4. Docker Setup for ROS 2

In the ROS 2 Docker images both for the target SK board and Ubuntu PC, two popular DDS implementations are installed by default:

eProsima Fast DDS (default DDS for ROS 2 Foxy)
Eclipse Cyclone DDS (additionally installed)

To ensure smooth running of the out-of-box demos, the following DDS selections are made in the ROS 2 Docker containers by default on each platform.

Platform	DDS Choice	Note
Target SK board	Eclipse Cyclone DDS	Provides better performance, especially with “rosbag play”
Visualization PC	eProsima Fast DDS	Provides better `Ctrl+C` response

You can switch the DDS implementation in each launch session by setting the environment variable RMW_IMPLEMENTATION. For example,

To use the eProsima Fast DDS,

RMW_IMPLEMENTATION=rmw_fastrtps_cpp ros2 ...

To use the Eclipse Cyclone DDS,

RMW_IMPLEMENTATION=rmw_cyclonedds_cpp ros2 ...

4.1. Set Up Docker Environment on the Target

In the ROS 2 Docker container environment, ROS Foxy and necessary libraries and tools are installed.

To generate the scripts for building and running a Docker image for ROS 2 Foxy:
```
root@am6x-sk:~/j7ros_home$ make scripts ROS_VER=2
```
Make sure that two bash scripts, docker_build_ros2.sh and docker_run_ros2.sh, are generated.
To build the Docker image:
```
root@am6x-sk:~/j7ros_home$ ./docker_build_ros2.sh
```
This step may take some time minutes depending on the network speed. Once “docker build” is completed, you can check the resulting Docker image with docker images.
To start/run the Docker container:
```
root@am6x-sk:~/j7ros_home$ ./docker_run_ros2.sh
```
It is important to use docker_run_ros2.sh script to start a Docker container since the script includes all the necessary settings to leverage all the cores and hardware accelerators of the TI Processor.

To build the ROS applications, inside the Docker container:

root@j7-docker:~/j7ros_home/ros_ws$ colcon build --base-paths /opt/robotics_sdk/ros2 --cmake-force-configure
# TDA4VM: In case catkin_make fails due to limited memory, "--executor sequential" option can be added as follows
root@j7-docker:~/j7ros_home/ros_ws$ colcon build --base-paths /opt/robotics_sdk/ros2 --executor sequential --cmake-force-configure
root@j7-docker:~/j7ros_home/ros_ws$ source install/setup.bash

The ROSBAG data downloaded is in ROS 1 specific format, and the format and storage mechanism have changed in ROS 2. To convert the ROS 1 bag data to ROS 2 format, use rosbags-convert <ros1_bag_name.bag>. This will create a directory named <ros_bag_name> and contain the data under this directory. To convert the downloaded ROSBAG file, run the following inside the ROS 2 Docker container.
```
root@j7-docker:~/j7ros_home$ rosbags-convert $WORK_DIR/data/ros_bag/zed1_2020-11-09-18-01-08.bag
```

4.2. Set Up Docker Environment on the Remote PC for Visualization

You can choose any folder, but init_setup.sh script sets up ${HOME}/j7ros_home as the working directory.

To generate bash scripts for building and running a Docker image for ROS 2 Foxy:
```
user@pc:~/j7ros_home$ make scripts ROS_VER=2
```
If the Ubuntu PC uses an Nvidia GPU driver, please add one more argument GPUS=y:
```
user@pc:~/j7ros_home$ make scripts ROS_VER=2 GPUS=y
```
Make sure that two bash scripts, docker_build_ros2.sh and docker_run_ros2.sh, are generated.
To build the ROS 2 Docker image:
```
user@pc:~/j7ros_home$ ./docker_build_ros2.sh
```
It may take some time to build the Docker image. The Docker image built can be listed with docker images.

Run the ROS 2 Docker container:

user@pc:~/j7ros_home$ ./docker_run_ros2.sh

Build the ROS nodes for visualization:

root@pc-docker:~/j7ros_home/ros_ws$ colcon build --base-paths src/robotics_sdk/ros2
root@pc-docker:~/j7ros_home/ros_ws$ source install/setup.bash

4.3. Run Demo Applications

The table below summarizes the launch commands that you can use in the Docker container for each demo, on the target SK board, and on the remote visualization PC. For more details, see the following subsections.

Launch arguments can be passed to the following launch commands.

To specify a camera recognized as /dev/videoX, use the argument video_id:=X.
To specify the serial number of the ZED camera (found in the original box), use the argument zed_sn, which should start with ‘SN’ followed by the serial number.

Demo (Input Source)	Launch command on Target	Launch command on Remote Visualization PC
Stereo Vision (ZED camera)	ros2 launch ti_sde zed_sde_launch.py video_id:=x zed_sn:=SNxxxxx	ros2 launch ti_viz_nodes rviz_sde_launch.py
Stereo Vision with point-cloud (ZED camera)	ros2 launch ti_sde zed_sde_pcl_launch.py video_id:=x zed_sn:=SNxxxxx	ros2 launch ti_viz_nodes rviz_sde_pcl_launch.py
Semantic Segmentation CNN (ZED camera)	ros2 launch ti_vision_cnn zed_semseg_cnn_launch.py video_id:=x zed_sn:=SNxxxxx	ros2 launch ti_viz_nodes rviz_semseg_cnn_launch.py
Semantic Segmentation CNN (Mono camera)	ros2 launch ti_vision_cnn gscam_semseg_cnn_launch.py video_id:=x	same as above
Semantic Segmentation CNN (IMX219 camera)	ros2 launch ti_vision_cnn gscam_semseg_cnn_imx219_launch.py video_id:=x subdev_id:=y	same as above
Semantic Segmentation CNN (IMX390 camera)	ros2 launch ti_vision_cnn gscam_semseg_cnn_imx390_launch.py video_id:=x subdev_id:=y	same as above
Object Detection CNN (ZED camera)	ros2 launch ti_vision_cnn zed_objdet_cnn_launch.py video_id:=x zed_sn:=SNxxxxx	ros2 launch ti_viz_nodes rviz_objdet_cnn_launch.py
Object Detection CNN (Mono camera)	ros2 launch ti_vision_cnn gscam_objdet_cnn_launch.py video_id:=x	same as above
Object Detection CNN (IMX219 camera)	ros2 launch ti_vision_cnn gscam_objdet_cnn_imx219_launch.py video_id:=x subdev_id:=y	same as above
Object Detection CNN (IMX390 camera)	ros2 launch ti_vision_cnn gscam_objdet_cnn_imx390_launch.py video_id:=x subdev_id:=y	same as above
3D Obstacle Detection (ZED camera)	ros2 launch ti_estop zed_estop_launch.py video_id:=x zed_sn:=SNxxxxx	ros2 launch ti_viz_nodes rviz_estop_launch.py

Running Demos with ROSBAG

It is recommended to launch the demos in two terminals on the target SK board, specifically, launch ros2 bag play in a separate terminal as shown in the following table.

Demo	ROSBAG launch command on Target (Terminal 1)	Demo launch command on Target (Terminal 2)	Launch command on Remote Visualization PC
Stereo Vision	ros2 launch ti_sde rosbag_launch.py	ros2 launch ti_sde sde_launch.py	ros2 launch ti_viz_nodes rviz_sde_launch.py
Stereo Vision with point-cloud	ros2 launch ti_sde rosbag_launch.py	ros2 launch ti_sde sde_pcl_launch.py	ros2 launch ti_viz_nodes rviz_sde_pcl_launch.py
Semantic Segmentation CNN	ros2 launch ti_sde rosbag_remap_launch.py	ros2 launch ti_vision_cnn semseg_cnn_launch.py	ros2 launch ti_viz_nodes rviz_semseg_cnn_launch.py
Object Detection CNN	ros2 launch ti_sde rosbag_remap_launch.py	ros2 launch ti_vision_cnn objdet_cnn_launch.py	ros2 launch ti_viz_nodes rviz_objdet_cnn_launch.py
3D Obstacle Detection	ros2 launch ti_sde rosbag_launch.py	ros2 launch ti_estop estop_launch.py	ros2 launch ti_viz_nodes rviz_estop_launch.py

Tip

You can use TMUX inside the ROS Docker container to split the current terminal window into multiple panes. Below are some useful basic keys for using TMUX. You can find a full list of keys here.

tmux: Start a tmux session.
Ctrl + b, followed by ": Split pane vertically.
Ctrl + b, followed by ↑ or ↓: Switch to the pane in the respective direction.
Ctrl + b, followed by x: Close the current pane.

In the following, [SK] and [PC] indicate the steps that should be launched, either on the target SK board or on the PC.

Run Stereo Vision Application

[SK] To launch ti_sde node with a ZED stereo camera, run the following launch command inside the ROS 2 container:
```
root@j7-docker:~/j7ros_home/ros_ws$ ros2 launch ti_sde zed_sde_launch.py
```
Alternatively, you can run the following directly on the target host Linux:
```
root@am6x-sk:~/j7ros_home$ ./docker_run_ros2.sh ros2 launch ti_sde zed_sde_launch.py
```