PID控制在8位单片机中仍然有广泛的应用,比如温度控制,利用比例、积分、微分补偿来做恒温补偿控制,当然由于有这些数学处理,用C语言相对方便一些,以下是一个具体的实例。
#include
struct PID {
unsigned int SetPoint; // 设定目标 Desired Value
unsigned int Proportion; // 比例常数 Proportional Const
unsigned int Integral; // 积分常数 Integral Const
unsigned int Derivative; // 微分常数 Derivative Const
unsigned int LastError; // Error[-1]
unsigned int PrevError; // Error[-2]
unsigned int SumError; // Sums of Errors
};
struct PID spid; // PID Control Structure
unsigned int rout; // PID Response (Output)
unsigned int rin; // PID Feedback (Input)
sbit data1=P1^0;
sbit clk=P1^1;
sbit plus=P2^0;
sbit subs=P2^1;
sbit stop=P2^2;
sbit output=P3^4;
sbit DQ=P3^3;
unsigned char flag,flag_1=0;
unsigned char high_time,low_time,count=0;//占空比调节参数
unsigned char set_temper=35;
unsigned char temper;
unsigned char i;
unsigned char j=0;
unsigned int s;
/***********************************************************
延时子程序,延时时间以12M晶振为准,延时时间为30us×time
***********************************************************/
void delay(unsigned char time)
{
unsigned char m,n;
for(n=0;n for(m=0;m<2;m++){} } /*********************************************************** 写一位数据子程序 ***********************************************************/ void write_bit(unsigned char bitval) { EA=0; DQ=0; /*拉低DQ以开始一个写时序*/ if(bitval==1) { _nop_(); DQ=1; /*如要写1,则将总线置高*/ } delay(5); /*延时90us供DA18B20采样*/ DQ=1; /*释放DQ总线*/ _nop_(); _nop_(); EA=1; } /*********************************************************** 写一字节数据子程序 ***********************************************************/ void write_byte(unsigned char val) { unsigned char i; unsigned char temp; EA=0; TR0=0; for(i=0;i<8;i++) /*写一字节数据,一次写一位*/ { temp=val>>i; /*移位操作,将本次要写的位移到最低位*/ temp=temp&1; write_bit(temp); /*向总线写该位*/ } delay(7); /*延时120us后*/ // TR0=1; EA=1; } /*********************************************************** 读一位数据子程序 ***********************************************************/ unsigned char read_bit() { unsigned char i,value_bit; EA=0; DQ=0; /*拉低DQ,开始读时序*/ _nop_(); _nop_(); DQ=1; /*释放总线*/ for(i=0;i<2;i++){} value_bit=DQ; EA=1; return(value_bit); } /*********************************************************** 读一字节数据子程序 ***********************************************************/ unsigned char read_byte() { unsigned char i,value=0; EA=0; for(i=0;i<8;i++) { if(read_bit()) /*读一字节数据,一个时序中读一次,并作移位处理*/ value|=0x01< delay(4); /*延时80us以完成此次都时序,之后再读下一数据*/ } EA=1; return(value); } /*********************************************************** 复位子程序 ***********************************************************/ unsigned char reset() { unsigned char presence; EA=0; DQ=0; /*拉低DQ总线开始复位*/ delay(30); /*保持低电平480us*/ DQ=1; /*释放总线*/ delay(3); presence=DQ; /*获取应答信号*/ delay(28); /*延时以完成整个时序*/ EA=1; return(presence); /*返回应答信号,有芯片应答返回0,无芯片则返回1*/ } /*********************************************************** 获取温度子程序 ***********************************************************/ void get_temper() { unsigned char i,j; do { i=reset(); /*复位*/ } while(i!=0); /*1为无反馈信号*/ i=0xcc; /*发送设备定位命令*/ write_byte(i); i=0x44; /*发送开始转换命令*/ write_byte(i); delay(180); /*延时*/ do { i=reset(); /*复位*/ } while(i!=0); i=0xcc; /*设备定位*/ write_byte(i); i=0xbe; /*读出缓冲区内容*/ write_byte(i); j=read_byte(); i=read_byte(); i=(i<<4)&0x7f; s=(unsigned int)(j&0x0f); //得到小数部分 s=(s*100)/16; j=j>>4; temper=i|j; /*获取的温度放在temper中*/ } /*==================================================================================================== Initialize PID Structure =====================================================================================================*/ void PIDInit (struct PID *pp) { memset ( pp,0,sizeof(struct PID)); //全部初始化为0 } /*==================================================================================================== PID计算部分 =====================================================================================================*/ unsigned int PIDCalc( struct PID *pp, unsigned int NextPoint ) { unsigned int 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 } /*********************************************************** 温度比较处理子程序 ***********************************************************/ void compare_temper() { unsigned char i; if(set_temper>temper) //是否设置的温度大于实际温度 { if(set_temper-temper>1) //设置的温度比实际的温度是否是大于1度 { high_time=100; //如果是,则全速加热 low_time=0; } else //如果是在1度范围内,则运行PID计算 { for(i=0;i<10;i++) { get_temper(); //获取温度 rin = s; // Read Input rout = PIDCalc ( &spid,rin ); // Perform PID Interation } if (high_time<=100) high_time=(unsigned char)(rout/800); else high_time=100; low_time= (100-high_time); } } else if(set_temper<=temper) { if(temper-set_temper>0) { high_time=0; low_time=100; } else { for(i=0;i<10;i++) { get_temper(); rin = s; // Read Input rout = PIDCalc ( &spid,rin ); // Perform PID Interation } if (high_time<100) high_time=(unsigned char)(rout/10000); else high_time=0; low_time= (100-high_time); } } // else // {} } /***************************************************** T0中断服务子程序,用于控制电平的翻转 ,40us*100=4ms周期 ******************************************************/ void serve_T0() interrupt 1 using 1 { if(++count<=(high_time)) output=1; else if(count<=100) { output=0; } else count=0; TH0=0x2f; TL0=0xe0; } /***************************************************** 串行口中断服务程序,用于上位机通讯 ******************************************************/ void serve_sio() interrupt 4 using 2 { /* EA=0; RI=0; i=SBUF; if(i==2) { while(RI==0){} RI=0; set_temper=SBUF; SBUF=0x02; while(TI==0){} TI=0; } else if(i==3) { TI=0; SBUF=temper; while(TI==0){} TI=0; } EA=1; */ } void disp_1(unsigned char disp_num1[6]) { unsigned char n,a,m; for(n=0;n<6;n++) { // k=disp_num1[n]; for(a=0;a<8;a++) { clk=0; m=(disp_num1[n]&1); disp_num1[n]=disp_num1[n]>>1; if(m==1) data1=1; else data1=0; _nop_(); clk=1; _nop_(); } } } /***************************************************** 显示子程序 功能:将占空比温度转化为单个字符,显示占空比和测得到的温度 ******************************************************/ void display() { unsigned char code number[]={0xfc,0x60,0xda,0xf2,0x66,0xb6,0xbe,0xe0,0xfe,0xf6}; unsigned char disp_num[6]; unsigned int k,k1; k=high_time; k=k%1000; k1=k/100; if(k1==0) disp_num[0]=0; else disp_num[0]=0x60; k=k%100; disp_num[1]=number[k/10]; disp_num[2]=number[k%10]; k=temper; k=k%100; disp_num[3]=number[k/10]; disp_num[4]=number[k%10]+1; disp_num[5]=number[s/10]; disp_1(disp_num); } /*********************************************************** 主程序 ***********************************************************/ void main() { unsigned char z; unsigned char a,b,flag_2=1,count1=0; unsigned char phil[]={2,0xce,0x6e,0x60,0x1c,2}; TMOD=0x21; TH0=0x2f; TL0=0x40; SCON=0x50; PCON=0x00; TH1=0xfd; TL1=0xfd; PS=1; EA=1; EX1=0; ET0=1; ES=1; TR0=1; TR1=1; high_time=50; low_time=50; PIDInit ( &spid ); // Initialize Structure spid.Proportion = 10; // Set PID Coefficients 比例常数 Proportional Const spid.Integral = 8; //积分常数 Integral Const spid.Derivative =6; //微分常数 Derivative Const spid.SetPoint = 100; // Set PID Setpoint 设定目标 Desired Value while(1) { if(plus==0) { EA=0; for(a=0;a<5;a++) for(b=0;b<102;b++){} if(plus==0) { set_temper++; flag=0; } } else if(subs==0) { for(a=0;a<5;a++) for(b=0;a<102;b++){} if(subs==0) { set_temper--; flag=0; } } else if(stop==0) { for(a=0;a<5;a++) for(b=0;b<102;b++){} if(stop==0) { flag=0; break; } EA=1; } get_temper(); b=temper; if(flag_2==1) a=b; if((abs(a-b))>5) temper=a; else temper=b; a=temper; flag_2=0; if(++count1>30) { display(); count1=0; } compare_temper(); } TR0=0; z=1; while(1) { EA=0; if(stop==0) { for(a=0;a<5;a++) for(b=0;b<102;b++){} if(stop==0) disp_1(phil); // break; } EA=1; } }
for(m=0;m<2;m++){}
}
写一位数据子程序
void write_bit(unsigned char bitval)
EA=0;
DQ=0; /*拉低DQ以开始一个写时序*/
if(bitval==1)
_nop_();
DQ=1; /*如要写1,则将总线置高*/
delay(5); /*延时90us供DA18B20采样*/
DQ=1; /*释放DQ总线*/
EA=1;
写一字节数据子程序
void write_byte(unsigned char val)
unsigned char temp;
TR0=0;
for(i=0;i<8;i++) /*写一字节数据,一次写一位*/
temp=val>>i; /*移位操作,将本次要写的位移到最低位*/
temp=temp&1;
write_bit(temp); /*向总线写该位*/
delay(7); /*延时120us后*/
// TR0=1;
读一位数据子程序
unsigned char read_bit()
unsigned char i,value_bit;
DQ=0; /*拉低DQ,开始读时序*/
DQ=1; /*释放总线*/
for(i=0;i<2;i++){}
value_bit=DQ;
return(value_bit);
读一字节数据子程序
unsigned char read_byte()
unsigned char i,value=0;
for(i=0;i<8;i++)
if(read_bit()) /*读一字节数据,一个时序中读一次,并作移位处理*/
value|=0x01<
delay(4); /*延时80us以完成此次都时序,之后再读下一数据*/
return(value);
复位子程序
unsigned char reset()
unsigned char presence;
DQ=0; /*拉低DQ总线开始复位*/
delay(30); /*保持低电平480us*/
delay(3);
presence=DQ; /*获取应答信号*/
delay(28); /*延时以完成整个时序*/
return(presence); /*返回应答信号,有芯片应答返回0,无芯片则返回1*/
获取温度子程序
void get_temper()
unsigned char i,j;
do
i=reset(); /*复位*/
} while(i!=0); /*1为无反馈信号*/
i=0xcc; /*发送设备定位命令*/
write_byte(i);
i=0x44; /*发送开始转换命令*/
delay(180); /*延时*/
} while(i!=0);
i=0xcc; /*设备定位*/
i=0xbe; /*读出缓冲区内容*/
j=read_byte();
i=read_byte();
i=(i<<4)&0x7f;
s=(unsigned int)(j&0x0f); //得到小数部分
s=(s*100)/16;
j=j>>4;
temper=i|j; /*获取的温度放在temper中*/
/*====================================================================================================
Initialize PID Structure
=====================================================================================================*/
void PIDInit (struct PID *pp)
memset ( pp,0,sizeof(struct PID)); //全部初始化为0
PID计算部分
unsigned int PIDCalc( struct PID *pp, unsigned int NextPoint )
unsigned int 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
温度比较处理子程序
void compare_temper()
if(set_temper>temper) //是否设置的温度大于实际温度
if(set_temper-temper>1) //设置的温度比实际的温度是否是大于1度
high_time=100; //如果是,则全速加热
low_time=0;
else //如果是在1度范围内,则运行PID计算
for(i=0;i<10;i++)
get_temper(); //获取温度
rin = s; // Read Input
rout = PIDCalc ( &spid,rin ); // Perform PID Interation
if (high_time<=100)
high_time=(unsigned char)(rout/800);
else
high_time=100;
low_time= (100-high_time);
else if(set_temper<=temper)
if(temper-set_temper>0)
high_time=0;
low_time=100;
get_temper();
if (high_time<100)
high_time=(unsigned char)(rout/10000);
// else
// {}
/*****************************************************
T0中断服务子程序,用于控制电平的翻转 ,40us*100=4ms周期
******************************************************/
void serve_T0() interrupt 1 using 1
if(++count<=(high_time))
output=1;
else if(count<=100)
output=0;
count=0;
TH0=0x2f;
TL0=0xe0;
串行口中断服务程序,用于上位机通讯
void serve_sio() interrupt 4 using 2
/* EA=0;
RI=0;
i=SBUF;
if(i==2)
while(RI==0){}
set_temper=SBUF;
SBUF=0x02;
while(TI==0){}
TI=0;
else if(i==3)
SBUF=temper;
EA=1; */
void disp_1(unsigned char disp_num1[6])
unsigned char n,a,m;
for(n=0;n<6;n++)
// k=disp_num1[n];
for(a=0;a<8;a++)
clk=0;
m=(disp_num1[n]&1);
disp_num1[n]=disp_num1[n]>>1;
if(m==1)
data1=1;
data1=0;
clk=1;
显示子程序
功能:将占空比温度转化为单个字符,显示占空比和测得到的温度
void display()
unsigned char code number[]={0xfc,0x60,0xda,0xf2,0x66,0xb6,0xbe,0xe0,0xfe,0xf6};
unsigned char disp_num[6];
unsigned int k,k1;
k=high_time;
k=k%1000;
k1=k/100;
if(k1==0)
disp_num[0]=0;
disp_num[0]=0x60;
k=k%100;
disp_num[1]=number[k/10];
disp_num[2]=number[k%10];
k=temper;
disp_num[3]=number[k/10];
disp_num[4]=number[k%10]+1;
disp_num[5]=number[s/10];
disp_1(disp_num);
主程序
void main()
unsigned char z;
unsigned char a,b,flag_2=1,count1=0;
unsigned char phil[]={2,0xce,0x6e,0x60,0x1c,2};
TMOD=0x21;
TL0=0x40;
SCON=0x50;
PCON=0x00;
TH1=0xfd;
TL1=0xfd;
PS=1;
EX1=0;
ET0=1;
ES=1;
TR0=1;
TR1=1;
high_time=50;
low_time=50;
PIDInit ( &spid ); // Initialize Structure
spid.Proportion = 10; // Set PID Coefficients 比例常数 Proportional Const
spid.Integral = 8; //积分常数 Integral Const
spid.Derivative =6; //微分常数 Derivative Const
spid.SetPoint = 100; // Set PID Setpoint 设定目标 Desired Value
while(1)
if(plus==0)
for(a=0;a<5;a++)
for(b=0;b<102;b++){}
set_temper++;
flag=0;
else if(subs==0)
for(b=0;a<102;b++){}
if(subs==0)
set_temper--;
else if(stop==0)
if(stop==0)
break;
b=temper;
if(flag_2==1)
a=b;
if((abs(a-b))>5)
temper=a;
temper=b;
a=temper;
flag_2=0;
if(++count1>30)
display();
count1=0;
compare_temper();
z=1;
disp_1(phil);
// break;
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直接配置单片机PWM输出的占空比就行了啊