TurtleBot3 has three models, burger, waffle, and waffle_pi, so you have to set which model to use before using. To do this, we specify the model to be used with the export command.
export TURTLEBOT3_MODEL=burger
export TURTLEBOT3_MODEL=waffle
export TURTLEBOT3_MODEL=waffle_pi
The Bash export command is used to export a variable or function to the environment of all the child processes running in the current shell.
You can run this export command each time in the terminal window. But it is very inconvenient to set it up every time.
So we recommend that add your settings in bashrc file. The following example is an example for the user of TurtleBot3 Burger model. If you use a different model, you just change the value of TURTLEBOT3_MODEL.
$ gedit ~/.bashrc
$ source ~/.bashrc