Introduction to Tutorials

This section contains multiple tutorials on how to achieve basic tasks in ARIAC. Some competitors may find these tutorials useful as a starting point for their own code.

The tutorials are written using python and rclpy. MoveItPy is used for interacting with the robots. If your team would like to use C++ and MoveGroupInterface refer to the test_competitor package.

The source code for tutorials can be found in a GitHub repository which is separate from the main ARIAC repository.

Prerequisites

Ensure your environment is already configured using the installation instructions.
Clone the tutorials repository into the same ROS workspace used for ARIAC.
cd ~/ariac_ws && git clone https://github.com/usnistgov/ARIAC_tutorials.git src/ARIAC_tutorials
Install necessary ROS dependencies
rosdep install --from-paths src -y --ignore-src
Install necessary pip dependencies
pip install -r src/ARIAC_tutorials/requirements.txt
Build/source the workspace.
colcon build && . install/setup.bash

List of Tutorials

A brief description of each tutorial is provided below.

Tutorial 1: Starting the competition

Demonstrates how to call a ROS service to start the competition.

Tutorial 2: Reading data from a break beam sensor

Demonstrates how to add a sensor to the sensor configuration file. The sensor is then used to keep track of the number of parts that are spawned on the conveyor belt.

Tutorial 3: Processing Data from an RGBD Camera

Demonstrates how to read an image from an RGB to classify objects in a parts bin.

Tutorial 4: Reading an order

Demonstrates how to retrieve published orders.

Tutorial 5: Moving AGVs between stations

Demonstrates how to use service calls to move AGVs between stations.

Tutorial 6: Picking a part

Demonstrates how to use MoveItPy to direct the floor robot to pick a part from the bins.

Tutorial 7: Picking and placing a kit tray

Demonstrates how to use MoveItPy to direct the floor robot to change the robot gripper type, then pick and place a kit tray onto an AGV.

Tutorial 8: Completing a Kitting Task

Demonstrates how to complete and submit a kitting task.

Creating a Competition Package

The following example demonstrates how to create a minimal competition ROS package using python.

Package Structure

Start by creating a folder named example_package inside the src directory of the ROS workspace. Create the following files and folders shown in Listing 14.

Listing 14 Example Package Tree

ariac_ws/
├── src/
    ├── example_package/
        ├── config/
        │   └── my_sensors.yaml
        ├── example_package/
        │   ├── __init__.py
        │   └── example.py
        └── scripts/
            └── example_node.py
        ├── CMakeLists.txt
        ├── package.xml

List of Files

Copy the contents below into each corresponding file.

`my_sensors.yaml`

robot_cameras:
  floor_robot_camera:
    active: false
    type: rgb

  ceiling_robot_camera:
    active: false
    type: rgbd

static_sensors:
  conveyor_breakbeam:
    type: break_beam
    visualize_fov: true
    pose:
      xyz: [-0.36, 3.5, 0.88]
      rpy: [0, 0, pi]

`example.py`

import rclpy
from rclpy.node import Node

class ExampleNode(Node):

    def __init__(self):
        super().__init__('example_node')
        self.timer = self.create_timer(1, self.timer_callback)

    def timer_callback(self):
        self.get_logger().info("Example node running")

`example_node.py`

#!/usr/bin/env python3

import rclpy

from example_package.example import ExampleNode

def main(args=None):
    rclpy.init(args=args)

    example_node = ExampleNode()

    rclpy.spin(example_node)

    example_node.destroy_node()
    rclpy.shutdown()

if __name__ == '__main__':
    main()

`CMakeLists.txt`

cmake_minimum_required(VERSION 3.8)
project(example_package)

if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
  add_compile_options(-Wall -Wextra -Wpedantic)
endif()

find_package(ament_cmake REQUIRED)
find_package(ament_cmake_python REQUIRED)
find_package(rclpy REQUIRED)

# Install the config directory to the package share directory
install(DIRECTORY
  config
  DESTINATION share/${PROJECT_NAME}
)

# Install Python modules
ament_python_install_package(${PROJECT_NAME} SCRIPTS_DESTINATION lib/${PROJECT_NAME})

# Install Python executables
install(PROGRAMS
  scripts/example_node.py
  DESTINATION lib/${PROJECT_NAME}
)

ament_package()

`package.xml`

<?xml version="1.0"?>
<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
<package format="3">
  <name>example_package</name>
  <version>1.0.0</version>
  <description>Example competition package for ARIAC</description>
  <maintainer email="you@email.com">Your Name</maintainer>
  <license>Apache License 2.0</license>

  <buildtool_depend>ament_cmake</buildtool_depend>

  <depend>rclpy</depend>

  <export>
    <build_type>ament_cmake</build_type>
  </export>
</package>

Testing the Package

First build the package

cd ~/ariac_ws && colcon build --packages-select example_package && . install/setup.bash

Start the competition with the sensor configuration
```
ros2 launch ariac_gazebo ariac.launch.py competitor_pkg:=example_package sensor_config:=my_sensors
```
This should launch the environment with the sensors specified in my_sensors.yaml

Run the example node in another terminal

ros2 run example_package example_node.py

You should see this output:

[INFO] [1705512918.432221530] [example_node]: Example node running
[INFO] [1705512919.420483814] [example_node]: Example node running
[INFO] [1705512920.420387437] [example_node]: Example node running

The node will continue to log once a second until the process is stopped.

Introduction to Tutorials

List of Tutorials

Creating a Competition Package

Package Structure

List of Files

my_sensors.yaml

example.py

example_node.py

CMakeLists.txt

package.xml