This could be an issue of different minimum RPM the motors are actually spinning on - or similar...

Originally Posted by leopold1

Hi,

I've been following this thread for quite some time now.
I to got bitten by the arducopter and got started with the APM and IMU and ordered a seperate from from mikrokopter.
In the beginning I had some trouble with PID tuning but after playing arround for a little bit I'm quite happy.
The problem now is that sometimes a motor just stops resulting in a crash. I had this previously but thought this was because of the PID tuning. Yesterday I did a flighttest with no wind and everything looked just perfect until 1 motor stopped. It's not always teh same motor. If I test the motor seperatly all works fine.
I allready did a couple of things like change ESC, new motor, re install firmware, resolder all headers, recalibration, ...
Before I want to contunue to invest I want to make sur what the problem is.

My setup is the following
APM +IMU
MK frame 50cm
KD 20-22L
SP 30A ESC
3S LIPO 2100mAh 18C
Eurgle 2,4Ghz
Kindercramer software with Alpha release.

Hope you guys can point me in the right direction in finding a solution.

Here a small video of the problem. Each timethe motor stops I have to put throttleback to zero.
http://www.youtube.com/watch?v=V-ViXg-qBzs

I one's had a problem where the one motor was turning much faster then the rest. I thought it was the ESC or the motor. After moving from the Aeroquad board to the Arducopter project and loosing the ArduMega I found that my power distribution soldering had a ground problem. So in the end ground was not not going directly from the battery to the ESC (thick black wire) but through the servo connection (small black cable) which burned some tracks.....

That could also be your problem.
Another thought....What size battery do you have S3 mA? C15 or lower? Maybe the battery can not handle the load.

I will try to do a couple reinstallation with ESC calibration, Eeprom reset en IMU calibration.
The strange thing is that its not always the same motor.
Could it be related with the fact that I'm using a 18C battery?
The motors get a sort of nodge just before they stop.

Originally Posted by lohnieh

I update my firmware to include the Sparfkun Magnetometer orientation.

See attached Quad version and Hexa version. I included the latest libraries also.

Use at own risk. Thanx rmackay for the sparkfun orientation

lohnieh - Just flew your latest code and it is pretty nice - I havent yet tried altitude hold or gps but will do so soon

Thanks!!!
Mike

Hi.
Before i go and spend some more on a new magneto, can somebody please tell me if i can check the magneto or the oilpan to pinpoint my problem? Problem is that on apm_compass test i get all values zero and nothing changes.
I have checked the connections, i measure 4.7V on vcc, and continuity between all 4 pins of magneto and corresponding pins on oilpan. The solder blob is also checked and measured to make sure it doesn't short anything.
Do i need a new oilpan or a new mag?
thanks

Originally Posted by tigar

Hi.
Before i go and spend some more on a new magneto, can somebody please tell me if i can check the magneto or the oilpan to pinpoint my problem? Problem is that on apm_compass test i get all values zero and nothing changes.
I have checked the connections, i measure 4.7V on vcc, and continuity between all 4 pins of magneto and corresponding pins on oilpan. The solder blob is also checked and measured to make sure it doesn't short anything.
Do i need a new oilpan or a new mag?
thanks

Tigar - I realized that you are desperately asking for help. It seems to me that nobody really knows how to find out. What helped me before is to address your issue to Randy of the core dev team: rmackay9@yahoo.com. He might be the one to help. - Phil

Originally Posted by PhilippMaloney

Tigar - I realized that you are desperately asking for help. It seems to me that nobody really knows how to find out. What helped me before is to address your issue to Randy of the core dev team: rmackay9@yahoo.com. He might be the one to help. - Phil

Thank you. I will try that.

Originally Posted by cdi3d

lohnieh - Just flew your latest code and it is pretty nice - I havent yet tried altitude hold or gps but will do so soon

Thanks!!!
Mike

Yeah!

Please everybody with magnetos and gps test Hein's latest code.

... except for John who'll be flying his release #139 forever, I think.

Originally Posted by cdi3d

lohnieh - Just flew your latest code and it is pretty nice - I havent yet tried altitude hold or gps but will do so soon

Thanks!!!
Mike

Lipos can always be a problem. But I guess you got spares?
Valuing from what you have posted your lipo should work - unless it's old, worn out or badly charged (different voltage in the cells).

Good luck!

I did a full reinstall of everything, ESC calibration, firmware, Eeprom reset, calibration of tx and accels. During the ESC calibration of right motor it gave a nodge but didn't stop. Calibration is without APM so I would suggets ESC????
Did a test flight and it worked for about 30 sec.Then back motor went out and ... crash. Pffffffffffff No more props.
A have a ESC from a different brand and will test all the motors with this one.If this is OK Iwill change all the ESC's with another brand an check for a 25C+ battery.
Hope this works. If not, I'm going for something else and sell everything.

Originally Posted by leopold1

I will try to do a couple reinstallation with ESC calibration, Eeprom reset en IMU calibration.
The strange thing is that its not always the same motor.
Could it be related with the fact that I'm using a 18C battery?

Yes, it could be.
Your battery is 2100 MAh and 18C. That means it is capable of 2.1*18= 37.8 Amps current. You have 4 motors which is 9.45 Amps per motor. Now, KDA description says:

Standard Current: 6-15A
Max Current: 19A

So you are really pushing your battery hard.

Igor

I have two of the same batteries if I put themin parallel, could this be a solution?

I would suggest perhaps taking a look at the ESCīs programming. It could be your lowvoltage cutoff, timing or brake setting that is wrong.

I dont know those "SP" escs, but if they are anything like a Turnigy/RCT/OEM/Hobbywing, you should have these settings:

Brake: off
Batterytype: Nimh (to get lowest possible cutoff voltage)
cut off type: Soft Cut
cut off voltage: low (or disable, if possible)
Start mode: Normal
Timing: Typically medium or high (I run the KDAīs on High)
Music: OFF
Governor: Off

Always use some form of audible/visible Lipo alarm to tell you when your battery is low.

Originally Posted by leopold1

I have two of the same batteries if I put themin parallel, could this be a solution?

Theoretically - yes. But getting more powerful battery might be better. When I used Turnigy 2650 MAh, my flying time was 7 minutes. I guess with 2100 it will be closer to 5 minutes which really is not enough. BTW, that Turnigy battery has rating of 25C which would mean 66 Amps max and it got warm after the flight.

Igor

Originally Posted by kinderkram

Yeah!

Please everybody with magnetos and gps test Hein's latest code.

... except for John who'll be flying his release #139 forever, I think.

Gentlemen, thatīs exactly what I am doing right now - looks very good to me (at least on the desk). I will fly tomorrow and let you know.

ONE thing I need to remark: allthough I am very sure that I have set all parameters correct my magneto showed exactly 22 1/2 degrees into the wrong direction . (Hein, this is probably why it drifted always to the right ?? Does this reflect a wrong matrix programming between X and + config? I am flying X and magnetos upside down pins front.

I suggest to test with a real compass and the artificial horizon of the configurator:




-Phil