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

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