pid算法C语言学习知识.doc

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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_

2、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

3、_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_

4、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

5、 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 deri

6、vative 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. -*/ void pid_bumpless(struct _pid *pid) pid-last_error = (pid-sp)-(pid-pv); /*- pid_calc DESCRIPTION Perfo

7、rms PID 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

8、new output 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 1

9、00 | pterm 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 (

10、result); void main(void) float display_value; int count=0; pid = &warm;/ printf(Enter the values of Process point, Set point, P gain, I gain, D gain n);/ scanf(%d%d%f%f%f, &process_point, &set_point, &p_gain, &i_gain, &d_gain); process_point = 30; set_point = 40; p_gain = (float)(5.2); i_gain = (flo

11、at)(0.77); d_gain = (float)(0.18); dead_band = 2; integral_val =(float)(0.01); 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(

12、%d,&process_point); pid_init(&warm, process_point, set_point); pid_tune(&warm, p_gain,i_gain,d_gain,dead_band); pid_setinteg(&warm,0.0); /pid_setinteg(&warm,30.0); /Get input value for process point pid_bumpless(&warm); / how to display output display_value = pid_calc(&warm); printf(%fn, display_value); /printf(n%f%f%f%f,warm.pv,warm.sp,warm.igain,warm.dgain); count+;