Detailed Description

template<typename T>
class drake::systems::SystemConstraint< T >

A SystemConstraint is a generic base-class for constraints on Systems.

A SystemConstraint is a means to inform our algorithms about the implemented system behavior – declaring the constraint does not cause the system behavior to change. It is meant to improve analysis by telling our algorithms that "all valid solutions of this dynamical system will satisfy the following (in)equalities". Examples could include conserved quantities or joint limits on a mechanism.

This class is intentionally similar to, but (so far) independent from solvers::Constraint. This is primarily because there is no notion of decision variables in the system classes (yet); rather each individual algorithm (e.g. trajectory optimization, or system identification) constructs decision variables for the particular mathematical program that is being formulated, and must bind the system constraint to those variables (e.g. by populating the Context with the decision variables and calling Calc).

We can convert a SystemConstraint to a solvers::Constraint by using SystemConstraintWrapper or SystemConstraintAdapter.

See also: LeafSystem<T>::DeclareEqualityConstraint and LeafSystem<T>::DeclareInequalityConstraint for use cases.

Template Parameters

T	The scalar type, which must be one of the default scalars.

#include <drake/systems/framework/system_constraint.h>

Public Member Functions
	SystemConstraint (const System< T > *system, std::string description)
	(Advanced) Constructs a default (zero-sized) SystemConstraint. More...

	SystemConstraint (const System< T > *system, ContextConstraintCalc< T > calc_function, SystemConstraintBounds bounds, std::string description)
	(Advanced) Constructs a SystemConstraint. More...

	SystemConstraint (const System< T > *system, SystemConstraintCalc< T > calc_function, SystemConstraintBounds bounds, std::string description)
	(Advanced) Constructs a SystemConstraint. More...

void	Calc (const Context< T > &context, VectorX< T > *value) const
	Evaluates the function pointer passed in through the constructor, writing the output to `value`. More...

boolean< T >	CheckSatisfied (const Context< T > &context, double tol) const
	Evaluates the function pointer, and check if all of the outputs are within the desired bounds. More...

const System< T > &	get_system () const
	Returns a reference to the System that owns this constraint. More...

const SystemConstraintBounds &	bounds () const

int	size () const

SystemConstraintType	type () const

bool	is_equality_constraint () const

const Eigen::VectorXd &	lower_bound () const

const Eigen::VectorXd &	upper_bound () const

const std::string &	description () const

Does not allow copy, move, or assignment
	SystemConstraint (const SystemConstraint &)=delete

SystemConstraint &	operator= (const SystemConstraint &)=delete

	SystemConstraint (SystemConstraint &&)=delete

SystemConstraint &	operator= (SystemConstraint &&)=delete

System compatibility
See System Compatibility.
const std::optional< internal::SystemId > &	get_system_id () const
	(Internal use only) Gets the id of the subsystem associated with this object, if one has been set. More...

void	set_system_id (internal::SystemId id)
	(Internal use only) Records the id of the subsystem associated with this object. More...

Constructor & Destructor Documentation

◆ SystemConstraint() [1/5]

SystemConstraint ( const SystemConstraint< T > & )

delete

◆ SystemConstraint() [2/5]

SystemConstraint ( SystemConstraint< T > && )

delete

◆ SystemConstraint() [3/5]

SystemConstraint	(	const System< T > *	system,
		std::string	description
	)

(Advanced) Constructs a default (zero-sized) SystemConstraint.

Most users should call a LeafSystem method like DeclareEqualityConstraint to create (and add) constraints, not call this constructor directly.

Parameters

description a human-readable description useful for debugging.

◆ SystemConstraint() [4/5]

SystemConstraint	(	const System< T > *	system,
		ContextConstraintCalc< T >	calc_function,
		SystemConstraintBounds	bounds,
		std::string	description
	)

(Advanced) Constructs a SystemConstraint.

Depending on the bounds it could be an equality constraint f(x) = 0, or an inequality constraint lower_bound <= f(x) <= upper_bound.

Most users should call a LeafSystem method like DeclareEqualityConstraint to create (and add) constraints, not call this constructor directly.

Parameters

description a human-readable description useful for debugging.

◆ SystemConstraint() [5/5]

SystemConstraint	(	const System< T > *	system,
		SystemConstraintCalc< T >	calc_function,
		SystemConstraintBounds	bounds,
		std::string	description
	)

(Advanced) Constructs a SystemConstraint.

Depending on the bounds it could be an equality constraint f(x) = 0, or an inequality constraint lower_bound <= f(x) <= upper_bound.

Most users should call a LeafSystem method like DeclareEqualityConstraint to create (and add) constraints, not call this constructor directly.

Parameters

description a human-readable description useful for debugging.

Member Function Documentation

◆ bounds()

const SystemConstraintBounds& bounds ( ) const

◆ Calc()

void Calc	(	const Context< T > &	context,
		VectorX< T > *	value
	)		const

Evaluates the function pointer passed in through the constructor, writing the output to value.

value will be (non-conservatively) resized to match the constraint function output.

◆ CheckSatisfied()

boolean<T> CheckSatisfied	(	const Context< T > &	context,
		double	tol
	)		const

Evaluates the function pointer, and check if all of the outputs are within the desired bounds.

◆ description()

const std::string& description ( ) const

◆ get_system()

const System<T>& get_system ( ) const

Returns a reference to the System that owns this constraint.

Note that for a constraint on a diagram this will be the diagram itself, never a leaf system whose constraint was re-expressed.

◆ get_system_id()

const std::optional<internal::SystemId>& get_system_id ( ) const

(Internal use only) Gets the id of the subsystem associated with this object, if one has been set.

◆ is_equality_constraint()

bool is_equality_constraint ( ) const

◆ lower_bound()

const Eigen::VectorXd& lower_bound ( ) const

◆ operator=() [1/2]

SystemConstraint& operator= ( SystemConstraint< T > && )

delete

◆ operator=() [2/2]

SystemConstraint& operator= ( const SystemConstraint< T > & )

delete

◆ set_system_id()

void set_system_id ( internal::SystemId id )

(Internal use only) Records the id of the subsystem associated with this object.

◆ size()

int size ( ) const

◆ type()

SystemConstraintType type ( ) const

◆ upper_bound()

const Eigen::VectorXd& upper_bound ( ) const

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

drake/systems/framework/system_constraint.h

Detailed Description

template<typename T> class drake::systems::SystemConstraint< T >

Public Member Functions

Constructor & Destructor Documentation

◆ SystemConstraint() [1/5]

◆ SystemConstraint() [2/5]

◆ SystemConstraint() [3/5]

◆ SystemConstraint() [4/5]

◆ SystemConstraint() [5/5]

Member Function Documentation

◆ bounds()

◆ Calc()

◆ CheckSatisfied()

◆ description()

◆ get_system()

◆ get_system_id()

◆ is_equality_constraint()

◆ lower_bound()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ set_system_id()

◆ size()

◆ type()

◆ upper_bound()

template<typename T>
class drake::systems::SystemConstraint< T >