Turtlebot

From Robin

Revision as of 12:11, 29 June 2023

Setup

Connecting to the turtlebot via ssh

The turtlebot is connected to the network called “nettbrett”, so you should use a development computer that is connected to this network. It is recommended to use the vixen-machine because all ports between the turtlebot and computer are open.

You can connect to the turtlebot by ssh-ing into it. The turtlebot is configured with key authentification, so it you have to generate a key pair for authentication purposes before connecting to the turtlebot. Follow these steps to do so:

1) On your computer, navigate to the .ssh folder:

$ cd ~/.ssh 

2) Create the key pair and give the key pair a suitable name key-name:

$ ssh-keygen

3) Send the public key to robin-engineer@ifi.uio.no. This key is in the key-name.pub file. HERE: DO THEMSELVES OR SEND MAIL?

4) Write the following lines in the .ssh/config file:

Host turtle
  Hostname 193.157.209.133
  User ubuntu
  IdentityFile ~/.ssh/your_key_pair_name
   

When the public key is added to the authorized keys on the turtlebot, you can connect to the turtlebot by running the command:

$ ssh turtle

If you want to use GUI on the turtlebot, add the -Y flag in the line above:

$ ssh -Y turtle

Setting up the ROS network

To be able to control the turtlebot, it is important that the ROS network configuration is set up properly. This entails setting up the environment variables correctly so that the turtlebot is able to communicate with the ROS master running on the computer (it is usually what we do). This is done according to the image here under the title “Network configuration”.

The turtlebot side is already set up, where the ROS_MASTER_URI is set to the vixen computer. If you are using any other computer, it needs to be connected to the hidden network “nettbrett” and you need to change the ROS_MASTER_URI on the turtlebot to use the IP of your computer for example by running this command in the terminal:

export ROS_MASTER_URI=http://IP_OF_YOUR_COMPUTER:11311

On the side of your computer you also need to set the ROS_MASTER_URI and ROS_HOSTNAME variables according to this, where you use the IP of your computer. To make it easier, you can add these lines to a FILENAME.sh file that you can source.

Updating the .sh file

In each terminal on the development computer you have to specify the model of the turtlebot you are using. To make it easier, you can add this line (export TURTLEBOT3_MODEL=turtlebot model) in the same FILENAME.sh file as above.

In addition, you can add the following lines in the FILENAME.sh as well to avoid writing it when entering a new terminal.

source /opt/ros/noetic/setup.bash
source /turtlebot_ws/devel/setup.bash

Containers

- Currently the robot is running ROS Noetic. To interact with the robot from the development computer, you can use a ROS Noetic-based container which is available on Robin’s project area (IT'S NOT UP YET). You can enter the container by running the following command:

$ apptainer shell —nv /uio/kant/ifi-project06/robin/programs/sing-con/ros-noetic /turtlebot.sif

Charging

The turtlebot is equipped with a LiPo battery which can be charged using the ISDT Q8 smart charger, as shown in figure 1. In this charger you can plug the power supply (shown in figure 2) on the left side that is marked with “DC IN” and the battery on the right side that is marked with “BATTERY”. You also need to plug in the pin connector of the battery into the charger on the side marked with “2S”. The full setup is shown in image 3.

A dog

One more dog

When you have connected everything you need to start the charging. Tap the round button beside the screen to get the “Task setting” menu. Make sure that the task is set to charging. Then click “Start”. When the battery is done charging, the charger will make a loud noise and the screen will be green. Then disconnect the battery.

If you plan on using the battery frequently, you can charge it normally by setting “Task” is set to “Charging”. But if you don’t plan to use the battery for a longer period of time, it is recommended to set the battery in “storage mode”. You do this by setting “Task” to “Storage” instead.

You can read more about this charger in the manual: https://www.isdt.co/down/pdf/Q8_EN.pdf