ROS2 Micro-ROS Robot Control System

Complete System Architecture

graph TD
    User[Operator] -->|Keyboard Input| Teleop[teleop_twist_pkg]
    Phone[Mobile Phone] -->|DroidCam WiFi Stream| Camera[camera_feed_pkg]
    Teleop -->|/cmd_vel| Agent[micro_ros_agent_pkg]
    Agent -->|UDP| ESP32[ESP32 Microcontroller]
    ESP32 -->|DAC1: 0-3.3V| Driver[36V Brushless Driver]
    ESP32 -->|DAC2: 0-3.3V| Driver
    Driver -->|Speed Control| Motors[Brushless Motors]
    Driver -->|Steer Control| Motors
    Battery[36V Li-ion Battery] --> Driver
    Camera -->|/image_raw| UI[Operator Display]
    
    subgraph ROS2 Ecosystem
        Teleop
        Camera
        Agent
    end
    
    subgraph Embedded System
        ESP32
        Driver
        Motors
        Battery
    end

Loading

A ROS2-based project to control a robot via WiFi using Micro-ROS, featuring:

• Twist command input from keyboard
• Visual feedback via DroidCam smartphone camera
• ESP32-based motor control with brushless bi-motor driver

Features

• 📷 Real-time camera streaming using DroidCam
• ⌨️ Keyboard teleoperation with Twist messages
• 📶 Micro-ROS agent communication over WiFi
• 🎮 Dual motor control with linear/angular velocity conversion
• ⚙️ Parameterised configuration for different devices

Repository Structure (Expanded)

ros2_robot_control/
├── firmware/
│   └── esp32_motor_control_wifi_twist.ino
│      
├── media/
│   ├── diagramwiring.png
│  
├
└── ros2_ws/
    └── src/                     # Previous ROS2 packages
        ├── camera_py/
        ├── teleop_twist_pkg/
        ├── micro_ros_agent/
        └── my_launch_package/

Installation

Prerequisites

• ROS2 Humble Hawksbill
• Micro-ROS setup for ESP32
• Python 3.8+
• DroidCam app (Android / iOS)

Packages Overview

1. camera_py

Description: Handles DroidCam video stream processing
Parameters:

• device_index (default: 0) - DroidCam device number
• resolution_width (default: 640)
• resolution_height (default: 480)
• fps (default: 30)

2. micro_ros_agent

Description: Manages Micro-ROS agent communication
Parameters:

• port (default: 8888)
• agent_address - ESP32 IP address

3. teleop_twist_pkg

Description: Keyboard teleoperation node
Parameters:

• linear_speed
• angular_speed

4. my_launch_package

Description: Master launch file for system integration
Launch Command:

ros2 launch my_launch_package test_launch.py

Hardware Setup

1. ESP32 Configuration:

   • WiFi STA mode with static IP

    // WiFi Settings in esp32_motor_control_wifi_twist.ino
    char* ssid = "SSID";
    char* password = "password";
    char* agent_ip = "172.20.10.10";  // Your PC's IP running micro-ROS agent
    const uint16_t agent_port = 8888;
   

   • Brushless motor driver interface
   • DAC output range: 0-3.3V

2. Motor Control:

   • Linear velocity → Motor speed (DAC)
   • Angular velocity → Steering control

Usage

1. Start DroidCam:

   • Connect phone to same network
   • Note the displayed IP and port

2. Launch System:

ros2 launch my_launch_package test_launch.py
  camera_device:=<droidcam_device_number> 
  host_ip:=<esp32_ip> 
  agent_port:=<micro_ros_port>

3. Control Interface:
   • Keyboard Controls:

     i - forward
     , - backward
     j - left
     l - right
     k - Emergency stop
     q/z- increase linear and angular velocity
     

Parameters Configuration

Parameter	Description	Default Value
camera/device_index	DroidCam device number	0
agent/port	Micro-ROS agent port	8888
agent/address	ESP32 IP address	192.168.1.10

Safety Features

• Voltage monitoring for 36V battery pack
• Emergency stop circuit (physical button + software command)
• DAC output smoothing filter (prevents sudden voltage changes)
• Temperature monitoring on motor driver
• Low-voltage cutoff at 30V

Known Limitations

• DroidCam latency: 150-300ms
• Maximum control frequency: 30Hz (ESP32 limitation)
• DAC resolution: 8-bit (0.0129V/step)
• Operating range: <50m (WiFi reliability)

Troubleshooting

Camera Feed Issues:

• Verify DroidCam connection with ffplay http://<phone_ip>:<port>
• Check camera permissions

Micro-ROS Connection Problems:

ros2 run micro_ros_agent micro_ros_agent udp4 --port 8888 --dev 172.20.10.2 //change with your esp32 adress

Motor Response:

• Verify ESP32 output with serial debug
• Check DAC output with multimeter

Contributing

PRs welcome! Please follow ROS2 development guidelines.

License

Apache 2.0

---

Maintainer: [achref-ak]
Contact: achrafakik11@gmail.com
Version: 1.0.0