RViz simulation

Run a simulated Marty V2 in ROS 2 and display it in RViz. Joint sliders or ROS topic commands set the pose; MuJoCo computes the joint feedback and floating base position. No physical Marty connection is needed.

Build

Use Ubuntu 24.04, ROS 2 Jazzy, Python 3.12 and Bash. Complete the Install and build and Machine configuration sections of Install and connect. Robot connection configuration and driver launch are not needed for this simulation.

From the repository root: 

source scripts/setup_env.sh
python -m pip install -r requirements-simulation.txt
rosdep install --from-paths src --ignore-src -r -y
python "$(command -v colcon)" build --base-paths src --symlink-install
source scripts/setup_env.sh

marty2_description contains the URDF and meshes; marty_simulation contains the MuJoCo bridge and RViz setup. Avoid a second package named marty2_description in the same workspace.

Open RViz and joint controls

ros2 launch marty_simulation simulation.launch.py

RViz opens with Marty and a ground grid. Move the sliders in Joint State Publisher to change the simulated pose. Nine independent joints drive eleven mimic joints, including the opposite eyebrow and the arm gears.

The launch starts only the simulation, joint controls, robot-state publisher and RViz. It does not start the physical driver. Ctrl+C in the launch terminal closes them.

Send a pose from the console

Stop the previous launch with Ctrl+C, then restart with the sliders disabled so they do not replace console commands: 

ros2 launch marty_simulation simulation.launch.py gui:=false

In another terminal, from the repository root: 

source scripts/setup_env.sh
ros2 topic pub --once /marty_sim/joint_commands sensor_msgs/msg/JointState \
  '{name: [eye_left_joint, arm_servo_gear_left_joint, arm_servo_gear_right_joint], position: [-0.5, 0.7, 0.7]}'
ros2 topic echo /marty_sim/joint_states --once

The command changes the eyebrows and both arms. Positions are radians. Partial commands retain the other targets. Unknown joints, duplicate names, non-finite values and targets outside the actuator limits are rejected.

ROS graph

joint controls / console
        |
        v
/marty_sim/joint_commands
        |
        v
/marty_sim/marty_simulation (MuJoCo)
        |                         |
        v                         v
/marty_sim/joint_states       floating-base TF
        |                         |
        v                         |
/marty_sim/robot_state_publisher    |
        |                         |
        +----------> /tf <--------+
                      |
                      v
                     RViz
Topic Type Purpose
/marty_sim/joint_commands sensor_msgs/msg/JointState Target positions for the nine independent joints.
/marty_sim/joint_states sensor_msgs/msg/JointState Simulated positions and velocities, published at approximately 50 Hz.
/marty_sim/robot_description std_msgs/msg/String URDF geometry used by RViz and joint controls.
/tf and /tf_static tf2_msgs/msg/TFMessage Link transforms and the floating base pose.

Inspect the running setup with: 

ros2 node list
ros2 node info /marty_sim/marty_simulation
ros2 topic list -t

Simulation modes

The default mode:=stabilized uses height/tilt assistance and estimated joint damping to keep the model stable. mode:=free removes those aids: 

ros2 launch marty_simulation simulation.launch.py mode:=free

The URDF, meshes and generated MuJoCo model come from the Marty URDF simulator. Contact, actuator and mass calibration is incomplete; physical motion accuracy and free walking are not validated. This setup accepts joint targets, rather than the physical driver's firmware Motion action.

For a headless run, add gui:=false rviz:=false. Simulation reference includes model provenance and timing details.

Task Runner