Dynamixel Hardware Interface User Guide

1. Introduction

ROS 2 package providing a hardware interface for controlling Dynamixel motors via the ros2_control framework. This repository includes the dynamixel_hardware_interface plugin for seamless integration with ROS 2 control, along with the dynamixel_interfaces package containing custom message definitions used by the interface

2. Prerequisites

This package currently supports ROS 2 Humble only. Ensure that ROS 2 Humble is properly installed (ROS 2 Humble installation guide).

• Hardware Requirements:

  • Dynamixel servos
  • USB2 Dynamixel or U2D2 adapter
  • Proper power supply for Dynamixel motors

3. Installation

1. Clone the repository into your ROS workspace:

   cd ~/${WORKSPACE}/src
   git clone -b humble https://github.com/ROBOTIS-GIT/DynamixelSDK.git
   git clone -b humble https://github.com/ROBOTIS-GIT/dynamixel_hardware_interface.git
   git clone -b humble https://github.com/ROBOTIS-GIT/dynamixel_interfaces.git
   

1. Build the package:

   cd ~/${WORKSPACE}
   colcon build
   

1. Source your workspace:

   source ~/${WORKSPACE}/install/setup.bash
   

4. Currently Used Packages

This project integrates with the following ROS 2 packages to provide extended functionality:

• open_manipulator_x A ROS-based open-source software package designed for the Open Manipulator-X, a 4-DOF robotic arm. It provides essential features like motion planning, kinematics, and control utilities for seamless integration with ROS 2 environments.

• open_manipulator_y A ROS-based package tailored for the Open Manipulator-Y, a 6-DOF robotic arm. This package offers enhanced compatibility and extended functionalities for advanced manipulator control and operations.

5. Configuration

To effectively use the Dynamixel Hardware Interface in a ROS 2 control system, you need to configure specific parameters in your ros2_control hardware description file. Below is a concise explanation of the key parameters, illustrated with examples from the OpenManipulator-X ROS 2 control.xacro file.

1. Port Settings: Define serial port and baud rate for communication.
2. Hardware Setup: Configure joints and transmissions.
3. Joints: Control and monitor robot joints.
4. GPIO: Define and control Dynamixel motors.

1. Port and Communication Settings

These parameters define how the interface communicates with the Dynamixel motors:

• port_name: Serial port for communication.

• baud_rate: Communication baud rate.

• error_timeout_ms: Timeout for communication errors (in milliseconds).

2. Hardware Configuration

These parameters define the hardware setup:

• number_of_joints: Total number of joints.

• number_of_transmissions: Number of transmissions.

• Transmission Matrices: Define joint-to-transmission mappings.

3. Joint Configuration

Joints define the control and state interfaces for robot movement:

Key Attributes

• name: Unique joint name. Example: ${prefix}joint1

Sub-Elements

1. <command_interface>: Sends commands to joints.

```xml

Changelog for package dynamixel_hardware_interface

1.4.6 (2025-05-30)

• Changed dynamixel_sdk_TARGETS to dynamixel_sdk_LIBRARIES in target_link_libraries
• Contributors: Woojin Wie

1.4.5 (2025-05-30)

• Deprecate ament_include_dependency usage in CMakeLists.txt
• Contributors: Wonho Yun

1.4.4 (2025-05-28)

• Added proper command interface support with ROS2-Dynamixel interface mapping
• Improved error handling and robustness throughout the codebase
• Implemented per-device torque enable control (replacing global control)
• Added support for new sensor model (sensorxel_joy)
• Enhanced joint state-command synchronization
• Improved parameter initialization organization
• Added robust error handling for model file reading
• Contributors: Woojin Wie

1.4.3 (2025-04-10)

• Fixed build errors
• Contributors: Wonho Yun

1.4.2 (2025-04-05)

• Added OM-Y dynamixel model files
• Added a function to enable torque
• Fixed the configuration for OM-Y robots
• Contributors: Woojin Wie, Wonho Yun

1.4.1 (2025-03-31)

• Modified the Model File
• Contributors: Wonho Yun

1.4.0 (2025-03-20)

• Added Torque Constant Parameter to DXL Model Files
• Enhanced Transmission Command Calculation
• Unified Initialization Structure
• Support for Goal Current Control
• Contributors: Woojin Wie

1.3.0 (2025-02-17)

• Enhance Error Handling and Timeout Management
• Use GroupFastSyncRead and GroupFastBulkRead
• Remove deprecated parameter ros_update_freq to prevent stoi failure
• Contributors: Woojin Wie

1.2.0 (2025-01-17)

• Extend Bulk/Sync Selection Logic to Include Indirect Operations
• Enhance DXL item initialization by prioritizing 'Limit' parameters
• Contributors: Woojin Wie

1.1.0 (2024-12-27)

• Added new control table entries for Dynamixel X
• Contributors: Woojin Wie, Hye-Jong Kim

1.0.0 (2024-12-04)

• First release of dynamixel_hardware_interface package
• Contributors: Hye-Jong Kim, Sungho Woo