Gazebo Apply Command

Send command to Gazebo simulator

• Library:

• Robotics System Toolbox / Gazebo Co-Simulation

• 

Description

The Apply Command block sends commands to a Gazebo simulation. The block accepts a command message, input as a bus signal, and sends the command to the Gazebo server.

To send command messages, 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.

Limitations

• Models that use this block do not support Code Generation or Rapid Accelerator mode.

Ports

Input

Cmd — Gazebo Command

bus

Gazebo command message, specified as a bus. The command is an instruction for a specified model link or joint. Specify the model name as part of the bus signal using the Gazebo Select Entity block.

There are seven different command types with specific fields:

• ApplyLinkWrench:

  • model_name –– Variable-size uint8 array representing the name of the model in the Gazebo simulator. You can specify this field using the Gazebo Select Entity block.

  • link_name –– Variable-size uint8 array representing the name of the link in the model in the Gazebo simulator. You can specify this field using the Gazebo Select Entity block.

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

  • 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 command for the specified duration. 'ADD' adds the value with existing commands.

  • 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. You can specify this field using the Gazebo Select Entity block.

  • joint_name –– Variable-size uint8 array representing the name of the joint in the model in the Gazebo simulator. You can specify this field using the Gazebo Select Entity block.

  • 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 — Set world pose in Gazebo world for selected link of Gazebo model

• SetLinkLinearVelocity — Set linear velocity of selected link of Gazebo model

• SetLinkAngularVelocity — Set angular velocity of selected link of Gazebo model

• SetJointPosition — Set position (angle) of selected joint of Gazebo model

• SetJointVelocity — Set velocity of selected joint of Gazebo model

Data Types: bus

Parameters

Command type — Type of command

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

Click Select to get a list of command types available in Gazebo. The input Cmd must contain the correct command message structure that matches this type.

Sample time — Sampling time of input

0.001 (default) | positive

Sample time indicates the interval which commands are sent to the Gazebo simulator.

Model 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

Control Differential Drive Robot in Gazebo with Simulink

Control a differential drive robot in Gazebo co-simulation using Simulink. The robot follows a set of waypoints by reading the pose and wheel encoder positions and generates torque-control commands to drive it.

Open Live Script

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