BNO055 IMU Data Acquisition with micro-ROS on ESP32

This project demonstrates how to acquire data from a BNO055 Inertial Measurement Unit (IMU) using an ESP32 microcontroller, running FreeRTOS and micro-ROS. The firmware reads accelerometer, gyroscope, and quaternion data from the BNO055 sensor, publishes it as a sensor_msgs/Imu message over a ROS 2 network, and allows visualization on a ROS 2 host (e.g., using RViz or rqt). The project is built with ESP-IDF and integrates micro-ROS for seamless ROS 2 compatibility.

Features

• Reads BNO055 IMU data (acceleration in m/s², angular velocity in rad/s, and orientation quaternions).
• Publishes IMU data to the /imu_data topic using micro-ROS.
• Uses FreeRTOS for task management and mutex-based data synchronization.
• Configurable for UDP communication with a micro-ROS agent.
• Includes error handling and logging for robust operation.

Hardware Requirements

• Microcontroller: ESP32-based board (e.g., ESP32-DevKitC).
• IMU Sensor: BNO055 connected via I2C (SDA: GPIO 21, SCL: GPIO 22).
• Host PC: Ubuntu 22.04+ with ROS 2 Humble installed.
• Connection: USB for flashing and optional serial debugging; Wi-Fi for micro-ROS communication.

Software Requirements

• ESP-IDF: Version 4.4 or 5.0 (recommended).
• micro-ROS: ESP-IDF component for ROS 2 integration (included as a submodule).
• ROS 2: Humble distribution on the host PC.
• Docker: For micro-ROS agent setup (optional).
• Tools: idf.py, git, and cmake.

Setup Instructions

1. Clone the Repository

Clone this repository and initialize submodules:

git clone <your-repo-url> BNO055_microROS
cd BNO055_microROS
git submodule update --init --recursive

2. Install ESP-IDF

Install ESP-IDF (v4.4 recommended):

mkdir -p ~/esp
cd ~/esp
git clone -b v4.4 --recursive https://github.com/espressif/esp-idf.git
cd esp-idf
./install.sh
. ./export.sh

3. Configure micro-ROS Component

The components/micro_ros_espidf_component directory is a Git submodule. Ensure it’s properly initialized (see above). If you encounter Git warnings, refer to the Troubleshooting section.

4. Build the Firmware

Navigate to the project directory and build:

cd ~/esp/BNO055_microROS
idf.py build

5. Flash the Firmware

Connect your ESP32 via USB and flash:

idf.py -p /dev/ttyUSB0 flash

6. Set Up ROS 2 Host

Install ROS 2 Humble and the micro-ROS agent on your host PC:

sudo apt update
sudo apt install ros-humble-desktop ros-humble-micro-ros-agent

7. Configure Network

Update main/main.c with your Wi-Fi credentials and micro-ROS agent IP/port:

#define CONFIG_MICRO_ROS_AGENT_IP "your-agent-ip"
#define CONFIG_MICRO_ROS_AGENT_PORT "8888"

Alternatively, use serial communication by modifying the micro-ROS transport settings.

8. Run the micro-ROS Agent

Start the agent on the host PC:

source /opt/ros/humble/setup.bash
ros2 run micro_ros_agent micro_ros_agent udp4 --port 8888

For serial communication:

ros2 run micro_ros_agent micro_ros_agent serial --dev /dev/ttyUSB0

Usage

1. Monitor Serial Output (optional): View logs from the ESP32:

   idf.py -p /dev/ttyUSB0 monitor

   Logs include BNO055 initialization status and IMU data.

2. Verify Published Topics: On the ROS 2 host, check for the /imu_data topic:

   source /opt/ros/humble/setup.bash
   ros2 topic list

   Expected output includes /imu_data (type: sensor_msgs/Imu).

3. Visualize IMU Data:

   • RViz:

     rviz2

     Add an Imu display, set the topic to /imu_data, and configure visualization (e.g., orientation arrows).
   • rqt:

     rqt

     Use rqt_plot to plot fields like /imu_data/linear_acceleration/x.

Code Structure

• main/main.c: Main application code.
  • Initializes I2C and BNO055 sensor.
  • Runs two FreeRTOS tasks:
    • bno055_task: Reads IMU data at 10 Hz and stores it in a mutex-protected structure.
    • micro_ros_task: Publishes IMU data to /imu_data using micro-ROS.
  • Uses a mutex for thread-safe data access.
• components/micro_ros_espidf_component: micro-ROS ESP-IDF component (submodule).

Troubleshooting

• Git Submodule Warning: If you see a warning about components/micro_ros_espidf_component being an embedded repository:

  git rm --cached components/micro_ros_espidf_component
  git submodule add https://github.com/micro-ROS/micro_ros_espidf_component.git components/micro_ros_espidf_component

• I2C Errors: Verify BNO055 wiring (SDA: GPIO 21, SCL: GPIO 22) and I2C address (0x28 or 0x29).
• micro-ROS Connection Issues: Ensure the agent’s IP/port matches CONFIG_MICRO_ROS_AGENT_IP and CONFIG_MICRO_ROS_AGENT_PORT.
• BNO055 Initialization Failure: Check power supply (3.3V) and I2C pull-up resistors.

Notes

• The BNO055 is configured in NDOF mode for fused orientation data.
• IMU data is scaled to SI units (m/s² for acceleration, rad/s for angular velocity, normalized quaternions).
• Covariance values in sensor_msgs/Imu are placeholders; adjust based on sensor specifications.
• For serial communication, modify the micro-ROS transport in main.c and agent settings.

License

This project is licensed under the MIT License. See the LICENSE file for details.