Constructs a control-affine plant inversion model-based feedforward from given model dynamics. More...

#include <frc/controller/ControlAffinePlantInversionFeedforward.h>

Public Types
using	StateVector = Vectord< States >

using	InputVector = Vectord< Inputs >

Public Member Functions
	ControlAffinePlantInversionFeedforward (std::function< StateVector(const StateVector &, const InputVector &)> f, units::second_t dt)
	Constructs a feedforward with given model dynamics as a function of state and input. More...

	ControlAffinePlantInversionFeedforward (std::function< StateVector(const StateVector &)> f, const Matrixd< States, Inputs > &B, units::second_t dt)
	Constructs a feedforward with given model dynamics as a function of state, and the plant's B matrix(continuous input matrix). More...

	ControlAffinePlantInversionFeedforward (ControlAffinePlantInversionFeedforward &&)=default

ControlAffinePlantInversionFeedforward &	operator= (ControlAffinePlantInversionFeedforward &&)=default

const InputVector &	Uff () const
	Returns the previously calculated feedforward as an input vector. More...

double	Uff (int i) const
	Returns an element of the previously calculated feedforward. More...

const StateVector &	R () const
	Returns the current reference vector r. More...

double	R (int i) const
	Returns an element of the reference vector r. More...

void	Reset (const StateVector &initialState)
	Resets the feedforward with a specified initial state vector. More...

void	Reset ()
	Resets the feedforward with a zero initial state vector. More...

InputVector	Calculate (const StateVector &nextR)
	Calculate the feedforward with only the desired future reference. More...

InputVector	Calculate (const StateVector &r, const StateVector &nextR)
	Calculate the feedforward with current and future reference vectors. More...

Detailed Description

template<int States, int Inputs>
class frc::ControlAffinePlantInversionFeedforward< States, Inputs >

Constructs a control-affine plant inversion model-based feedforward from given model dynamics.

If given the vector valued function as f(x, u) where x is the state vector and u is the input vector, the B matrix(continuous input matrix) is calculated through a NumericalJacobian. In this case f has to be control-affine (of the form f(x) + Bu).

The feedforward is calculated as u_ff = B⁺ (rDot - f(x)) , where B⁺ is the pseudoinverse of B.

This feedforward does not account for a dynamic B matrix, B is either determined or supplied when the feedforward is created and remains constant.

For more on the underlying math, read https://file.tavsys.net/control/controls-engineering-in-frc.pdf.

Template Parameters

States	The number of states.
Inputs	the number of inputs.

Member Typedef Documentation

◆ InputVector

template<int States, int Inputs>

using frc::ControlAffinePlantInversionFeedforward< States, Inputs >::InputVector = Vectord<Inputs>

◆ StateVector

template<int States, int Inputs>

using frc::ControlAffinePlantInversionFeedforward< States, Inputs >::StateVector = Vectord<States>

Constructor & Destructor Documentation

◆ ControlAffinePlantInversionFeedforward() [1/3]

template<int States, int Inputs>

frc::ControlAffinePlantInversionFeedforward< States, Inputs >::ControlAffinePlantInversionFeedforward	(	std::function< StateVector(const StateVector &, const InputVector &)>	f,
		units::second_t	dt
	)

inline

Constructs a feedforward with given model dynamics as a function of state and input.

Parameters

f	A vector-valued function of x, the state, and u, the input, that returns the derivative of the state vector. HAS to be control-affine (of the form f(x) + Bu).
dt	The timestep between calls of calculate().

◆ ControlAffinePlantInversionFeedforward() [2/3]

template<int States, int Inputs>

frc::ControlAffinePlantInversionFeedforward< States, Inputs >::ControlAffinePlantInversionFeedforward	(	std::function< StateVector(const StateVector &)>	f,
		const Matrixd< States, Inputs > &	B,
		units::second_t	dt
	)

inline

Constructs a feedforward with given model dynamics as a function of state, and the plant's B matrix(continuous input matrix).

Parameters

f	A vector-valued function of x, the state, that returns the derivative of the state vector.
B	Continuous input matrix of the plant being controlled.
dt	The timestep between calls of calculate().

◆ ControlAffinePlantInversionFeedforward() [3/3]

template<int States, int Inputs>

frc::ControlAffinePlantInversionFeedforward< States, Inputs >::ControlAffinePlantInversionFeedforward ( ControlAffinePlantInversionFeedforward< States, Inputs > && )

default

Member Function Documentation

◆ Calculate() [1/2]

template<int States, int Inputs>

InputVector frc::ControlAffinePlantInversionFeedforward< States, Inputs >::Calculate ( const StateVector & nextR )

inline

Calculate the feedforward with only the desired future reference.

This uses the internally stored "current" reference.

If this method is used the initial state of the system is the one set using Reset(const StateVector&). If the initial state is not set it defaults to a zero vector.

Parameters

nextR The reference state of the future timestep (k + dt).

Returns: The calculated feedforward.

◆ Calculate() [2/2]

template<int States, int Inputs>

InputVector frc::ControlAffinePlantInversionFeedforward< States, Inputs >::Calculate	(	const StateVector &	r,
		const StateVector &	nextR
	)

inline

Calculate the feedforward with current and future reference vectors.

Parameters

r	The reference state of the current timestep (k).
nextR	The reference state of the future timestep (k + dt).

Returns: The calculated feedforward.

◆ operator=()

template<int States, int Inputs>

ControlAffinePlantInversionFeedforward & frc::ControlAffinePlantInversionFeedforward< States, Inputs >::operator= ( ControlAffinePlantInversionFeedforward< States, Inputs > && )

default

◆ R() [1/2]

template<int States, int Inputs>

const StateVector & frc::ControlAffinePlantInversionFeedforward< States, Inputs >::R ( ) const

inline

Returns the current reference vector r.

Returns: The current reference vector.

◆ R() [2/2]

template<int States, int Inputs>

double frc::ControlAffinePlantInversionFeedforward< States, Inputs >::R ( int i ) const

inline

Returns an element of the reference vector r.

Parameters

i Row of r.

Returns: The row of the current reference vector.

◆ Reset() [1/2]

template<int States, int Inputs>

void frc::ControlAffinePlantInversionFeedforward< States, Inputs >::Reset ( )

inline

Resets the feedforward with a zero initial state vector.

◆ Reset() [2/2]

template<int States, int Inputs>

void frc::ControlAffinePlantInversionFeedforward< States, Inputs >::Reset ( const StateVector & initialState )

inline

Resets the feedforward with a specified initial state vector.

Parameters

initialState The initial state vector.

◆ Uff() [1/2]

template<int States, int Inputs>

const InputVector & frc::ControlAffinePlantInversionFeedforward< States, Inputs >::Uff ( ) const

inline

Returns the previously calculated feedforward as an input vector.

Returns: The calculated feedforward.

◆ Uff() [2/2]

template<int States, int Inputs>

double frc::ControlAffinePlantInversionFeedforward< States, Inputs >::Uff ( int i ) const

inline

Returns an element of the previously calculated feedforward.

Parameters

i	Row of uff.

Returns: The row of the calculated feedforward.

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

frc/controller/ControlAffinePlantInversionFeedforward.h

Public Types

Public Member Functions

Detailed Description

Member Typedef Documentation

◆ InputVector

◆ StateVector

Constructor & Destructor Documentation

◆ ControlAffinePlantInversionFeedforward() [1/3]

◆ ControlAffinePlantInversionFeedforward() [2/3]

◆ ControlAffinePlantInversionFeedforward() [3/3]

Member Function Documentation

◆ Calculate() [1/2]

◆ Calculate() [2/2]

◆ operator=()

◆ R() [1/2]

◆ R() [2/2]

◆ Reset() [1/2]

◆ Reset() [2/2]

◆ Uff() [1/2]

◆ Uff() [2/2]