File content as of revision 10:b4abecccec7a:

#include "includes.h"
#include "meta.h"

PidController::PidController(float ki, float kp, float kd, float out_max, float out_min) {
    _ki = ki;
    _kp = kp;
    _kd = kd;
    _last_in = 0.0f;
    _integral = 0.0f;
    _out_max = out_max;
    _out_min = out_min;
}

float PidController::Update(float ref, float in) {  //starts positive, integrator is adding up the error to get there.  cranking throttle makes it go negative.  that makes sense.
    float error = ref - in;
    //_integral += error;
    _integral = 0.0f;
    if (_integral*_ki > _out_max) _integral = _out_max/_ki;
    if (_integral*_ki < _out_min) _integral = _out_min/_ki;
    float deriv = _last_in - in;
    _last_in = in;
    float tmp = _ki * _integral + _kp * error + _kd * deriv;
    if (tmp > _out_max) tmp = _out_max;
    if (tmp < _out_min) tmp = _out_min;
    return tmp;
}