:44 AM.
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Old Jul 13, 2012, 06:53 AM
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schumixmd's Avatar
Moldova
Joined Jun 2010
1,217 Posts
Hi folks,

Ordered my KK2.0 first day I saw it on HK sites. Glad that I was quick because in the evening it was just out of stock..
Yesterday I have received it, and with no delay I switch old KK board to new one.
The entire initial setup took less than 5 minutes. So i did it a try. On my frame it flew like on rails out of the box with default PI values.

For autolevel to work properly had to calibrate sensors many times until quad was holding Horizontal position. Acc is showing for me x=616 and y=621 when it level in air, but it not so level on a level surface

Next in the line will come Self Leveling tuning.

Cheers,
schumixmd
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Old Jul 13, 2012, 07:41 AM
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Indonesia, Jakarta Capital Region, Djakarta
Joined Apr 2007
473 Posts
Thanks for the explanation, i think i understand most of it

Do you have tips on how should i proceed next to dampened the vibration?


Quote:
Originally Posted by jesolins View Post
R,
Yep. What you have discovered is that changing the weight of a multicopter changes the hover motor/prop RPM which changes that particular multicopter build's vibration frequency and amplitude. Your adding the weight of the Lipos and mounted very tightly to the arms also has a damping effect on the transmitted vibrations. All frames vibrate at different frequencies. If those vibration frequencies are in the resonant ranges of the gyros and particularly the accelerometers,then the data the FCB uses from them can be corrupted by that noise. Some frames and designs use materials that tend to amplify these vibration frequencies and cause higher amplitude harmonics. Multicopter FCBs that have accelerometers are particularly susceptible to the noise these vibrations cause in the the data the FCB uses from the sensors and therefore has to filter the noise to maintain proper level. Gyro only FCBs not so much. Note that the DJI and Sheng Tian modules have the IMUs suspended and weighted to provide the sensors an environment that is somewhat less susceptible to frame vibrations. Therefore those modules are less susceptible to the vibrations some of those plastic type frames tend to modulate. Note that there have been several changes to the plastics in those types of frames since they were introduced and also in the variety of the clone types being sold by various Vendors. YMMV
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
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Old Jul 13, 2012, 08:12 AM
Registered User
United States, TX, Richmond
Joined Aug 2010
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Quote:
Originally Posted by mashi View Post
Another newbie question: Am I right there is no way to reverse one or more motors direction in software on this thing? I soldered all motor connections and now it looks like I'll have to redo three motors x 2 wires.
Check your ESC's as some have a reverse feature that can be activated via programming. If it has it, you will need either a programming card for the ESC or it can be programmed via your transmitter.
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