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ROS Interface#

autonomysim_ros_pkgs: a C++ ROS wrapper over the AutonomySim client library.

Setup#

The below steps are for Linux. If you're running AutonomySim on Windows, you can use Windows Subsystem for Linux (WSL) to run the ROS wrapper. See the instructions below. If you are unable or prefer not to install ROS and related tools on your host Linux machine, you can also try it using Docker. See the steps below.

  • If your default gcc version is less than 8 (see gcc --version output)
  • Install gcc >= 8.0.0: sudo apt-get install gcc-11 g++-11
  • Verify installation by gcc-11 --version
  • Ubuntu 16.04
    • Install ROS kinetic
    • Install tf2-sensor and mavros packages: sudo apt-get install ros-kinetic-tf2-sensor-msgs ros-kinetic-tf2-geometry-msgs ros-kinetic-mavros*
  • Ubuntu 18.04
    • Install ROS melodic
    • Install tf2-sensor and mavros packages: sudo apt-get install ros-melodic-tf2-sensor-msgs ros-melodic-tf2-geometry-msgs ros-melodic-mavros*

  • Ubuntu 20.04 | 22.04

    • Install ROS noetic
    • Install tf2-sensor and mavros packages: sudo apt-get install ros-noetic-tf2-sensor-msgs ros-noetic-tf2-geometry-msgs ros-noetic-mavros*

  • Install catkin_tools sudo apt-get install python-catkin-tools or pip install catkin_tools. If using Ubuntu 20.04 use pip install "git+https://github.com/catkin/catkin_tools.git#egg=catkin_tools"

Build#

Build AutonomySim:

git clone https://github.com/nervosys/AutonomySim.git;
cd AutonomySim;
./setup.sh;
./build.sh;

Ensure that you have setup the environment variables for ROS, as mentioned in the installation pages above. Add the source command to your .bashrc for convenience (replace melodic with specfic version name):

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

Build the ROS package:

cd ros;
catkin build;  # or catkin_make

If your default gcc version is less than 8 (see gcc --version output), compilation will fail. In that case, use gcc-11 explicitly as follows:

catkin build -DCMAKE_C_COMPILER=/usr/bin/gcc-11 -DCMAKE_CXX_COMPILER=/usr/bin/g++-11

Running autonomysim_ros_pkgs#

source devel/setup.bash;
roslaunch autonomysim_ros_pkgs autonomysim_node.launch;
roslaunch autonomysim_ros_pkgs rviz.launch;

Note

If you get an error running roslaunch autonomysim_ros_pkgs autonomysim_node.launch, run catkin clean and try again

Using the AutonomySim ROS Wrapper#

The ROS wrapper is composed of two ROS nodes:

  1. A wrapper over the AutonomySim multirotor C++ client library.
  2. A simple proportional derivative (PD) or proportional integral derivative (PID) position controller.

Let's look at the ROS API for both nodes below.

ROS Wrapper Node#

Publishers#

  • /autonomysim_node/origin_geo_point autonomysim_ros_pkgs/GPSYaw GPS coordinates corresponding to global NED frame. This is set in the AutonomySim's settings.json file under the OriginGeopoint key.

  • /autonomysim_node/VEHICLE_NAME/global_gps sensor_msgs/NavSatFix This the current GPS coordinates of the drone in AutonomySim.

  • /autonomysim_node/VEHICLE_NAME/odom_local_ned nav_msgs/Odometry Odometry in NED frame (default name: odom_local_ned, launch name and frame type are configurable) wrt take-off point.

  • /autonomysim_node/VEHICLE_NAME/CAMERA_NAME/IMAGE_TYPE/camera_info sensor_msgs/CameraInfo

  • /autonomysim_node/VEHICLE_NAME/CAMERA_NAME/IMAGE_TYPE sensor_msgs/Image RGB or float image depending on image type requested in settings.json.

  • /tf tf2_msgs/TFMessage

  • /autonomysim_node/VEHICLE_NAME/altimeter/SENSOR_NAME autonomysim_ros_pkgs/Altimeter This the current altimeter reading for altitude, pressure, and QNH

  • /autonomysim_node/VEHICLE_NAME/imu/SENSOR_NAME sensor_msgs::Imu IMU sensor data

  • /autonomysim_node/VEHICLE_NAME/magnetometer/SENSOR_NAME sensor_msgs::MagneticField Meausrement of magnetic field vector/compass

  • /autonomysim_node/VEHICLE_NAME/distance/SENSOR_NAME sensor_msgs::Range Meausrement of distance from an active ranger, such as infrared or IR

  • /autonomysim_node/VEHICLE_NAME/lidar/SENSOR_NAME sensor_msgs::PointCloud2 LIDAR pointcloud

Subscribers#

Services#

Parameters#

  • /autonomysim_node/world_frame_id [string] Set in: $(autonomysim_ros_pkgs)/launch/autonomysim_node.launch Default: world_ned Set to "world_enu" to switch to ENU frames automatically

  • /autonomysim_node/odom_frame_id [string] Set in: $(autonomysim_ros_pkgs)/launch/autonomysim_node.launch Default: odom_local_ned If you set world_frame_id to "world_enu", the default odom name will instead default to "odom_local_enu"

  • /autonomysim_node/coordinate_system_enu [boolean] Set in: $(autonomysim_ros_pkgs)/launch/autonomysim_node.launch Default: false If you set world_frame_id to "world_enu", this setting will instead default to true

  • /autonomysim_node/update_autonomysim_control_every_n_sec [double] Set in: $(autonomysim_ros_pkgs)/launch/autonomysim_node.launch Default: 0.01 seconds. Timer callback frequency for updating drone odom and state from AutonomySim, and sending in control commands. The current RPClib interface to unreal engine maxes out at 50 Hz. Timer callbacks in ROS run at maximum rate possible, so it's best to not touch this parameter.

  • /autonomysim_node/update_autonomysim_img_response_every_n_sec [double] Set in: $(autonomysim_ros_pkgs)/launch/autonomysim_node.launch Default: 0.01 seconds. Timer callback frequency for receiving images from all cameras in AutonomySim. The speed will depend on number of images requested and their resolution. Timer callbacks in ROS run at maximum rate possible, so it's best to not touch this parameter.

  • /autonomysim_node/publish_clock [double] Set in: $(autonomysim_ros_pkgs)/launch/autonomysim_node.launch Default: false Will publish the ros /clock topic if set to true.

Position Controller Node#

Parameters#

  • PD controller parameters:

  • /pd_position_node/kd_x [double], /pd_position_node/kp_y [double], /pd_position_node/kp_z [double], /pd_position_node/kp_yaw [double] Proportional gains

  • /pd_position_node/kd_x [double], /pd_position_node/kd_y [double], /pd_position_node/kd_z [double], /pd_position_node/kd_yaw [double] Derivative gains

  • /pd_position_node/reached_thresh_xyz [double] Threshold euler distance (meters) from current position to setpoint position

  • /pd_position_node/reached_yaw_degrees [double] Threshold yaw distance (degrees) from current position to setpoint position

  • /pd_position_node/update_control_every_n_sec [double] Default: 0.01 seconds

Services#

  • /autonomysim_node/VEHICLE_NAME/gps_goal [Request: srv/SetGPSPosition] Target gps position + yaw. In absolute altitude.

  • /autonomysim_node/VEHICLE_NAME/local_position_goal [Request: srv/SetLocalPosition] Target local position + yaw in global NED frame.

Subscribers#

  • /autonomysim_node/origin_geo_point autonomysim_ros_pkgs/GPSYaw Listens to home geo coordinates published by autonomysim_node.

  • /autonomysim_node/VEHICLE_NAME/odom_local_ned nav_msgs/Odometry Listens to odometry published by autonomysim_node

Publishers#

Globals#

  • Dynamic constraints. These can be changed in dynamic_constraints.launch:

  • /max_vel_horz_abs [double] Maximum horizontal velocity of the drone (meters/second)

  • /max_vel_vert_abs [double] Maximum vertical velocity of the drone (meters/second)

  • /max_yaw_rate_degree [double] Maximum yaw rate (degrees/second)

Miscellaneous#

Configuring the Build Environment on WSL#

These setup instructions describe how to setup the Windows Subsystem for Linux version 2 (WSL2). It involves enabling WSL2, installing a Linux OS image, and installing the build environment as if it were a native Linux system. Upon completion, you will be able to build and run the ROS wrapper as with any Linux machine.

Note

We recommend using the native file system in /home/... rather than Windows-mounted folders under /mnt/..., as the former is significantly faster.

Setup on WSL#

  1. Follow the instructions here. Ensure that the ROS version you want to use is supported by the Linux/Ubuntu version you want to install.
  2. You now have a working Ubuntu subsystem under Windows, you can now go to Ubuntu 16/18/20/22 instructions and then Running AutonomySim with ROS on WSL.

Note

You can run XWindows applications (including SITL) by installing VcXsrv on Windows. To use it find and run XLaunch from the Windows start menu. Select Multiple Windows in first popup, Start no client in second popup, only Clipboard in third popup. Do not select Native Opengl (and if you are not able to connect select Disable access control). You will need to set the DISPLAY variable to point to your display: in WSL it is 127.0.0.1:0, in WSL2 it will be the ip address of the PC's network port and can be set by using the code below. Also in WSL2 you may have to disable the firewall for public networks, or create an exception in order for VcXsrv to communicate with WSL2:

export DISPLAY=$(cat /etc/resolv.conf | grep nameserver | awk '{print $2}'):0

Tip

  • If you add this line to your ~/.bashrc file you won't need to run this command again
  • For code editing you can install VSCode inside WSL.
  • Windows 10 includes "Windows Defender" virus scanner. It will slow down WSL quite a bit. Disabling it greatly improves disk performance but increases your risk to viruses so disable at your own risk. Here is one of many resources/videos that show you how to disable it: How to Disable or Enable Windows Defender on Windows 10

File System Access between WSL and Windows 10/11#

Inside WSL, Windows drives are referenced in the /mnt directory. For example, in order to list documents within your () documents folder:

ls /mnt/c/'Documents and Settings'/<username>/Documents or ls /mnt/c/Users/<username>/Documents

Inside Windows, the WSL distribution files are located at:

\\wsl$\<distribution name> e.g., \\wsl$\Ubuntu-22.04

Running AutonomySim with ROS on WSL#

WSL1: export WSL_HOST_IP=127.0.0.1 WSL2: export WSL_HOST_IP=$(cat /etc/resolv.conf | grep nameserver | awk '{print $2}')

Now, as in the running on Linux section, execute the following:

source devel/setup.bash
roslaunch autonomysim_ros_pkgs autonomysim_node.launch output:=screen host:=$WSL_HOST_IP
roslaunch autonomysim_ros_pkgs rviz.launch

Using ROS with Docker#

A Dockerfile is present in the docker directory. To build the autonomysim-ros image, run the following:

cd tools
docker build -t autonomysim-ros -f Dockerfile-ROS .

To run, replace the path of the AutonomySim folder below:

docker run --rm -it --net=host -v <your-AutonomySim-folder-path>:/home/testuser/AutonomySim AutonomySim-ros:latest bash

The above command mounts the AutonomySim directory to the home directory inside the container. Any changes you make in the source files from your host will be visible inside the container, which is useful for development and testing. Now follow the steps from Build to compile and run the ROS wrapper.