Contact sensor. More...

#include <sensors/sensors.hh>

Inheritance diagram for gazebo::sensors::ContactSensor:

Public Member Functions
	ContactSensor ()
	Constructor.

virtual	~ContactSensor ()
	Destructor.

unsigned int	GetCollisionContactCount (const std::string &_collisionName) const
	Return the number of contacts for an observed collision.

unsigned int	GetCollisionCount () const
	Get the number of collisions that the sensor is observing.

std::string	GetCollisionName (unsigned int _index) const
	Get a collision name at index _index.

msgs::Contacts	GetContacts () const
	Get all the contacts for the ContactSensor.

std::map< std::string, physics::Contact >	GetContacts (const std::string &_collisionName)
	Gets contacts of a collision.

virtual void	Init ()
	Initialize the sensor.

virtual bool	IsActive ()
	Returns true if sensor generation is active.

virtual void	Load (const std::string &_worldName, sdf::ElementPtr _sdf)
	Load the sensor with SDF parameters.

virtual void	Load (const std::string &_worldName)
	Load the sensor with default parameters.

Public Member Functions inherited from gazebo::sensors::Sensor
	Sensor (SensorCategory _cat)
	Constructor.

virtual	~Sensor ()
	Destructor.

template<typename T >
event::ConnectionPtr	ConnectUpdated (T _subscriber)
	Connect a signal that is triggered when the sensor is updated.

void	DisconnectUpdated (event::ConnectionPtr &_c)
	Disconnect from a the updated signal.

void	FillMsg (msgs::Sensor &_msg)
	fills a msgs::Sensor message.

SensorCategory	GetCategory () const
	Get the category of the sensor.

common::Time	GetLastMeasurementTime ()
	Return last measurement time.

common::Time	GetLastUpdateTime ()
	Return last update time.

std::string	GetName () const
	Get name.

std::string	GetParentName () const
	Returns the name of the sensor parent.

virtual math::Pose	GetPose () const
	Get the current pose.

std::string	GetScopedName () const
	Get fully scoped name of the sensor.

virtual std::string	GetTopic () const
	Returns the topic name as set in SDF.

std::string	GetType () const
	Get sensor type.

double	GetUpdateRate ()
	Get the update rate of the sensor.

bool	GetVisualize () const
	Return true if user requests the sensor to be visualized via tag: <visualize>true</visualize> in SDF.

std::string	GetWorldName () const
	Returns the name of the world the sensor is in.

void	ResetLastUpdateTime ()
	Reset the lastUpdateTime to zero.

virtual void	SetActive (bool _value)
	Set whether the sensor is active or not.

virtual void	SetParent (const std::string &_name)
	Set the parent of the sensor.

void	SetUpdateRate (double _hz)
	Set the update rate of the sensor.

void	Update (bool _force)
	Update the sensor.

Protected Member Functions
virtual void	Fini ()
	Finalize the sensor.

virtual void	UpdateImpl (bool _force)
	Update the sensor information.

Additional Inherited Members
Protected Attributes inherited from gazebo::sensors::Sensor
bool	active
	True if sensor generation is active.

std::vector< event::ConnectionPtr >	connections
	All event connections.

common::Time	lastMeasurementTime
	Stores last time that a sensor measurement was generated; this value must be updated within each sensor's UpdateImpl.

common::Time	lastUpdateTime
	Time of the last update.

transport::NodePtr	node
	Node for communication.

std::string	parentName
	Name of the parent.

std::vector< SensorPluginPtr >	plugins
	All the plugins for the sensor.

math::Pose	pose
	Pose of the sensor.

transport::SubscriberPtr	poseSub
	Subscribe to pose updates.

sdf::ElementPtr	sdf
	Pointer the the SDF element for the sensor.

common::Time	updatePeriod
	Desired time between updates, set indirectly by Sensor::SetUpdateRate.

gazebo::physics::WorldPtr	world
	Pointer to the world.

Detailed Description

Contact sensor.

This sensor detects and reports contacts between objects

Constructor & Destructor Documentation

gazebo::sensors::ContactSensor::ContactSensor ( )

Constructor.

virtual gazebo::sensors::ContactSensor::~ContactSensor ( )

virtual

Destructor.

Member Function Documentation

virtual void gazebo::sensors::ContactSensor::Fini ( )

protectedvirtual

Finalize the sensor.

Reimplemented from gazebo::sensors::Sensor.

unsigned int gazebo::sensors::ContactSensor::GetCollisionContactCount ( const std::string & _collisionName ) const

Return the number of contacts for an observed collision.

Parameters

[in] _collisionName The name of the observed collision.

Returns: The collision contact count.

unsigned int gazebo::sensors::ContactSensor::GetCollisionCount ( ) const

Get the number of collisions that the sensor is observing.

Returns: Number of collisions.

std::string gazebo::sensors::ContactSensor::GetCollisionName ( unsigned int _index ) const

Get a collision name at index _index.

Parameters

[in] _index Index of collision in collection of collisions.

Returns: name of collision.

msgs::Contacts gazebo::sensors::ContactSensor::GetContacts ( ) const

Get all the contacts for the ContactSensor.

Returns: Message that contains contact information between collision pairs.

During ODEPhysics::UpdateCollisions, all collision pairs in the world are pushed into a buffer within ContactManager. Subsequently, World::Update invokes ContactManager::PublishContacts to publish all contacts generated within a timestep onto Gazebo topic ~/physics/contacts.

Each ContactSensor subscribes to the Gazebo ~/physics/contacts topic, retrieves all contact pairs in a time step and filters them wthin ContactSensor::OnContacts against <collision> body name specified by the ContactSensor SDF. All collision pairs between ContactSensor <collision> body and other bodies in the world are stored in an array inside contacts.proto.

Within each element of the contact.proto array inside contacts.proto, list of collisions between collision bodies (collision1 and collision 2) are stored in an array of elements, (position, normal, depth, wrench). A timestamp has also been added (time). Details are described below:

string collision1 name of the first collision object.
string collision2 name of the second collision object.
Vector3d position position of the contact joint in inertial frame.
Vector3d normal normal of the contact joint in inertial frame.
double depth intersection (penetration) depth of two collision bodies.
JointWrench wrench Forces and torques acting on both collision bodies. See joint_wrench.proto for details. The forces and torques are applied at the CG of perspective links for each collision body, specified in the inertial frame.
Time time time at which this contact happened.

std::map<std::string, physics::Contact> gazebo::sensors::ContactSensor::GetContacts ( const std::string & _collisionName )

Gets contacts of a collision.

Parameters

[in] _collisionName Name of collision