[Paparazzi-devel] Yaw from AHRS

[Loic Drumettaz]

Hello,

I performed the calibration of aspirin IMU on a Lisa M board of the accelerometers and magnetometers, using the phyton program. For the gyrometers, I have tuned the neutral, but i have no possibility to calibrate the sensitivity. Then, I checked the phi, theta and psi angles using the AHRS telemetry message.

phi and theta are looking fine, but psi response is weird: see attached plot showing the psi angle measurement, moving the quadrirotor stepwize. The initial transient goes in the opposite direction of the movement, and the response time is 8 seconds! For AHRS, I'm using the "int_cmpl_euler" configuration.

I have investigated and plotted the FILTER message and it appears that this behaviour is due to the filtering process in the AHRS: INT32_measure_psi is OK. (except noise and offset...)

- Are there parameters available in Paparazzi for tuning the AHRS filter?

- In AHRS section of the airframe configuration file, what does PROPAGATE_FREQUENCY parameter stand for? I tried different values but didn't see any difference.

- Is this problem due to wrong measurement/ calibration of the magnetometer? 

Thanks in advance

Loïc

psi_overshoot_int_cmpl_euler.png
Description: PNG image