This class provides wrappers around entities and components which are more convenient and straight-forward to use than dealing with the EntityComponentManager directly. All the functions provided here are meant to be used with a link entity. More...

#include <gz/sim/Link.hh>

Public Member Functions
	Link (const Link &_link)
	Copy constructor.

	Link (Link &&_link) noexcept
	Move constructor.

	Link (sim::Entity _entity=kNullEntity)
	Constructor.

	~Link ()
	Destructor.

void	AddWorldForce (EntityComponentManager &_ecm, const math::Vector3d &_force) const
	Add a force expressed in world coordinates and applied at the center of mass of the link.

void	AddWorldForce (EntityComponentManager &_ecm, const math::Vector3d &_force, const math::Vector3d &_position) const
	Add a force expressed in world coordinates and applied at an offset from the center of mass of the link.

void	AddWorldWrench (EntityComponentManager &_ecm, const math::Vector3d &_force, const math::Vector3d &_torque) const
	Add a wrench expressed in world coordinates and applied to the link at the link's origin. This wrench is applied for one simulation step.

void	AddWorldWrench (EntityComponentManager &_ecm, const math::Vector3d &_force, const math::Vector3d &_torque, const math::Vector3d &_offset) const
	Add a wrench expressed in world coordinates and applied to the link at an offset from the link's origin. This wrench is applied for one simulation step.

sim::Entity	CollisionByName (const EntityComponentManager &_ecm, const std::string &_name) const
	Get the ID of a collision entity which is an immediate child of this link.

uint64_t	CollisionCount (const EntityComponentManager &_ecm) const
	Get the number of collisions which are immediate children of this link.

std::vector< sim::Entity >	Collisions (const EntityComponentManager &_ecm) const
	Get all collisions which are immediate children of this link.

void	EnableAccelerationChecks (EntityComponentManager &_ecm, bool _enable=true) const
	By default, Gazebo will not report accelerations for a link, so functions like `WorldLinearAcceleration` will return nullopt. This function can be used to enable all acceleration checks.

void	EnableVelocityChecks (EntityComponentManager &_ecm, bool _enable=true) const
	By default, Gazebo will not report velocities for a link, so functions like `WorldLinearVelocity` will return nullopt. This function can be used to enable all velocity checks.

sim::Entity	Entity () const
	Get the entity which this Link is related to.

bool	IsCanonical (const EntityComponentManager &_ecm) const
	Check if this is the canonical link.

std::optional< std::string >	Name (const EntityComponentManager &_ecm) const
	Get the link's unscoped name.

Link &	operator= (const Link &_link)
	Copy assignment operator.

Link &	operator= (Link &&_link) noexcept
	Move assignment operator.

std::optional< Model >	ParentModel (const EntityComponentManager &_ecm) const
	Get the parent model.

void	ResetEntity (sim::Entity _newEntity)
	Reset Entity to a new one.

void	SetAngularVelocity (EntityComponentManager &_ecm, const math::Vector3d &_vel) const
	Set the angular velocity on this link. If this is set, wrenches on this link will be ignored for the current time step.

void	SetLinearVelocity (EntityComponentManager &_ecm, const math::Vector3d &_vel) const
	Set the linear velocity on this link. If this is set, wrenches on this link will be ignored for the current time step.

bool	Valid (const EntityComponentManager &_ecm) const
	Check whether this link correctly refers to an entity that has a components::Link.

sim::Entity	VisualByName (const EntityComponentManager &_ecm, const std::string &_name) const
	Get the ID of a visual entity which is an immediate child of this link.

uint64_t	VisualCount (const EntityComponentManager &_ecm) const
	Get the number of visuals which are immediate children of this link.

std::vector< sim::Entity >	Visuals (const EntityComponentManager &_ecm) const
	Get all visuals which are immediate children of this link.

bool	WindMode (const EntityComponentManager &_ecm) const
	Get whether this link has wind enabled.

std::optional< math::Vector3d >	WorldAngularAcceleration (const EntityComponentManager &_ecm) const
	Get the angular acceleration of the body in the world frame.

std::optional< math::Vector3d >	WorldAngularVelocity (const EntityComponentManager &_ecm) const
	Get the angular velocity of the link in the world frame.

std::optional< math::Matrix6d >	WorldFluidAddedMassMatrix (const EntityComponentManager &_ecm) const
	Get the fluid added mass matrix in the world frame.

std::optional< math::Inertiald >	WorldInertial (const EntityComponentManager &_ecm) const
	Get the world inertia of the link.

std::optional< math::Pose3d >	WorldInertialPose (const EntityComponentManager &_ecm) const
	Get the world pose of the link inertia.

std::optional< math::Matrix3d >	WorldInertiaMatrix (const EntityComponentManager &_ecm) const
	Get the inertia matrix in the world frame.

std::optional< double >	WorldKineticEnergy (const EntityComponentManager &_ecm) const
	Get the rotational and translational kinetic energy of the link with respect to the world frame.

std::optional< math::Vector3d >	WorldLinearAcceleration (const EntityComponentManager &_ecm) const
	Get the linear acceleration of the body in the world frame.

std::optional< math::Vector3d >	WorldLinearVelocity (const EntityComponentManager &_ecm) const
	Get the linear velocity at the origin of of the link frame expressed in the world frame, using an offset expressed in a body-fixed frame. If no offset is given, the velocity at the origin of the Link frame will be returned.

std::optional< math::Vector3d >	WorldLinearVelocity (const EntityComponentManager &_ecm, const math::Vector3d &_offset) const
	Get the linear velocity of a point on the body in the world frame, using an offset expressed in a body-fixed frame.

std::optional< math::Pose3d >	WorldPose (const EntityComponentManager &_ecm) const
	Get the pose of the link frame in the world coordinate frame.

Detailed Description

This class provides wrappers around entities and components which are more convenient and straight-forward to use than dealing with the EntityComponentManager directly. All the functions provided here are meant to be used with a link entity.

For example, given a link's entity, to find the value of its name component, one could use the entity-component manager (ecm) directly as follows:

std::string name = ecm.Component<components::Name>(entity)->Data();

Using this class however, the same information can be obtained with a simpler function call:

Link link(entity); std::string name = link.Name(ecm);

Constructor & Destructor Documentation

◆ Link() [1/3]

Link ( sim::Entity _entity = kNullEntity )

explicit

Constructor.

Parameters

[in] _entity Link entity

◆ Link() [2/3]

Link ( const Link & _link )

Copy constructor.

Parameters

[in] _link Link to copy.

◆ Link() [3/3]

Link ( Link && _link )

noexcept

Move constructor.

Parameters

[in] _link Link to move.

◆ ~Link()

~Link ( )

Destructor.

Member Function Documentation

◆ AddWorldForce() [1/2]

void AddWorldForce	(	EntityComponentManager &	_ecm,
		const math::Vector3d &	_force
	)		const

Add a force expressed in world coordinates and applied at the center of mass of the link.

Parameters

[in]	_ecm	Mutable Entity-component manager.
[in]	_force	Force to be applied expressed in world coordinates

◆ AddWorldForce() [2/2]

void AddWorldForce	(	EntityComponentManager &	_ecm,
		const math::Vector3d &	_force,
		const math::Vector3d &	_position
	)		const

Add a force expressed in world coordinates and applied at an offset from the center of mass of the link.

Parameters

[in]	_ecm	Mutable Entity-component manager.
[in]	_force	Force to be applied expressed in world coordinates
[in]	_position	The point of application of the force expressed in the link-fixed frame.

◆ AddWorldWrench() [1/2]

void AddWorldWrench	(	EntityComponentManager &	_ecm,
		const math::Vector3d &	_force,
		const math::Vector3d &	_torque
	)		const

Add a wrench expressed in world coordinates and applied to the link at the link's origin. This wrench is applied for one simulation step.

Parameters

[in]	_ecm	Mutable Entity-component manager.
[in]	_force	Force to be applied expressed in world coordinates
[in]	_torque	Torque to be applied expressed in world coordinates

◆ AddWorldWrench() [2/2]

void AddWorldWrench	(	EntityComponentManager &	_ecm,
		const math::Vector3d &	_force,
		const math::Vector3d &	_torque,
		const math::Vector3d &	_offset
	)		const

Add a wrench expressed in world coordinates and applied to the link at an offset from the link's origin. This wrench is applied for one simulation step.

Parameters

[in]	_ecm	Mutable Entity-component manager.
[in]	_force	Force to be applied expressed in world coordinates
[in]	_torque	Torque to be applied expressed in world coordinates
[in]	_offset	The point of application of the force expressed in the link frame

◆ CollisionByName()

sim::Entity CollisionByName	(	const EntityComponentManager &	_ecm,
		const std::string &	_name
	)		const

Get the ID of a collision entity which is an immediate child of this link.

Parameters

[in]	_ecm	Entity-component manager.
[in]	_name	Collision name.

Returns: Collision entity.

◆ CollisionCount()

uint64_t CollisionCount ( const EntityComponentManager & _ecm ) const

Get the number of collisions which are immediate children of this link.

Parameters

[in] _ecm Entity-component manager.

Returns: Number of collisions in this link.

◆ Collisions()

std::vector< sim::Entity > Collisions ( const EntityComponentManager & _ecm ) const

Get all collisions which are immediate children of this link.

Parameters

[in] _ecm Entity-component manager.

Returns: All collisions in this link.

◆ EnableAccelerationChecks()

void EnableAccelerationChecks	(	EntityComponentManager &	_ecm,
		bool	_enable = `true`
	)		const

By default, Gazebo will not report accelerations for a link, so functions like WorldLinearAcceleration will return nullopt. This function can be used to enable all acceleration checks.

Parameters

[in]	_ecm	Mutable reference to the ECM.
[in]	_enable	True to enable checks, false to disable. Defaults to true.

◆ EnableVelocityChecks()

void EnableVelocityChecks	(	EntityComponentManager &	_ecm,
		bool	_enable = `true`
	)		const

By default, Gazebo will not report velocities for a link, so functions like WorldLinearVelocity will return nullopt. This function can be used to enable all velocity checks.

Parameters

[in]	_ecm	Mutable reference to the ECM.
[in]	_enable	True to enable checks, false to disable. Defaults to true.

◆ Entity()

sim::Entity Entity ( ) const

Get the entity which this Link is related to.

Returns: Link entity.

◆ IsCanonical()

bool IsCanonical ( const EntityComponentManager & _ecm ) const

Check if this is the canonical link.

Parameters

[in] _ecm Entity-component manager.

Returns: True if it is the canonical link.

◆ Name()

std::optional< std::string > Name ( const EntityComponentManager & _ecm ) const

Get the link's unscoped name.

Parameters

[in] _ecm Entity-component manager.

Returns: Link's name or nullopt if the entity does not have a components::Name component

◆ operator=() [1/2]

Link & operator= ( const Link & _link )

Copy assignment operator.

Parameters

[in] _link Link to copy.

Returns: Reference to this.

◆ operator=() [2/2]

Link & operator= ( Link && _link )

noexcept

Move assignment operator.

Parameters

[in] _link Link component to move.

Returns: Reference to this.

◆ ParentModel()

std::optional< Model > ParentModel ( const EntityComponentManager & _ecm ) const

Get the parent model.

Parameters

[in] _ecm Entity-component manager.

Returns: Parent Model or nullopt if the entity does not have a components::ParentEntity component.

◆ ResetEntity()

void ResetEntity ( sim::Entity _newEntity )

Reset Entity to a new one.

Parameters

[in] _newEntity New link entity.

◆ SetAngularVelocity()

void SetAngularVelocity	(	EntityComponentManager &	_ecm,
		const math::Vector3d &	_vel
	)		const

Set the angular velocity on this link. If this is set, wrenches on this link will be ignored for the current time step.

Parameters

[in]	_ecm	Entity Component manager.
[in]	_vel	Angular velocity to set in Link's Frame.

◆ SetLinearVelocity()

void SetLinearVelocity	(	EntityComponentManager &	_ecm,
		const math::Vector3d &	_vel
	)		const

Set the linear velocity on this link. If this is set, wrenches on this link will be ignored for the current time step.

Parameters

[in]	_ecm	Entity Component manager.
[in]	_vel	Linear velocity to set in Link's Frame.

◆ Valid()

bool Valid ( const EntityComponentManager & _ecm ) const

Check whether this link correctly refers to an entity that has a components::Link.

Parameters

[in] _ecm Entity-component manager.

Returns: True if it's a valid link in the manager.

◆ VisualByName()

sim::Entity VisualByName	(	const EntityComponentManager &	_ecm,
		const std::string &	_name
	)		const

Get the ID of a visual entity which is an immediate child of this link.

Parameters

[in]	_ecm	Entity-component manager.
[in]	_name	Visual name.

Returns: Visual entity.

◆ VisualCount()

uint64_t VisualCount ( const EntityComponentManager & _ecm ) const

Get the number of visuals which are immediate children of this link.

Parameters

[in] _ecm Entity-component manager.

Returns: Number of visuals in this link.

◆ Visuals()

std::vector< sim::Entity > Visuals ( const EntityComponentManager & _ecm ) const

Get all visuals which are immediate children of this link.

Parameters

[in] _ecm Entity-component manager.

Returns: All visuals in this link.

◆ WindMode()

bool WindMode ( const EntityComponentManager & _ecm ) const

Get whether this link has wind enabled.

Parameters

[in] _ecm Entity-component manager.

Returns: True if wind mode is on.

◆ WorldAngularAcceleration()

std::optional< math::Vector3d > WorldAngularAcceleration ( const EntityComponentManager & _ecm ) const

Get the angular acceleration of the body in the world frame.

Parameters

[in] _ecm Entity-component manager.

Returns: Angular acceleration of the body in the world frame or nullopt if acceleration checks aren't enabled.

See also: EnableAccelerationChecks

◆ WorldAngularVelocity()

std::optional< math::Vector3d > WorldAngularVelocity ( const EntityComponentManager & _ecm ) const

Get the angular velocity of the link in the world frame.

Parameters

[in] _ecm Entity-component manager.

Returns: Angular velocity of the link or nullopt if velocity checks aren't enabled.

See also: EnableVelocityChecks

◆ WorldFluidAddedMassMatrix()

std::optional< math::Matrix6d > WorldFluidAddedMassMatrix ( const EntityComponentManager & _ecm ) const

Get the fluid added mass matrix in the world frame.

Parameters

[in] _ecm Entity-component manager.

Returns: Fluide added matrix in world frame, returns nullopt if link does not have components components::Inertial and components::WorldPose.

◆ WorldInertial()

std::optional< math::Inertiald > WorldInertial ( const EntityComponentManager & _ecm ) const

Get the world inertia of the link.

Parameters

[in] _ecm Entity-component manager.

Returns: Inertia of the link pose in world frame or nullopt if the link does not have the component components::Inertial.

◆ WorldInertialPose()

std::optional< math::Pose3d > WorldInertialPose ( const EntityComponentManager & _ecm ) const

Get the world pose of the link inertia.

Parameters

[in] _ecm Entity-component manager.

Returns: Inertial pose in world frame or nullopt if the link does not have the components components::WorldPose and components::Inertial.

◆ WorldInertiaMatrix()

std::optional< math::Matrix3d > WorldInertiaMatrix ( const EntityComponentManager & _ecm ) const

Get the inertia matrix in the world frame.

Parameters

[in] _ecm Entity-component manager.

Returns: Inertia matrix in world frame, returns nullopt if link does not have components components::Inertial and components::WorldPose.

◆ WorldKineticEnergy()

std::optional< double > WorldKineticEnergy ( const EntityComponentManager & _ecm ) const

Get the rotational and translational kinetic energy of the link with respect to the world frame.

Parameters

[in] _ecm Entity-component manager.

Returns: Kinetic energy in world frame, returns nullopt if link does not have components components::Inertial, components::WorldAngularVelocity, components::WorldLinearVelocity, and components::WorldPose.

◆ WorldLinearAcceleration()

std::optional< math::Vector3d > WorldLinearAcceleration ( const EntityComponentManager & _ecm ) const

Get the linear acceleration of the body in the world frame.

Parameters

[in] _ecm Entity-component manager.

Returns: Linear acceleration of the body in the world frame or nullopt if acceleration checks aren't enabled.

See also: EnableAccelerationChecks

◆ WorldLinearVelocity() [1/2]

std::optional< math::Vector3d > WorldLinearVelocity ( const EntityComponentManager & _ecm ) const

Get the linear velocity at the origin of of the link frame expressed in the world frame, using an offset expressed in a body-fixed frame. If no offset is given, the velocity at the origin of the Link frame will be returned.

Parameters

[in] _ecm Entity-component manager.

Returns: Linear velocity of the link or nullopt if the velocity checks aren't enabled.

See also: EnableVelocityChecks

◆ WorldLinearVelocity() [2/2]

std::optional< math::Vector3d > WorldLinearVelocity	(	const EntityComponentManager &	_ecm,
		const math::Vector3d &	_offset
	)		const

Get the linear velocity of a point on the body in the world frame, using an offset expressed in a body-fixed frame.

Parameters

[in]	_ecm	Entity-component manager.
[in]	_offset	Offset of the point from the origin of the Link frame, expressed in the body-fixed frame.

Returns: Linear velocity of the point on the body or nullopt if velocity checks aren't enabled.

See also: EnableVelocityChecks

◆ WorldPose()

std::optional< math::Pose3d > WorldPose ( const EntityComponentManager & _ecm ) const

Get the pose of the link frame in the world coordinate frame.

Parameters

[in] _ecm Entity-component manager.

Returns: Absolute Pose of the link or nullopt if the entity does not have a components::WorldPose component.

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

Link.hh

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ Link() [1/3]

◆ Link() [2/3]

◆ Link() [3/3]

◆ ~Link()

Member Function Documentation

◆ AddWorldForce() [1/2]

◆ AddWorldForce() [2/2]

◆ AddWorldWrench() [1/2]

◆ AddWorldWrench() [2/2]

◆ CollisionByName()

◆ CollisionCount()

◆ Collisions()

◆ EnableAccelerationChecks()

◆ EnableVelocityChecks()

◆ Entity()

◆ IsCanonical()

◆ Name()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ ParentModel()

◆ ResetEntity()

◆ SetAngularVelocity()

◆ SetLinearVelocity()

◆ Valid()

◆ VisualByName()

◆ VisualCount()

◆ Visuals()

◆ WindMode()

◆ WorldAngularAcceleration()

◆ WorldAngularVelocity()

◆ WorldFluidAddedMassMatrix()

◆ WorldInertial()

◆ WorldInertialPose()

◆ WorldInertiaMatrix()

◆ WorldKineticEnergy()

◆ WorldLinearAcceleration()

◆ WorldLinearVelocity() [1/2]

◆ WorldLinearVelocity() [2/2]

◆ WorldPose()