Re: [Paparazzi-devel] Drotek imu calibration problem

[Felix Ruess]

Hi Chris,

in which orientation did you mount your imu? If you get a positive value on z when your imu is level, it is either upside down or your accel signs are wrong.

If it is mounted upside down, you need to set your BODY_TO_IMU accordingly.

The imu measurements are always in the imu axes and not the body axes.

So please check if all your signs and axes are correct, according to http://paparazzi.enac.fr/wiki/ImuCalibration#Finding_and_Checking_Signs

Cheers, Felix

On Wed, Apr 10, 2013 at 2:02 PM, Chris <address@hidden> wrote:

Hi Felix
I checked the scaled values and it was over 20m/s so i switched to the calculated defines

<define name="ACCEL_X_NEUTRAL" value="61"/>
<define name="ACCEL_Y_NEUTRAL" value="6"/>
<define name="ACCEL_Z_NEUTRAL" value="-67"/>

<define name="ACCEL_X_SENS" value="4.87542830698" integer="16"/>
<define name="ACCEL_Y_SENS" value="4.89064537368" integer="16"/>
<define name="ACCEL_Z_SENS" value="4.81527520369" integer="16"/>

With the above values i get 9.81m/s but the artificial horizon starts to drift immediately and after 10 seconds is upside down. With the older values it worked ok i think but the scaled values were just above 20m/s (the neutral values are ok).
What could be wrong?
Btw i obtained those values by following the directions in the wiki (create log files etc)
Chris

On 04/10/2013 04:27 AM, paparazzi-devel-request@nongnu.org wrote:

the calibration result looks good. Did you create the log with the same
subsystem/configuration?
To check your scale, please switch telemetry to scaled_sensors and make

sure you get -9.81 m/s? on z when the IMU is level.

Cheers, Felix

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