PID problem ? sd card not recognized....now crash

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PID problem ? sd card not recognized....now crash

Postby soul4u » Sat May 23, 2015 4:12 pm

A first hover test, which was in general fine, showed some visible vibrations.
I modified the frame and did another test. The quad has now 800 gramms less weight with ready to fly at 2400 gramms.
The AQ6 which was slightly dampened before is now hard mounted on the frame.

I was not able to hover, because the quad was that hard shaking although its stiff.
Without the props and running motors everything was fine, no hard vibrations also the props are balanced properly.
Can the 800 gramms less weight make such a big difference?
Mounting the AQ hard is suggested?!?

Next I wanted to have a look at the log file, but the sd card is not recognized by any computer.
The pc is asking for formatting, but ends with error message...its a brand new sandisk ultra 8 gb which was fine before.
Does a log have to be started, or is every flight logged on the sd card? I couldnt find that in the WIKI.
Any idea is welcome!
Last edited by soul4u on Tue Jun 02, 2015 5:23 pm, edited 1 time in total.
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Re: PID problem ? sd card not recognized

Postby aBUGSworstnightmare » Wed May 27, 2015 7:32 am

AQ needs class 10 uSD cards.
What type of FC do you have - AQ6 or M4? With the M4 you can access the uSD in the socket as MSC (mass storage class) device, in case of the AQ6 you need to use a card reader.
Please format the card to FAT file system and insert it into the socket. An excellent tool for dealing with SD cards is the SDFormatter from SD card association (https://www.sdcard.org/downloads/formatter_4/).
Logging will start immediately after booting when a card is recognized (or when inserted with a FC running already).

If you still have no success you should try another card.

Yes, less weight will call for other PIDs. 800g is a huge difference!
Please report back.
Joerg
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Re: PID problem ? sd card not recognized

Postby soul4u » Wed May 27, 2015 4:17 pm

Hi Joerg,
thanks for your reply.
As said, its a AQ6. I tried with different pc`s, notebooks, netbooks and cell phone...on some its not recognized at all...others recognized, but no chance to format without an error message. I also tried with formatter_4 without success.
The card is dead by AQ ;-).
So I ordered a new micro sd card as suggested in the wiki. The "old one" was a brandnew sandisc ultra class 10.


But if there are shadows, there must be light!
One step further now with the vibrations. I changed the center plates from wood (I thought that could dampen vibrations as noticed before) to 2 x 2,3 mm carbon plates.
The frame is now stiff as never before ...and what can I say...vibrations about 1m/s2 ..before there have been destroying spikes up to 10m/s2 and more.
So once again as I read in the forum. For AQ the frame cant be stiff enough.
All in all weight ready to fly is now 2620 grams with a 6000 mAh 4s battery.
I now tried to record the log via ftdi @433 MHz on the laptop in flight , but all I can get is a txt file...instead I wanted a *.log file to see the curves.
Can *.log files just be created by the AQ at the micro SD card, or is there a chance to record a *.log on the laptop instead of the *.txt file??

Also there are now some smaller movements on roll and pitch. Altitude stick control is extremely sensible. One click more or less definces climbing or descending...
It would be fine if there is an idle setting in min. position with lift power a bit less than hover...now the copter can fall like a stone when I pull the stick.

What is the best way to start with finetuning now?
The 18A kiss are in the arms, a little heating up through the carbon arms can be noticed, Tiger U3 are handwarm after a few minutes flight.
I think the FC is too much regulating the motors.
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Re: PID problem ? sd card not recognized

Postby chschmid » Wed May 27, 2015 4:31 pm

soul4u wrote:One click more or less definces climbing or descending...


Hi

The first thing I would do is remove the ratchet from your Tx. Usually loosen or tighten a screw. There should be no clicks as used with planes.

Second, you can define the deadband. Thats the response around Centerstick -> how much stickinput is needed to start the craft move.


Cheers
Christof
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Re: PID problem ? sd card not recognized

Postby Max » Wed May 27, 2015 4:45 pm

soul4u wrote:Altitude stick control is extremely sensible. One click more or less definces climbing or descending...

Assuming you mean "sensitive," a throttle curve or exponential on the throttle stick can also be a big help. This would give you much finer control around the hover point (center) w/out sacrificing full control range. Definitely get rid of the ratchet as Christof suggests. Expo on the roll/pitch stick can also be useful.

The deadband setting only affects the throttle when in autonomous modes (AH/PH/Mission).

But In general if the MR is hard to keep at a given altitude I would reduce Tilt Rate D to start with. This is typically manifested by needing to "chase the throttle" in order to keep the MR at steady altitude (constantly needing to adjust it even in calm air), or if in AH/PH you'll hear the motors constantly changing speed to adjust.

Regarding formatting the SD card, it is often best to let the AQ format it for you. When it detects a card but can't write to it, it will try to format it automatically.

-Max
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Re: PID problem ? sd card not recognized...crash

Postby soul4u » Tue Jun 02, 2015 4:45 pm

Hi Christof, hi Max,
good thing first ...the microSD card of Samsung, which is suggested in the WIKI works! ...so I do have a log file of the crash that happened today.
The copter was hovering one meter over ground in a hall, I had removed the ratchet and changed the CTRL_FACT_THRO. Also I did expo for the sticks on the taranis frsky.

The motors stopped suddenly, it felt, the landing gear took most of the energy.
I am happy that just one esc is gone ...motors are Tiger U3 with 13", the esc`s are KISS18A.
One esc was on all 3 wires dissoldered on the board, another on one wire!! ..and the soldering work was fine and controlled and worked before, all fully enclosed in shrinktube . Please have a look at the log file here:

https://www.wetransfer.com/downloads/2f5653d6e7c425367260434172a5317c20150602152640/f0290e420bd4e2389186ae1362ea181d20150602152640/4a07ec

The motors are on MOT_MOTOR0,1,10,11 and do clearly show a problem ...I am sure you have never seen a clipping like that :shock: all motors have been hot after that short flight.
Image

All esc`s had been programmed just before that flight.

I did just the TARE calibration before. A little bit frustrated now, but I know with the help of the forum it will soon be back in the air ..this time propperly tuned.
Last edited by soul4u on Tue Jun 02, 2015 6:48 pm, edited 1 time in total.
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Re: PID problem ? sd card not recognized....now crash

Postby aBUGSworstnightmare » Tue Jun 02, 2015 6:42 pm

Hi,
What is your flight battery voltage? U3 with 14x4.8CF is rated with 17.3A@3S --> no overhead margin for the ESC.
If it's desoldered then it got way to hot there. Also post your parameters.
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Re: PID problem ? sd card not recognized....now crash

Postby soul4u » Tue Jun 02, 2015 6:59 pm

Hi, its a 4S setup.
Sorry, the size is 13x4,4 CF, which should be fine. With a weight of 2620 grams it would be less than 5A/motor when running smooth..but they did not run that smooth as thought.
Image
The motors are accelerating and decelerating in a speed that I couldnt notice by looking at it, but now its recorded in the log.

I think thats the reason for the temperature, but what did cause that permanent speed changing?

All parameters are default
Last edited by soul4u on Tue Jun 02, 2015 7:49 pm, edited 1 time in total.
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Re: PID problem ? sd card not recognized....now crash

Postby aBUGSworstnightmare » Tue Jun 02, 2015 7:47 pm

soul4u wrote:All parameters are default

Thema are too high for your setup
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Re: PID problem ? sd card not recognized....now crash

Postby Heisenberg » Tue Jun 02, 2015 8:35 pm

Hey guys,

i'm new to this forum, first entry :)
I have been there with "soul4u" today when the crash occured... everything seemed to be ok before

The flight before already showed that the motoroutputs of the autoquad ranged from 0 to 100 percent, so the kiss esc are chasing between full power and zero power i think. Can that cause the dissoldering?

In the next step will be adjusting the pid params... but i dont really understand how to come along with this.
i understand the issue with the inner and outer loops (rate and angle) explained in the documentation but it is not very helpful to find a point to start with.

Sould we start to adjust the tilt rates or the angle rates and wich of them is most probably the cause for the extreme motor outputs?

What do yu mean with "thema"?

Thanks for your help!
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