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Send Action Goal

Send action goal messages to ROS 2 network

Since R2024a

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  • ROS 2 Send Action Goal icon.

Libraries:
ROS Toolbox / ROS 2

Description

The Send Action Goal block enables you to send action goal messages to an action server available in a ROS 2 network. It takes in a simulink non-virtual bus as its Goal input, that corresponds to the specified ROS 2 action type.

To create a ROS 2 action client, create a ROS 2 Blank Message block with class set to Action Goal. The output of this block is connected to the Goal input of the Send Action Goal block. The action client is associated with the node of the Simulink® model.

Note

To monitor an active action goal, you must first create a paired Monitor Action Goal block. The paired block will be based on the action parameters specified in the Send Action Goal block.

Behavior

On each simulation step, the Send Action Goal block examines whether a goal is currently in progress (active goal), leading to one of these possible outcomes or occurrences:

  • If true, the block ignores any goal message available at Goal input and outputs the active goal UUID as a Simulink non-virtual bus of unique_identifier_msgs/UUID message type.

  • If there is no goal running and the Enable port is true, the block sends any goal message available at Goal input and outputs new goal UUID as a Simulink non-virtual bus of unique_identifier_msgs/UUID message type.

  • If there is no goal running and the Enable port is false, the block ignores any goal message available at Goal input and outputs default goal UUID (empty message) as a Simulink non-virtual bus of unique_identifier_msgs/UUID message type.

ROS 2 Action Client Block Behavior

Ports

Input

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ROS 2 action goal message input, specified as a non-virtual bus.

Data Types: bus

Boolean value to send action goal if there is no goal running, specified as 1 (true) or 0 (false). If there is no goal running and the Enable port is true, the block sends any goal message available at Goal input. To check if a goal is running, use the StatusCode output of the paired Monitor Action Goal block.

Data Types: Boolean

Output

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Unique ID dedicated to any goal message, specified as a non-virtual bus of message type unique_identifier_msgs/UUID.

Data Types: bus

Error conditions corresponding to the send action goal request, specified as an integer.

Error CodeCondition
0The action client sent the goal successfully and the action server accepted the goal.
1The action client sent the goal but the action server rejected the goal.
2The action client failed to send the goal but the action server is available.
3The action client failed to send the goal because the action server is not available.

Dependencies

This output is enabled when the Show ErrorCode output port is checked.

Data Types: uint8

Parameters

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To edit block parameters interactively, use the Property Inspector. From the Simulink Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Main

Source for specifying the action name:

  • Select from ROS network — Use Select... to select an action name and type from a full list of supported ROS 2 actions. The Name and Type parameters are set automatically. You must be connected to a ROS 2 network.

  • Specify your own — Enter an action name in Name and specify its type in Type. You must match an action name exactly.

ROS 2 action name, specified as a character vector. The action name must match the one available on the ROS 2 network.

ROS 2 action type, specified as a character vector. Each action name has a corresponding action type.

Path to the Monitor Action Goal block paired with this Send Action Goal block. To create a paired Monitor Action Goal for the first time, click Create paired Monitor Action Goal block.

After you create a paired Monitor Action Goal block, clicking the path displays and highlights the Monitor Action Goal block in your model.

Tips

For correct action client implementation, use only Create paired Monitor Action Goal block to create the Monitor Action Goal associated with this Send Action Goal block. Adding a Monitor Action Goal block from the library is not recommended.

Check this box to enable the ErrorCode output.

QoS

Quality of Service (QoS) settings of action client for establishing communication with the action server, returned as a character vector. You can set the Goal Service QoS, Result Service QoS, Cancel Service QoS, Feedback Topic QoS and Status QoS with these following options:

Determines the mode of storing send goal requests in the queue. If the queue fills with requests waiting to be processed, then old requests will be dropped to make room for new. If set to Keep last, the queue stores the number of requests set by the Depth parameter. If set to Keep all, the queue stores all requests up to the MATLAB® resource limits.

Size of the goal request queue, specified as a non-negative scalar integer. This only applies when History is set to Keep last.

Requirement on delivery guarantee of goal requests, specified as Reliable or Best effort. If Reliable, then delivery is guaranteed, but may retry multiple times. If Best effort, then attempt delivery and do not retry. Reliable setting is recommended for actions.

Requirement on persistence of the action goal requests, specified as Volatile or Transient local. If Volatile, then requests are not required to persist. If Transient local, then the server will require clients to persist the most recent requests specified by Depth. Volatile setting is recommended to prevent servers from receiving out of date requests in the event of a server restart.

Maximum amount of time allowed between receiving a goal request and sending a goal result, specified as a positive scalar. The Deadline QoS parameter of action clients sending goal requests must be greater than or equal to the value of the action server Deadline QoS parameter. The default value is Inf which implies that expected interval between subsequent messages is infinite.

Length of time a goal request is considered valid, specified as a positive scalar. The block does not process goal requests persisting longer than the specified lifespan in the queue. The default value is Inf which implies that a goal request is valid for infinite length of time.

Liveliness check of action server by action client, specified as automatic. This parameter is a measure of whether the action server is still alive.

Liveliness set to automatic implies that after the action server has sent a goal response to the action client, the client considers the server to be alive for an additional Lease Duration.

Maximum amount of time before an action client has to assert liveliness, specified as a positive scalar. The Lease Duration QoS parameter of action clients sending goal requests must be greater than or equal to the value of the action server Lease Duration QoS parameter. The default value is Inf which implies that action client can assert its liveliness for infinite amount of time.

QoS Compatibility Considerations

Note

The quality of service (QoS) settings must be compatible between action servers and action clients for a connection to be made.

Extended Capabilities

Version History

Introduced in R2024a

See Also

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