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C语言实现PID算法
关键词 PID pid算法 pid控制算法 pid程序 pid调节
BC31 TC30 编译过,可运行。
- #include
- #include
-
- 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.
- ------------------------------------------------------------------------*/
- void pid_bumpless(struct _pid *pid)
- {
-
- pid->last_error = (pid->sp)-(pid->pv);
-
- }
-
- /*------------------------------------------------------------------------
- pid_calc
-
- DESCRIPTION Performs 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 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 > 100 || pterm < -100)
- {
- pid->integral = 0.0;
- }
- else
- {
- pid->integral += pid->igain * ferror;
- if (pid->integral > 100.0)
- {
- pid->integral = 100.0;
- }
- else if (pid->integral < 0.0) pid->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);
- }
-
-
- 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 = (float)(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 %4f\n", process_point, set_point, p_gain, i_gain, d_gain);
-
- printf("Enter the values of Process point\n");
-
- while(count<=20)
- {
-
-
-
- scanf("%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("%f\n", display_value);
- //printf("\n%f%f%f%f",warm.pv,warm.sp,warm.igain,warm.dgain);
- count++;
-
- }
-
- }
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