mujoco_ros2_control_plugins

This package provides a plugin interface for extending the functionality of mujoco_ros2_control.

Overview

The mujoco_ros2_control_plugins package is designed to contain plugins that extend the capabilities of the main mujoco_ros2_control package. This separation allows for modular development and optional features without adding complexity to the core package.

[!NOTE] This interface provides flexibility for accessing information from the MuJoCo model and data. Users are responsible for handling that data correctly and avoiding changes to critical information.

Available Plugins

HeartbeatPublisherPlugin

A simple demonstration plugin that publishes a heartbeat message every second to the /mujoco_heartbeat topic.

Topic: mujoco_heartbeat (std_msgs/String) Rate: 1 Hz (every 1 second) Message Format: “MuJoCo ROS2 Control Heartbeat #N | Simulation time: Xs”

Dependencies

• mujoco_vendor: Provides the MuJoCo physics simulator library
• rclcpp: ROS 2 C++ client library
• pluginlib: Plugin loading framework
• std_msgs: Standard ROS message types

Building

This package is part of the mujoco_ros2_control workspace. Build it using:

colcon build --packages-select mujoco_ros2_control_plugins

Usage

Plugins are loaded from ROS 2 parameters under mujoco_plugins.

Each plugin must have:

• A unique key (for example heart_beat_plugin)
• A type field with the pluginlib class name

Use a parameters file like this:

/**:
  ros__parameters:
    mujoco_plugins:
      heart_beat_plugin:
        type: "mujoco_ros2_control_plugins/HeartbeatPublisherPlugin"
        update_rate: 1.0

Then pass that file to the mujoco_ros2_control node (for example with ParameterFile(...) in your launch file).

[!NOTE] In this repository, mujoco_ros2_control_demos/launch/01_basic_robot.launch.py already loads mujoco_ros2_control_demos/config/mujoco_ros2_control_plugins.yaml.

Example: Monitoring the Heartbeat

# Terminal 1: Launch your mujoco_ros2_control simulation
ros2 launch mujoco_ros2_control_demos 01_basic_robot.launch.py

# Terminal 2: Echo the heartbeat messages
ros2 topic echo /mujoco_heartbeat

Creating Your Own Plugin

1. Create Plugin Header

Create a header file that inherits from MuJoCoROS2ControlPluginBase:

#include "mujoco_ros2_control_plugins/mujoco_ros2_control_plugins_base.hpp"

namespace my_namespace
{

class MyCustomPlugin : public mujoco_ros2_control_plugins::MuJoCoROS2ControlPluginBase
{
public:
  bool init(rclcpp::Node::SharedPtr node, const mjModel* model, mjData* data) override;
  void update(const mjModel* model, mjData* data) override;
  void cleanup() override;

private:
  // Your member variables
};

}  // namespace my_namespace

2. Implement Plugin Methods

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