robot_controllers::PID Class Reference

#include <pid.h>

Public Member Functions
bool	init (const ros::NodeHandle &nh)
	initialize gain settings from ROS parameter values More...
	PID (double p, double i, double d, double i_max, double i_min)
	Constructor. More...
	PID ()
	Constructor. Starts all gains and limits at zero. More...
void	reset ()
	Reset integral wind-up term. More...
double	update (double error, double dt)
	Run PID calculation and return control result. More...
double	update (double error, double error_dot, double dt)
	Run PID calculation and return control result. More...

Protected Member Functions
bool	checkGains ()
	Checks and fixes gain settings. More...

Protected Attributes
double	d_gain_
	derivative gain More...
double	error_last_
	Last error value, used for calculating error_dot when not provided. More...
double	i_gain_
	integral gain More...
double	i_max_
	integral gain min and max limits More...
double	i_min_
double	i_term_
	integral wind-up term More...
double	p_gain_
	proportial gain More...

Detailed Description

Definition at line 45 of file pid.h.

Constructor & Destructor Documentation

robot_controllers::PID::PID	(	double	p,
		double	i,
		double	d,
		double	i_max,
		double	i_min
	)

Constructor.

Parameters

p	proportional gain
i	integral gain
d	derivative gain
i_max	integral wind-up max value
i_min	integral wind-up min value

Definition at line 47 of file pid.cpp.

robot_controllers::PID::PID

(

)

Constructor. Starts all gains and limits at zero.

Definition at line 58 of file pid.cpp.

Member Function Documentation

bool robot_controllers::PID::checkGains ( )

protected

Checks and fixes gain settings.

Returns

true is gains are ok, false if gains are invalid

Definition at line 92 of file pid.cpp.

bool robot_controllers::PID::init

(

const ros::NodeHandle &

nh

)

initialize gain settings from ROS parameter values

Definition at line 68 of file pid.cpp.

void robot_controllers::PID::reset

(

)

Reset integral wind-up term.

Definition at line 140 of file pid.cpp.

double robot_controllers::PID::update	(	double	error,
		double	dt
	)

Run PID calculation and return control result.

Parameters

error	error term (goal-actual)
dt	timestep used for calculating derivative term and integral windup

Returns

calculated PID command

PID derivate term is calculated from change in error value and dt

Definition at line 146 of file pid.cpp.

double robot_controllers::PID::update	(	double	error,
		double	error_dot,
		double	dt
	)

Run PID calculation and return control result.

Parameters

error	error term (goal-actual)
error_dot	value that is used for derivative term calculation
dt	timestep used for integral windup

Returns

calculated PID command

Definition at line 164 of file pid.cpp.

Member Data Documentation

double robot_controllers::PID::d_gain_

protected

derivative gain

Definition at line 99 of file pid.h.

double robot_controllers::PID::error_last_

protected

Last error value, used for calculating error_dot when not provided.

Definition at line 107 of file pid.h.

double robot_controllers::PID::i_gain_

protected

integral gain

Definition at line 97 of file pid.h.

double robot_controllers::PID::i_max_

protected

integral gain min and max limits

Definition at line 101 of file pid.h.

double robot_controllers::PID::i_min_

protected

Definition at line 101 of file pid.h.

double robot_controllers::PID::i_term_

protected

integral wind-up term

Definition at line 104 of file pid.h.

double robot_controllers::PID::p_gain_

protected

proportial gain

Definition at line 95 of file pid.h.

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The documentation for this class was generated from the following files:

• pid.h
• pid.cpp