FRA501_exam1_6434_6438

"turtlesim_plus_controller" is a ROS2 custom package that launches a turtlesim_plus node with 4 turtles, 4 controller and scheduler nodes for each turtle. Each turtle has a role to draw one of the letters of the word "FIBO" using 20 pizzas each.

Installation

1. Clone the repository and move turtlesim_plus_controller and turtlesim_plus_controller_interface to the src folder of your ROS2 workspace.
2. Build turtlesim_plus_controller and turtlesim_plus_controller_interface

colcon build --packages-select turtlesim_plus_controller turtlesim_plus_controller_interface

3. Source the workspace

source install/setup.bash

Usage

Launch the turtlesim_plus_controller package

ros2 launch turtlesim_plus_controller turtlesimplus.launch.py

You can select between controller_config_1.yaml and controller_config_2.yaml to change the speed of the turtles. You can also specify the amount of pizza per character by adjusting pizza_amt

ros2 launch turtlesim_plus_controller turtlesimplus.launch.py config_path:="controller_config_2.yaml" pizza_amt:=20

If the launch complains about missing folder on the first run, please try running again.

System Architecture

Packages and nodes

turtlesim_plus

• turtlesim_plus_node.py: A modified version of the turtlesim node by AJ.Pi.

turtlesim_plus_interface

• A package that provides a custom service for turtlesim_plus_node.

turtlesim_plus_controller

• path_generator.py: A node that generates YAML files for each turtle to follow.
• turtle_controller.py: A node that controls the turtlesim_plus node to reach target and drop a pizza.
• turtle_scheduler.py: The node that controls the turtlesim_plus node by sending targets to draw the word "FIBO".
• status_checker.py: A python script that checks the status of the turtlesim_plus node and move all turtle to top right on completion. It also trigger the launch file to spawn Melodic, the destructor turtle.

turtlesim_plus_controller_interface

• The node that provides a custom service so the controller and scheduler can communicate.

Nodes interaction

• turtlesim_plus_node.py
  • Subscribes to /<namespace>/cmd_vel to move the turtle.
  • Publishes to /<namespace>/pose to get the turtle's position.
  • Svc server to /spawn_pizza to drop a pizza.
  • Svc server to /<namespace>/eat to let Melodic eat pizza.
• path_generator.py do not interact with any other node. Is called by the launch file.
  • Receive parameters pizza_amt from the launch file for pizza per character (Defaults to 20).
• turtle_controller.py
  • Publishes to /<namespace>/cmd_vel to move the turtle.
  • Subscribes to /<namespace>/pose to get the turtle's position.
  • Svc client to /<namespace>/spawn_pizza to drop a pizza.
  • Svc client to /<namespace>/eat to let Melodic eat pizza.
  • Svc server to /<namespace>/go to get target location.
  • Svc server to /<namespace>/go_and_place to get target location to drop a pizza.
• turtle_scheduler.py
  • Receive parameters config_path from the launch file to get the YAML file path.
  • Svc client to /<namespace>/go_and_place to set target location to drop a pizza.
  • Parameter -f to get viapoints from the YAML file path.
• status_checker.py
  • Svc client to /<namespace>/go to set target location.
  • get_node_names() to scan for running scheduler nodes.