PID(二、位置型PID)

#include <stdio.h>

typedef struct {
    float SetLocation;    /*you want to set location*/
    float LastLocation;   /*the last location*/
    float err_now_0;
    float err_last_1;
    float err_sum;
    float Kp;
    float Ki;
    float Kd;
    float output;
}PID;

PID pid;

void
PID_Config(PID *pid)
{
    (*pid).SetLocation = 0.0;
    (*pid).LastLocation = 0.0;
    (*pid).err_now_0 = 0.0;
    (*pid).err_last_1= 0.0;
    (*pid).err_sum = 0.0;
    (*pid).Kp = 0.2;
    (*pid).Ki = 0.015;
    (*pid).Kd = 0.2;
    (*pid).output = 0.0;
}

float
PID_SetLocation(PID *pid, float speed)
{
    (*pid).SetLocation = speed;
    (*pid).err_now_0 = (*pid).SetLocation-(*pid).LastLocation;
    (*pid).err_sum += (*pid).err_now_0;
    (*pid).output = (*pid).Kp * (*pid).err_now_0 + (*pid).Ki * (*pid).err_sum + (*pid).Kd * ((*pid).err_now_0-(*pid).err_last_1);
    /*Uo(n) = P *e(n) + I *[e(n)+e(n-1)+...+e(0)]+ D *[e(n)-e(n-1)]*/
    (*pid).err_last_1 = (*pid).err_now_0;
    (*pid).LastLocation = (*pid).output;

    return  (*pid).output;
}

int
main(int argc, char *argv[])
{
    int count = 0;
    float speed;

    PID_Config(&pid);

    while (count < 10000) {
        speed = PID_SetLocation(&pid, 200.0);
        count++;

        if (speed > 199.99) {
            break;
        }
    }



    printf("program had exe %d times \n", count);

    return 0;
}
/**
program had exe 773 times

Process returned 0 (0x0)   execution time : 0.165 s
*/