Publish

Send messages to ROS network

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Libraries:
ROS Toolbox / ROS

Description

The Publish block takes in as its input a Simulink^® nonvirtual bus that corresponds to the specified ROS message type and publishes it to the ROS network. It uses the node of the Simulink model to create a ROS publisher for a specific topic. This node is created when the model runs and is deleted when the model terminates. If the model does not have a node, the block creates one.

On each sample hit, the block converts the Msg input from a Simulink bus signal to a ROS message and publishes it. The block does not distinguish whether the input is a new message but merely publishes it on every sample hit. For simulation, this input is a MATLAB^® ROS message. In code generation, it is a C++ ROS message.

Examples

Publish and Subscribe to ROS Messages in Simulink

Publish and subscribe to a ROS topic using Simulink.

• Open Live Script

Get Started with ROS

Set up ROS within MATLAB, and get information about ROS network and ROS messages.

• Open Live Script

Connect to a ROS-enabled Robot from Simulink

Configure Simulink to connect to a separate robot simulator using ROS and then send velocity commands, and receive position information from a simulated robot.

• Open Live Script

Feedback Control of a ROS-Enabled Robot

Use Simulink to control a simulated robot running in a separate ROS-based simulator.

• Open Live Script

Ports

Input

Msg — ROS message

nonvirtual bus

ROS message, specified as a nonvirtual bus. To specify the type of ROS message, use the Message type parameter.

Data Types: bus

Parameters

Topic source — Source for specifying topic name

Select from ROS network | Specify your own

Source for specifying the topic name, specified as one of the following:

• Select from ROS network — Use Select to select a topic name. The Topic and Message type parameters are set automatically. You must be connected to a ROS network.

• Specify your own — Enter a topic name in Topic and specify its message type in Message type. You must match a topic name exactly.

Topic — Topic name to publish to

string

Topic name to publish to, specified as a string. When Topic source is set to Select from ROS network, use Select to select a topic from the ROS network. You must be connected to a ROS network to get a list of topics. Otherwise, set Topic source to Specify your own and specify the topic you want.

Message type — ROS message type

string

ROS message type, specified as a string. Use Select to select from a full list of supported ROS messages. Service message types are not supported and are not included in the list.

Length of publish queue — Message queue length

1 (default) | integer

Message queue length in code generation, specified as an integer. In simulation, the message queue is always 1 and cannot be adjusted. To ensure each message is processed, use a smaller model step or only execute the model when publishing a new message.

Tips

You can also set the addresses for the ROS master and node host by clicking the Configure network addresses link in the block.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2019b