PID Implementation in C++. More...

#include <PID.hpp>

Public Member Functions
	PID ()
	Constructor. More...

void	setParallelCoefficients (double _Ts, double _Kp=0, double _Ki=0, double _Kd=0, double _N=0, double _B=1, double _Tt=-1, double _YMin=0, double _YMax=0)
	Sets the coefficients for a 'PARALLEL' type PID. More...

void	setIdealCoefficients (double _Ts, double _K=0, double _Ti=0, double _Td=0, double _N=0, double _B=1, double _Tt=-1, double _YMin=0, double _YMax=0)
	Sets the coefficients for a 'PARALLEL' type PID. More...

void	setParallelPIDSettings (const ParallelPIDSettings &_settings)
	Sets the coefficients for a 'PARALLEL' type PID using the `struct` `ParallelPIDSettings`. More...

void	setPIDSettings (const PIDSettings &_settings)
	Sets the coefficients for a 'IDEAL' type PID using the `struct` `PIDSettings`. More...

double	saturate (double _val)
	Sets the saturation limit to +/- `_val`, disables if `_val` = 0.0. More...

double	update (double _measuredValue, double _referenceValue, double time=0.0)
	Returns the Controller command at each sampling time. More...

void	reset ()
	Resets the controller. More...

void	printCoefficients ()
	Prints the controller coefficients. More...

void	disableIntegral ()
	Diables the integral part of the controller. More...

void	enableIntegral ()
	Enables the integral part of the controller. More...

void	enableIntegral (double _Ti)
	Enables the integral part of the controller with time constant `_Ti`. More...

bool	isIntegralEnabled () const
	Returns whether integral part is enabled. More...

void	disableDerivative ()
	Diables the derivative part of the controller. More...

void	enableDerivative ()
	Enables the derivative part of the controller. More...

void	enableDerivative (double _Td)
	Enables the derivative part of the controller with time constant `_Td`. More...

bool	isDerivativeEnabled () const
	Returns whether derivative part is enabled. More...

void	disableDerivativeFiltering ()
	Diables the derivative filtering. More...

void	enableDerivativeFiltering ()
	Enables the derivative filtering. More...

void	enableDerivativeFiltering (double _N)
	Enables the derivative filtering with time constant `_N`. More...

bool	isDerivativeFilteringEnabled () const
	Returns whether derivative filtering part is enabled. More...

void	setDerivativeMode (DerivativeMode mode)
	Sets the derivative mode. More...

DerivativeMode	getDerivativeMode () const
	Returns the current derivative mode. More...

bool	isSaturated ()
	Returns true if the controller got saturated in the last run. More...

PIDState	getState () const
	Returns the internal state of the controller. More...

Detailed Description

PID Implementation in C++.

Implementation based on "Control System Design" by Karl Johan Åström. implements 'IDEAL TYPE' PID with

anti-integrator windup
derivative filtering
setpoint weighing
bumpless parameter change
'Backward difference' approximation of parameters
uses the output derivative instead of error derivative

Ideal design: $u(t) = K_p \left\{ e(t) + \frac{1}{T_i}\int e(t) + T_d \dot{y}(t)) \right\}$ where $u(t)$ is the controller output, $e(t)$ is the error and $y(t)$ is measured control variable.

USAGE:

A simple PID usage is setParallelCoefficients(Ts, Kp, Ki, Kd) which uses the parallel form of PID(as seen in most textbooks). In this case almost all the other features of the controller are disabled.

GUIDELINES :

Derivative action $\frac{1}{T_s} >> \frac{N}{T_d}$ ( Rule of thumb, $0.2 \leq \frac{T_sN}{T_d} \leq 0.6}$ )

Author: Ajish Babu (ajish.nosp@m..bab.nosp@m.u@dfk.nosp@m.i.de)

Constructor & Destructor Documentation

PID::PID ( )

Constructor.

Member Function Documentation

void PID::disableDerivative ( )

Diables the derivative part of the controller.

void PID::disableDerivativeFiltering ( )

Diables the derivative filtering.

void PID::disableIntegral ( )

Diables the integral part of the controller.

void PID::enableDerivative ( )

Enables the derivative part of the controller.

void PID::enableDerivative ( double _Td )

Enables the derivative part of the controller with time constant _Td.

void PID::enableDerivativeFiltering ( )

Enables the derivative filtering.

void PID::enableDerivativeFiltering ( double _N )

Enables the derivative filtering with time constant _N.

void PID::enableIntegral ( )

Enables the integral part of the controller.

void PID::enableIntegral ( double _Ti )

Enables the integral part of the controller with time constant _Ti.

DerivativeMode PID::getDerivativeMode ( ) const

Returns the current derivative mode.

PIDState PID::getState ( ) const

Returns the internal state of the controller.

bool motor_controller::PID::isDerivativeEnabled ( ) const

inline

Returns whether derivative part is enabled.

bool motor_controller::PID::isDerivativeFilteringEnabled ( ) const

inline

Returns whether derivative filtering part is enabled.

bool motor_controller::PID::isIntegralEnabled ( ) const

inline

Returns whether integral part is enabled.

bool PID::isSaturated ( )

Returns true if the controller got saturated in the last run.

void PID::printCoefficients ( )

Prints the controller coefficients.

void PID::reset ( )

Resets the controller.

double PID::saturate ( double _val )

Sets the saturation limit to +/- _val, disables if _val = 0.0.

void PID::setDerivativeMode ( DerivativeMode mode )

Sets the derivative mode.

Parameters

mode	- Defines if the derivative will be applied to the error or only to the output

void PID::setIdealCoefficients	(	double	_Ts,
		double	_K = `0`,
		double	_Ti = `0`,
		double	_Td = `0`,
		double	_N = `0`,
		double	_B = `1`,
		double	_Tt = `-1`,
		double	_YMin = `0`,
		double	_YMax = `0`
	)

Sets the coefficients for a 'PARALLEL' type PID.

Ideal design: $u(t) = K_p \left\{ e(t) + \frac{1}{T_i}\int e(t) + T_d \dot{y}(t)) \right\}$ where $u(t)$ is the controller output, $e(t)$ is the error and $y(t)$ is measured control variable.

Parameters

_Kp	gain for proportional error, integral error and derivative output
_Ti	integral time constant
_Td	derivative time constant

see PIDSettings for details of the rest of the parameters

void PID::setParallelCoefficients	(	double	_Ts,
		double	_Kp = `0`,
		double	_Ki = `0`,
		double	_Kd = `0`,
		double	_N = `0`,
		double	_B = `1`,
		double	_Tt = `-1`,
		double	_YMin = `0`,
		double	_YMax = `0`
	)

Sets the coefficients for a 'PARALLEL' type PID.

Parallel design: $u(t) = K_p e(t) + K_i\int e(t) + K_d \dot{y}(t))$ where $u(t)$ is the controller output, $e(t)$ is the error and $y(t)$ is measured control variable.

Parameters

_Kp	proportional gain
_Ki	integral gain
_Kd	derivative gain

see PIDSettings for details of the rest of the parameters

void PID::setParallelPIDSettings ( const ParallelPIDSettings & _settings )

Sets the coefficients for a 'PARALLEL' type PID using the struct ParallelPIDSettings.

void PID::setPIDSettings ( const PIDSettings & _settings )

Sets the coefficients for a 'IDEAL' type PID using the struct PIDSettings.

double PID::update	(	double	_measuredValue,
		double	_referenceValue,
		double	time = `0.0`
	)

Returns the Controller command at each sampling time.

Parameters

_measuredValue	is the measured system output
_referenceValue	is the reference input for the controller
time	is the optional current time

Applies the derivative action either to the error or only to the output

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

/build/rock-master-18.09-control-motor-controller-0.20160617/src/PID.hpp
/build/rock-master-18.09-control-motor-controller-0.20160617/src/PID.cpp

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation