PX4FLOW: need 3D fix when Arming

[Ming Xu]

Hi guys,

I purchased PX4Flow sensor, I manully adjust the camera focus with 3m distance, after that, put the copter 1m distance from ground to calibrate, the OF.flowX, OF.bodyX, IMU.GyrX looks good.

now I want arm the copter on ground with loiter mode(the copter is ~15-20cm distance from ground). Mission Plan display "Need 3D Fix".

I do some test:

1. Lift the copter 1m distance, arm the copter successfully with loiter mode.

2. put back the copter to ground again, arm failed with "need 3d fix".

so, I guess, this maybe the camera focus introduced, 15-20cm is too short.

my question is, if I focus the camera with 3m distance, how to take off with loiter mode with px4flow position is not okay with short distance.

Now I focus the camera again with 15-20cm distance, althougth the copter can arm with loiter mode, but 3m or higher distance, the ground picture is not clear. it will impact loiter in air.

Thanks, 

[Randy Mackay]

Ming,

 

     You checked the “Pre-Arm checks” section of the wiki?

           http://ardupilot.org/copter/docs/common-px4flow-overview.html#pre-arm-checks

 

-Randy

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[Ming Xu]

Yes, the "all" and GPS" check box are unchecked.

 I check the souce code :

Copter::loiter_init  --> position_ok() --> return (ekf_position_ok() || optflow_position_ok());

I think "optflow_position_ok" "ekf_position_ok()" both return false.

 

 

[Allan Matthew]

Ming-

Have you disabled the geo-fence?  Additionally, if you are operating without good GPS, you'll need to set EK2_GPS_TYPE to 3.

-Allan

[Ming Xu]

Hi Randy,

sorry to make mistake, not in control_loiter.cpp: loiter_init  --> position_ok() --> return (ekf_position_ok() || optflow_position_ok());

it's in: motors.cpp:pre_arm_gps_checks()--> position_ok() --> return (ekf_position_ok() || optflow_position_ok());

both ekf_position_ok() and optflow_position_ok() are failed.

[Ming Xu]

Thanks Matthew:

Geo Fence not enabled.

here is my parameters setting:

EKF_GPS_TYPE: 3   // only use Optical Flow

FLOW_ENABLE:1 

FLOW_FXSCALER: 160

FLOW_FYSCALER:160

FLOW_ORIENT_YAW:  Y axis aligin to he head

GPS_HDOP_GOOD: 9999

LOG_BITMASK:131071