pid.c

工业数据采集控制系统中

#include <iom128v.h>
#include <string.h>
#include <stdio.h>
/*====================================================================================================
    PID Function
    The PID (比例、积分、微分) function is used in mainly
    control applications. PIDCalc performs one iteration of the PID
    algorithm.
    While the PID function works, main is just a dummy program showing
    a typical usage.
=====================================================================================================*/
typedef struct PID {
        double  SetPoint;           //  设定目标 Desired Value
        double  Proportion;         //  比例常数 Proportional Const
        double  Integral;           //  积分常数 Integral Const
        double  Derivative;         //  微分常数 Derivative Const
        double  LastError;          //  Error[-1]
        double  PrevError;          //  Error[-2]
        double  SumError;           //  Sums of Errors
} PID;
/*====================================================================================================
   PID计算部分
=====================================================================================================*/
double PIDCalc( PID *pp, double NextPoint )
{
    double  dError,
            Error;
        Error = pp->SetPoint -  NextPoint;          // 偏差
        pp->SumError += Error;                      // 积分
        dError = pp->LastError - pp->PrevError;     // 当前微分
        pp->PrevError = pp->LastError;
        pp->LastError = Error;
        return (pp->Proportion * Error              // 比例项
            +   pp->Integral * pp->SumError         // 积分项
            +   pp->Derivative * dError             // 微分项
        );
}
/*====================================================================================================
   Initialize PID Structure
=====================================================================================================*/
void PIDInit (PID *pp)
{
    memset ( pp,0,sizeof(PID));
}
/*====================================================================================================
    Main Program
=====================================================================================================*/
double sensor (void)                    //  Dummy Sensor Function
{

    return 100;
}
void actuator(double rDelta)            //  Dummy Actuator Function
{

}
void main(void)
{
    PID         sPID;                   //  PID Control Structure
    double      rOut;                   //  PID Response (Output)
    double      rIn;                    //  PID Feedback (Input)
    PIDInit ( &sPID );                  //  Initialize Structure
    sPID.Proportion = 0.5;              //  Set PID Coefficients
    sPID.Integral   = 0.5;
    sPID.Derivative = 0.0;
    sPID.SetPoint   = 100.0;            //  Set PID Setpoint
    for (;;) {                          //  Mock Up of PID Processing
        rIn = sensor ();                //  Read Input
        rOut = PIDCalc ( &sPID,rIn );   //  Perform PID Interation
        actuator ( rOut );              //  Effect Needed Changes
    }
}