ROS Collision Detection

ROS Collision Detection package provides a ROS node that calculates the Time-To-Collision (TTC) between a subject vehicle and all perceived vehicles in the subject vehicle's sourroundings and publishes warnings accordingly. A circle-based algorithm is used to calculate the TTC. The collision warnings are based on the TTC.

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Table of Contents

1. Install ROS and Setup Workspace
2. Install and Build the Package
3. Run the ROS Node
4. Details

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1. Install ROS and Setup Workspace

This section describes which steps are required to install and build the ros_collision_detection package.

1.1 Prerequisites

• Ubuntu 20.04 Focal (recommended)
• ROS Noetic (recommended)

The package might also work with other operating systems and ROS distributions. However, it was only tested for the ones listed above.

1.2 Install ROS

If you have already installed ROS and set up a catkin workspace, you can skip the following sections and directly head over to section 2. Install and Build the Package.

In order to build and use the ros_collision_detection package, the Robot Operating System (ROS) middleware must be installed on your computer.

If you have not yet installed ROS, follow the installation instructions on the ROS Wiki.

To fully utilize the possiblities of ROS, you should choose the full ROS install:

$ sudo apt install ros-noetic-desktop-full

1.3 Check ROS Installation

After you have set up ROS, check continue with the first two sections of the ROS Environment Check on the ROS Wiki. This makes sure your ROS installation works as intended.

1.4 Create a Catkin Workspace

After you have confirmed that the ROS installation works fine, create a catkin workspace:

$ mkdir -p ~/catkin_ws/src

Instead of catkin_make this project recommends to use catkin build to build the package. You can install it with the catkin_tools via apt as described on the catkin_tools installation page. Then, inside the catkin workspace folder, call catkin build to build the empty workspace:

$ cd ~/catkin_ws/
$ catkin build

If you would rather like to use catkin_make, follow the instructions in Create a ROS Workspace on the Wiki.

Make sure you also add the following line for the setup.bash script to your .bashrc file (adjust the workspace path if necessary):

source ~/catkin_ws/devel/setup.bash

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2. Install and Build the Package

This section explains how this ROS package can be built from source.

2.1 Get the Source Code

Clone this repository into the src folder of your catkin workspace.

$ cd ~/catkin_ws/src/
$ git clone https://github.com/CoFra-CaLa/ros_collision_detection.git

2.2 Install the Package Dependencies

The package dependencies can be found in package.xml. To install the dependencies of all packages in your workspace, run the following commands:

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

This should install the apt package libgsl-dev, which includes the GNU Scientifc Library (GSL). This library is used to solve polynomial equations during the TTC calculation.

2.3 Build the Package

When all dependencies are installed, you can build the package:

$ cd ~/catkin_ws/
$ catkin build

Make sure to open a new shell or re-source the devel/setup.bash script to allow ROS to find the new executable.

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3. Run the ROS Node

The preferred way to run the node is to use roslaunch command. This allows to pass launch parameters to the node with .launch files. You can find some examples for .launch files in the launch/ folder of this package.

For example, you can launch the node with default parameters:

$ roslaunch ros_collision_detection default.launch

You can set the following launch parameters:

Parameter Name	Description
publish_topic	Name of the topic that the collision warnings are published to
ttc_algorithm_classname	Name of the concrete TTC Algorithm plugin to be loaded
warning_generator_algorithm_classname	Name of the concrete Warning Generator Algorithm plugin to be loaded
ttc_algorithm_circle_count	Number of circles used to represent a vehicle
subject_vehicle_length	Length of the subject vehicle
subject_vehicle_width	Width of the subject vehicle

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4. Details

This section contains additional information about the package and the node.

4.1 Node Topics

The node uses the following default topics to receive input and publish warnings:

Topic	Message Type	Input/Output	Description
/ego_position	SubjectVehicleMotion	Input	The motion of the subject vehicle
/fused_objects	PerceivedObjects	Input	The motions of all perceived objects
/collision_warning	CollisionCheckResult	Output	The collision warning based on the TTC

4.2 Package Structure

The package structure is predefined by ROS:

├── CMakeLists.txt
├── include
│   └── ros_collision_detection
│       └── *.h (C++ Headers)
├── launch
│   └── *.launch (Launch files)
├── LICENSE
├── msg
│   └── *.msg (Message definitions)
├── package.xml
├── README.md
├── src
│   └── *.cpp (Node source code)
├── test
│   └── *.cpp (Tests)
├── ttc_algorithm_plugins.xml
└── warning_generator_algorithm_plugins.xml

4.3 Detailed Documentation

You can generate a detailed documentation of the package with the ROS Documentation Tool rosdoc_lite.
To install the tool, execute the follwing command in your shell:

$ sudo apt install ros-noetic-rosdoc-lite

To generate the Doxygen documentation for the package, use the rosdoc_lite command with the path to the folder where you would like to generate the documentation:

$ rosdoc-lite -o /path/to/doc/folder/ ~/catkin_ws/src/ros_collision_detection