[Paparazzi-devel] AR.Drone vertical velocity without SONAR

[Eric Poppe]

Hi all,

During some tests using an airframe file similar to ardrone_raw.xml without USE_SONAR running on the AR.Drone 2 I noticed 2 issues with the vertical velocity. I attached some log files recorded while holding the AR.Drone in my hand.

In the first log (14:31:40) I hold the AR.Drone in a constant position, vertically and horizontally, while rotating it around the pitch and roll axis. In the log file from 20 to 60 seconds you can see that the vertical velocity develops a large bias while rotating around the roll axis, and the bias goes the other way around while rotating back to zero.
Somehow the vertical velocity is influenced by the tilt angle even though all velocities are supposed to be zero.

In the second log (14:39:33) I hold the AR.Drone in a horizontal attitude and fixed position from 0 to 45 seconds. From 45 seconds to the end I keep it horizontal while moving it up and down. As you can see in the log files during the up and down movement the vertical velocity is 90 degrees out of phase with the vertical position (when the position goes through 0 the velocity is large) as expected. However, if you look at the noise effects in the first part of the log the position and velocity follow each other almost exactly except for a bias.
Somehow the influence of the noise on the vertical position is the same as on the vertical velocity.

Can anyone tell whether these two effects are supposed to happen and if so why?

Kind regards,

Eric

14_05_14__14_39_33.log
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14_05_14__14_31_40.log
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14_05_14__14_31_40.data
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