http://ww1.microchip.com/downloads/en/Appnotes/Atmel-2558-Discrete-PID-Controller-on-tinyAVR-and-megaAVR_ApplicationNote_AVR221.pdf
pid.h
[syntax=c]#ifndef PID_H_
#define PID_H_
#define SCALE_FACTOR 128
#define Q(x) ((float)x * SCALE_FACTOR)
typedef struct{
int32_t Kp;
int32_t Ki;
int32_t Kd;
int32_t lim_min;
int32_t lim_max;
int32_t lim_i_min;
int32_t lim_i_max;
int32_t integrator;
int32_t error_prev;
int32_t out;
}PID_t;
void pid_init(PID_t* pid);
void pid_reset_integrator(PID_t* pid);
int16_t pid_calculate(PID_t* pid, int16_t setpoint, int16_t measurement);
#endif /* PID_H_ */[/syntax]
pid.c
[syntax=c]#include <inttypes.h>
#include "pid.h"
void pid_init(PID_t* pid){
pid->integrator = 0;
pid->error_prev = 0;
pid->out = 0;
}
void pid_reset_integrator(PID_t* pid){
pid->integrator = 0;
}
int16_t pid_calculate(PID_t* pid, int16_t setpoint, int16_t measurement){
int32_t error;
int32_t p;
int32_t d;
// error
error = setpoint - measurement;
// proportional
p = pid->Kp * error;
// integral
pid->integrator = pid->integrator + pid->Ki * error;
// integral anti-wind-up
if(pid->integrator < pid->lim_i_min){
pid->integrator = pid->lim_i_min;
}
if(pid->integrator > pid->lim_i_max){
pid->integrator = pid->lim_i_max;
}
// derivative
d = pid->Kd * (error - pid->error_prev);
// output
pid->out = (p + pid->integrator + d);
// output limits
if(pid->out < pid->lim_min){
pid->out = pid->lim_min;
}
if(pid->out > pid->lim_max){
pid->out = pid->lim_max;
}
pid->out = pid->out / SCALE_FACTOR;
pid->error_prev = error;
return pid->out;
}[/syntax]
main.c
[syntax=c]#include <avr/io.h>
#include <avr/interrupt.h>
#include "pid.h"
Timer_t timer0;
PID_t pid;
uint8_t pwm;
void timer0_timeout(void);
int main( void ){
TCCR1A |= (1<<WGM11) | (1<<WGM10) | (1<<COM1A1);
TCCR1B |= (1<<WGM12) | (1<<CS10);
OCR1A = 0;
timerSet(&timer0, 10, timer0_timeout, TIMER_MODE_CONTINUOUS);
timerStart(&timer0);
pid.Kp = Q(1.0);
pid.Ki = Q(0.3);
pid.Kd = Q(0.05);
pid.lim_min = Q(0);
pid.lim_max = Q(1023);
pid.lim_i_min = Q(-1000);
pid.lim_i_max = Q(1000);
pid_init(&pid);
sei();
while(1){
TIMER_EVENT();
}
}
void timer0_timeout(void){
int16_t setpoint = 50;
int16_t temp;
temp = get_temp();
pwm = pid_calculate(&pid, setpoint, temp);
OCR1A = pwm;
}[/syntax]Statystyki: Napisane przez Mario17 — 19 maja 2021, o 09:26
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