# Cyber-Physical System **Domain:** Control Systems / Computing / Engineering **Doc Type:** Canonical Bridge Concept **Maturity:** Developed ## Definition A **cyber-physical system** is a system in which computation, communication, sensing and physical processes operate in a closed relationship. Software does not merely describe the physical system; it receives evidence from it and can help change its subsequent state. ## Historical Lineage Mechanical governors and feedback control linked measurement to physical response before digital computing. Industrial automation added programmable controllers and supervisory systems. Networked sensing, identity and modeling now connect many local loops to higher-order operational representations. ## Governing Variable The system governs physical state through measured variables, inferred state, objectives, constraints and actuation. ## Material and Institutional Manifestation Vehicles, factories, grids, medical devices, buildings, robots and data centers are cyber-physical when computation participates materially in their operation. [[wiki/Industrial Control System|Industrial Control System]] is a major implementation family; [[wiki/Cyber-Physical Enclosure|Cyber-Physical Enclosure]] emphasizes bounded environments and access. ## Computational Analogue The defining loop is actual rather than analogical: sensors produce [[wiki/Telemetry|telemetry]], [[wiki/State Estimation|state estimation]] constructs usable state, a controller selects action and an [[wiki/Actuator|actuator]] changes the physical process. ## Relation to Governance Cyber-physical systems make infrastructure dynamically addressable. The governing question shifts from who owns an asset to who can observe its state, change its setpoints, update its software and define the model through which intervention appears necessary. ## Constitutional Question and Failure Modes Cybersecurity, safety and due process converge when a digital decision opens a door, changes treatment, redirects power or stops machinery. Failure modes include sensor error, unsafe actuation, time desynchronization, brittle automation, remote compromise and loss of local competence. ## Related Ontology [[wiki/Infrastructure as Executable Social Order|Infrastructure as Executable Social Order]] · [[wiki/Control Loop|Control Loop]] · [[wiki/Operational Technology|Operational Technology]] · [[wiki/Operational Representation|Operational Representation]] · [[wiki/Digital Twin|Digital Twin]]