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

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

Postby Max » Tue Jun 02, 2015 9:46 pm

Guys, how about providing way more details on your setup/build? And please post logs somewhere that doesn't require agreeing to some privacy policy involving 6 PDFs.

E-calc says your maximum Amp draw would be >24A ! That explains the burned ESCs.

Any new electric setup should be measured with a current (amp/watt) meter. Not only is this simply prudent to prevent mishaps such as yours, but it is also a good way to spot any potential issues before you put it up in the air.

I typically start by reducing Tilt Rate D setting by a factor of 10% or more. You'll know it is too low when the controls get extremely sluggish.

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

Postby chschmid » Tue Jun 02, 2015 10:08 pm

Your log shows extreme vibs and extreme clipping.
Looking at the outputs, CW/CCW does not have equal thrust. Maybe a slightly twisted motormount. (see MOT_YAW)
Futhermore your cal data from eprom can not be read, maybe was never stored?

Did you take a video?
If yes, please post it and post some pict of the copter.

You must have noticed heavy vibrations.
Whats your TILT_RATE_D?
Whats your CTRL_FACT_THRO?
Did you cover your baro with foam?


How did you set your KISS Escs?
What I do not understand is that your vibs start at spoolup. What props do you use?
Having the ESC's in the arms is not the best idea. You can not compare a copter with an airplane where the 5Amps may apply. The copter is regulating fast and uses all resources for that. So the avg may be 5 amps but if you have a closer look, the power throughput without cooling may be to high.



Cheers
Christof
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Re: PID problem ? sd card not recognized....now crash

Postby aBUGSworstnightmare » Wed Jun 03, 2015 8:10 am

Heisenberg wrote:
What do yu mean with "thema"?

Thanks for your help!


Sorry, that happens when I fail to correct the 'autocorrect' function of my tablet phone! Sorry, that's a typo there! I wanted to tell you - as Max/Christof did in the meantime - that 'default PIDs' might be way to high for your setup!
u3.jpg
Current draw of the T-Motor U3 @ 4S
u3.jpg (62.92 KiB) Viewed 5440 times

Who told you something about 5A average current draw? What I read from this chart is 19.4A at full load --> your 18A KISS will stand this --> ESC will burn/wire will de-solder (that's exactly what happened).
This is what a quick&dirty ecalc calculation (http://www.ecalc.ch) shows us:
ecalc.jpg

Never look at the current draw when hovering! Watch the max. current when selecting an ESC!

Again: Please post some more details on the setup/pics/parameters.
Joerg
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Re: PID problem ? sd card not recognized....now crash

Postby LPR » Wed Jun 03, 2015 1:18 pm

Guys

I found that if your using freewheeling you can greatly increase the amount of heat that an ESC generates when the input signals have a large variations.

If you think about this it makes sense. It takes more power to accelerate than to run at a set rate and the amount of heat generated in the ESC by braking is also high.

When testing the ESC32 V3 I find that the temperature of an ESC climbs many much faster when inputing large variation in throttle settings, then with a constant full throttle.

Larry
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Re: PID problem ? sd card not recognized....now crash

Postby Heisenberg » Thu Jun 04, 2015 7:16 pm

thank you very much for your hints!

the last days we recognized lots of improvements! but first of all some construction details.

our quadrocopter uses kiss18 with tiger u3 running 13*4,4 tiger props, as you already know. they are mounted on 20x0,5mm carbon fiber tubes with a length of round about 400mm. these tubes are mounted foldable between two strong carbon fiber plates, same machanism as the jordana from rosewhite (google shows many pictures). total weight is about 2700grams

so now our improvements:
tilt rate d ist now about 12000, 1/3 of the value before (34600)!!!
that killed nearly all vibrations, so i think that the freewheeling escs caused many vibrations due to much to high parameters and with that hard and fast regulation.

1)
but im not sure how to set the right value, at 8000 to 9000 it starts oscillating, from 10000 to 11000 it is not clearly visible and at 12000 it is absolute stable. Is this the right value to set? or should we go higher to be sure?

2)
what about the angle parameters? in wich cases schould i touch them?

we installed a current sensor after testing for the right params carefully. it is the fcs-150, which shows a total hover current of about 20 amps. that means 5A each motor!
the full throttle current is about 65A, 16 to 17 each... that is not above the limit!?!
in my opinion the fcs-150 is a sufficient messure method to have an idea of the currents. do you agree?
last option will be the soon release of the kiss30 for up to 6s.

3)
since we solved the first problems with your help, i would like to ask you for a hint for the autonomous navigation parameters... before crashing :D
i found some videos on youtube about testing the navigation. some times a copter starts up with full throttle or is chasing very fast to a side to reach the goal.
we would like to prevent our copter from going too fast for first tests with the navigation.
is my idea of the system right when i say that the stability of the drone is not affected by navigation rates? for example the values are set to low, so the copter will not be able to fight against wind, but it can not crash?
Just to be sure what this parameters will do! ;)


at least, our new logfile:
014-AQL.LOG
there are some vibrations left but we can live with that at the moment, next big step is a new construction of the arms and motor mounts, hoping that will solve the vibration issue and the different thrusts/motor outputs.
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Re: PID problem ? sd card not recognized....now crash

Postby LPR » Thu Jun 04, 2015 9:08 pm

I found that using freewheel did not work as well as would like when using an AQ 6 with PID control.

I really like how well freewheel works with Quatos.


The way I like to start out navigation is to first get APH ( altitude, position hold ) to work well and then set home and do a very short RTH. Slowly increase the distance between home point and the RTH point. If you can have your quad stop at home with no over shoot then a mission will be no problem.

You can change the Max. Speed for RTH and APH with QGC, on the Config page goto Misc. Settings in the top left corner.

Most of the time default Navi setting work very well. If you need to change Navi setting more than likely your quad is not working well in manual flight mode.

Larry
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Re: PID problem ? sd card not recognized....now crash

Postby Heisenberg » Thu Jun 04, 2015 10:36 pm

thank you larry, seems to be a good way!

can you explain where the difference is? why can the freewheel work better or worse? i thought that is an issue of the esc, they get a signal and try to reach it?

would it be possible to work with our construction and quatos? thougt that it is limited by the weight... i red something somewhere :D reliable information, i know ;)


we will have to work a few days on that copter, probably no results not before next week...

never the less, dont worry to answer my other quastions ;)

best regards!
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Re: PID problem ? sd card not recognized....now crash

Postby aBUGSworstnightmare » Fri Jun 05, 2015 7:58 am

Heisenberg wrote:at least, our new logfile:
014-AQL.LOG
there are some vibrations left but we can live with that at the moment, next big step is a new construction of the arms and motor mounts, hoping that will solve the vibration issue and the different thrusts/motor outputs.

From your log:
uncalibrated IMU.jpg
IMU-ACCX/Y/Z from 014-AQL.LOG

First thing you should do is calibrating your DIMU (TARE; http://autoquad.org/wiki/wiki/configuri ... libration/) and ensure the data get's stored in the EEPROM. Check your Pitch stick first; there is the chance you will have to reverse it.
If this happened we can have a look at your new log files.
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Re: PID problem ? sd card not recognized....now crash

Postby LPR » Fri Jun 05, 2015 2:03 pm

Heisenberg wrote:thank you larry, seems to be a good way!

can you explain where the difference is? why can the freewheel work better or worse? i thought that is an issue of the esc, they get a signal and try to reach it?

would it be possible to work with our construction and quatos? thougt that it is limited by the weight... i red something somewhere :D reliable information, i know ;)


we will have to work a few days on that copter, probably no results not before next week...

never the less, dont worry to answer my other quastions ;)

best regards!



PID control was the first method of control for the AQ flight controller.

Quatos is a new add on firmware that is designed for using freewheel ESC along with more precise control of a multicopter.

Larry
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Re: PID problem ? sd card not recognized....now crash

Postby aBUGSworstnightmare » Fri Jun 05, 2015 4:45 pm

Heisenberg wrote:would it be possible to work with our construction and quatos? thougt that it is limited by the weight... i red something somewhere reliable information, i know


Hi Heisenberg,
yes, you can use QUATOS on 'your construction'. Since your AUW is above 2.5kg this will require a commercial license (regardless if used commercially or not).
Personal Hobby license for crafts up to 2.5kg is priced at 99 USD. If your hobby craft weighs more than 2.5Kg commercial rates apply.

Commercial license for crafts up to 10kg is priced at 995 USD.

Full details are here (applies to M4 and AQ6): http://autoquad.org/wiki/wiki/quatos-ad ... or-the-m4/

So, If you can get below 2.5kg it is only 99USD to use QUATOS (hobby use only!).
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