Only 3 Motors spinning at any one time

Hi guys,

I'm new to the hobby and I've a diy drone that i'm working on, using the APM 2.6 on 3.2.1 Firmware.I've calibrated my ESCs,and all the manual calibrations that have to be done (radio,accelerometer,comapss,etc), and am able to arm my quad.

However, whenever i rev the throttle, i only get 3 motors spinning, and am not able to get all 4 motors spinning.Although the "dead" motor does not spin when i rev the throttle, when i increase the yaw and/or pitch on my transmitter, the "dead" motor starts spinning, however, there will be another motor that stops spinning, so that at any one time, i only have 3 motors spinning on my quad.Furthermore, when i pick up my quad (props off) in stabilize mode and tilt it manually, the "dead" motor starts spinning to correct the quad, as i assume it is meant to do.( There will be another motor that shuts down, with only a total of 3 motors spinning at any one time).

I've looked on google for people with only 3 motors spinning and only came across ESC calibration issues , where 3 motors slowly start up together while the 4 one does not. I do not think that this is my problem as i've calibrated my ESCs (all together) , and the 3 working motors spin immediately instead of slowling starting up 1 by 1. I'm not sure if the people with the esc calibration issues on google have the same issue as me where the "dead" motor is able to spin when they apply yaw and/or pitch as they do not make any mention of it.

I would appreciate any help rendered, opinions given to help me get my quad up into the air.

Thanks!

P.S I'm trying to get my logs up but can't seem to figure out how to do it, if someone could kindly direct me to a page with instructions, or tell me how to extract and upload my log giles, and how to analysis it, that would be great!.

EDIT: I uploaded the firmware using the mission planner's wizard, and did all the calibrations, with arming and takeoff attempt in the stabilize flight mode.

Build:

- APM 2.6 with external compass & GPS

- 2800maH Battery,

- 4 EMAX motors

- F450 frame

- Castle Creations 25A ESC Quad pack.

EDIT 2: Uploaded log files, and auto analysis results as follows :-

Log File C:/Program Files (x86)/Mission Planner/logs/QUADROTOR/1/2015-02-21 21-08-11.log
Size (kb) 1541.7314453125
No of lines 22051
Duration -1 day, 20:35:15
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 - mag_field interference within limits (21.90%)

Test: Dupe Log Data = GOOD -
Test: Empty = FAIL - Empty log? Throttle never above 20%
Test: Event/Failsafe = GOOD -
Test: GPS = FAIL - Min satellites: 4, Max HDop: 9.82
Test: IMU Mismatch = NA -
Test: Parameters = GOOD -
Test: PM = GOOD -
Test: Pitch/Roll = GOOD -
Test: Thrust = GOOD -
Test: VCC = GOOD -

2015-02-21 21-08-11.bin

2015-02-21 20-59-13.bin

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Replies

  • swap the motor and ESC with one that is working , simpler to swap the motor only first . if the motor works when you move it to another position on the quad it's not the problem , then move the ESC to another position on the quad if the issue follows the ESC , the ESC is the issue. if any thing that's plunged it to APM output on the same port that not working you have other issue .  

  • sound like the crappy ESC you are using is the root of your issue your not configuring motor RC input correctly. one motor thinks YAW input is throtle input?

    • Hi OG,

      Thanks for taking the time to reply, how would i go about checking if the ESCs are faulty? I think the ESCs should be working fine as I've tried attaching the props and having it try to take off, but it is unable to do so.Upon arming, when i rev throttle to max, 3 motors start spinning while 1 motor doesn't even twitch at all, and the quad is unable to take off. However, when i apply yaw/pitch/roll, the "dead" motor reacts accordingly, and my quad is able to limp around on the ground.It manages to pitch forward and back, with 2 out of the 4 legs off the ground, but it never manages to clear the ground totally. During the rolling/yawing/pitching, the "dead" motor switch around accordingly( the "dead" motor switches between motors 1 ~ 4,) while rolling/pitching/yawing accordingly.

      The quad is working perfectly(the motors react with all TX input) EXCEPT for the fact that i only have 3 motors working at any one time, and one falsely "dead" motor that spins whenever i roll/pitch or yaw. Only when i do nothing except rev the throttle does it not spin at all.

      I've uploaded the logs ( i think), you can have a look at them if you want to.

      EDIT: The throttle is not working fine as i thought, an auto analysis of the log gave me the following,

      Test: Autotune = UNKNOWN - No ATUN log data
      Test: Balance/Twist = GOOD -
      Test: Brownout = GOOD -
      Test: Compass = GOOD - mag_field interference within limits (21.90%)

      Test: Dupe Log Data = GOOD -
      Test: Empty = FAIL - Empty log? Throttle never above 20%
      Test: Event/Failsafe = GOOD -
      Test: GPS = FAIL - Min satellites: 4, Max HDop: 9.82
      Test: IMU Mismatch = NA -
      Test: Parameters = GOOD -
      Test: PM = GOOD -
      Test: Pitch/Roll = GOOD -
      Test: Thrust = GOOD -
      Test: VCC = GOOD -

      I'm getting an error with the throttle not going over 20%?

      2015-02-21 21-08-11.bin

      2015-02-21 20-59-13.bin

      ground.it
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