I saw two examples that implement filters, I noticed the speed with which you can implement filters in a dspic.

But I have a question:



How has been calculated Band pass filter?

Low pass filter with a cut off frequency at 1 Hz :

1Hz means 2*pi rad/s which is approximatively 6 rad/s.



matlab code :

>> Filter_1Hz = tf([6],[1 6])

Transfer function:
  6
-----
s + 6

>> bode(Filter_1Hz)
>> 

You will get :

We have a 45° phase and a -3db cut off at 6 rad/s which is approximatively 1Hz.

6 should be replace by 2*pi so as to get a precise 1Hz low pass filter.



If you are note familiar with theses math, have a look on the Laplace transform.



The filter is then discretized for a sampling rate of 200Hz using the c2d function with the tustin method.

can simu kalman filter ????

I will have a look on kalman filter to estimate the gyro bias. But I could not give a date when I will do it.



You could do it anyway !