Baro problem or PID? [semi-solved]

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Re: Baro problem or PID?

Postby jet » Thu Jun 11, 2015 12:58 pm

Hi, all.
Based on your suggestions, I tested my AQ6 again.

1.I made various Thr_Factor. I got the best value.
In manual mode, the middle thro was close to 700 (695-698), Fig1.

2.Based on the configuration, I engaged in Position_Hold.
Why did the middle thr become 820 (or a little more), Fig2? Should be 700? My deadband of thr was 100.

3.I checked the Hacc. The value was lower then 1.5 when I let my AQ6 fly forward, Fig3.
However, altitude still dropped.
The difference between Pres_ALT and ALT was much, Fig 4.

These tests were executed in night.
I also changed a different foam and removed Pixhawk anti-vibration platform, Fig 5.
I did not rotate my IMU, Fig (I added blue gel to fix the board).
Today's log was here (https://www.dropbox.com/s/ob9gmuriez3d6 ... L.LOG?dl=0).

So tired....and sorry for your inconvenience....><....
Attachments
imu.jpg
Fig6
IMG_20150611_110252.jpg
Fig5
alt.jpg
Fig4
hacc.jpg
Fig3
ch0.jpg
Fig2
ch00.jpg
Fig1
jet
 
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Re: Baro problem or PID?

Postby plexus » Thu Jun 11, 2015 9:11 pm

Hi,
Just see on your last upload, there is a problem with your motors. They are clipped close to zero. I dont know how to do: ESC ?
For the throttle factor if you have registred 800 on your log: in hold position . The new trottle factor will be:
New Factor trottle = 0.7 x 800/ 700
I see a mistake in your channel but your trottlle are on the left or on right ?
could you upload a copy screen of the :
Radio&control
Mixing output
PID tuning
Misc setting.


Alain
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Re: Baro problem or PID?

Postby jet » Mon Jun 15, 2015 1:38 am

Hi, Aliain.
Please check my motors in the latest log(Fig1).
Sorry, I did not really know what the problem was.
My ESC was QBrain 4-in-1 25A ESC.
What should be fine for motors in a log?

Regarding Throttle_Factor, I was confused.
In the AQ Wiki, this factor was based on the "Manual" hover instead of "Position_Hold" hover.
So, what was correct? Hover in "Manual" mode or in "Position_Hold" mode?

My RC was Mode 2 (Throttle in the left).
I applied your suggested PID in my AQ6.
I showed you the Radio&control(Fig2), Mixing output(Fig3), PID tuning(Fig4), and Misc setting(Fig5).
Thanks so much.
Attachments
mis.jpg
Misc setting
pid.jpg
PID tuning
mot.jpg
Mixing output
rad.jpg
Radio&control
motor.jpg
Motors 0-3 in log
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Re: Baro problem or PID?

Postby plexus » Mon Jun 15, 2015 4:05 pm

Hi,
I see you have a lot of mistake.
Motors:
the motors are clipped at >4000 and 0. The motors must be between 3500 and 2600.
I dont know your ESC, are they calibrated ?
Throttle factor:
Takeoff, 2 meters or more above the ground
Put the throttle stick at 50% and switch the Hold position.
Be care with your config the motors can reduce or powered full, control with the throttle stick and search a hover position.
read the value on your sdcard: it must be close to 700 on the graph, If not apply the magic formula:
New throttle factor= 0.7 X value read on channel 0 /700

Channel 0
On your upload I dont see the action of the throttle stick.
You have a beautifull line a 700 it is not correct, you must have something like that:
Screenshot - 15_06_2015 , 16_36_44.jpg

And on your upload 004-log, that is not the same , you have change something, but too the curves are not good.
May be see your spectrum transmiter ? false channel.
Channel 5:this is the switch for the flight mode manual/hold/ mission
I dont see the action of the switch.
See your RC to the attribution of channels. Do you see the action on the QGC ?

Radio control:
You can lowered the low battery stage 1 to 3.50V to get an alarm at 14V if 4S
3.40 for the stage 2.
PID setting/
seems to be OK, but I dont knows what is good for your quad. See with the specialist on that forum

Mixing:
Your bird is not in X, and these values are they good ? I cannot tell it.

Good brain storming
Alain
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Re: Baro problem or PID?

Postby chschmid » Mon Jun 15, 2015 7:52 pm

plexus wrote:Throttle factor:
Takeoff, 2 meters or more above the ground
Put the throttle stick at 50% and switch the Hold position.


I would fly manual at least 2m from ground and try to keep the multi at the same alt for a while.
Then go and read your manual throttle from the log and calculate the Th_factor as I told you before.

The final test is: fly in hover at steady altitude. When switching to PH, there should be no change in alt because your stick is centered. When switching back to manual (TH stick centered) there is no change in alt.

Cheers
CHristof
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Re: Baro problem or PID?

Postby plexus » Mon Jun 15, 2015 10:07 pm

Ah ok, that is an other way that i did not know.

Alain
plexus
 
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Re: Baro problem or PID?

Postby jet » Tue Jun 16, 2015 1:50 am

Hi, Alain and Christof.
Thanks for help.

Regarding Throttle_Factor, my method was similar to Christof.
My question was what I should set based on manual hover or position_hold hover.
For example, my middle throttle was 650 in manual hover and 750 in position_hold hover, respectively.
What is the Ctrl_Thr_Factor? 0.65 or 0.75?

Regarding Motor clip, although I had calibrated my motors, the log seemed to be affected by Tilt rate and Tilt angle.
Fig 1, the Tilt rate D was 4600 and Tilt angle D was 70.
Fig 2, the Tilt rate D was 32000 and Tilt angle D was 160.
So, can I assume that Fig 2 was inappropriate for my AQ6?

I appreciated your help.
Attachments
11.jpg
Tilt rate D was 4600 and Tilt angle was 70
motor.jpg
Tilt rate D was 32000 and Tilt angle was 160
motor.jpg (41.68 KiB) Viewed 4865 times
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Re: Baro problem or PID?

Postby chschmid » Tue Jun 16, 2015 5:16 am

Fig 1 looks good if your system flies nice and crisp.

As long as you can switch between manual and PH without changing alt, you have it right.
Regarding your example, given that your Th_factor is set to 0.7 and you manually hover at 650, set the th_factor to 0.65 and you are good to go.

Cheers
Christof
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Re: Baro problem or PID?

Postby plexus » Tue Jun 16, 2015 8:50 am

I like figure one.
+1 with christof

Alain
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Re: Baro problem or PID?

Postby EX_TRUE » Sun Jun 28, 2015 6:41 am

I wonder if jet have resolved the problem of altitude drop.

And which method did you take?

:D


Best regards
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