Workcell Obstacle Mapping Standard (CAD-to-Occupancy Grid Conversion Guide)

At its core, the standard addresses the critical gap between static, precise CAD representations—typically defined in millimeter-scale parametric modeling environments—and the discretized, sensor-aligned spatial abstractions required by sampling-based planners (e.g., RRT*, A*) or learning-based navigation systems. It mandates rigorous coordinate system harmonization: all CAD parts must be transformed into a common workcell reference frame (e.g., ISO 9787 'robot base frame') using homogeneous transformation matrices before voxelization, ensuring geometric consistency across multi-part assemblies. The standard prescribes resolution selection heuristics based on robot kinematic envelope and minimum safe clearance—e.g., grid cell size ≤ 0.5 × smallest manipulator link width—to balance accuracy and memory footprint. It further defines occupancy semantics: cells are labeled as 'occupied' if ≥50% of their volume intersects solid geometry (using conservative ray-casting or exact Boolean voxelization), 'free' if entirely unobstructed, and 'unknown' only for regions outside sensor reach or intentionally masked (e.g., dynamic human zones). Validation procedures—including mesh-to-grid fidelity metrics (Hausdorff distance < 2× grid resolution) and runtime collision-checking equivalence tests—are integral to certification compliance. This enables plug-and-play integration with ROS 2 Navigation2, MoveIt! 2, and industrial digital twin platforms, significantly reducing commissioning time and eliminating ad-hoc conversion scripts prone to aliasing or misalignment errors.