Arducopter just not reliable.

Hi all.

I could really use some help trying to figure out if Arducopter 2.6 is ever going to work for me.

I have had a total of 4 units 2x genuine 3DR APMs and 2 generic arducopter.

2 buddies also have 1 unit each.

We all have major issues with all units.

to cut a long story short. We can have 3x perfect return to launches, then the the 4th one will result in a toiletbowl effect. Just randomness like that.

I've given up on using ANY failsafe as APM is just too unreliable.

That was a week ago, now things have gotten much worse.

Even stabalize mode does not work. If the quad makes it off the ground it will sometimes dart off in one direction, other times it just falls out of the sky The quad also "pulses"

Some times the quad will just stop responding to the controls and has to be knocked out of the sky to stop it from flying.

Othertimes the unit will just disarm on takeoff.

Have tried multiple recievers, boards etc, NOTHING fixes these issues. Both my buddies have given up on their board and now fly perfectly with another (closed source) autopilot. I would like to get this going correctly but the APM just seems so unstable.

I have attached some logs in case that helps.

Please help!

2014-08-20 16-58-55 9.log

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  • Hi Mike,

    I had a similar issue with my Y6B RTF. I have plenty of time in the air and several different multi rotors and fixed wing all running Ardupulot/Copter (Pixhawk and APM)

    Never had a problem, So I was very frustrated and surprised I started to have major issues with my Y6B.

    No matter what I tried it seemed that motor 5 always glitches or stalled at some point. I replaced motors, ESC's, power distros and even FC boards. Always the same.

    After going through three sets of motors and esc from 3DR I really thought it was a software issue but it was not. It turned out that the folding of the front arms had split the insulation on the Black motor wire. Just enough not to see on inspection with the Arms deployed in flight position and all of the guts hanging out.

    Out of frustration I replaced everything and lo and behold it seems to be solid and working. However, I am not sure that at least two of the three ESC's were not also faulty or if the damaged wire somehow caused the ESC's fault. I suppose it cause cause an unbalanced load on the motor phases and damage the esc output.

    However, as you say the proof is in the flying and I am happy to have finally got back I the air. So far so good.

    I am certain that the fault is a hardware issue and it took several rebuilds to lock it down, mainly caused by an intermittent fault that would only show up under flight conditions and I am sure that I had a couple of bad ESC's along the way.
    It coincided with a software upgrade so I naturally thought that was the problem. However, strange, one off behaviours are probably not bugs in the code.

    My faith in the software is restored and I am happy that I have learnt a lot. My latest Quad, a Cinetank with Tirger motors and RSC's flys great and I have had no problems with the setup unless it is a use fault. But I have found that while it take a bit more to setup Arducopter than NAZA it also make me a better pilot. Getting all of the failsafes set makes you get things right and you also HAVE to get things tuned in the correct (& logical) order. If that is done I have found that everything works as expected and if a fault or bug does occur you can usually recover (but not always!!!).
    • I agree Alex. I guess the challenge is part of the appeal but it gets less appealing if it takes months to figure out the problem. I also think that after you get used to the degree of control you have with APM via the parameters it is hard to accept the limitations of DJI's product. Glad you also got yours flying reliably and are enjoying it.

      I am happy to be at that stage too! Now back to tuning the PID's on my gimbal!

      • Hi,

        I found this thread with Google and honestly I am in the same boat right now having done new build, dealing for the first time with APM, seemingly got it working as expected but having issues with Loiter mode and desperately trying to find what and where to look at to understand what does not work as expected or should work as expected.

        I also see similar output from log review - made 2 flights and see this:

        Log File C:/Program Files (x86)/Mission Planner/logs/QUADROTOR/1/2015-05-14 14-30-25.log
        Size (kb) 1570.357421875
        No of lines 21091
        Duration 0:09:07
        Vehicletype ArduCopter
        Firmware Version V3.2.1
        Firmware Hash 36b405fb
        Hardware Type
        Free Mem 0
        Skipped Lines 0

        Test: Autotune = UNKNOWN - No ATUN log data
        Test: Balance/Twist = GOOD -
        Test: Brownout = GOOD -
        Test: Compass = GOOD - No MAG data, unable to test mag_field interference

        Test: Dupe Log Data = GOOD -
        Test: Empty = GOOD -
        Test: Event/Failsafe = FAIL - ERR found: FS_THR
        Test: GPS = WARN - Min satellites: 7, Max HDop: 3.6
        Test: IMU Mismatch = UNKNOWN - No IMU log data
        Test: Parameters = GOOD -
        Test: PM = GOOD -
        Test: Pitch/Roll = GOOD -
        Test: Thrust = GOOD -
        Test: VCC = WARN - VCC min/max diff 0.561v, should be <0.3v

        and this:

        Log File C:/Users/paul/AppData/Local/Temp/tmpCAD7.tmp.log
        Size (kb) 1570.3212890625
        No of lines 20740
        Duration -5 days, 5:15:29
        Vehicletype ArduCopter
        Firmware Version V3.2.1
        Firmware Hash 36b405fb
        Hardware Type
        Free Mem 0
        Skipped Lines 0

        Test: Autotune = UNKNOWN - No ATUN log data
        Test: Balance/Twist = GOOD -
        Test: Brownout = GOOD -
        Test: Compass = GOOD - No MAG data, unable to test mag_field interference

        Test: Dupe Log Data = GOOD -
        Test: Empty = GOOD -
        Test: Event/Failsafe = FAIL - ERRs found: FS_BATT FLT_MODE
        Test: GPS = FAIL - Min satellites: 0, Max HDop: 99.99
        Test: IMU Mismatch = UNKNOWN - No IMU log data
        Test: Parameters = GOOD -
        Test: PM = GOOD -
        Test: Pitch/Roll = GOOD -
        Test: Thrust = FAIL - Avg climb rate -1.65 cm/s for throttle avg 857
        Test: VCC = WARN - VCC min/max diff 0.589v, should be <0.3v

        In log review I also see barometer graph having severe jerks sometime, and it is covered completely with foam. APM is on the vibration pad, frame is armattan - with an additional vibration reduction.

        Loiter mode reactions to throttle are very delayed, it literally does not so anything for a half sec or so and then drone darts up or down. WTF... It is really puzzling as in the stabilize mode it seems to react perfectly fine.

        Compass was calibrated - but from this log review is says like it was not? How to check that?

        And what is "IMU Mismatch" is about? If it is too much to explain about APM - could anybody point to some article or guide that has step by step review of how to tune this?

        • Paul,

          Loiter requires a good GPS lock. If the FC doesn't have a good quality lock then it can't hold the position. The developers have determined that a GPS quality measurement "hdop" of <2 is required to be able to use Loiter. In fact with the newer firmware if you don't have an HDOP of < 2 it would not allow you to arm and take off. So it is not a matter of just getting a 3D lock but a high quality lock. This can change during the flight if you get behind objects that block one or more of the satellites you are using. So the line that says:

          Test: GPS = FAIL - Min satellites: 0, Max HDop: 99.99

          Test: GPS = WARN - Min satellites: 7, Max HDop: 3.6

          indicate problems with your GPS. It might be a matter of waiting until more or better satelites come into view or it might be interference on your aircraft or possibly a poor quality or defective GPS.

          You have two entries that indicate failsafes were triggered:

          Test: Event/Failsafe = FAIL - ERRs found: FS_BATT FLT_MODE

          Test: Event/Failsafe = FAIL - ERR found: FS_THR

          The IMU and MAG notes are because you did not have logging turned on for those parameters. If you want to turn logging on for those items go to the advanced parameters and search for "log" and you will find the parameter that controls what is being logged. If you turn on "everything" be aware that it can cause the cpu to be stressed on the FC so you might not want to leave it on at a high logging level all the time.

          Test: VCC = WARN - VCC min/max diff 0.589v, should be <0.3v

          The voltage that the fc "sees" is bouncing to a level that the developers consider too low. From normal your voltage is dipping .589v which can cause the fc to "brown-out". Not a complete power failure but a condition where the FC may be getting confused by the low voltage. It will cause problems if not attended to. You may have a bad ubec or power module or possible a bad flight controller.

          With multicopters the devil is in the details.

          • Paul, welcome to this fascinating ...but not so easy  APM world, to add Mike complete explanation, I suppose you are new at this forum too; It's better to have help (and better to others find topics) If you open your oun topic describing your principal issues on the title Ej "New APM build need help with Loiter" and you can post in arducopter user groups or flying /tuning arducopter or the category that you find nearer than your problem. http://diydrones.com/forum?page=1  http://diydrones.com/group/arducopterusergroup

            and try to share your log for better help ;)

            Another way is, if you feel that your problem is the same as an especific discussion like this http://diydrones.com/forum/topics/ac3-2-1-apm-2-5-throttle-pulsates... perhaps you can add there, read first if you find there ideas and if it is your problem too.

            Diy Drones search is better to find answers here than google. Good Luck

            • I just spent 48 minutes reading that thread and frankly i am very concerned. People seem to change multiple parameters randomly and then posting results and none of that has any structure, logic or method.
              I guess i will try to reinstall 3.1.5 firmware and see what will happen.

              All i can think of what to do on a hardware side is to measure vibrations and add capacitor to 5v line.
              • Yes, mesuring vibrations is the start point here,

                • Got it measured, it is fine. I am still not sure how to get to baro data and test it. I placed foam inside of the case and it is in contact with baro - was it supposed be touch the chip or just be on the case shell but with no direct contact?

                  Most issues were with 5V rail. I rewired whole thing and feed it now from 2 BACs, one into default APM power port and one from second power board into 1st port on the input rail.

                  Looks kinda stupid to me to do it this way, there is something wrong in the internal power distribution in the APM imho, as current draw is not justifying voltage jitter, but now it is stable at 5.15V. But it solved problem with complaints about 5V to be out of range or too low.

                  I reflashed 3.2 firmware, did all calibrations. Did not do autotune yet, will go to the field in 30min time from now.

                  I am still puzzled why in the log it continues to complaint :

                  Test: Autotune = UNKNOWN - No ATUN log data
                  Test: Balance/Twist = GOOD -
                  Test: Brownout = GOOD -
                  Test: Compass = GOOD - No MAG data, unable to test mag_field interference

                  Test: Dupe Log Data = GOOD -
                  Test: Empty = GOOD -
                  Test: Event/Failsafe = GOOD -
                  Test: GPS = FAIL - Min satellites: 0, Max HDop: 99.99
                  Test: IMU Mismatch = NA -
                  Test: Parameters = GOOD -
                  Test: PM = GOOD -
                  Test: Pitch/Roll = GOOD -
                  Test: Thrust = GOOD -
                  Test: VCC = GOOD -

                  About "No Mag data". I executed both standard compass calibration and motors interference. What else does it want? Search is not conclusive other than referring to some bug? GPS error is fine - it was indoors test.

                  • I fixed autotune issue. "User error. Replace the user and try again..." Duh.  

                    I also found a post stating a need to recompile firmware to include angle_rate_max parameter.

                    Is it something that indeed should be done? Anybody knows?

                    http://diydrones.com/group/arducopterusergroup/forum/topics/loiter-...

                  • Just did 2 tests flights. Odd.

                    Well, I got to say - 3.2 firmware is way better than 3.2.1. It worked.

                    I was able to complete autotune with no issues. And after than it flew like a dream. In all modes, no issues. All was perfectly fine. All modes, one after another, flew perfect.

                    Then I removed depleted battery, placed new same one in the same exact spot. I have it marked and Velcro secured it, so I know it is same spot.

                    Then it was odd. It flew normal first, but then in loiter mode several times it resulted in a crash after bird went into auto resonance mode trying to swing wings left and right and this amplitude would increase and increase, I was able every time to lower it down to safety but it would not recover.

                    Then it flew OK, then did it again. Next time as it started rocking sideways I switched into stabilize and after some sharp stick movements I stabilized it.

                    then landed, flew up in stabilize, lowered down, switched to loiter, tried to raise it up in the air - it rocked and quickly flipped over right there on the spot.

                    I rearmed in the stabilize, flew up, lowered, switched to loiter, was able to raise it up like it should without any issues.

                    I am really puzzled, not sure what to look, will get to logs now. I hope I switched all what was supposed to be switched in there.

                    What really puzzles me - right after autotune it was all fine, could not have been better. loiter, simple loiter, alt hold - all worked.

                    also, in second session once after switching from alt hold to stabilize it dropped from the sky like a rock. Happened only once like that. Throttle was at the middle setting where it should hover. So, I have very mixed feelings.

                    of the bird - it is 1770g, powered by 4S 5000Mah battery, DJI 2212 920kv motors. 9" props, as it was suggested by other people - not to overheat motors on 4S and indeed motors feel fine, not hot at all.  

                    mass center is almost ideal in the middle, it flew 10-11 minutes, close to what eCalc suggested. I see no direct flaws on the hardware side...

                    What else I should look at? Why does it go into auto resonance trying to correct itself in loiter and what should be done.  

                    It also feels that in loiter it flies quite slowish, compared to how agile and fast it is in the stabilize and alt hold, but it is nowhere like it was with 3.2.1 when it would be completely lethargic and would not respond to controls within 2-3 sec, it is totally usable now, but those issues worry me as I cannot see what to look at, what is the issue? 

                    Can it be about some specific parameters for loiter only - to deal with this overcorrection resonance that results in the side flip?  

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