Gazebo Select Entity

R2026b

Select a Gazebo entity

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Gazebo Select Entity block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Robotics System Toolbox / Gazebo Co-Simulation

Description

The Gazebo Select Entity block retrieves the model name of a Gazebo entity, such as a link or joint, from a simulated environment. The block outputs a string for both the model and associated joint or link name. Use both these names when specifying commands using the Gazebo Apply Command block.

Before selecting an entity, 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

model — Model name of entity

model1 (default) | string (uint8[])

Model name of entity, output as string scalar. Strings are output as a variable-size uint8 array for Gazebo.

Data Types: uint8

Joint/Link — Associated joint or link name of entity

joint1 (default) | string (uint8[])

Associated joint or link, output as a string scalar. Strings are output as a uint8 array for Gazebo.

Data Types: uint8

Parameters

Model Name — Choose model name

'model1/joint1' (default) | string scalar

Choose a model by clicking Select, which brings up a list of available names available on the Gazebo server. The block assumes you are already connected to a Gazebo simulation. If not, click Configure Gazebo network and simulation settings in the block mask.

Output vector size upper bound — Upper limit of output array

128 (default)

Upper limit of the size of the output uint8 arrays, Model Name and Joint/Link. Increase the upper bound when the names are longer than the default value 128.

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"robotgazebolib/Gazebo Select Entity"

Example: add_block("robotgazebolib/Gazebo Select Entity","myModel/myBlock",MakeNameUnique="on")

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