rdl_model_parser

Utilities for loading robot models into the Robot Dynamics Library (RDL). Supports URDF and MJCF sources, producing fully populated RobotDynamics::Model instances without manual post-processing.

Features

• URDF reader: Parses URDF (via urdfdom) including inertial frames and hydrodynamics extensions used in this repository.
• MJCF reader:
  • Parses MJCF XML directly with TinyXML2 (no MuJoCo runtime required).
  • Computes inertial properties analytically from geoms when inertiafromgeom="true", or uses explicit <inertial> tags otherwise.
  • Supports multiple joints per body (folded into multi-DoF joints), fixed bodies merged into parents, floating bases, and arbitrary joint axes.
• Common helpers for mapping joint/body names to RDL IDs and verifying kinematics/dynamics via the bundled unit tests.

Entry points

• RobotDynamics::ModelParser::parseModelFile(...) — Detects URDF vs MJCF by file contents and builds an RDL model.
• RobotDynamics::ModelParser::urdfReadFromString(...) — Parse URDF XML string.
• RobotDynamics::ModelParser::mjcfReadFromString(...) — Parse MJCF XML string and build an RDL model directly from the XML (preferred).
• RobotDynamics::ModelParser::mjcfReadFromMjModel(...) — Legacy path that consumes a compiled mjModel* (MuJoCo) if you already have one.

Requirements

• RDL (rdl_dynamics) headers and libraries.
• urdfdom (for URDF parsing).
• tinyxml2 (for XML parsing).
• MuJoCo is only required if you use the legacy mjcfReadFromMjModel entry point; direct MJCF parsing does not depend on it.

Testing

parser_test exercises URDF and MJCF loading, kinematics parity, and inertial calculations (including geom-derived inertias). Run:

colcon test --packages-select rdl_model_parser

Licensing

The parser code is released under the zlib license. Some CMake snippets may be subject to different terms; see the LICENSE files in this repository.