ROS 2

This tutorial assumes you have either pre-installed ROS 2 or launched the included VS Code development container. For more details, please see .devcontainer/readme.md.

Note

Before proceeding, please install the Reach Robotics SDK. Instructions for installation can found in the Getting Started section.

Setup

First, source the ROS 2 underlay:

source /opt/ros/foxy/setup.bash

Note

It can be convenient to automatically source this script every time a new shell is launched.

echo "source /opt/ros/foxy/setup.bash" >> ~/.bashrc
source ~/.bashrc

Keep in mind, if you have more than one ROS distribution installed, ~/.bashrc must only source the setup.bash for the version you are currently using.

Build the ROS 2 packages:

cd ~/workspace
colcon build

Source the ROS 2 overlay packages:

source ~/workspace/install/local_setup.bash

At this point the Reach Robotics nodes have been built and are ready to use.

Note

If you are using a ROS 2 distribution other than Foxy, you’ll need to modify the source command accordingly. I.e. `source /opt/ros/humble/setup.bash`

Packages

The ROS 2 folder is split into several packages. Each package is briefly described below.

rs_passthrough

The RS passthrough is the core package that facilitates communication to Reach Robotics products. This passthrough converts ROS 2 messages into Serial or UDP packets that can be read by the connected product. Each node in the passthrough uses rs_msgs/Packet for messaging. The packet construct is defined as:

uint8 device_id
uint16 packet_id
uint8[] int_data
float32[] float_data

where device_id is the device identifier, packet_id is the packet identifier, int_data is a list of 8 bit integers representing the integer data to be sent, and float_data is a list of 32 bit floating point numbers representing the floating point data to be sent. It’s important to note, that only one of int_data or float_data should be populated in a given packet.

To launch the passthrough, run:

SerialUDP

ros2 run rs_passthrough serial_passthrough --ros-args -p serial_port:=</dev/ttyUSB0>

where,

• serial_port (string) - Serial Port to connect to the arm (Defaults to “/dev/ttyUSB0”)

• baudrate (int) - Baudrate port of the serial connection. (Defaults to 115200)

For both passthrough nodes, the published topic and the subscribed topic, respectively, are:

• /rx (rs_msgs/Packet) - Received Packets from the manipulator

• /tx (rs_msgs/Packet) - Packets that will be sent to the manipulator

Examples

This example demonstrates how to request read actuator telemetry from a manipulator.

To launch this example, run the launch file.

SerialUDP

ros2 launch rs_passthrough serial_passthrough_example.launch.py serial_port:="/dev/ttyUSB0"

The script communicates to the passthrough node via the /tx and /rx topics. It publishes request packets to the /tx topic at a set frequency. It subscribes the to /rx topic and listens for position packets.

reach_bravo_description

Reach Bravo Description package contains the Universal Robot description File (URDF) files for the Bravo range of manipulators.

Supported Products:

• RB-7002 - Reach Bravo 7 (PRO)

• RB-5002 - Reach Bravo 5 (PRO)

Examples

Examples of viewing URDFs in RVIZ.

Viewing a Bravo 7 URDF:

ros2 launch reach_bravo_description view_bravo_7.launch.py

Viewing a Bravo 5 URDF:

ros2 launch reach_bravo_description view_bravo_5.launch.py

Viewing a Bravo 5 and Bravo 7 URDF:

ros2 launch reach_bravo_description view_bravo_double.launch.py