Krabby HAL Server - Jetson

HAL server implementation for Jetson robot deployment with integrated parkour policy inference.

Overview

This package provides an entry point that runs both the Jetson HAL server and parkour inference client in the same process using inproc ZMQ for zero-copy communication.

Architecture

┌─────────────────────────────────────────┐
│         Jetson Process                  │
│                                         │
│  ┌──────────────┐    inproc (ZMQ)     │
│  │ HAL Server   │◄──────────────────┐  │
│  │ (main thread)│                   │  │
│  │  - ZED camera│                   │  │
│  │  - Sensors   │                   │  │
│  │  - Actuators │                   │  │
│  └──────────────┘                   │  │
│         │                           │  │
│         │ publishes observations    │  │
│         │ receives commands         │  │
│         │                           │  │
│  ┌──────────────────────────────────┴─┐│
│  │ Parkour Inference Client           ││
│  │ (separate thread)                  ││
│  │  - Polls observations              ││
│  │  - Runs policy inference           ││
│  │  - Sends joint commands            ││
│  └────────────────────────────────────┘│
└─────────────────────────────────────────┘

Installation

From source (development)

cd hal/server/jetson
pip install -e .

With optional dependencies

pip install -e ".[dev]"

Usage

Command line

After installation, use the krabby-hal-server-jetson command:

krabby-hal-server-jetson \
  --checkpoint /path/to/model.pt

Python module

python -m hal.server.jetson.main --checkpoint /path/to/model.pt

Arguments

Required:

• --checkpoint: Path to model checkpoint file

Optional:

• --log-level: Python logging level for this process (DEBUG, INFO, WARNING, ERROR, CRITICAL; default: INFO)

Components

HAL Server (hal.server.jetson.JetsonHalServer)

• Integrates with ZED camera for depth perception
• Interfaces with real sensors (IMU, encoders)
• Applies commands to actuators (motors)
• Publishes observations via ZMQ PUB socket
• Receives joint commands via ZMQ PULL socket

Parkour Inference Client (compute.parkour.inference_client.ParkourInferenceClient)

• Runs in separate thread
• Polls observations from HAL server
• Runs parkour policy inference
• Sends joint commands back to HAL server

Hardware Requirements

• NVIDIA Jetson (Orin, AGX Xavier, or compatible)
• ZED Camera (requires ZED SDK and pyzed)
• Robot Hardware (motors, IMU, encoders)

Development

Project Structure

hal/server/jetson/
├── pyproject.toml      # Package configuration
├── README.md           # This file
├── __init__.py         # Package init
├── main.py             # Entry point with integrated inference
└── hal_server.py       # JetsonHalServer implementation

Running Tests

pytest tests/integration/test_jetson_hal.py

Note: Most tests require Jetson hardware or ZED SDK and are skipped in x86 environments.

Notes

• This package uses inproc ZMQ by default for same-process communication (zero-copy, high performance)
• For distributed deployment, use TCP endpoints instead
• The parkour inference client runs on a separate thread to avoid blocking the sensor loop
• Camera, sensors, and actuators are initialized during startup