Vepryk 6+ Mobile Crawler Platform

Overview

The Vepryk 6+ is a tracked mobile platform designed for high-mobility operations in challenging environments. This project implements a hierarchical control architecture that bridges the gap between operator intent and hardware execution.

The system employs a Raspberry Pi 4 for high-level control (strategic tasks, data processing, operator communication) and an ESP32 for low-level motor management, communicating via the MAVLink protocol over SSH-encrypted channels. The platform features a discrete ternary control scheme for robust command interpretation.

System Architecture

The platform control system is built on a hierarchical architecture with two levels:

• High-Level Controller (Raspberry Pi 4 Model B): Handles strategic tasks, data processing, operator communication, and command generation. It runs the custom control logic and wrapper library.
• Low-Level Controller (ESP32): Responsible for real-time command execution, motor driver management, and stabilization. It runs firmware provided by the platform manufacturer and receives commands via serial interface (UART) using the MAVLink protocol.

Software Stack

The software is designed around a producer-consumer pattern:

• Host Computer: Runs a C++ control application (SDL2 for input, native sockets) that polls joystick state, applies quantization, encodes MAVLink messages, and transmits them via an SSH tunnel.
• Rover (Raspberry Pi): Executes a C++17 bridge service that maintains a TCP server for network packets and a UART interface (115200 baud, 8N1) to the ESP32.

Setup & Usage Instructions

1. Network Connection

Ensure both your host computer (laptop) and the Raspberry Pi are connected to the same network (e.g., sharing an internet connection or local hotspot).

2. Connect to the Platform (Raspberry Pi)

Open a terminal on your host computer and connect via SSH:

ssh platform@tank.local

Password: The password on your Raspberry Pi

3. Initialize Onboard Systems

Once logged into the Raspberry Pi, execute the following commands to set up the environment and start the MAVLink bridge:

# Navigate to the project directory
cd Crawler

# Activate the Python virtual environment
source my_env/bin/activate

# Start MAVProxy to bridge UART to the network
mavproxy.py --master=/dev/ttyS0 --baudrate=57600

4. Establish Secure Tunnel (Host Computer)

On your local machine (host), open a new terminal window. Create an SSH tunnel to forward the video stream port (and potentially control ports) from the rover to your localhost.

ssh -L 12341:127.0.0.1:12341 platform@tank.local

Enter the password best2025 if prompted.

5. Host Control Software Setup

The project includes a custom C++ control application with both a GUI and a CLI interface.

Prerequisites

Ensure you have the following dependencies installed on your host machine:

• CMake
• SDL2
• Qt5 (Core, Widgets, Network)
• FFmpeg (libavcodec, libavformat, libavutil, libswscale)

Build Instructions

1. Navigate to the vepryk-control directory:

   cd vepryk-control

2. Create a build directory and compile:

   mkdir build
   cd build
   cmake ..
   make

Running the Control Application

Option A: GUI (Recommended) The GUI provides integrated video streaming, joystick control, and telemetry.

./vepryk_gui

Option B: CLI (Headless) For control without video or graphical interface:

./vepryk_control

Option C: Python Script (Testing) For simple testing or development:

python3 src/simple_control.py

6. Controls

The default joystick mapping (configurable in config.json) is:

• Throttle: Axis 1
• Steering: Axis 3
• Gear Up: Button 5
• Gear Down: Button 4
• Arm: Button 7
• Disarm: Button 6

Note: Ensure that the camera software and MAVLink proxy are running on the Raspberry Pi before starting the GUI or video stream on your host machine.