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Bad gyro?

Posted by Sayan Andriyanov on December 15, 2011 at 9:48am

Greetings,

After crash, probably caused by unsoldered filters, my copter starts to immediately flip to an arbitrary side just after takeoff. In Mission Planner, I've found that it now takes 5-6 seconds for artificial horizon to come to display the actual IMU position. 

Here in the picture I quickly rotated copter 90 deg. right, and after some seconds artificial horizon is still rotating! Same thing in CLI-test-imu: first three values com to display current position very slow.

Did I broke the gyroscope? 

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Replies

  • Bill Jowitt December 20, 2011 at 5:58am

    I am having similar problems. Twice now just after take-off my quad has flipped into the deck, bending arms, motor shafts and mounts and breaking props. It then lies there shrieking until I disconnect the battery. It is getting pretty heartbreaking as earlier today I was making great progress.  I attach the log of the last incident. I would be most grateful if somebody could look at them and tell me what is going wrong.

    2011-12-20 01-50 13.log.gpx

    2011-12-20 01-50 13.kmz

    2011-12-20 01-50 13.log

  • Sayan Andriyanov December 20, 2011 at 4:57am

    I see noone answers me:(

    This is probably because of my bad english. If so, sorry, I'll try to explain it again.

     

    The main flaw is that gyroscope data come to the system very slowly - like if there previously was an airball in the water and now this airball is in the honey or melted wax (see upper right chart on the attached image). Also, there's something wrong with accelerometer (or not?) - looks like it sends quantized data, jumping from one value to another (bottom chart).

     

    I want someone to make the same test - quickly rotate IMU 90 deg. left or right to see if accel behaves same way, or smoother.

     

    I'm not familiar with electronics, but what do you think about this hypothesis: something did broke ADC's clock (does it have one?) and it started to work very slow. It bufferizes gyro data (and therefore it comes stretched to main processor) but does not do it for accelerometer (and its data become quantized). What do you think?

    Thre also might be flaw in  Atmega2560's clock, but I didn't see slowing of connection process or loading or something of this kind.

    Strongly need help!! 

  • Sayan Andriyanov December 17, 2011 at 8:30pm

    Up..

    There's also scale-like accelerometer date. Is it normal? Can someone try it on his/her IMU?

    I'm very sorry that invensense gyros intolerant to shock and cold:( 

  • Developer
    Jason Short December 15, 2011 at 10:01am

    Can you take a macro photo of your board so we can see if you accidentally shorted or knocked off a part?

    Jason

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