| pid算法应该算是所以算法中最稳定最可靠最简单的算法，在库函数中添加这种算法对实际控制的时延有非常大的帮助。 全部资料51hei下载地址：  C语言PID算法.doc PID算法（c语言)（来自老外） #include #include //定义PID的结构体 struct _pid { int pv; //integer that contains the process value 过程量 int sp; //＊integer that contains the set point 设定值 float integral; // 积分值 －－ 偏差累计值 float pgain; float igain; float dgain; int deadband; //死区 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. 设定PID参数 －－－－ P,I,D,死区 //－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ 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. 设定输出初始值 //－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ 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. pid_bumpless 实现无扰切换 当突然改变设定值时，或重新启动后，将引起扰动输出。这个函数将能实现平顺扰动，在调用该函数之前需要先更新PV值 //－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ void pid_bumpless(struct _pid *pid) { pid->last_error = (pid->sp)-(pid->pv); //设定值与反馈值偏差 } //－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ 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" 本函数使用位置式PID计算方式，并且采取了积分饱和限制运算 PID计算 //－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－ float pid_calc(struct _pid *pid) {• int err; float pterm, dterm, result, ferror; // 计算偏差 err = (pid->sp) - (pid->pv); // 判断是否大于死区 if (abs(err) > pid->deadband) { ferror = (float) err; //do integer to float conversion only once 数据类型转换 // 比例项 pterm = pid->pgain * ferror; if (pterm > 100 || pterm < -100) { pid->integral = 0.0; } else { // 积分项 pid->integral += pid->igain * ferror; // 输出为0－－100% // 如果计算结果大于100，则等于100 if (pid->integral > 100.0) { pid->integral = 100.0; } // 如果计算结果小于0.0，则等于0 else if (pid->integral < 0.0) pid->integral = 0.0; } // 微分项 dterm = ((float)(err - pid->last_error)) * pid->dgain; result = pterm + pid->integral + dterm; } else result = pid->integral; // 在死区范围内，保持现有输出 // 保存上次偏差 pid->last_error = err; // 输出PID值(0-100) 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); // 初始化参数 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 %4fn", process_point, set_point, p_gain, i_gain, d_gain); printf("Enter the values of Process pointn"); while(count<=20) { scanf("%d",&process_point); // 设定PV,SP值 pid_init(&warm, process_point, set_point); // 初始化PID参数值 pid_tune(&warm, p_gain,i_gain,d_gain,dead_band); // 初始化PID输出值 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("%fn", display_value); //printf("n%f%f%f%f",warm.pv,warm.sp,warm.igain,warm.dgain); count++; } } 增量式PID算法 #include #include struct _pid { double set; double actual; double err; double err_one; double err_two; double Kp,Ki,Kd; }pid; void PID_init() { pid.set=0.0; pid.actual=0.0; pid.err=0.0; pid.err_one=0.0; pid.err_two=0.0; pid.Kp=0.2; pid.Ki=0.02; pid.Kd=0.2; } double PID_real(double speed) { double increment; pid.set=speed; pid.err=pid.set-pid.actual; increment=pid.Kp*(pid.err-pid.err_one)+pid.Ki*pid.err+pid.Kd*(pid.err-2*pid.err_one+pid.err_two); pid.actual+=increment; pid.err_two=pid.err_one; pid.err_one=pid.err; return pid.actual; } main() { int i; PID_init(); for(i=0;i<1200;i++) { double speed=PID_real(100.0); printf("%fn",speed); }system("pause"); } |
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