Generic PID controller class. Generic proportional-integral-derivative controller class that keeps track of PID-error states and control inputs given the state of a system and a user specified target state. It includes a user-adjustable command offset term (feed-forward). More...

#include <ignition/math/PID.hh>

Public Member Functions
	PID (const double _p=0.0, const double _i=0.0, const double _d=0.0, const double _imax=-1.0, const double _imin=0.0, const double _cmdMax=-1.0, const double _cmdMin=0.0, const double _cmdOffset=0.0)
	Constructor, zeros out Pid values when created and initialize Pid-gains and integral term limits:[iMax:iMin]-[I1:I2]. More...

	~PID ()=default
	Destructor. More...

double	Cmd () const
	Return current command for this PID controller. More...

double	CmdMax () const
	Get the maximum value for the command. More...

double	CmdMin () const
	Get the minimun value for the command. More...

double	CmdOffset () const
	Get the offset value for the command. More...

double	DGain () const
	Get the derivative Gain. More...

void	Errors (double &_pe, double &_ie, double &_de) const
	Return PID error terms for the controller. More...

double	IGain () const
	Get the integral Gain. More...

double	IMax () const
	Get the integral upper limit. More...

double	IMin () const
	Get the integral lower limit. More...

void	Init (const double _p=0.0, const double _i=0.0, const double _d=0.0, const double _imax=-1.0, const double _imin=0.0, const double _cmdMax=-1.0, const double _cmdMin=0.0, const double _cmdOffset=0.0)
	Initialize PID-gains and integral term limits:[iMax:iMin]-[I1:I2]. More...

PID &	operator= (const PID &_p)
	Assignment operator. More...

double	PGain () const
	Get the proportional Gain. More...

void	Reset ()
	Reset the errors and command. More...

void	SetCmd (const double _cmd)
	Set current target command for this PID controller. More...

void	SetCmdMax (const double _c)
	Set the maximum value for the command. More...

void	SetCmdMin (const double _c)
	Set the minimum value for the command. More...

void	SetCmdOffset (const double _c)
	Set the offset value for the command, which is added to the result of the PID controller. More...

void	SetDGain (const double _d)
	Set the derivative Gain. More...

void	SetIGain (const double _i)
	Set the integral Gain. More...

void	SetIMax (const double _i)
	Set the integral upper limit. More...

void	SetIMin (const double _i)
	Set the integral lower limit. More...

void	SetPGain (const double _p)
	Set the proportional Gain. More...

double	Update (const double _error, const std::chrono::duration< double > &_dt)
	Update the Pid loop with nonuniform time step size. More...

double	Update (const double _error, double _errorRate, const std::chrono::duration< double > &_dt)
	Update the Pid loop with nonuniform time step size. More...

Detailed Description

Generic PID controller class. Generic proportional-integral-derivative controller class that keeps track of PID-error states and control inputs given the state of a system and a user specified target state. It includes a user-adjustable command offset term (feed-forward).

Constructor & Destructor Documentation

◆ PID()

PID	(	const double	_p = `0.0`,
		const double	_i = `0.0`,
		const double	_d = `0.0`,
		const double	_imax = `-1.0`,
		const double	_imin = `0.0`,
		const double	_cmdMax = `-1.0`,
		const double	_cmdMin = `0.0`,
		const double	_cmdOffset = `0.0`
	)

Constructor, zeros out Pid values when created and initialize Pid-gains and integral term limits:[iMax:iMin]-[I1:I2].

Disable command clamping by setting _cmdMin to a value larger than _cmdMax. Command clamping is disabled by default.

Disable integral clamping by setting _iMin to a value larger than _iMax. Integral clamping is disabled by default.

Parameters

[in]	_p	The proportional gain.
[in]	_i	The integral gain.
[in]	_d	The derivative gain.
[in]	_imax	The integral upper limit.
[in]	_imin	The integral lower limit.
[in]	_cmdMax	Output max value.
[in]	_cmdMin	Output min value.
[in]	_cmdOffset	Command offset (feed-forward).

◆ ~PID()

~PID ( )

default

Destructor.

Member Function Documentation

◆ Cmd()

double Cmd ( ) const

Return current command for this PID controller.

Returns: the command value

◆ CmdMax()

double CmdMax ( ) const

Get the maximum value for the command.

Returns: The maximum value

◆ CmdMin()

double CmdMin ( ) const

Get the minimun value for the command.

Returns: The maximum value

◆ CmdOffset()

double CmdOffset ( ) const

Get the offset value for the command.

Returns: The offset value

◆ DGain()

double DGain ( ) const

Get the derivative Gain.

Returns: The derivative gain value

◆ Errors()

void Errors	(	double &	_pe,
		double &	_ie,
		double &	_de
	)		const

Return PID error terms for the controller.

Parameters

[in]	_pe	The proportional error.
[in]	_ie	The integral of gain times error.
[in]	_de	The derivative error.

◆ IGain()

double IGain ( ) const

Get the integral Gain.

Returns: The integral gain value

◆ IMax()

double IMax ( ) const

Get the integral upper limit.

Returns: The integral upper limit value

◆ IMin()

double IMin ( ) const

Get the integral lower limit.

Returns: The integral lower limit value

◆ Init()

void Init	(	const double	_p = `0.0`,
		const double	_i = `0.0`,
		const double	_d = `0.0`,
		const double	_imax = `-1.0`,
		const double	_imin = `0.0`,
		const double	_cmdMax = `-1.0`,
		const double	_cmdMin = `0.0`,
		const double	_cmdOffset = `0.0`
	)

Initialize PID-gains and integral term limits:[iMax:iMin]-[I1:I2].

Disable command clamping by setting _cmdMin to a value larger than _cmdMax. Command clamping is disabled by default.

Disable integral clamping by setting _iMin to a value larger than _iMax. Integral clamping is disabled by default.

Parameters

[in]	_p	The proportional gain.
[in]	_i	The integral gain.
[in]	_d	The derivative gain.
[in]	_imax	The integral upper limit.
[in]	_imin	The integral lower limit.
[in]	_cmdMax	Output max value.
[in]	_cmdMin	Output min value.
[in]	_cmdOffset	Command offset (feed-forward).

◆ operator=()

PID& operator= ( const PID & _p )

Assignment operator.

Parameters

[in] _p a reference to a PID to assign values from

Returns: reference to this instance

◆ PGain()

double PGain ( ) const

Get the proportional Gain.

Returns: The proportional gain value

◆ Reset()

void Reset ( )

Reset the errors and command.

◆ SetCmd()

void SetCmd ( const double _cmd )

Set current target command for this PID controller.

Parameters

[in] _cmd New command

◆ SetCmdMax()

void SetCmdMax ( const double _c )

Set the maximum value for the command.

Parameters

[in] _c The maximum value

◆ SetCmdMin()

void SetCmdMin ( const double _c )

Set the minimum value for the command.

Parameters

[in] _c The minimum value

◆ SetCmdOffset()

void SetCmdOffset ( const double _c )

Set the offset value for the command, which is added to the result of the PID controller.

Parameters

[in] _c The offset value

◆ SetDGain()

void SetDGain ( const double _d )

Set the derivative Gain.

Parameters

[in] _d derivative gain value

◆ SetIGain()

void SetIGain ( const double _i )

Set the integral Gain.

Parameters

[in] _i integral gain value

◆ SetIMax()

void SetIMax ( const double _i )

Set the integral upper limit.

Parameters

[in] _i integral upper limit value

◆ SetIMin()

void SetIMin ( const double _i )

Set the integral lower limit.

Parameters

[in] _i integral lower limit value

◆ SetPGain()

void SetPGain ( const double _p )

Set the proportional Gain.

Parameters

[in] _p proportional gain value

◆ Update() [1/2]

double Update	(	const double	_error,
		const std::chrono::duration< double > &	_dt
	)

Update the Pid loop with nonuniform time step size.

Parameters

[in]	_error	Error since last call (p_state - p_target).
[in]	_dt	Change in time since last update call. Normally, this is called at every time step, The return value is an updated command to be passed to the object being controlled.

Returns: the command value

◆ Update() [2/2]

double Update	(	const double	_error,
		double	_errorRate,
		const std::chrono::duration< double > &	_dt
	)

Update the Pid loop with nonuniform time step size.

Parameters

[in]	_error	Error since last call (p_state - p_target).
[in]	_errorRate	Estimate of error rate, that can be used when a smoother estimate is available than the finite difference used by Update(const double _error, const std::chrono::duration<double> &_dt)
[in]	_dt	Change in time since last update call. Normally, this is called at every time step, The return value is an updated command to be passed to the object being controlled.

Returns: the command value

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

gz/math/PID.hh

Gazebo Math

API Reference

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ PID()

◆ ~PID()

Member Function Documentation

◆ Cmd()

◆ CmdMax()

◆ CmdMin()

◆ CmdOffset()

◆ DGain()

◆ Errors()

◆ IGain()

◆ IMax()

◆ IMin()

◆ Init()

◆ operator=()

◆ PGain()

◆ Reset()

◆ SetCmd()

◆ SetCmdMax()

◆ SetCmdMin()

◆ SetCmdOffset()

◆ SetDGain()

◆ SetIGain()

◆ SetIMax()

◆ SetIMin()

◆ SetPGain()

◆ Update() [1/2]

◆ Update() [2/2]