飞思卡尔PID算法详解与实时参数调整

#include <stdio.h> 
#include<math.h> 
struct _pid 
{ 
   int pv; //integer that contains the process value 过程量 
    int sp; //＊integer that contains the set point   设定值 
    float integral; // 积分值 －－ 偏差累计值 
    float pgain; 
    float igain; 
    float dgain; 
    int deadband;    //死区 
    int last_error; 

}; 
 
struct _pid warm,*pid; 
int process_point, set_point,dead_band; float p_gain, i_gain, d_gain,integral_val,new_integ; 
void pid_init(struct _pid *warm, int process_point, int set_point) 
{ 
    struct _pid *pid; 
    pid = warm; 
    pid->pv = process_point; 
    pid->sp = set_point; 
} 
void pid_tune(struct _pid *pid, float p_gain, float i_gain, float d_gain, int dead_band) 
{ 
    pid->pgain = p_gain; 
    pid->igain = i_gain; 
    pid->dgain = d_gain; 
    pid->deadband = dead_band; 

    pid->integral= integral_val; 
    pid->last_error=0; 

} 
void pid_setinteg(struct _pid *pid,float new_integ) 

{ 
    pid->integral = new_integ; 
    pid->last_error = 0; 
} 
 
void pid_bumpless(struct _pid *pid) 

{ 
    pid->last_error = (pid->sp)-(pid->pv);  //设定值与反馈值偏差 

} 

float pid_calc(struct _pid *pid) 

{
  int err; 
  float pterm, dterm, result, ferror; 
  err = (pid->sp) - (pid->pv); 
  if (abs(err) > pid->deadband) 
    { 
        ferror = (float) err;   
        pterm = pid->pgain * ferror; 

        if (pterm > 100 || pterm < -100)