ros2-assignments/doc/architecture/architecture.md

ROS2 IMU Reader — Design Document

Project Overview

This projects reads data from a ESP32 communicating with serial or MQTT and writes this into a database for further processing

System Architecture

High-Level Architecture

The system consists of multiple ROS2 nodes that communicate through standardized topics and services to process imu data and store it in a database

Key Design Principles

• Microservices Architecture: Each component has a single responsibility
• Asynchronous Communication: Uses ROS2 topics and services for loose coupling
• Data Persistence: Centralized database management for datastorage
• Comprehensive Testing: Unit tests ensure code reliability

System Components

ESP32-IMU

For ESP32 specific documentation see ESP32-IMU.md

Core Nodes

1. IMU Databse writer Node

Namespace: assignments::two::imu_database_writer

Brief Description: Recieves and stores IMU data.

Key Features: Database persistence

For detailed documentation, see: IMUDatabaseWriter.md

2. LifeCycle Node

Namespace: assignments::two::lifecycle_manager

Brief Description: Configures low level communication and manages the hardware interface to read on either serial or mqtt comunications.

Key Features: Configuration of communications, device read activation and deactivation.

For detailed documentation, see: LifecycleManager.md

3. Hardware Interface

Namespace: assignments::two::hardware_interface

Brief Description: Manages low-level communication protocols (Serial/MQTT) for ESP32 data acquisition and forwards raw sensor data to processing nodes.

Key Features: Multi-protocol communication support, connection management, raw data parsing and streaming.

For detailed documentation, see: HardwareInterface.md

Data Management

DatabaseManager

Brief Description: PostgreSQL database interface handling connections, table management, and data persistence.

Key Features: Connection management, automatic table creation, student enrollment tracking, exam result storage

For detailed documentation, see: DatabaseManager.md

ConfigManager

Brief Description: TOML-based configuration management system allowing runtime configuration without recompilation.

Key Features: Automatic config file discovery, type-safe TOML parsing, database connection configuration

For detailed documentation, see: ConfigManager.md

Communication Interfaces

ROS2 Message Interface

Brief Description: This project uses the ROS2 standard IMU sensor message

System Workflow

1. Imu data Processing

1. Input: IMU data is sent from the ESP32 to the lifecycle node
2. Collection: The lifcycle node recieves the data via a serial or MQTT connection
3. Data passthrough: When data is recieved it is sent to the database writer

2. Data Management

1. Database Storage: IMU data is persisted/stored in the database

Configuration Management

TOML Configuration Structure

The system uses TOML files for environment-specific configuration:

[database]
host = "localhost"
port = 5432
name = "grade_db"
user = "grade_user"
password = "secure_password"

[grade_calculation]
collection_amount = 5
min_grade = 10
max_grade = 100

[logging]
level = "INFO"
output_file = "grade_system.log"

Testing

The testing documentation can be found in the doc/tests folder for each node