1、PID 算法（c 语言）BC31 TC30 编译过，可运行。#include #includestruct _pid int pv; /*integer that contains the process value*/int sp; /*integer that contains the set point*/float integral;float pgain;float igain;float dgain;int deadband;int last_error;struct _pid warm,*pid;int process_point, set_point,dead_band; fl
2、oat p_gain, i_gain, d_gain, integral_val,new_integ; /*- pid_init DESCRIPTION This function initializes the pointers in the _pid structure to the process variable and the setpoint. *pv and *sp are integer pointers. -*/ void pid_init(struct _pid *warm, int process_point, int set_point) struct _pid *pi
3、d; pid = warm; pid-pv = process_point; pid-sp = set_point; /*- pid_tune DESCRIPTION Sets the proportional gain (p_gain), integral gain (i_gain), derivitive gain (d_gain), and the dead band (dead_band) of a pid control structure _pid. -*/ void pid_tune(struct _pid *pid, float p_gain, float i_gain, fl
4、oat 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; /*- pid_setinteg DESCRIPTION Set a new value for the integral term of the pid equation. This is useful for setting the initial output of the
5、pid controller at start up. -*/ void pid_setinteg(struct _pid *pid,float new_integ) pid-integral = new_integ; pid-last_error = 0; /*- pid_bumpless DESCRIPTION Bumpless transfer algorithim. When suddenly changing setpoints, or when restarting the PID equation after an extended pause, the derivative o
6、f the equation can cause a bump in the controller output. This function will help smooth out that bump. The process value in *pv should be the updated just before this function is used. -*/ void pid_bumpless(struct _pid *pid) pid-last_error = (pid-sp)-(pid-pv); /*- pid_calc DESCRIPTION Performs PID
7、calculations for the _pid structure *a. This function uses the positional form of the pid equation, and incorporates an integral windup prevention algorithim. Rectangular integration is used, so this function must be repeated on a consistent time basis for accurate control. RETURN VALUE The new outp
8、ut value for the pid loop. USAGE #include “control.h“*/ 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; /*do integer to float conversion only once*/ pterm = pid-pgain * ferror; if (pterm 100 | pt
9、erm integral = 0.0; else pid-integral += pid-igain * ferror; if (pid-integral 100.0) pid-integral = 100.0; else if (pid-integral integral = 0.0; dterm = (float)(err - pid-last_error) * pid-dgain; result = pterm + pid-integral + dterm; else result = pid-integral; pid-last_error = err; return (result)
10、; void main(void)float display_value;int count=0;pid = / printf(“Enter the values of Process point, Set point, P gain, I gain, D gain n“);/ scanf(“%d%d%f%f%f“, process_point = 30;set_point = 40;p_gain = (float)(5.2);i_gain = (float)(0.77);d_gain = (float)(0.18);dead_band = 2;integral_val =(float)(0.
11、01);printf(“The values of Process point, Set point, P gain, I gain, D gain n“);printf(“ %6d %6d %4f %4f %4fn“, process_point, set_point, p_gain, i_gain, d_gain);printf(“Enter the values of Process pointn“);while(count=20)scanf(“%d“,pid_init(pid_tune(pid_setinteg( /pid_setinteg(/Get input value for process pointpid_bumpless(/ how to display outputdisplay_value = pid_calc( printf(“%fn“, display_value); /printf(“n%f%f%f%f“,warm.pv,warm.sp,warm.igain,warm.dgain); count+;
