ros2-assignments

Assignments made for the first semester of ROS2

Table of contents

• System Architecture
• Components
• Installation

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System Architecture

The TI Minor Grade Generator is a ROS2-based distributed system for managing student exam results and calculating final grades. The system follows a microservices architecture with clear separation of concerns.

Overview

The system consists of multiple ROS2 nodes that communicate through topics and services to process exam data, calculate grades, and store the results in a database.

Components

Core Nodes

1. ExamResultGenerator (assignments::one::exam_resutl_generator)

   • Publishes random exam results for students and courses
   • Simulates exam result generation for testing and demonstration
   • (Full documentation)

2. FinalGradeDeterminator (assignments::one::final_grade_determinator)

   • Collect grades from ExamResultGenerator
   • Send results to the GradeCalculator
   • Put resulting grade in the Database
   • (Full documentation)

3. GradeCalculator (assignments::one::grade_calculator)

   • Provides ROS2 service for calculating student exam grades
   • Ensures grade results are within valid bounds (10-100)
   • (Full documentation)

Database Management

• DatabaseManager: Handles all database operations including storing final course results
• (Full documentation)

Configuration Management

• ConfigManager: Loads and validates system configuration from TOML files
• Provides runtime access to configuration parameters for all nodes
• Ensures consistent environment setup and error handling for misconfigurations
• (Full documentation)

Message Interfaces

• Exam Messages (g2_2025_interfaces::msg::Exam): Contains student name, course name, result, and timestamp
• Student Messages (g2_2025_interfaces::msg::Student): Contains student and course information with timestamp
• Grade Calculation Service (g2_2025_interfaces::srv::Exams): Service interface for grade calculation requests

Workflow

1. Exam Result Collection: Exam results are published to the exam_results topic
2. Result Aggregation: FinalGradeDeterminator collects results until the configured threshold is met
3. Grade Calculation: When enough results are available, a service call is made to GradeCalculator
4. Result Processing: Calculated grades are published and stored in the database
5. Student Management: Final student information is published to student_course_management topic as this stops the random generation of grades
6. Retake scheduler: Schedule an exam retake for the grades below 55 by resending information to student_course_management as this will re-enable grade generation
7. Retake grade determination: repeat steps 1 through 6 using the retake_grade_determinator node instead of final_grade_determinator until every student hase a passing grade

Configuration

The system uses TOML configuration files for environment-specific settings:

• Database connection parameters
• ROS2 node configurations
• Grade collection thresholds

Testing

Unit tests are implemented using Google Test framework:

• Mock services and database managers for isolated testing
• Parameterized tests for various grade calculation scenarios
• Documentation on the tests are located in the full documentation of the nodes themselves

Installation

Prerequisites

• ROS2 Jazzy or newer installed (ROS2 Installation Guide)
• CMake (version 3.8+)
• Python 3.8+
• libtomlplusplus-dev
• libpqxx-dev
• Colcon build tool
• Docker compose

Clone the Repository

git clone https://git.wessel.gg/inholland/ros2-assignments.git
cd ros2-assignments

Build the Workspace

colcon build

Any parameters can be changed before building by editing the grade_calculator.launch.xml in the launch folder

Source the Workspace

source install/setup.bash

Run the System

sudo docker-compose up
ros2 launch g2_2025_grade_calculator_pkg grade_calculator.launch.xml