ardupilot/libraries/AC_PID/AC_PI.cpp

47 lines
1.3 KiB
C++

/*
Generic PI algorithm for controllers that don't need filtering (such as heaters)
*/
#include <AP_Math/AP_Math.h>
#include "AC_PI.h"
const AP_Param::GroupInfo AC_PI::var_info[] = {
// @Param: P
// @DisplayName: PID Proportional Gain
// @Description: P Gain which produces an output value that is proportional to the current error value
AP_GROUPINFO("P", 1, AC_PI, kP, 0),
// @Param: I
// @DisplayName: PID Integral Gain
// @Description: I Gain which produces an output that is proportional to both the magnitude and the duration of the error
AP_GROUPINFO("I", 2, AC_PI, kI, 0),
// @Param: IMAX
// @DisplayName: PID Integral Maximum
// @Description: The maximum/minimum value that the I term can output
AP_GROUPINFO("IMAX", 3, AC_PI, imax, 0),
AP_GROUPEND
};
// Constructor
AC_PI::AC_PI(float initial_p, float initial_i, float initial_imax) :
default_kp(initial_p),
default_ki(initial_i),
default_imax(initial_imax)
{
// load parameter values from eeprom
AP_Param::setup_object_defaults(this, var_info);
}
float AC_PI::update(float measurement, float target, float dt)
{
const float err = target - measurement;
integrator += kI * err * dt;
integrator = constrain_float(integrator, 0, imax);
output_P = kP * err;
return output_P + integrator;
}