Robot Format Converter

A universal robot description format converter that enables seamless conversion between different robot modeling formats including URDF, SDF, MJCF, USD, and a unified schema format.

Features

• Multi-Format Support: Convert between URDF, SDF, MJCF, USD, and custom schema formats
• Unified Schema: Common intermediate representation preserving robot structure and properties
• Command-Line Interface: Easy-to-use CLI for single file and batch conversions
• Python API: Programmatic access for integration into robotics pipelines
• Format Detection: Automatic format detection from file extensions and content
• Validation: Built-in schema validation and error checking
• Extensible Architecture: Easy to add support for new formats

Supported Formats

Format	Extension	Read	Write	Description
URDF	.urdf	✅	✅	Unified Robot Description Format
SDF	.sdf	🚧	🚧	Simulation Description Format
MJCF	.xml	🚧	🚧	MuJoCo Modeling Format
USD	.usd, .usda	🚧	🚧	Universal Scene Description
Schema	.yaml, .json	✅	✅	Custom unified schema

Legend: ✅ Implemented, 🚧 In Development

Installation

From PyPI (Recommended)

pip install robot-format-converter

From Source

git clone https://github.com/thanhndv212/robot_format_converter.git
cd robot_format_converter
pip install -e .

Development Installation

git clone https://github.com/thanhndv212/robot_format_converter.git
cd robot_format_converter
pip install -e .[dev]

Quick Start

Command Line Interface

Single File Conversion:

# Convert URDF to SDF
robot-convert convert robot.urdf robot.sdf

# Convert with explicit format specification
robot-convert convert --source urdf --target mjcf robot.urdf robot.xml

# Get file information
robot-convert info robot.urdf

Batch Conversion:

# Convert all URDF files in a directory to SDF
robot-convert batch-convert models/ output/ urdf sdf

# Convert with file pattern
robot-convert batch-convert models/ output/ urdf sdf --pattern "*.urdf"

Validation:

# Validate a schema file
robot-convert validate robot_schema.yaml

# List supported formats
robot-convert list-formats

Python API

Basic Conversion:

from robot_format_converter import FormatConverter

# Create converter instance
converter = FormatConverter()

# Convert single file
schema = converter.convert('robot.urdf', 'robot.sdf')
print(f"Converted robot: {schema.metadata.name}")
print(f"Links: {len(schema.links)}, Joints: {len(schema.joints)}")

# Batch convert directory
converted_files = converter.batch_convert(
    'input_models/', 
    'output_models/', 
    'urdf', 
    'sdf'
)
print(f"Converted {len(converted_files)} files")

Advanced Usage:

from robot_format_converter import FormatConverter, CommonSchema
from pathlib import Path

converter = FormatConverter()

# Convert to intermediate schema format
schema = converter.to_schema('robot.urdf', 'robot_schema.yaml')

# Access robot components
for link in schema.links:
    print(f"Link: {link.name}")
    if link.visual:
        print(f"  Visual: {link.visual.geometry}")
    if link.collision:
        print(f"  Collision: {link.collision.geometry}")

for joint in schema.joints:
    print(f"Joint: {joint.name} ({joint.type})")
    print(f"  Parent: {joint.parent} -> Child: {joint.child}")

# Convert from schema to target format
converter.from_schema('robot_schema.yaml', 'output.sdf')

Format Detection:

from robot_format_converter.utils import detect_format, get_format_info

# Detect format from file
format_name = detect_format('robot.urdf')
print(f"Detected format: {format_name}")

# Get format information
info = get_format_info(format_name)
print(f"Format description: {info['description']}")
print(f"Supported features: {info['features']}")

Schema Format

The unified schema format provides a common intermediate representation:

metadata:
  name: "my_robot"
  version: "1.0"
  author: "Robot Designer"
  description: "A sample robot description"

links:
  - name: "base_link"
    inertial:
      mass: 1.0
      center_of_mass: [0, 0, 0]
      inertia_matrix: [1, 0, 0, 1, 0, 1]
    visual:
      geometry:
        type: "box"
        size: [0.1, 0.1, 0.1]
      material:
        color: [1, 0, 0, 1]
    collision:
      geometry:
        type: "box"
        size: [0.1, 0.1, 0.1]

joints:
  - name: "joint1"
    type: "revolute"
    parent: "base_link"
    child: "link1"
    origin:
      xyz: [0, 0, 0.1]
      rpy: [0, 0, 0]
    axis: [0, 0, 1]
    limits:
      lower: -3.14
      upper: 3.14
      effort: 10
      velocity: 1

Architecture

The converter uses a modular architecture with clear separation of concerns:

robot_format_converter/
├── __init__.py          # Public API
├── core.py              # Core conversion engine
├── schema.py            # Unified schema definition
├── parsers.py           # Format-specific parsers
├── exporters.py         # Format-specific exporters
├── utils.py             # Utility functions
└── __main__.py          # CLI interface

Key Components:

• FormatConverter: Main interface for conversions
• ConversionEngine: Orchestrates parsing and exporting
• CommonSchema: Unified intermediate representation
• BaseParser/BaseExporter: Abstract base classes for format handlers
• Format-specific parsers/exporters: Handle individual format details

Adding New Formats

To add support for a new format:

1. Create Parser Class:

from robot_format_converter.core import BaseParser
from robot_format_converter.schema import CommonSchema

class MyFormatParser(BaseParser):
    def can_parse(self, file_path: str) -> bool:
        return file_path.endswith('.myformat')
    
    def parse(self, file_path: str) -> CommonSchema:
        # Implementation here
        pass

2. Create Exporter Class:

from robot_format_converter.core import BaseExporter
from robot_format_converter.schema import CommonSchema

class MyFormatExporter(BaseExporter):
    def can_export(self, format_name: str) -> bool:
        return format_name == 'myformat'
    
    def export(self, schema: CommonSchema, file_path: str) -> None:
        # Implementation here
        pass

3. Register with Engine:

from robot_format_converter import ConversionEngine

engine = ConversionEngine()
engine.register_parser('myformat', MyFormatParser())
engine.register_exporter('myformat', MyFormatExporter())

Contributing

We welcome contributions! Please see our Contributing Guide for details.

Development Setup

# Clone repository
git clone https://github.com/thanhndv212/robot_format_converter.git
cd robot_format_converter

# Install development dependencies
pip install -e .[dev]

# Install pre-commit hooks
pre-commit install

# Run tests
pytest

# Run linting
flake8 robot_format_converter/
black robot_format_converter/
isort robot_format_converter/

Running Tests

# Run all tests
pytest

# Run with coverage
pytest --cov=format_converter

# Run specific test
pytest tests/test_urdf_parser.py

Examples

Check out the examples directory for more usage examples:

• Basic conversion
• Batch processing
• Custom format integration
• Schema validation

Roadmap

• ✅ URDF parser and exporter
• ✅ Unified schema format
• ✅ Command-line interface
• 🚧 SDF parser and exporter
• 🚧 MJCF parser and exporter
• 🚧 USD parser and exporter
• 📋 ROS2 integration
• 📋 Gazebo integration
• 📋 MuJoCo integration
• 📋 Isaac Sim integration

Legend: ✅ Complete, 🚧 In Progress, 📋 Planned

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.

Related Projects

• FIGAROH: Robot calibration and identification library
• URDF Parser: ROS URDF parsing library
• PyBullet: Physics simulation supporting URDF and SDF
• MuJoCo: Physics simulator with MJCF format

Citation

If you use this package in your research, please cite:

@software{robot_format_converter,
  author = {Nguyen, Thanh},
  title = {Robot Format Converter: Universal Robot Description Format Converter},
  year = {2025},
  url = {https://github.com/thanhndv212/robot_format_converter},
  version = {1.0.0}
}