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Send messages to ROS 2 network

Since R2019b

  • Publish ROS 2 block

ROS Toolbox / ROS 2


The Publish ROS 2 block takes in as its input a Simulink® non-virtual bus that corresponds to the specified ROS 2 message type and publishes it to the ROS 2 network. It uses the node of the Simulink model to create a ROS 2 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 2 message and publishes it. The block does not distinguish whether the input is a new message but instead publishes it on every sample hit. For simulation, this input is a MATLAB® ROS 2 message. In code generation, it is a C++ ROS 2 message.



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

Data Types: bus


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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 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 2 network to get a list of topics. Otherwise, set Topic source to Specify your own and specify the topic you want.

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.

Quality of Service (QoS)

Determines the mode of storing messages in the queue. The queued messages will be sent to late-joining subscribers. If the queue fills with messages waiting to be processed, then old messages will be dropped to make room for new. If set to 'keeplast', the queue stores the number of messages set by the Depth parameter. If set to 'keepall', the queue stores all messages up to the MATLAB resource limits.

Number of messages stored in the message queue when History is set to Keep last.

Affects the guarantee of message delivery. If Reliable, then delivery is guaranteed, but may retry multiple times. If Best effort, then attempt delivery and do not retry.

Affects persistence of messages in publishers, which allows late-joining subscribers to receive the number of old messages specified by Depth. If Volatile, then messages do not persist. If Transient local, then publisher will persist most recent messages.

Extended Capabilities

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

Version History

Introduced in R2019b