Digital Twin Interface Specification for Chassis Health Monitoring (CAN DB & Signal Mapping)

This specification serves as the foundational bridge between embedded vehicle electronics and cloud- or edge-based digital twin platforms for agricultural tractors. It formalizes the mapping of raw CAN frames—including identifiers (CAN IDs), multiplexed signals, bit positions, byte ordering (endianness), scaling factors (slope/offset), and engineering units—to domain-specific health indicators such as frame stress indices, weld fatigue accumulation, suspension load asymmetry, and torsional twist rates. The specification mandates version-controlled DBC files compliant with ISO 14229 (UDS) and SAE J1939-71 conventions where applicable, and includes signal validation rules (e.g., range checks, monotonicity for strain-derived signals, timeout thresholds) to ensure data integrity before ingestion into the twin’s physics-informed models. Furthermore, it defines metadata schemas for traceability—linking each signal to its physical sensor location (e.g., 'Rear Axle Left Trailing Arm Strain Gauge'), mechanical subsystem (e.g., 'Rear Suspension Subsystem'), failure mode association (e.g., 'High-Cycle Fatigue – Weld Joint WJ-07'), and calibration lifecycle status. Implementation enables closed-loop health monitoring: anomalies detected in the digital twin (e.g., exceeding von Mises stress thresholds derived from fused CAN-accelerometer and torque signals) can trigger diagnostic workflows, maintenance recommendations, or over-the-air firmware updates to adjust operational limits.