Re: [Paparazzi-devel] Hff Filter Tests

[Kadir ÇİMENCİ]

Sorry, forget the attachment..

2014-03-05 13:56 GMT+02:00 Kadir ÇİMENCİ <address@hidden>:

Hello everyone ,

Today i start to test the hff filter on my quadrotor. First of all i observe the acceleration inputs for the filter ('b2_hff_xdd_meas' and 'b2_hff_ydd_meas'). The output is 'xdd.jpg' at the attachment(don't care about the label of the data, this is 'b2_hff_xdd_meas'). Here i want to mention the local tangent plane approximation works good. This log is holded while the rotorcraft flying, I believe the main source of noise  on this output is the vibration. Secondly i observe there is some noisy effects while the multirotor changes its orientation, due to some errors and delays on Ahrs side, but this effect is little then i expected. In conclusion the real horizontal accelerations can be seperated from the noisy output and i have decided that this acceleration input  may be useful with some little healings.

Here i have two options on my mind, what is your opinion?

1) The source for 'b2_hff_xdd_meas' is derived by taking LTP of 'acc_body_mean' which is the arithmetic mean value of the latest 16 acc. values coming from imu. Maybe more sharpener (IIR may be useful) filter with smaller phase delay (4-5 order etc) can be used rather than mean value of 16 inputs?

2) A filter on 'b2_hff_xdd_meas' directly before the input of Hff filter may be useful. I am not sure about this idea, it may cause the loss the meaningful data of horizontal acceleration.

Anyway with this point, i have decided to move a step forward without any modification in the source code. Afternoon, i will try to make deeper tests with position and speed estimates. By the way, i make settings on Hff as;

Accel_Noise = 4;

USE_GPS_ACC4R = TRUE  (I observe the pacc and sacc values coming from GPS, they seems correct to me)

HFF_UPDATE_SPEED =TRUE

Best regards,

Kadir

xdd.jpg
Description: JPEG image