Gazebo Read

Receive messages from Gazebo server

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Libraries:
Robotics System Toolbox / Gazebo Co-Simulation

Description

The Gazebo Read block receives messages from the Gazebo server based on the topic and message type that the block specifies. The block outputs the latest message received as a bus signal, Msg, and a Boolean, IsNew, which indicates whether a message was received during the previous time step.

To receive messages from Gazebo server, connect to a Gazebo simulation. Open the block mask and click Configure Gazebo network and simulation settings. For more information see Configure Gazebo Simulation.

This block is part of a co-simulation interface between MATLAB^® and Gazebo for exchanging data and sending commands. To see a basic example, check Perform Co-Simulation Between Simulink and Gazebo

Examples

Perform Co-Simulation Between Simulink and Gazebo

Set up a synchronized simulation between Simulink^®and Gazebo to send commands and receive data from Gazebo.

• Open Live Script

Limitations

• Models that use this block do not support Code Generation or Rapid Accelerator mode.

Ports

Output

IsNew — Status of messages in the previous time step

0 (default) | 1

Status of the message received, output as a Boolean, which indicates whether the block output Msg was received in the previous time step.

Data Types: Boolean

Msg — Gazebo message

bus

Gazebo message, output as a bus signal, with elements relevant to the specific Topic and Message type.

The Msg output always outputs the most recent message received.

Data Types: bus

Parameters

Topic source — Source for specifying topic

From Gazebo (default) | Specify your own

To get a topic from an existing Gazebo simulation, select From Gazebo. Click the Select button to see a list of available topics. To connect to a Gazebo simulation, click Configure Gazebo network and simulation settings in the block mask.

To enter a custom topic without an active Gazebo connection, select Specify your own. Use the Topic parameter to type the name of the message.

Topic — Topic name of message

/my_topic (default) | string

Topic name of message, specified as a string.

To get a topic from an existing Gazebo simulation, select From Gazebo. Click the Select button to see a list of available topics. To connect to a Gazebo simulation, click Configure Gazebo network and simulation settings in the block mask.

To specify a topic without connecting, select Specify your own.

Message type — Gazebo message type

gazebo_msgs/Pose (default) | gazebo_msgs/Image | gazebo_msgs/IMU | gazebo_msgs/LaserScan | gazebo_msgs/JointState | gazebo_msgs/LinkState

Click Select to get a list of message types available in Gazebo. If you choose your Topic from a connected Gazebo simulation, this parameter is set automatically.

Sample time — Sampling time of input

0.001 (default) | positive scalar

Sample time indicates when, during simulation, the block produces outputs and if appropriate, updates its internal state.

Number of Joint Axis — Number of joint axis

2 (default) | positive integer in range [1, 100]

Select Make Joint Axis Related Bus Signal to Fixed Dimensions to convert the joint-axis-related bus signal from variable dimension to fixed dimension. Then specify the number of joint axis.

Dependencies

To enable this parameter, set Message type to gazebo_msgs/JointState and select the Make Joint Axis Related Bus Signal to Fixed Dimensions check box.

More About

Configure Gazebo Simulation

Click Configure Gazebo network and simulation settings in the block mask to launch the Configure Gazebo Simulation dialog box, which configures the synchronized stepping between Gazebo and Simulink. You can select the Network Address and specify Hostname/IP Address and Port of the computer running the Gazebo simulator with the Gazebo plugin installed. Then click Test to test the connection to the running Gazebo simulator. You can also specify the Response timeout in seconds. These settings apply to all Gazebo blocks for all open Simulink models.

Starting from R2022b, you can connect to multiple Gazebo simulations from one or more machines. You can now specify a cell array of IP addresses and a cell array of port numbers in the MATLAB workspace and then specify their variable names to the Hostname/IP Address and Port boxes, respectively.

To connect to a single Gazebo session from MATLAB, specify the port number and IP address of the computer running the Gazebo simulator.

portnum = 14580; 
ipaddress = '172.18.250.125'; 

To connect to multiple Gazebo sessions from MATLAB, specify the port numbers and IP addresses of the computers running the Gazebo simulator.

portnum = {14580,14581};
ipaddress = {'172.18.250.125','172.18.250.125'}; 

Version History

Introduced in R2019b