位置式PID与增量式PID

//位置式PID

float Kp;
float Ki;
float Kd;

float eSum,e0,e1;

float pid_control(float now,float target)
{
    float pe,ie,de;
    float out;

    e0 = target - now;
    eSum += e0;

    pe = e0;
    ie = eSum;
    de = e0 - e1;

    out = pe*Kp + ie*Ki + de*Kd;

    out = limit(out,-LIMIT,LIMIT);

    e1 = e0;

    return out;
}

//增量式PID

float Kp;
float Ki;
float Kd;

float eSum,e0,e1,e2;

float pid_control(float now,float target)
{
    float pe,ie,de;
    float out;

    e0 = target - now;

    pe = e0 - e1;
    ie = e0;
    de = e0 - *e1 + e2;

    out = pe*Kp + ie*Ki + de*Kd;
    out = limit(out,-LIMIT,LIMIT);

    e2 = e1;
    e1 = e0;

    return out;

}