PID Class Reference

A standard PID controller with advanced features. More...

#include <PID.h>

Public Member Functions
	PID (double kP, double kI, double kD, double kF=0, double windupRange=0, bool signFlipReset=false, double slew=0)
	Construct a new PID controller.
	PID (const PIDGains &gains, double windupRange=0, bool signFlipReset=false)
	Construct a new PID controller from a PIDGains struct.
PIDGains	getGains ()
	Get the current gains of the PID controller.
void	setGains (PIDGains gains)
	Set new gains for the PID controller.
double	update (double error)
	Update the PID controller based on the current error.
double	update (double error, double measurement)
	Update the PID controller based on error and actual measurement (to prevent derivative kick).
void	reset ()
	Reset the PID controller's internal state (integral, previous error, etc.).
void	setSignFlipReset (bool signFlipReset)
	Enable or disable resetting the integral term when the error sign flips.
bool	getSignFlipReset ()
	Check if sign-flip integral reset is enabled.
void	setWindupRange (double windupRange)
	Set the windup range within which the integral term is allowed to accumulate.
double	getWindupRange ()
	Get the current windup range.
void	setAlpha (double alpha)
	Set the alpha value for the derivative filter.
double	getAlpha ()
	Get the alpha value for the derivative filter.
void	setIntegralLimit (double limit)
	Set the maximum absolute value for the integral term.
double	getIntegralLimit ()
	Get the integral limit.
void	setStaticThreshold (double threshold)
	Set the static threshold error value.
double	getStaticThreshold ()
	Get the static threshold error value.

Detailed Description

A standard PID controller with advanced features.

Includes support for windup range limits, sign-flip resets, slew rate limits, filtered derivatives, and integral limits.

Definition at line 22 of file PID.h.

Constructor & Destructor Documentation

PID() [1/2]

PID::PID	(	double	kP,
		double	kI,
		double	kD,
		double	kF = 0,
		double	windupRange = 0,
		bool	signFlipReset = false,
		double	slew = 0
	)

Construct a new PID controller.

Parameters

kP	Proportional gain.
kI	Integral gain.
kD	Derivative gain.
kF	Feed-forward gain.
windupRange	Range within which the integral term accumulates.
signFlipReset	If true, resets the integral when the error sign flips.
slew	Maximum change in output per update.

PID() [2/2]

PID::PID	(	const PIDGains &	gains,
		double	windupRange = 0,
		bool	signFlipReset = false
	)

Construct a new PID controller from a PIDGains struct.

Parameters

gains	A struct containing the Kp, Ki, Kd, Kf, and slew rate.
windupRange	Range within which the integral term accumulates.
signFlipReset	If true, resets the integral when the error sign flips.

Member Function Documentation

getGains()

PIDGains PID::getGains

(

)

Get the current gains of the PID controller.

Returns

PIDGains The current gains.

setGains()

void PID::setGains

(

PIDGains

gains

)

Set new gains for the PID controller.

Parameters

gains

The new gains to apply.

update() [1/2]

double PID::update

(

double

error

)

Update the PID controller based on the current error.

Parameters

error

The current error (target - measurement).

Returns

double The computed output from the PID controller.

update() [2/2]

double PID::update	(	double	error,
		double	measurement
	)

Update the PID controller based on error and actual measurement (to prevent derivative kick).

Parameters

error	The current error.
measurement	The current measurement/sensor value.

Returns

double The computed output from the PID controller.

reset()

void PID::reset

(

)

Reset the PID controller's internal state (integral, previous error, etc.).

setSignFlipReset()

void PID::setSignFlipReset

(

bool

signFlipReset

)

Enable or disable resetting the integral term when the error sign flips.

Parameters

signFlipReset

True to enable, false to disable.

getSignFlipReset()

bool PID::getSignFlipReset

(

)

Check if sign-flip integral reset is enabled.

Returns

true if enabled, false otherwise.

setWindupRange()

void PID::setWindupRange

(

double

windupRange

)

Set the windup range within which the integral term is allowed to accumulate.

Parameters

windupRange

The windup range.

getWindupRange()

double PID::getWindupRange

(

)

Get the current windup range.

Returns

double The windup range.

setAlpha()

void PID::setAlpha ( double  alpha )

inline

Set the alpha value for the derivative filter.

Parameters

alpha

The filter constant (0.0 to 1.0).

Definition at line 138 of file PID.h.

getAlpha()

double PID::getAlpha ( )

inline

Get the alpha value for the derivative filter.

Returns

double The current alpha value.

Definition at line 145 of file PID.h.

setIntegralLimit()

void PID::setIntegralLimit ( double  limit )

inline

Set the maximum absolute value for the integral term.

Parameters

limit

The maximum integral value.

Definition at line 152 of file PID.h.

getIntegralLimit()

double PID::getIntegralLimit ( )

inline

Get the integral limit.

Returns

double The integral limit.

Definition at line 159 of file PID.h.

setStaticThreshold()

void PID::setStaticThreshold ( double  threshold )

inline

Set the static threshold error value.

Parameters

threshold

The threshold value.

Definition at line 166 of file PID.h.

getStaticThreshold()

double PID::getStaticThreshold ( )

inline

Get the static threshold error value.

Returns

double The static threshold value.

Definition at line 173 of file PID.h.