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.

std::optional< math::AxisAlignedBox >	AxisAlignedBox (const EntityComponentManager &_ecm) const
	Get the link's axis-aligned bounding box in the link frame.

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.

std::optional< math::AxisAlignedBox >	ComputeAxisAlignedBox (const EntityComponentManager &_ecm) const
	Compute the axis-aligned bounding box of the link. It generates an axis-aligned bounding box for a link based on the collision shapes attached to the it. The link bounding box is generated by merging all the bounding boxes of the collision geometry shapes attached to the 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	EnableBoundingBoxChecks (EntityComponentManager &_ecm, bool _enable=true) const
	By default, Gazebo will not report bounding box for a link, so functions like `AxisAlignedBox` and `WorldAxisAlignedBox` will return nullopt. This function can be used to enable bounding box checks and it also initializes the bounding box based on the link's collision shapes.

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.

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

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

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

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::AxisAlignedBox >	WorldAxisAlignedBox (const EntityComponentManager &_ecm) const
	Get the link's axis-aligned bounding box 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

◆ AxisAlignedBox()

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

Get the link's axis-aligned bounding box in the link frame.

Parameters

[in] _ecm Entity-component manager.

Returns: Link's AxisAlignedBox in the link frame or nullopt if the link entity does not have a components::AxisAlignedBox component.

See also: EnableBoundingBoxChecks

◆ 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.

◆ ComputeAxisAlignedBox()

std::optional< math::AxisAlignedBox > ComputeAxisAlignedBox ( const EntityComponentManager & _ecm ) const

Compute the axis-aligned bounding box of the link. It generates an axis-aligned bounding box for a link based on the collision shapes attached to the it. The link bounding box is generated by merging all the bounding boxes of the collision geometry shapes attached to the link.

Parameters

[in] _ecm Entity-component manager.

Returns: Link's axis-aligned bounding box in the link frame or nullopt if the link does not have collisions. It returns an invalid bounding box if all of the link collisions are empty.

◆ 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.

◆ EnableBoundingBoxChecks()

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

By default, Gazebo will not report bounding box for a link, so functions like AxisAlignedBox and WorldAxisAlignedBox will return nullopt. This function can be used to enable bounding box checks and it also initializes the bounding box based on the link's collision shapes.

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.

◆ SensorByName()

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

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

Parameters

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

Returns: Sensor entity.

◆ SensorCount()

uint64_t SensorCount ( const EntityComponentManager & _ecm ) const

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

Parameters

[in] _ecm Entity-component manager.

Returns: Number of sensors in this link.

◆ Sensors()

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

Get all sensors which are immediate children of this link.

Parameters

[in] _ecm Entity-component manager.

Returns: All sensors in this link.

◆ 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

◆ WorldAxisAlignedBox()

std::optional< math::AxisAlignedBox > WorldAxisAlignedBox ( const EntityComponentManager & _ecm ) const

Get the link's axis-aligned bounding box in the world frame.

Parameters

[in] _ecm Entity-component manager.

Returns: Link's AxisAlignedBox in the world frame or nullopt if the link entity does not have a components::AxisAlignedBox component.

See also: AxisAlignedBox

◆ 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]

◆ AxisAlignedBox()

◆ CollisionByName()

◆ CollisionCount()

◆ Collisions()

◆ ComputeAxisAlignedBox()

◆ EnableAccelerationChecks()

◆ EnableBoundingBoxChecks()

◆ EnableVelocityChecks()

◆ Entity()

◆ IsCanonical()

◆ Name()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ ParentModel()

◆ ResetEntity()

◆ SensorByName()

◆ SensorCount()

◆ Sensors()

◆ SetAngularVelocity()

◆ SetLinearVelocity()

◆ Valid()

◆ VisualByName()

◆ VisualCount()

◆ Visuals()

◆ WindMode()

◆ WorldAngularAcceleration()

◆ WorldAngularVelocity()

◆ WorldAxisAlignedBox()

◆ WorldFluidAddedMassMatrix()

◆ WorldInertial()

◆ WorldInertialPose()

◆ WorldInertiaMatrix()

◆ WorldKineticEnergy()

◆ WorldLinearAcceleration()

◆ WorldLinearVelocity() [1/2]

◆ WorldLinearVelocity() [2/2]

◆ WorldPose()