Baro problem or PID? [semi-solved]

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Re: Baro problem or PID?

Postby aBUGSworstnightmare » Wed Jun 10, 2015 6:37 am

gpsqual.jpg
HACC and VACC

Your GPS signal is not the best. Which type of GPS antenna do you use (size) and is there a GPS Ground shield or not? Pic please!
thrchannel.jpg
Throttle channel not set right; Throttle factor not adjusted

Your Throttle channel seems odd to me (should be 0 to 1400, middle at 700) -> verify your TX settings and adjust the throttle factor (http://autoquad.org/wiki/wiki/configuri ... -override/)

Same question as Christof's: post a picture showing how you've covered your baro.
Joerg
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Re: Baro problem or PID?

Postby jet » Wed Jun 10, 2015 9:28 am

Hi, Joerg,
Thanks for help.

I tuned throttle factor again.
Based on the test result, I set CTRL_Thro_Factor=0.65.
Is it correct?

For throttle channel, the lowest was -98(0%)/702(50%)/1406(100%).
I tried to tune 0 and 0% in my RC.
However, I never succeed.
Is it necessary to let 0% (The lowest Thro) be 0?

Also, associated with GPS Shield, I used a foam to cover Baro between AQ6 and DIMU.

Appreciate your participation.
Attachments
IMG_20150610_144606.jpg
baro
1400.jpg
highest thr
1400.jpg (43.05 KiB) Viewed 3612 times
700.jpg
mid thr
700.jpg (42.8 KiB) Viewed 3612 times
0.jpg
lowest thr
0.jpg (42.25 KiB) Viewed 3612 times
thr.jpg
Thr factor
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Re: Baro problem or PID?

Postby chschmid » Wed Jun 10, 2015 10:13 am

jet wrote:Hi, Joerg,
Thanks for help.

I tuned throttle factor again.
Based on the test result, I set CTRL_Thro_Factor=0.65.
Is it correct?

For throttle channel, the lowest was -98(0%)/702(50%)/1406(100%).
I tried to tune 0 and 0% in my RC.
However, I never succeed.
Is it necessary to let 0% (The lowest Thro) be 0?

Also, associated with GPS Shield, I used a foam to cover Baro between AQ6 and DIMU.

Appreciate your participation.


Hi Jet

To check if your trottle factor is right, take the multi in a manual hover. If your channel 0 is at 700 when hovering, you have it right. You will see that in the log after flight. if not, calculate the right TF from your readings. (actual TF / 700 * chanal 0 reading = new TF). Easiest is to set TF to 0.700, hover, calculate.
Regarding the radio settings, center should be as close as possible at 700 or 0 depending on the channel.
If you can adjust the endpoints, do for 0 -1400 and -700 to plus 700 as close as possible.
if you are unsure if your throttle is centered in PH (which is mandatory for constant alt), you can raise the throttle deadband to 80 or so.

Foam position looks good. Is your foam letting air thru? This is very important. You should be able to blow thru the foam with your mouth.

Cheers
Christof
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Re: Baro problem or PID?

Postby jet » Wed Jun 10, 2015 10:48 am

Thanks Christof,
I would try to tune TF carefully associated with Futaba 14SG instead of Spektrum DX8S.
I could feel air flow when I blew the foam.
Thanks so much.
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Re: Baro problem or PID?

Postby aBUGSworstnightmare » Wed Jun 10, 2015 11:27 am

jet wrote:I would try to tune TF carefully associated with Futaba 14SG instead of Spektrum DX8S.

Hi Jet,
with the DX8 you should be able to adjust the throttle perfectly (I also have a DX8 besides my (favoured) DX10):
- use it in airplane mode!
- be sure to set TRIM STEP to 1 (SYSTEM SETUP -> TRIM SETUP)
- under FUNCTION MODE you will have to adjust the travel for the channels. With the stick/Switch in the centered Position your changes will apply to higher and lower Limits (in %) --> place the throttle stick in the lower Position to trim Close to ZERO; once done put it in HIGH Position and adjust travel close to 1400. Use the QGC channel Monitor when trimming to verify your results.
- if you don't get Close (enough) you can use SUB TRIM to adjust. STAY AWAY FROM THE TRIM SWITCHES AND KEEP THEM CENTERED!

Manual is here https://www.spektrumrc.com/Products/Def ... d=SPMR8810 . Also make sure your TX runs the latest AIRWARE (you can download it form the Spektrum community https://www.spektrumrc.com/MyAccount/Lo ... ault.aspx; V3.01 (Feb 2014) is the latest for SPM8800 = DX8)

For throttle factor calculation do as pointed out by Christof already:
- back to 0.7
- do a manual hover (watch the value on your TX (servo monitor screen - throttle = 50%; maybe good to make serveral ones --> start/hover/land --repeat)
- check the log
- calculate new factor and change it
- do a manual hover to verify (watch the value on your TX (servo monitor screen - throttle = 50% ))
--> your factor is right if your craft's altitude doesn't change when switching between manual/PH mode.

REMOVE THE RUBBER DAMPENERS ON THE AQ6 (black Thing under the standoff)!!!!!!!!!!!!!!!!!!!!! What is the blue ball like Thing?? is this a dampened Mount? Pleace make another Picture showing it entierly.
If this is a dampened Mount (i.e. Pixhawk anit-vibration Mount) -> get rid of it!


Joerg
Last edited by aBUGSworstnightmare on Wed Jun 10, 2015 2:41 pm, edited 2 times in total.
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Re: Baro problem or PID?

Postby LPR » Wed Jun 10, 2015 1:16 pm

Jet

I had a similar altitude control problem after I added foam to the barometer on the M4 board.

My mistake was to use foam that comes with some electron components. Steve pointed out to me that the foam is treated with an static electricity control chemical and will cause a lot of trouble because the foam will conduct electricity!!

I've found that if you have the AQ board mounted solid and vibration are low, that I don't need to adjust altitude PIDs.

Larry
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Re: Baro problem or PID?

Postby plexus » Wed Jun 10, 2015 2:05 pm

+1, Take care with foam and test if not stop air.
Your HACC is not good, you must have it below 1 to get a good stability in hold position and to dont loose altitude on RTH.
Your pid seems to be a little bit wrong. Try these values:
Tilt rate D= 32000
Tilt angle P=165
Tilt Angle I= 0.0025
Tilt angle D=8500
Navigation Distance rate P=0.5
Navigation Altitude speed P=200 +/-
Navigation altitude spped I=2.85 -/+
Navigation altitude Position P=0.2
For the hold your throttle stick must be at 50%, Read the value on your log and adjust with the methode given by Christoff or the wiki.

With the original values your bird must fly !
Alain
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Re: Baro problem or PID?

Postby jet » Wed Jun 10, 2015 3:43 pm

WOW~learn much from you all.
So appreciative.^^

To Joerg,
1.I also liked Spektrum RC. I tried to tune my DX8 again based on your suggestion.
My DX8 was the latest firmware (V3.0.1) associated with stick calibration.
2.The blue ball was anti-vibration platform for Pixhawk (as well as figure).
Although I felt it was good to reduce vibration, I will remove them and try again.

To Larry,
It's cool to understand the truth regarding foams associated with electronic components.
I had to change my foam.
Nice information!

To plexus,
My frame was 550mm not big.
Meantime, the frame looked like "V" style instead of "X" style.
I had tried the default PID.
However, my AQ6 oscillated.
So, I decreased the default PID.
I may try your suggestion again.
Attachments
76727_1_High.jpg
blue ball
76727_1_High.jpg (71.17 KiB) Viewed 3593 times
jet
 
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Re: Baro problem or PID?

Postby aBUGSworstnightmare » Wed Jun 10, 2015 5:10 pm

jet wrote:..
2.The blue ball was anti-vibration platform for Pixhawk (as well as figure).
Although I felt it was good to reduce vibration, I will remove them and try again.
..


Yes, please remove it! AQ like no soft mounting!
If your vibration level is too hight then you need to find the root cause (i.e. soft frame, bad props, ..) and eliminate it.
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Re: Baro problem or PID?

Postby plexus » Wed Jun 10, 2015 6:03 pm

Have you the good angle (IMU rotation) ?
and too, lower your tilt rate D if vibrate.
A good balance of the motors and props is very appreciated by AQ .
Have a glance on your ACC X, It must be between +/-1 or +/-2.
3 begin to be worse.
Alain
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