C语言实现51单片机中的PID算法

#ifndef __PID__
#define __PID__
/*PID = Uk + KP*[E(k)-E(k-1)]+KI*E(k)+KD*[E(k)-2E(k-1)+E(k-2)];(增量型PID算式)
函数入口: RK(设定值),CK(实际值),KP,KI,KD
函数出口: U(K)*/
typedef struct PIDValue
{
	int8 KP;
	int8 KI;
	int8 KD;
	int8 F;
	int8 BITMOV;
	int EK[3];
	
	int UK;
	int RK;
	int CK;
	int UK_REAL;

}pid_str;
//PIDValueStr  PID;
void    pid_exe(pid_str *PID)  ;
#endif

//pid.c
/*PID = PID->UK_REAL + PID->KP*[E(k)-E(k-1)]+PID->KI*E(k)+PID->KD*[E(k)-2E(k-1)+E(k-2)];(增量型PID算式)
函数入口: PID->RK(设定值),PID->CK(实际值),PID->KP,PID->KI,PID->KD
函数出口: U(K)*/
#include'defines.h'
#include'pid.h'
#define MAXOUT 0xff
//#define MAXGAP 100

void pid_exe(pid_str*PID)
{
	PID->EK[2]=PID->EK[1];
	PID->EK[1]=PID->EK[0];
	PID->EK[0]=PID->RK-PID->CK;
	PID->UK_REAL=PID->UK_REAL
		+PID->KP*(PID->EK[0]-PID->EK[1])//微分一次后积分即原数
		+(float)PID->KI*PID->EK[0]/PID->F//直接积分
		+(float)PID->KD*(PID->EK[0]-2*PID->EK[1]+PID->EK[2])*PID->F;//二阶微分后积分即一阶微分
	if((PID->UK_REAL>>PID->BITMOV)>=MAXOUT)
	{
		PID->UK=MAXOUT;
	}else if(PID->UK_REAL>>PID->BITMOV<=-MAXOUT)
	{
		PID->UK=-MAXOUT;
	}else
	{
		PID->UK=PID->UK_REAL>>PID->BITMOV;
	}
		
}