Gazebo Blank Message

Create blank Gazebo command

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Libraries:
Robotics System Toolbox / Gazebo Co-Simulation

Description

The Gazebo Blank Message block creates a blank Gazebo message or a command based on the specified type. The block output is a bus signal that contains the required elements for the type of command. Use a Bus Assignment block to modify specific fields in the bus signal. The bus signal initializes with zero value (ground).

To create blank Gazebo command, 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

Msg — Blank message

bus

Blank message, returns as a bus signal with elements relevant to the specific Message type. The Msg output always outputs the most recent message received.

There are seven different message types with specific fields:

• ApplyLinkWrench:

  • model_name –– Variable-size uint8 array representing the name of the model in the Gazebo simulator.

  • link_name –– Variable-size uint8 array representing the name of the link in the model in the Gazebo simulator.

  • force_type –– Variable-size uint8 array specified as 'SET' or 'ADD'. 'SET' overwrites any existing force message for the specified duration. 'ADD' adds the value with existing messages.

  • Fx, fy, fz –– double values specifying the amount of force applied to the Gazebo model link in world coordinates and Newtons.

  • torque_type –– Variable-size uint8 array specified as 'SET' or 'ADD'. 'SET' overwrites any existing torque message for the specified duration. 'ADD' adds the value with existing messages.

  • Tx, ty, tz –– double values specifying the amount of torque applied to the Gazebo model link in world coordinates and Newton-meters.

  • duration –– Bus containing seconds and nanoseconds as double integers, which specify how long to apply the torque in simulation time.

• ApplyJointTorque:

  • model_name –– Variable-size uint8 array representing the name of the model in the Gazebo simulator.

  • joint_name –– Variable-size uint8 array representing the name of the joint in the model in the Gazebo simulator.

  • index –– uint32 integer that identifies which joint axis the torque should be applied to.

  • effort –– double scalar value specifying the amount of torque or force to apply to the joint.

  • duration –– Bus containing seconds and nanoseconds as double integers, which specify how long to apply the torque in simulation time.

• SetLinkWorldPose:

  • model_name –– Variable-size uint8 array representing the name of the model in the Gazebo simulator.

  • link_name –– Variable-size uint8 array representing the name of the link in the model in the Gazebo simulator.

  • world_pose –– Bus containing position and orientation as [x y z] and [x y z w] double vectors, respectively.

  • duration –– Bus containing seconds and nanoseconds as double integers, which specify how long to apply the torque in simulation time.

• SetLinkLinearVelocity:

  • model_name –– Variable-size uint8 array representing the name of the model in the Gazebo simulator.

  • link_name –– Variable-size uint8 array representing the name of the link in the model in the Gazebo simulator.

  • velocity –– Bus containing linear velocity as [x y z] double vector.

  • duration –– Bus containing seconds and nanoseconds as double integers, which specify how long to apply the torque in simulation time.

• SetLinkAngularVelocity:

  • model_name –– Variable-size uint8 array representing the name of the model in the Gazebo simulator.

  • link_name –– Variable-size uint8 array representing the name of the link in the model in the Gazebo simulator.

  • velocity –– Bus containing angular velocity as [x y z] double vector.

  • duration –– Bus containing seconds and nanoseconds as double integers, which specify how long to apply the torque in simulation time.

• SetJointPosition:

  • model_name –– Variable-size uint8 array representing the name of the model in the Gazebo simulator.

  • joint_name –– Variable-size uint8 array representing the name of the joint in the model in the Gazebo simulator.

  • index –– uint32 integer that identifies which joint axis the torque should be applied to.

  • position –– double scalar value representing the joint position.

  • duration –– Bus containing seconds and nanoseconds as double integers, which specify how long to apply the torque in simulation time.

• SetJointVelocity:

  • model_name –– Variable-size uint8 array representing the name of the model in the Gazebo simulator.

  • joint_name –– Variable-size uint8 array representing the name of the joint in the model in the Gazebo simulator.

  • index –– uint32 integer that identifies which joint axis the torque should be applied to.

  • velocity –– double scalar value representing the joint velocity.

  • duration –– Bus containing seconds and nanoseconds as double integers, which specify how long to apply the torque in simulation time.

  Note

  SetJointVelocity uses the Set Instantaneous Velocity method to set the joint velocity. For more information see, Setting Velocity on Links And Joints.

Note

• If a duration is 1.005 seconds, it would be 1 second and 5000000 nanoseconds as a bus.

Data Types: bus

Parameters

Message type — Type of message

ApplyLinkWrench (default) | ApplyJointTorque | SetLinkWorldPose | SetLinkLinearVelocity | SetLinkAngularVelocity | SetJointPosition | SetJointVelocity

Click Select to get a list of message types available in Gazebo.

Sample time — Sampling time of input

0.001 (default) | positive

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

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