ieee_avc

A repository for the USU AVC Team launch files and configurations

This includes 5 ros packages: four for the VESC (vesc_driver, which communicates with the VESC, vesc_ackerman, which converts between VESC and ackermann ROS messages, vesc_msgs, which contains definitions for the VESC messages, and ackermann_cmd_mux, which is an input multiplexer for ackermann commands), and one called avc. The avc package contains all the launch and configuration files we are using, and it is the focus of this documentation.

Here is a diagram of the system setup.

Table of Contents

1. Directory Tree
2. Launch Files
   2.1 Launch File Locations
   2.2 How to use the Launch Files
   2.3 The Master Launch File
   2.4 Recording Bag Files
3. Configuration Files
   3.1 Config File Locations
   3.2 Config File Descriptions

Directory tree of the avc package

avc                                           <-- The package root directory 
├── CMakeLists.txt  
├── config                                    <-- The configuration files (used by launch files)  
│   ├── amcl.yaml  
│   ├── ekf_global.yaml  
│   ├── ekf_local.yaml  
│   ├── gps.yaml  
│   ├── imu.yaml  
│   ├── joy_teleop.yaml  
│   ├── laser.yaml  
│   ├── mux.yaml  
│   └── vesc.yaml  
├── launch                                    <-- The launch files
│   ├── amcl.launch  
│   ├── includes                              <-- Modular XML files used by the launch files
│   │   ├── amcl  
│   │   │   ├── amcl.launch.xml  
│   │   │   └── map.launch.xml  
│   │   ├── inputs  
│   │   │   └── joy_teleop.launch.xml  
│   │   ├── localization  
│   │   │   ├── ekf_global_localization.launch.xml  
│   │   │   ├── ekf_local_localization.launch.xml  
│   │   │   └── navsat_transform.launch.xml  
│   │   ├── sensors  
│   │   │   ├── sensors.launch.xml  
│   │   │   └── static_transforms.launch.xml  
│   │   └── vesc  
│   │       └── vesc.launch.xml  
│   ├── localization.launch  
│   ├── master.launch  
│   ├── sensors.launch  
│   └── teleop.launch  
├── map                                       <-- The map and its configuration
│   ├── map.pgm  
│   └── map.yaml  
└── package.xml  

Launch files

The launch files are the user front-end for making things happen on the car. They are written in xml syntax. You'll notice that there is an includes folder inside the launch file directory. Inside there are several *.xml files (e.g. 'sensors.launch.xml'). Each one performs a very specific function, such as launching the sensor nodes, launching the localization nodes, or publishing static transforms. These are included and used by the higher-level launch files (the ones in the launch directory). That way, when creating a new launch file, you can include the files that do the things you want instead of re-writting all the code each time.

Launch file locations:

Launch files are located in the ieee_avc/src/avc/launch/ directory. (Use roscd avc/launch to get there)

How to use the launch files:

• roslaunch avc sensors.launch launches only the sensors (GPS, IMU, and Lidar) with their static_transforms
• roslaunch avc teleop.launch launches teleop (joystick controller and vesc to drive the car around)
• roslaunch avc localization.launch launches global and local localization nodes
• roslaunch avc amcl.launch launches amcl and map_server nodes

Several of these launch files can be run simultaneously (for example, if you want to run teleop with sensors, you could run both of the launch files).

The master launch file:

There is one more launch file called master.launch. This launch file is configurable via command line to run whatever you want. For example, running

roslaunch avc master.launch teleop:=true vesc:=true sensors:=true local_localization:=true

will start the teleop, launch the sensor nodes, and start just the local localization node.
Here is a list of possible command line arguments:

• teleop:=true starts the joystick nodes that provide teleop commands (does not start the vesc driver, only the joystick)
• vesc:=true starts the vesc driver node and ackermann command multiplexer (for example, use with the teleop option to be able to drive the car around with the controller.
• sensors:=true starts the IMU, GPS, and Lidar nodes
• localization:=true starts local and global localization nodes (undefined behavior if used with the individual local or global localization arguments)
• local_localization:=true starts only the local localization node (undefined behavior if used with any other localization arguments)
• global_localization:=true starts only the global localization node (undefined behavior if used with any other localization arguments)
• amcl:=true starts the amcl node
• map_server:=true starts the map_server node

Recording bag files

All launch files can be used to create bag files. Simply add the bag:=true argument when you launch it. (NOTE: this only needs to be done once, so if you start multiple launch files then only use the argument once). Once the launched nodes are killed, the .bag file can be found in the ~/.ros directory.

Configuration files

Configuration files are all *.yaml files, and contain the parameters that are used by the launchfiles.

Config file locations:

Launch files are located in the ieee_avc/src/avc/config/ directory. (Use roscd avc/config to get there). The only exception to this is the map.yaml file, which is located in the map directory of the avc package.

Config files:

• laser.yaml configuration for the Lidar (link)
• gps.yaml configuration parameters for the GPS (link)
• imu.yaml configuration parameters for the IMU (link)
• vesc.yaml configuration for the VESC
• amcl.yaml filter parameters for the AMCL algorithm (link)
• ekf_global.yaml configuration parameters for the global localization algorithm (link)
• efk_local.yaml configuration parameters for the local localization algorithm (link)
• joy_teleop.yaml configuration for the node that transforms the joystick messages into ackermann messages (link)
• mux.yaml configuration for the ackermann command multiplexer
• map.yaml map parameters (automatically generated with the map) (link)