strange behaviour of pixhawk-request help to understand

Posted by moriarty on January 5, 2018 at 10:17am

Hi

I am building a 1300mm octocopter with 30AH lipo. I want to be using a tegra tx1 for onboard visual processing coming from a sony a6000. 

I have built the drone and assembled it. I have configured it as usual. I was using the external compass on the m8n gps. and when the compass calibration happened both of them had similar reading all under 150. I have also done a compass motor calibration for the offset.

however when I took it to the field and wanted to test it in autonomous mode, it started behaving weirdly. below is the auto diagnosis of the data log and also please find attached the flight log.

I fail to understand what could have gone wrong. I would appreciate any help solving it. I wish to fly the machine and then work the tegra part.

Size (kb) 856.1298828125
No of lines 10433
Duration 0:00:28
Vehicletype ArduCopter
Firmware Version V3.5.3
Firmware Hash 1a85c237
Hardware Type
Free Mem 0
Skipped Lines 0
Test: Autotune = UNKNOWN - No ATUN log data
Test: Brownout = GOOD -
Test: Compass = FAIL - Large change in mag_field (257.75%)
Max mag field length (1112.76) > recommended (550.00)

Test: Dupe Log Data = GOOD -
Test: Empty = GOOD -
Test: Event/Failsafe = FAIL - ERRs found: CRASH GPS_GLITCH
Test: GPS = UNKNOWN - join() takes exactly one argument (2 given)
Test: IMU Mismatch = WARN - Check vibration or accelerometer calibration. (Mismatch: 0.81, WARN: 0.75, FAIL: 1.50)
Test: Motor Balance = FAIL - Motor channel averages = [1722, 1684, 1360, 1314, 1480, 1441, 1754, 1650]
Average motor output = 1550
Difference between min and max motor averages = 440
Test: NaNs = GOOD -
Test: OpticalFlow = FAIL - FAIL: no optical flow data

Test: Parameters = FAIL - 'THR_MIN' not found
Test: PM = GOOD -
Test: Pitch/Roll = UNKNOWN - 'BarAlt'
Test: Thrust = GOOD -
Test: VCC = WARN - VCC min/max diff 0.563965v, should be <0.3v

thanks in advance 

2017-12-22 12-53-31.tlog

2017-12-22 11-18-53.bin

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Replies

  • moriarty January 23, 2018 at 2:20am

    Hi Greg,

    thank you for the insights. I am using a 30AH,25c TATTU battery with foxtech S5010 288kv motors with 17"*5.5" propellers.

    Also do you think the magnetic field is in check now? and what is this about motor balance .I was not able to get that.

    Regarding the tuning. I was hoping to auto tune the machine if it flies, but if the apparent reason for bad flight is its tuning, how do you suggest I solve it.

    Also PFA the image of the copter and a video.The image has the older configuration of the copter. the lastest configuration after changing the FC has the FC right on the top plate, where the gps mast is screwed to. the battery is way more than 20 cms below the compass on the mast. the Fc is also quiet far away from the battery and reasonably far away from the PDB.



    Greg Fletcher said:

    hello moriaty,

    I have just looked at some of your latest logs. Same critical problem exists, bad voltage to the pixhawk, excessive battery voltage drop from idle to flight.

    your power

    bad%20power.PNG

    power from my copter

    good%20voltage.PNG

    It is also very badly tuned apparently. The real attitude is not fallowing the desired attitude. Most likely because your large machine does not fit the default values. Do you have the corrrect props for your motors ect.? I don't know,but your machine has a lot of issues that would cause me to ground it until i figured it out. Below is a desired(by the FC) angle and the actual. Your copter and then mine as an example as with the power thing above.

    bad%20tune.PNG

    good%20tune.PNG

    Other than that I don't know what, but I do know that that machine is not safe to fly as it is. Can you advise what your motor/props are. A picture of this machine would be nice.

    Be carfull!

    WhatsApp Image 2018-01-19 at 20.32.13 (1).jpeg

    WhatsApp Image 2018-01-19 at 20.32.13.jpeg

    WhatsApp Video 2018-01-19 at 20.31.12.mp4

  • Greg Fletcher January 22, 2018 at 8:36pm

    hello moriaty,

    I have just looked at some of your latest logs. Same critical problem exists, bad voltage to the pixhawk, excessive battery voltage drop from idle to flight.

    your power

    bad%20power.PNG

    power from my copter

    good%20voltage.PNG

    It is also very badly tuned apparently. The real attitude is not fallowing the desired attitude. Most likely because your large machine does not fit the default values. Do you have the corrrect props for your motors ect.? I don't know,but your machine has a lot of issues that would cause me to ground it until i figured it out. Below is a desired(by the FC) angle and the actual. Your copter and then mine as an example as with the power thing above.

    bad%20tune.PNG

    good%20tune.PNG

    Other than that I don't know what, but I do know that that machine is not safe to fly as it is. Can you advise what your motor/props are. A picture of this machine would be nice.

    Be carfull!

  • moriarty January 22, 2018 at 2:44pm

     Thanks Javier,

    I shall do a flight test with stabilize mode see how that performs

    Javier Cerna said:

    To be completely honest, I'm not sure why that's happening. But try to flight the drone first in Stabilize Mode. In one of your logs, it seems that you start in Loiter and go up to 2 m and then crash it. I'm not quite sure how it influences the current, but maybe one of your gains is too high. To simplify the troubleshooting of your flight logs, try to make sure the drone flies well in Stabilize, please.

    Best,

    Javier

  • Javier Cerna January 22, 2018 at 2:38pm

    To be completely honest, I'm not sure why that's happening. But try to flight the drone first in Stabilize Mode. In one of your logs, it seems that you start in Loiter and go up to 2 m and then crash it. I'm not quite sure how it influences the current, but maybe one of your gains is too high. To simplify the troubleshooting of your flight logs, try to make sure the drone flies well in Stabilize, please.

    Best,

    Javier

  • moriarty January 22, 2018 at 1:21pm

    Hi Javier,

    Thanks for the Suggestion. I shall check on the Battery and the Motors. But how do you explain the volatility in the voltage and the magnetic field. some flights show good voltage some show a bad difference and same is the case with eh magnetic interference

    Cheers

    Javier Cerna said:

    Hi,

    Judging from your flight log, you have a really high voltage drop. I'm not sure if that's the issue, but going from 24 V to 17 V on launch seems unusual. Maybe the C parameter of your battery is too low, or they are not in good shape. The peak of 90 A seems to cause this voltage drop, but the voltage drop is too high to be acceptable.

    3702412690?profile=original

    Regarding the motor balance, it could be that your motors are indeed not well balanced (test them with a level tool, just in case).

    Best,

    Javier

    moriarty said:

    HI all

    today I performed my flight after much suggested changes in the power module and other power issues.

    FIRST FLIGHT:

    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = FAIL - Large change in mag_field (59.65%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = GOOD -
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.46, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = FAIL - Motor channel averages = [1768, 1679, 1535, 1441, 1543, 1457, 1736, 1726]
    Average motor output = 1610
    Difference between min and max motor averages = 327
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = UNKNOWN - 'BarAlt'
    Test: Thrust = GOOD -
    Test: VCC = WARN - VCC min/max diff 0.338379v, should be <0.3v

    SECOND FLIGHT:

    No of lines 5584
    Duration 0:00:13
    Vehicletype ArduCopter
    Firmware Version V3.5.4
    Firmware Hash 284349c3
    Hardware Type
    Free Mem 0
    Skipped Lines 0
    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = GOOD - mag_field interference within limits (1.09%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = FAIL - Empty log? Throttle never above 20%
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.14, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = WARN - Motor channel averages = [1231, 1229, 1167, 1176, 1220, 1216, 1253, 1201]
    Average motor output = 1211
    Difference between min and max motor averages = 86
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = GOOD -
    Test: Thrust = GOOD -
    Test: VCC = GOOD -

    THIRD FLIGHT:

    No of lines 51355
    Duration 0:05:26
    Vehicletype ArduCopter
    Firmware Version V3.5.4
    Firmware Hash 284349c3
    Hardware Type
    Free Mem 0
    Skipped Lines 0
    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = GOOD - mag_field interference within limits (9.63%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = GOOD -
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.19, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = WARN - Motor channel averages = [1196, 1268, 1246, 1289, 1178, 1237, 1179, 1277]
    Average motor output = 1233
    Difference between min and max motor averages = 111
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = GOOD -
    Test: Thrust = GOOD -
    Test: VCC = WARN - VCC min/max diff 0.362548v, should be <0.3v

    Now firstly all these three flights were on the same machine without changing anything on the machine, except the first flight was where the drone took off and crashed and the following two were flights with the drone tied down(bench tested). I fail to understand the following:

    1) The volatility in the vcc when its all the same battery(TATTU 30AH 6S) same current sensor(ATTOPILOT 180AMP).

    2) The volatility in the magnetic field.(my last bench tests, to which I uploaded the logs just a while ago, showed the magnetic fields in check when throttled all the way up and down and thru the other channels of roll/pitch/yaw.however today all of them had different values on the exact same setup)

    3) the second and the third flights were actually bench tests with the drone tied down. I fail to understand why it has a crash error. further, I had the same issue bench testing the drone the other day, when it was absolutely static and tied down . still  had the same error message. following is a read from that log

    No of lines 10375
    Duration 0:00:28
    Vehicletype ArduCopter
    Firmware Version V3.5.4
    Firmware Hash 284349c3
    Hardware Type
    Free Mem 0
    Skipped Lines 0
    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = GOOD - mag_field interference within limits (1.91%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = GOOD -
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.18, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = FAIL - Motor channel averages = [1570, 1422, 1558, 1453, 1386, 1209, 1369, 1605]
    Average motor output = 1446
    Difference between min and max motor averages = 396
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = GOOD -
    Test: Thrust = GOOD -
    Test: VCC = FAIL - VCC below minimum of 4.6v (4.485938v)

    4) I don't understand why all these flights have the following error messages:

    a) Test: Motor Balance = FAIL - 

    b) Test: Parameters = FAIL - 'THR_MIN' not found

    *any help is greatly appreciated. I have been trying to build this huge 1300mm octocopter with a 30AH battery and haven't been able to have a successful flight yet bcos of a lot of issues encountered 

    Thanks in Advance

    Cheers

  • Javier Cerna January 22, 2018 at 1:00pm

    Hi,

    Judging from your flight log, you have a really high voltage drop. I'm not sure if that's the issue, but going from 24 V to 17 V on launch seems unusual. Maybe the C parameter of your battery is too low, or they are not in good shape. The peak of 90 A seems to cause this voltage drop, but the voltage drop is too high to be acceptable.

    3702412690?profile=original

    Regarding the motor balance, it could be that your motors are indeed not well balanced (test them with a level tool, just in case).

    Best,

    Javier

    moriarty said:

    HI all

    today I performed my flight after much suggested changes in the power module and other power issues.

    FIRST FLIGHT:

    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = FAIL - Large change in mag_field (59.65%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = GOOD -
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.46, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = FAIL - Motor channel averages = [1768, 1679, 1535, 1441, 1543, 1457, 1736, 1726]
    Average motor output = 1610
    Difference between min and max motor averages = 327
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = UNKNOWN - 'BarAlt'
    Test: Thrust = GOOD -
    Test: VCC = WARN - VCC min/max diff 0.338379v, should be <0.3v

    SECOND FLIGHT:

    No of lines 5584
    Duration 0:00:13
    Vehicletype ArduCopter
    Firmware Version V3.5.4
    Firmware Hash 284349c3
    Hardware Type
    Free Mem 0
    Skipped Lines 0
    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = GOOD - mag_field interference within limits (1.09%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = FAIL - Empty log? Throttle never above 20%
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.14, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = WARN - Motor channel averages = [1231, 1229, 1167, 1176, 1220, 1216, 1253, 1201]
    Average motor output = 1211
    Difference between min and max motor averages = 86
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = GOOD -
    Test: Thrust = GOOD -
    Test: VCC = GOOD -

    THIRD FLIGHT:

    No of lines 51355
    Duration 0:05:26
    Vehicletype ArduCopter
    Firmware Version V3.5.4
    Firmware Hash 284349c3
    Hardware Type
    Free Mem 0
    Skipped Lines 0
    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = GOOD - mag_field interference within limits (9.63%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = GOOD -
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.19, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = WARN - Motor channel averages = [1196, 1268, 1246, 1289, 1178, 1237, 1179, 1277]
    Average motor output = 1233
    Difference between min and max motor averages = 111
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = GOOD -
    Test: Thrust = GOOD -
    Test: VCC = WARN - VCC min/max diff 0.362548v, should be <0.3v

    Now firstly all these three flights were on the same machine without changing anything on the machine, except the first flight was where the drone took off and crashed and the following two were flights with the drone tied down(bench tested). I fail to understand the following:

    1) The volatility in the vcc when its all the same battery(TATTU 30AH 6S) same current sensor(ATTOPILOT 180AMP).

    2) The volatility in the magnetic field.(my last bench tests, to which I uploaded the logs just a while ago, showed the magnetic fields in check when throttled all the way up and down and thru the other channels of roll/pitch/yaw.however today all of them had different values on the exact same setup)

    3) the second and the third flights were actually bench tests with the drone tied down. I fail to understand why it has a crash error. further, I had the same issue bench testing the drone the other day, when it was absolutely static and tied down . still  had the same error message. following is a read from that log

    No of lines 10375
    Duration 0:00:28
    Vehicletype ArduCopter
    Firmware Version V3.5.4
    Firmware Hash 284349c3
    Hardware Type
    Free Mem 0
    Skipped Lines 0
    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = GOOD - mag_field interference within limits (1.91%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = GOOD -
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.18, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = FAIL - Motor channel averages = [1570, 1422, 1558, 1453, 1386, 1209, 1369, 1605]
    Average motor output = 1446
    Difference between min and max motor averages = 396
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = GOOD -
    Test: Thrust = GOOD -
    Test: VCC = FAIL - VCC below minimum of 4.6v (4.485938v)

    4) I don't understand why all these flights have the following error messages:

    a) Test: Motor Balance = FAIL - 

    b) Test: Parameters = FAIL - 'THR_MIN' not found

    *any help is greatly appreciated. I have been trying to build this huge 1300mm octocopter with a 30AH battery and haven't been able to have a successful flight yet bcos of a lot of issues encountered 

    Thanks in Advance

    Cheers

  • moriarty January 22, 2018 at 11:48am

    HI all

    today I performed my flight after much suggested changes in the power module and other power issues.

    FIRST FLIGHT:

    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = FAIL - Large change in mag_field (59.65%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = GOOD -
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.46, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = FAIL - Motor channel averages = [1768, 1679, 1535, 1441, 1543, 1457, 1736, 1726]
    Average motor output = 1610
    Difference between min and max motor averages = 327
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = UNKNOWN - 'BarAlt'
    Test: Thrust = GOOD -
    Test: VCC = WARN - VCC min/max diff 0.338379v, should be <0.3v

    SECOND FLIGHT:

    No of lines 5584
    Duration 0:00:13
    Vehicletype ArduCopter
    Firmware Version V3.5.4
    Firmware Hash 284349c3
    Hardware Type
    Free Mem 0
    Skipped Lines 0
    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = GOOD - mag_field interference within limits (1.09%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = FAIL - Empty log? Throttle never above 20%
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.14, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = WARN - Motor channel averages = [1231, 1229, 1167, 1176, 1220, 1216, 1253, 1201]
    Average motor output = 1211
    Difference between min and max motor averages = 86
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = GOOD -
    Test: Thrust = GOOD -
    Test: VCC = GOOD -

    THIRD FLIGHT:

    No of lines 51355
    Duration 0:05:26
    Vehicletype ArduCopter
    Firmware Version V3.5.4
    Firmware Hash 284349c3
    Hardware Type
    Free Mem 0
    Skipped Lines 0
    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = GOOD - mag_field interference within limits (9.63%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = GOOD -
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.19, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = WARN - Motor channel averages = [1196, 1268, 1246, 1289, 1178, 1237, 1179, 1277]
    Average motor output = 1233
    Difference between min and max motor averages = 111
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = GOOD -
    Test: Thrust = GOOD -
    Test: VCC = WARN - VCC min/max diff 0.362548v, should be <0.3v

    Now firstly all these three flights were on the same machine without changing anything on the machine, except the first flight was where the drone took off and crashed and the following two were flights with the drone tied down(bench tested). I fail to understand the following:

    1) The volatility in the vcc when its all the same battery(TATTU 30AH 6S) same current sensor(ATTOPILOT 180AMP).

    2) The volatility in the magnetic field.(my last bench tests, to which I uploaded the logs just a while ago, showed the magnetic fields in check when throttled all the way up and down and thru the other channels of roll/pitch/yaw.however today all of them had different values on the exact same setup)

    3) the second and the third flights were actually bench tests with the drone tied down. I fail to understand why it has a crash error. further, I had the same issue bench testing the drone the other day, when it was absolutely static and tied down . still  had the same error message. following is a read from that log

    No of lines 10375
    Duration 0:00:28
    Vehicletype ArduCopter
    Firmware Version V3.5.4
    Firmware Hash 284349c3
    Hardware Type
    Free Mem 0
    Skipped Lines 0
    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = GOOD - mag_field interference within limits (1.91%)

    Test: Dupe Log Data = GOOD -
    Test: Empty = GOOD -
    Test: Event/Failsafe = FAIL - ERR found: CRASH
    Test: GPS = GOOD -
    Test: IMU Mismatch = GOOD - (Mismatch: 0.18, WARN: 0.75, FAIL: 1.50)
    Test: Motor Balance = FAIL - Motor channel averages = [1570, 1422, 1558, 1453, 1386, 1209, 1369, 1605]
    Average motor output = 1446
    Difference between min and max motor averages = 396
    Test: NaNs = GOOD -
    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found
    Test: PM = GOOD -
    Test: Pitch/Roll = GOOD -
    Test: Thrust = GOOD -
    Test: VCC = FAIL - VCC below minimum of 4.6v (4.485938v)

    4) I don't understand why all these flights have the following error messages:

    a) Test: Motor Balance = FAIL - 

    b) Test: Parameters = FAIL - 'THR_MIN' not found

    *any help is greatly appreciated. I have been trying to build this huge 1300mm octocopter with a 30AH battery and haven't been able to have a successful flight yet bcos of a lot of issues encountered 

    Thanks in Advance

    Cheers

    2018-01-22 18-20-24.bin

    2018-01-22 18-18-36.bin

    2018-01-22 18-06-12.bin

  • moriarty January 20, 2018 at 7:16pm

    Hi Greg,

    Finally I had my attopilot 180amp current sensor delivered. I have bench tested the drone before taking it to field for an actual flight. I also did an auto analyse on the flight log. interference and other parameters seem to be in check. however I found this:

    Test: Motor Balance = FAIL - Motor channel averages = [1612, 1653, 1325, 1371, 1224, 1288, 1600, 1663]
    Average motor output = 1467
    Difference between min and max motor averages = 439

    Test: OpticalFlow = FAIL - FAIL: no optical flow data

    Test: Parameters = FAIL - 'THR_MIN' not found

    Test: VCC = FAIL - VCC below minimum of 4.6v (4.534277v)

    Also please find attached the flight log.

    please suggest if the machine is okie for me to go for a flight test on field

    Regards



    Greg Fletcher said:

    moriati, please do not attempt to fly this machine until it is fixed. I noticed something. You are using a Pixhawk power module on a big copter and totally overloading it. You are lucky not to have a total power failure. The standard power module is only rated for a 4 cell and only measures up to 60 amps. The data shows you were above 60 amps(flat line at 60). That also explains the vcc drop when the copter stars flying. That is the problem that didn't yet cause a crash. The other is the magnatometer interference. When the current increases the mag readings change before the copter moves. That is the cause of the crash.

    The current sensor is a shunt resistor that has a maximum rating of 100 amps. If your machine hovers near 60 amps it will easily exceed 100 amps often during windy or fast flight. You really must redo your power power monitor. And get the mag/gps away from current conductors and your current indication can't go above 60 amps.

    2018-01-21 08-24-16.bin

  • moriarty January 19, 2018 at 12:55pm

    Thanks Javier for the suggestion. I found an interesting 180 amp attopilot current sensor on sparkfun and got that instead. 

    Javier Cerna said:

    Regarding the power module, you could use this one, from 3DR:

    https://store.3dr.com/products/10s-power-module

  • moriarty January 19, 2018 at 12:54pm

    Hi Greg,

    thank you so much for the support through out. I apologise for the late reply. I have recently changed my autopilot, Compass, shifted the battery a little further down and moved the autopilot also a little above its previous position. I have performed a bench test tying the drone down to ensure everything is alright before flight, Also as you suggested I have purchased the attopilot 180 Amp current sensor, and coupled it with a BEC to make a power module.I will be bench testing it with the power module changed and uploading the flight log later in the day.

    However I am uploading the last flight log when I bench tested the drone after I made reasonable changes. whiel I was going thru the log on auto analyse, I found a couple of things that don't seem right right to me:

    Test: Parameters = FAIL - 'THR_MIN' not found

    also when I try to arm the drone, it always doesn't respond to the command. I found it weird. it arms at times and at times does not respond to the command even if I hold the sticks centred for a while.
    Greg Fletcher said:

    I looked at your latest log. There is still a strong magnetic influence that follows current on both mags, one more than the other. there is also a large motor imbalance like one of the motors is not working or loosing sync.

    3702411012?profile=original

    2018-01-16 17-21-46.bin

    2018-01-16 17-09-25.bin

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