AC3.2.1 APM 2.5 Throttle pulsates in Loiter

Hi.

I have a problem after updating AC to 3.2.1 from 3.1.5.

When in Loiter, the the speed of the motors rev up and down/pulsate quite rapidly. This was working fine when I was using previous versions of arducopter.

I have downloaded the logs, and have looked into accX, accY and accZ. These seems to be inside the range specified in the wiki at arducopter. (Log_vibrations.bin)

Please have a look at the Log.bin, and note the difference between ThrIn and ThrOut when I'm in Loiter mode.

 

Anyone having any idea what the problem may be?

Log.bin

Log_Vibration.bin

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Replies

    • Well, after doing about 10 flights today... tuning the APM manually, I can get a very stable Stabilize flight... very responsive... actually, the Loiter isn't that all bad either... just a little flutter up and down.  The AltHold on the other hand is not behaving.  I then proceeded to try a version even further down the chain.  Hexa_ArduCopter_3.1.2.Hex and that had the same result.  I don't think the problem is software/firmware.  I believe we/I have a hardware problem. I don't know what it could be as my logs do indicate some Power Issues from more than 0.3v difference when in fact I get 0.429v delta.

      I am going to start with my Power Module and then test again.

      Here is the latest Logs... In case anyone is interested...

      • So, here are the results of a new PM put in place....

        3702693885?profile=original

        3702693729?profile=original

        3702693750?profile=original

        • It seems to me, your power module just not have enough power.

          • Still having the AltHld problem Changed several Parms Is the real problem vibrations ?

            Pleas have a look.................

            2015-04-18 13-33-12.log

            • High vibrations, you have to resolve that, here many great info to do it  http://diydrones.com/forum/topics/vibration-isolation-and-dampening...

            • Well, from a quick glance your X/Y are well over the -/+ limits of -3/+3

              3702879292?profile=original

              Your Z is well over the -5/-15.

              3702878835?profile=original

              I would definitely fix the Vibrations...

              Was your crash significant? Any damage?

      • oops.. the log file..

        2015-04-17 13-50-10.log

    • Question for those who know... 

      Does a fluctuation of 4.7v to 4.4v an issues in Power to the APM?

      3702560919?profile=original

      https://dl.dropboxusercontent.com/u/58223709/_WEB/Flight_6_Outside.log

      • With power issues like this I doubt you get steady flight, sensors need very stable power source to give accurate measured values. In your case 45 degree angle can give (for example) 1.5V and 1.4V depending on input voltage, system gets it as 45 degree -> 40 degree not knowing that it's just input voltage fluctuations.

        Get stable power source.

         I don't use APM power module power source at all. After a couple of brownouts I returned to my well tested 7-38V 7A BEC which works flawlessly powering ALL electronics without any limitations.

        I really don't understand why 3DR could not design 10A power module, which will be more than sufficient for any copter/plane/rover needs.

        • Hi Marko, thanks for replying... I don't like to problems in the logs so I am going to switch that Power Module out.  Its not 3DR but in an HK one.

          Power Module HK

          68694.jpg?width=300

          But I have never had problem with my 3DR Modules... have run those on all my quads... that being said, I give up at this point with tuning and firmwares and am going to try out the hardware change.

          Thanks again for replying... 

          Cheers

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