PID算法调参口诀及C语言程序示例

本文最后更新于:May 7, 2023 pm

  • 参数整定找最佳, 从小到大顺序查。
  • 先是比例后积分, 最后再把微分加。
  • 曲线振荡很频繁, 比例度盘要放大。
  • 曲线漂浮绕大弯, 比例度盘往小扳。
  • 曲线偏离回复慢, 积分时间往下降。
  • 曲线波动周期长, 积分时间再加长。
  • 曲线振荡频率快, 先把微分降下来。
  • 动差大来波动慢, 微分时间应加长。
  • 理想曲线两个波, 前高后低四比一。
  • 一看二调多分析, 调节质量不会低。

PID算法程序:

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/************  PID算法(C语言)  ************/

  #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.
  ------------------------------------------------------------------------*/
  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++;
   }
  }

PID算法调参口诀及C语言程序示例
https://cgabc.xyz/posts/29d89c66/
Author
Gavin Gao
Posted on
October 4, 2014
Licensed under