go2-sbus-unleashed

go2-sbus-unleashed is a project that enables control of the Unitree Go2 quadruped robot using the SBUS port, allowing for operation on non-edu (more affordable) models without requiring a jailbreak.

Project Structure

go2-sbus-unleashed/
│
├── esp32/
│   └── serial-bus-converter/
│       ├── include/
│       ├── lib/
│       ├── src/
│       └── test/
│
├── pc/
│
└── robot/

ESP32

The esp32 directory contains a PlatformIO project with code to convert incoming serial messages to SBUS format.

PC

The pc directory contains client code for handling gamepad access. While a PS5 controller is used by default, any gamepad recognized by Pygame should work.

Note: Users need to modify the SERVER_URL in pc/client.py to match their Go2's IP address.

Robot

The robot directory contains Python scripts designed to run on a Raspberry Pi 5, but should be platform-independent:

• constants.py: Defines the serial port for the ESP32.
• main.py: A test script that performs arming logic, walks forward for 2 seconds, then stops.
• teleop.py: Enables teleoperation control when client.py is running.

Serial Message Format

The project uses a custom serial message format to send PWM values for robot control. The message structure is as follows:

<strafe,forward,turn>\n

Where:

• strafe: PWM value for lateral movement (left/right)
• forward: PWM value for forward/backward movement
• turn: PWM value for rotation

Each value is an integer, and the message is enclosed in angle brackets with values separated by commas. The message is terminated with a newline character.

Example message:

<992,1400,992>\n

PWM values are constrained to a range of 192 to 1792, with 992 being the center point (neutral position).

• 192: Minimum value (full negative)
• 992: Neutral position
• 1792: Maximum value (full positive)

Here's the correct implementation of the send_values function:

def send_values(strafe, forward, turn):
    # Ensure values are within range and format as 4-digit strings
    strafe = max(192, min(1792, strafe))
    forward = max(192, min(1792, forward))
    turn = max(192, min(1792, turn))
    
    # Combine values into a single string with separators and terminator
    data = f"<{strafe},{forward},{turn}>\n"
    
    # Send the data
    ser.write(data.encode())

# Example usage
import time

start = time.time()
while time.time() - start < 2:
    strafe = 992   # No lateral movement
    forward = 1400 # Slight forward movement
    turn = 992     # No rotation
    
    send_values(strafe, forward, turn)
    time.sleep(0.1)  # Short delay to avoid flooding the serial port

send_values(992, 992, 992)  # Stop the robot

This format allows for precise control over the robot's movement in three dimensions while ensuring that the values are within the acceptable range.

Setup and Usage

ESP32 Setup

For setting up and using the ESP32 with PlatformIO, please refer to the PlatformIO tutorials: PlatformIO Tutorials

Raspberry Pi Setup

1. Connect your Raspberry Pi to your network.
2. Note the IP address of your Raspberry Pi. You can find this by:
   • Running ifconfig on the Raspberry Pi, or
   • Running arp -a on your PC to list all devices on the network
3. On both your Raspberry Pi and your PC, clone this repository:

   git clone [Your Repository URL]
   

4. On the Raspberry Pi, navigate to the robot directory and run:

   python teleop.py
   

5. On your PC, navigate to the pc directory, update the SERVER_URL in client.py with your Raspberry Pi's IP address, then run:

   python client.py
   

Now you should be able to control your Go2 robot using the gamepad connected to your PC.