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wangine
Joined: 07 Jul 2009
Posts: 98
Location: Curtea de Arges, Romania
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| recursive complementary filter |
 Posted: Mon Jul 25, 2011 11:31 am |
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I have been working with pointers, but at the structures.
I tried to apply complimentary Recursive filter in the example of Matthias Toussaint but without success.
I understand the error and to be honest I do not understand how it should be no argument function to call.
From what I understand:
angle / / angle from gyro already integrated
Rate / / conversion rate, time between conversions
* filter / / return value them after being filtered.
The error is: *** Error 12 "I: \ PIC_Lucru \ dspic33FJ128MC804 \ Kalman_1_test_1 \ 2 \ src \ complementary_f.c" Line 14 (17.18): Undefined identifier - comp_filter_step
I tried to call static.
| Code: | // Filter 'object' definition
//
typedef struct
{
float hp_x0, hp_x1;
float hp_y0;
float lp_x0, lp_x1;
float lp_y0;
float hp_last;
float hp_int;
} CompFilter;
// very simple complimentary filter
// (0.25% nyquist hp-lp combination)
//
float comp_filter_step( CompFilter *filter,
float angle,
float rate );
float comp_filter_step( CompFilter *filter,
float raw_angle,
float raw_angle_rate )
{
// highpass filter angle rate from gyro
//
filter->hp_x0 = filter->hp_x1;
filter->hp_x1 = raw_angle_rate * (1.0f/1.003927011f);
filter->hp_y0 = filter->hp_x1 - filter->hp_x0 +
0.9921767002f*filter->hp_y0;
// integrate angle rate using trapezoidal rule
//
filter->hp_int -= 0.5f*(filter->hp_last +
filter->hp_y0);
filter->hp_last = filter->hp_y0;
// lowpass filter angle from accelerometer
//
filter->lp_x0 = filter->lp_x1;
filter->lp_x1 = raw_angle * (1.0f/2.556465999e+02f);
float lp = filter->lp_y0 = filter->lp_x0 +
filter->lp_x1 +
0.9921767002f*filter->lp_y0;
return lp + filter->hp_int;
} |
| Code: | void testa ()
{
comp_filter_step(is,23,44);
} |
are lost in this  |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Jul 25, 2011 10:37 pm |
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Here is a demo program that shows how to create a structure, and
how to pass a pointer to it in a function. I added some printf statements
to prove to you that it's working. You can run it in MPLAB simulator
and see the output. I didn't look at the internal code in your step
function. I was only concerned with showing how to pass a structure pointer.
| Code: |
#include <18F452.h>
#fuses XT,NOWDT,PUT,BROWNOUT,NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
// Typedef the structure.
typedef struct
{
float hp_x0, hp_x1;
float hp_y0;
float lp_x0, lp_x1;
float lp_y0;
float hp_last;
float hp_int;
}CompFilter_t; // The '_t' at the end shows it is a data type.
// Create one instance of the structure and name it 'CompFilter'.
CompFilter_t CompFilter;
float comp_filter_step( CompFilter_t *filter,
float raw_angle,
float raw_angle_rate )
{
// Display the contents of the structure to show that
// the structure pointer is working.
printf("%7.3f \r", filter->hp_x0);
printf("%7.3f \r", filter->hp_x1);
printf("%7.3f \r", filter->hp_y0);
printf("%7.3f \r", filter->lp_x0);
printf("%7.3f \r", filter->lp_x1);
printf("%7.3f \r", filter->lp_y0);
printf("%7.3f \r", filter->hp_last);
printf("%7.3f \r", filter->hp_int);
// highpass filter angle rate from gyro
//
filter->hp_x0 = filter->hp_x1;
filter->hp_x1 = raw_angle_rate * (1.0f/1.003927011f);
filter->hp_y0 = filter->hp_x1 - filter->hp_x0 +
0.9921767002f*filter->hp_y0;
// integrate angle rate using trapezoidal rule
//
filter->hp_int -= 0.5f*(filter->hp_last +
filter->hp_y0);
filter->hp_last = filter->hp_y0;
// lowpass filter angle from accelerometer
//
filter->lp_x0 = filter->lp_x1;
filter->lp_x1 = raw_angle * (1.0f/2.556465999e+02f);
float lp = filter->lp_y0 = filter->lp_x0 +
filter->lp_x1 +
0.9921767002f*filter->lp_y0;
return lp + filter->hp_int;
}
//==========================================
void main()
{
// Load the structure instance with some nominal values.
CompFilter.hp_x0 = 1.23;
CompFilter.hp_x1 = 2.34;
CompFilter.hp_y0 = 3.45;
CompFilter.lp_x0 = 4.56;
CompFilter.lp_x1 = 5.67;
CompFilter.lp_y0 = 6.78;
CompFilter.hp_last = 7.89;
CompFilter.hp_int = 8.90;
// Call the step function and pass it the address of the
// structure instance. Note the '&'.
comp_filter_step(&CompFilter, 23, 44);
while(1);
} |
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wangine
Joined: 07 Jul 2009
Posts: 98
Location: Curtea de Arges, Romania
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| Posted: Wed Jul 27, 2011 12:34 pm |
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Thank you.
I appreciate your work, those who respond so quickly.
Thanks again. |
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