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.

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.

Control a 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.