Package Name

Overview

This package provides a ROS 2 lifecycle node to interface with the platform_driver_ethercat library for accessing Elmo drives and ATI force torque sensors via EtherCAT.

Keywords: ati fts, elmo, ethercat, joint control, soem

License

The source code is released under a GPLv3 License.

Author: Tim Wiese
Affiliation: European Space Agency
Maintainer: Tim Wiese, [email protected]

This package has been tested under ROS2 Foxy Fitzroy and Ubuntu 20.04. This is research code, expect that it changes often and any fitness for a particular purpose is disclaimed.

Installation

Building from Source

Dependencies

• Robot Operating System (ROS) (middleware for robotics)
• platform_driver_ethercat (library for Elmo Gold Twitter and ATI FTS communication over EtherCAT using SOEM
• rover_msgs (message definitions for ESA-PRL rovers)
• yaml-cpp (a YAML parser and emitter in C++)

Building

To build from source, clone the latest version from this repository into your ros2 workspace and compile the package using

cd ros2_ws/src
git clone https://github.com/esa-prl/platform_driver_ethercat_ros2.git
cd ../
colcon build

Usage

Since the platform_driver_ethercat library uses SOEM which needs raw socket access, the node needs to be run with root privileges. This could be circumvented in the future with setcap and ros2/rcpputils#44.

Change into a root shell while preserving your environment with

sudo -sE

Then launch the main node with

ros2 launch platform_driver_ethercat_ros2 platform_driver_ethercat.launch.py pd_config_file:=/path/to/config/file

Launch files

launch/

• platform_driver_ethercat.launch.py Minimal launch file to start the node and bring it to the Active state. Needs to be executed with root privileges.

  Arguments:

  • pd_config_file Full path to the configuration file

Config files

config/

• pd_marta.yaml Configuration file for the MaRTA rover, to configure SOEM, Elmo drives and joints. This is NOT a regular ROS 2 parameter file. It makes use of advanced yaml features and is parsed inside the node.

Nodes

platform_driver_ethercat_node

Lifecycle node to interface with the platform_driver_ethercat library.

Subscribed Topics

• joint_cmds (rover_msgs/JointCommandArray)

  Commanded position, velocity or torque for joints.

Published Topics

• joint_states (sensor_msgs/JointState)

  Measured position, velocity and effort of joints.

• fts_readings (rover_msgs/WrenchStampedArray)

  Measured force and torque values of sensors

• temp_readings (rover_msgs/TemperatureArray)

  Measured temperatures in degree Celsius.

Parameters

• config_file (string)

  Full path to the configuration file.

Bugs & Feature Requests

Please report bugs and request features using the GitHub issue tracker.