micro-ROS Firmware Demo

This repository contains a demo firmware project using micro-ROS, designed for enimia AI edition car . The firmware is compatible with STM32 and integrates essential micro-ROS features.

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Features

• Platform Support: Compatible with STM32F4 Discovery board.
• micro-ROS Integration: Includes micro-ROS client for seamless communication with ROS 2 nodes.
• Peripheral Support: CDC USB communication, LEDs.
• Extensibility: Easily adaptable to different hardware platforms.

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Requirements

Hardware

• STM32F4 Discovery Board
• USB cable

Software

• STM32CubeIDE
• ROS 2 Humble
• micro-ros agent

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Getting Started

1. Clone the Repository

git clone https://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@github.com/MansourACH/micro-ros_Demo.git
cd micro-ros_Demo

Code Explanation

The following code demonstrates the use of micro-ROS APIs to create a simple publisher and subscriber system.

Key Features:

1. Publisher: Publishes integer messages (std_msgs/Int32) to the topic stm32_publisher.
2. Subscriber: Subscribes to velocity commands (geometry_msgs/Twist) on the topic cmd_vel.
3. Executor: Manages the callback for the subscriber and ensures non-blocking execution.

Code:

// Include necessary libraries for ROS2 and micro-ROS
rcl_publisher_t publisher; // Publisher object
std_msgs__msg__Int32 msg;  // Message object for publishing an integer
rclc_support_t support;    // Support object for managing initialization
rcl_allocator_t allocator; // Allocator for memory management
rcl_node_t node;           // Node object representing the micro-ROS node
rcl_subscription_t subscriber; // Subscriber object
geometry_msgs__msg__Twist msg_sub; // Message object for receiving velocity commands
rclc_executor_t executor;  // Executor for managing callbacks

// Initialize the default allocator
allocator = rcl_get_default_allocator();

// Initialize the support structure with default options
rclc_support_init(&support, 0, NULL, &allocator);

// Create a micro-ROS node with the name "TPE_Publisher"
rclc_node_init_default(&node, "TPE_Publisher", "", &support);

// Initialize the publisher to send messages of type std_msgs/Int32 on the "stm32_publisher" topic
rclc_publisher_init_default(
    &publisher,
    &node,
    ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int32),
    "stm32_publisher"
);

// Initialize the subscriber to receive messages of type geometry_msgs/Twist on the "cmd_vel" topic
rclc_subscription_init_default(
    &subscriber,
    &node,
    ROSIDL_GET_MSG_TYPE_SUPPORT(geometry_msgs, msg, Twist),
    "cmd_vel"
);

// Initialize the executor to handle callbacks and link it to the context
rclc_executor_init(&executor, &support.context, 1, &allocator);

// Add the subscriber to the executor, linking it with a callback function
rclc_executor_add_subscription(&executor, &subscriber, &msg_sub, &subscription_callback, ON_NEW_DATA);

// Initialize the message data
msg.data = 0;

// Infinite loop for processing ROS2 communication
for (;;)
{
    // Spin the executor to process incoming subscriptions and callbacks
    rclc_executor_spin_some(&executor, RCL_MS_TO_NS(100));

    // Publish the message on the "stm32_publisher" topic
    rcl_ret_t ret = rcl_publish(&publisher, &msg, NULL);
    if (ret != RCL_RET_OK)
    {
        // Print an error message if publishing fails
        printf("Error publishing (line %d)\n", __LINE__);
    }

    // Increment the message data for the next publish cycle
    msg.data++;

    // Delay for 10 ms
    osDelay(10);
}

Useful Resources

If you're working on configuring micro-ROS for STM32 using STM32CubeMX, the following repository provides valuable utilities and setup instructions:

• micro-ROS STM32CubeMX Utilities: micro_ros_stm32cubemx_utils

This repository includes tools and guidelines for integrating micro-ROS into STM32 projects using STM32CubeMX. It covers:

• Setting up micro-ROS transport layers
• Generating necessary middleware
• Building the firmware with STM32 HAL and LL drivers

Issues

1. Topic Name Sensitivity

micro-ROS is case-sensitive with respect to topic names. Ensure that the topic names used in your micro-ROS application match exactly (including case) with the ones expected by the micro-ROS Agent or other nodes in the system.

2. Transport Configuration Challenges

Configuring the transport layer (e.g., UART, Ethernet) can be complex and may require careful attention to hardware-specific parameters. Refer to the Transport Configuration Guide for detailed instructions.

3. Limited Documentation on Custom Nodes

While the micro-ROS documentation covers standard use cases, custom node development might require additional exploration of the API. Check the examples folder or community forums for more insights.

4. Resource Constraints on STM32

When running micro-ROS on STM32 devices, ensure sufficient memory and processing power to avoid runtime issues. Profiling your application can help identify resource bottlenecks.