OpenZen Node for ROS

This software allows to forward sensor data from sensor connected via OpenZen to ROS.

OpenZen is a library for high performance sensor data streaming and processing and supports multiple sensor models: https://bitbucket.org/lpresearch/openzen/

The full documentation for OpenZen ROS can be found here: OpenZen ROS documentation.

Requirements

Tools & Compiler

To compile this software, at least G++ version 7.0 and cmake version 3.10 need to be installed. If your default compiler is an older version you can install a recent GCC with your distributions package manager and provide the name of the GCC to the catkin_make command like so:

catkin_make -DCMAKE_C_COMPILER=gcc-7 -DCMAKE_CXX_COMPILER=g++-7

Serial Port Access Rights

After this call, you should logout and login with this user to ensure the changed permissions are in effect.

To allow access to sensors connected via USB, you need to ensure that the user running the ROS sensor node has access to the /dev/ttyUSB devices. You can do this by adding the user to the dialout group.

sudo adduser <username> dialout

Installing via the Package Manager

The OpenZen ROS driver is part of the official ROS distribution and you can conveniently install it via the package manager of your Linux distribution. Please check this website to see if the OpenZen ROS driver is available for the ROS distribution you use:

OpenZen ROS Package

For example, on Ubuntu 18.04 and with ROS distribution Melodic Morenia, the OpenZen ROS driver can be installed with this command:

apt install ros-melodic-openzen-sensor

Compilation

To compile this driver in your ROS setup, follow these steps:

mkdir -p catskin_ws/src
cd catskin_ws/src

git clone --recurse-submodules https://bitbucket.org/lpresearch/openzenros.git

# get your ROS environment going
source /opt/ros/melodic/setup.bash
cd ../../..
catkin_make
source ./devel/setup.bash

Running the Driver

Open another terminal window and run the ROS core:

source /opt/ros/melodic/setup.bash
roscore

You can then run the OpenZen ROS driver with this command in the window you used to compile the software:

rosrun openzen_sensor openzen_sensor_node

By default, it will connect to the first available sensor. If you want to connect to a specific sensor, you can use the serial name of the sensor as parameter, for example:

rosrun openzen_sensor openzen_sensor_node _sensor_name:="devicefile:/dev/ttyUSB0"

If your sensor is configured for a different baud rate, you can use the baudrate parameter to give a specfic baud rate setting:

rosrun openzen_sensor openzen_sensor_node _sensor_name:="devicefile:/dev/ttyUSB0" _baudrate:=921600

Do note that the default sensor interface is LinuxDevice, so the value for _sensor_name will most likely be in the form of "devicefile:/dev/ttyUSB0". For more detail please refer to OpenZen’s docs.

Now you can print the IMU values from ROS with:

rostopic echo /imu/data

To output the values of a GPS unit (if available) use this command:

rostopic echo /imu/nav

Or plot some values (for example linear acceleration) with

rosrun rqt_plot rqt_plot /imu/data/linear_acceleration

If you want to readout the values of two OpenZen sensors simultanously, you need to rename the topics and the node names likes this:

rosrun openzen_sensor openzen_sensor_node __name:="cu2node" _sensor_name:="devicefile:/dev/ttyUSB0" imu:=/cu2_imu 
rosrun openzen_sensor openzen_sensor_node __name:="ig1_node" _sensor_name:="devicefile:/dev/ttyUSB1" imu:=/ig1_imu

Alternatively, we have prepared a sample launch file openzen_lpms_ig1.launch to demonstrate data acquisition and plotting using openzen_sensor_node:

roslaunch openzen_sensor openzen_lpms_ig1.launch