Specification

The HCDF schema defines the complete vocabulary for describing cyber-physical robotic systems. It covers physical structure (components, joints, geometry, kinematics), sensors and actuators (noise models, motor curves, control modes, encoders), networking and connectivity (topology, scheduling, security, power distribution), energy systems (batteries, fuel cells, charging), embodiment intelligence (joint groups, named states, self-collision), human-machine interfaces, dynamic surfaces, firmware identity, device discovery, and a structured extension mechanism for vendor and domain-specific data.

Validation: Use python3 validate.py hcdf.xsd your-file.hcdf for XSD structural validation. The Rust CLI (hcdf validate) provides additional cross-reference checking for port paths, joint references, and motor-encoder bindings.
147
Complex Types
42
Enumerations
5
Schemas
43
Validation Tests

Schema Reference

Core Schema

The main HCDF schema: components, joints (10 types including cylindrical and free), sensors (11 categories with noise models), motors (with load curves, control modes, and solenoids), compliant actuators (SEA/PEA/CPEA/AE-PEA/VSA via spring elements), networking (topology, scheduling, security), power systems (battery, tank, fuel cell, solar, supercapacitor), dynamic surfaces (including gripper), HMI, and embodiment features (groups, states, self-collision). 147 complex types, 42 enumerations.

Stream Profile

Separate .streams.xml schema for declaring application-level data flows with bandwidth, latency, and priority requirements. The same hardware can have multiple profiles for different operational modes (operational, calibration, safe-mode).

Extension Schemas

ROS 2 Extension org.ros2

Maps sensors and motors to ROS 2 topics with message types and QoS profiles. Enables declarative topic configuration from the hardware description.

Gazebo Extension org.gazebosim

Simulation parameters: physics engine settings, plugin bindings, aerodynamics, and contact properties for Gazebo-based simulation.

IEEE 1722 Extension org.ieee.1722

AVTP capabilities and per-stream framing configuration: audio, compressed and raw video, and control protocol tunneling over Ethernet.

Schema Architecture

HCDF uses a single-root XML document with <hcdf> as the document element. Every HCDF file is a self-describing module: standalone robot descriptions and reusable sub-assemblies share the same root element with the same metadata. When composed via <include>, each file retains its own name, author, and license for provenance tracking.

Root attributes

Root child elements