Commnunicating with the Husky directly

1. With the computer that you want to wirelessly connect to the husky, start a wifi hotspot with the ssid and password.

2. Connect to the husky using a wired connection and ssh into it. Edit the /etc/wpa_supplicant/wireless.conf file to include the ssid and password of the wifi hotspot.

3. Restart the wpa_supplicant service:

ifconfig # to find the name of the wireless interface

sudo killall wpa_supplicant # kill the current wpa_supplicant process
sudo wpa_supplicant -B -i <wireless-interface> -c /etc/wpa_supplicant/wireless.conf # start a new wpa_supplicant process

4. Upon receiving a successful connection message, run the following command to get the ip address of the husky:

ifconfig

5. On the computer that you want to connect to the husky, ssh into the husky using the ip address obtained in the previous step:

ssh administrator@<ip-address> # password is clearpath

Docker

Install docker and docker-compose.

Build the docker image:

docker-compose build

Start the docker container and an interactive shell:

docker compose up -d && docker compose exec velodyne /bin/bash

ROS

Installing dependencies

First try:

rosdep install --from-paths src --ignore-src --rosdistro noetic -y

If that doesn't work, try:

rosdep install --from-paths src/velodyne src/usb_cam src/velodyne_simulator --ignore-src --rosdistro noetic -y

Building the workspace

Make sure you are in the workspace directory, in this case ros_ws and run catkin_make

Setup correct hostname

In /etc/hosts file, add the following line at the top: <ip-address> cpr-a200-0971

The ROS_MASTER_URI and ROS_IP environment variables are set in the docker-compose.yml file to allow the container to communicate with the husky. Verify that ROS_MASTER_URI is set to http://cpr-a200-0971:11311 and the ROS_IP is set to the container's ip address.

Inside the container, verify that communication with the husky is working by running: rostopic list

Verify that the velodyne is publishing data by running: rostopic echo /velodyne_points

Adding a transform from map to velodyne

This ie required to visualize the point cloud in rviz. Run the following command to add a static transform from the map frame to the velodyne frame:

In the ssh terminal connected to the husky, run:

rosrun tf static_transform_publisher 0 0 0 0 0 0 1 map velodyne 10

It's important to note that this must be running in the husky's terminal for the transform to be published.

Visualizing the point cloud

Just run rviz in the container and add a point cloud display with the topic /velodyne_points

IGNORE BELOW

Launching Velodyne

roslaunch velodyne_pointcloud VLP16_points.launch

Running rosbag

rosbag record -a -o <session_name>

Remember to index rosbag before playback

rosbag reindex <bagfile>