SO-ARM100 Hardware Interface

Overview

The so_arm_100_hardware package provides a ROS 2 Control hardware interface plugin for the SO-ARM100 low-cost 5DoF robotic manipulator. This interface supports both direct serial communication with the physical robot and simulation via ROS topics.

Features

• ROS 2 Control hardware interface implementation
• Configurable communication modes:
  • Direct serial communication with the robot
  • ROS topic-based communication for simulation
• Position control interface for all joints
• Thread-safe feedback handling
• Lifecycle-managed node implementation

Package Details

• Name: so_arm_100_hardware
• Version: 0.0.0
• Description: ROS2 Control Hardware Interface for SO-ARM100 low-cost 5DoF robotic manipulator
• Maintainer: Bruk Gebregziabher (bruk@signalbotics.com)
• License: Apache-2.0

Dependencies

• rclcpp
• hardware_interface
• pluginlib
• rclcpp_lifecycle
• sensor_msgs

Communication Interface

The hardware interface communicates using the following ROS topics:

• Command Topic: command (sensor_msgs/msg/JointState)
  • Publishes joint position commands to the robot
• Feedback Topic: feedback (sensor_msgs/msg/JointState)
  • Subscribes to joint state feedback from the robot

Hardware Interface Details

The SOARM100Interface class implements:

• State and command interfaces for position control
• Lifecycle management (init, activate, deactivate)
• Read and write methods for communication
• Thread-safe feedback handling using mutex
• Asynchronous ROS communication using a dedicated executor thread

Installation

1. Clone the package into your ROS 2 workspace:

   cd ~/ros2_ws/src
   git clone git@github.com:brukg/so_arm_100_hardware.git
   

1. Install dependencies:

   cd ~/ros2_ws
   rosdep install --from-paths src --ignore-src -r -y
   

1. Build the package:

   colcon build --packages-select so_arm_100_hardware
   

1. Source the workspace:

   source install/setup.bash
   

Usage

Configuration

Create a ROS 2 Control configuration file (YAML) that includes the hardware interface:

so_arm_100:
  hardware_interface:
    use_serial: true  # Set to true for real robot, false for simulation
    serial_port: "/dev/ttyUSB0"  # Serial port for real robot
    serial_baudrate: 1000000  # Serial baudrate

Serial Communication Mode

When using serial communication (use_serial: true):

1. Ensure the robot is connected to the specified serial port
2. Grant serial port access permissions:

sudo usermod -a -G dialout $USER  # Log out and back in after this

1. Verify the serial port and baudrate settings match your robot’s configuration

Topic Communication Mode

When using topic communication (use_serial: false):

• Commands are published to the “command” topic
• Feedback is received from the “feedback” topic

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