PID控制程序PID控制程序.doc

#include stdio.h#includemath.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; 　　} 　　　　/*----------