gazebo::GazeboYarpModelPosePublisher Class Reference

Gazebo Plugin that publishes the pose of the root link of a model with respect to the Gazebo world frame. More...

#include <ModelPosePublisher.hh>

Inheritance diagram for gazebo::GazeboYarpModelPosePublisher:

Collaboration diagram for gazebo::GazeboYarpModelPosePublisher:

Public Member Functions
	~GazeboYarpModelPosePublisher ()
void	Load (gazebo::physics::ModelPtr, sdf::ElementPtr)
	Store pointer to the model, load parameters from the SDF, configure the frame transform client, reset the time of the last update and connect to the World update event of Gazebo.

Detailed Description

Gazebo Plugin that publishes the pose of the root link of a model with respect to the Gazebo world frame.

This plugin instantiates a yarp::dev::FrameTransformClient in order to publish the transform between the Gazebo world frame and the root link of the model. This requires a yarp::dev::FrameTransformServer to be actived and running before the model is inserted in Gazebo. It is not required to write code in order to have a working FrameTransfomServer. Instead yarpdev can be used from the command line, e.g.

yarpdev --device transformServer --ROS::enable_ros_publisher false --ROS::enable_ros_subscriber false

In the example above support to ROS is disabled.

Each transform published by the plugin contains as source frame the string "/inertial" and as target frame a string that depends on the name option of the model tag within the SDF. If such a name is <name> the string describing the target will be "/<name>/frame". In case the model <name> is inserted in the Gazebo environment more than once than the its name becomes <name>_x where x assumes the values 0, 1, 2.... This beavior depends on the internal behavior of Gazebo.

The pose published by the plugin is that of the root link of the model with respect to the Gazebo world frame. If the SDF of the model is the following

<sdf>
  <model name="object">
  <!-- pose of model frame w.r.t Gazebo world -->
  <pose> x_m y_m z_m roll_m pich_m yaw_m </pose>
 
    <link name="object_root_link">
    <!-- pose of the root link w.r.t the model frame -->
    <pose> x_l y_l z_l roll_l pich_l yaw_l </pose>    
    ...
    </link>
 
   <plugin name='...' filename='libgazebo_yarp_modelposepublisher.so'>
     <period>1.0</period>
   </plugin>
 
  </model>
<\sdf>

then the pose of the root link depends on both the transformation between the Gazebo world frame and the model frame and the transformation between the model frame and the root link.

In order to retrieve the published transform an istance of yarp::dev::FrameTransformClient can be used. An example is provided below

...
// Instantiate the driver
yarp::dev::PolyDriver m_drvTransformClient;
yarp::dev::IFrameTransform* m_tfClient;
yarp::os::Property propTfClient;
propTfClient.put("device", "transformClient");
propTfClient.put("local", "/transformClientLocal");
propTfClient.put("remote", "/transformServer");
 
// Check if the driver opened correctly
bool ok_open = m_drvTransformClient.open(propTfClient);
if (!ok) {
    // Error...
}
 
// Check if the view was obtained succesfully
bool ok_view = m_drvTransformClient.view(m_tfClient);
if (!ok_view || m_tfClient == nullptr) {
    // Error...
}
 
// Retrieve the transform
yarp::sig::Matrix transform(4, 4);
std::string source = "/inertial";
std::string target = "/<name>/frame";
bool ok_transform = m_tfClient->getTransform(target, source, transform);
if (!ok_transform) {
    // Transform not ready...
}

The update rate of the plugin can be configured using the period SDF tag in seconds. If the parameter is not provided a default value of 10 ms is used.

This plugin does not support Gazebo nested models since the method gazebo::physics::WorldPose() does not work properly with nested models (see [issue](https://github.com/osrf/gazebo/issues/2410")).

Constructor & Destructor Documentation

~GazeboYarpModelPosePublisher()

gazebo::GazeboYarpModelPosePublisher::~GazeboYarpModelPosePublisher

(

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Member Function Documentation

Load()

void gazebo::GazeboYarpModelPosePublisher::Load	(	gazebo::physics::ModelPtr	_parent,
		sdf::ElementPtr	_sdf )

Store pointer to the model, load parameters from the SDF, configure the frame transform client, reset the time of the last update and connect to the World update event of Gazebo.

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

• ModelPosePublisher.hh
• ModelPosePublisher.cc