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173 lines (144 loc) · 3.39 KB
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/**********************************************************************************************
* Arduino PID Library - Version 1.2.1
* by Brett Beauregard <br3ttb@gmail.com> brettbeauregard.com
*
* Modified by Kamnev Yuriy <kamnev.u1969@gmail.com>
*
* This Library is licensed under the MIT License
**********************************************************************************************/
#include "pid.hpp"
PID::PID(pid_config_t &cfg) :
inAuto(false),
last_input(0),
integration_sum(0),
setpoint(false)
{
config = cfg;
}
/**
* @brief Compute PID output
*
* @param[in] input - currently measured input
* @param[in] dinput - currently measured input derivative
*
* @return Output signal
*/
double PID::compute(double input, double dinput)
{
/*Compute all the working error variables*/
double output = compute_output(input, dinput);
return output;
}
/**
* @brief Compute PID output.
* In this function derivative of the input is approximated by first difference.
*
* @param[in] input - currently measured input
*
* @return Output signal
*/
double PID::compute(double input)
{
double dinput = (input - last_input);
return compute_output(input, dinput);
}
/**
* @brief Update setpoing
*
* @param[in] _setpoint - new setpoint
*/
void PID::update_setpoint(double _setpoint)
{
setpoint = _setpoint;
}
/**
* @brief Compute PID output
*
* @param[in] input - currently measured input
* @param[in] dinput - currently measured input derivative
*
* @return Output signal
*/
double PID::compute_output(double input, double dinput)
{
double error = (setpoint - input);
integration_sum += (config.Ki * error);
if(integration_sum > config.out_max)
{
integration_sum = config.out_max;
}
else if(integration_sum < config.out_min)
{
integration_sum = config.out_min;
}
double output = config.Kp*error - config.Kd*dinput + integration_sum;
if(output > config.out_max)
{
output = config.out_max;
}
else if(output < config.out_min)
{
output = config.out_min;
}
last_input = input;
return output;
}
/**
* @brief Update PID coefficients
*
* @param[in] Kp - proportional coefficient
* @param[in] Ki - integration coefficient
* @param[in] Kd - differential coefficient
*/
void PID::set_tunings(double Kp, double Ki, double Kd)
{
if(config.ControllerDirection == PID_BACKWARD)
{
Kp *= -1;
Ki *= -1;
Kd *= -1;
}
config.Kp = Kp;
config.Kd = Kd;
config.Ki = Ki;
}
/**
* @brief Update PID output limits
*
* @param[in] min - minimum output
* @param[in] max - maximum output
*
*/
void PID::set_limits(double min, double max)
{
if(min >= max)
{
return;
}
config.out_min = min;
config.out_max = max;
}
/**
* @brief Set controller direction
*
* @param[in] dir - new direction
*/
void PID::set_direction(pid_direction_t dir)
{
if(dir != config.ControllerDirection)
{
config.Kp *= -1;
config.Ki *= -1;
config.Kd *= -1;
config.ControllerDirection = dir;
}
}
/**
* @brief Retrieve current config
*
* @param[in] cfg - reference to where to store config
*/
void PID::get_config(pid_config_t &cfg)
{
cfg = config;
}