PID算法(C语言)

作者：61IC 文章来源：本站原创 点击数： 更新时间：2007-1-16
#include <stdio.h>
　　#include<math.h>
　　
　　struct _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;
　　float 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 *pid;
　　
　　 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, 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;
　　}
　　
　　/*------------------------------------------------------------------------
　　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
　　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 of 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.
　　----------------------------------------------------