Normative-Aware Ontology for Assistive Robotics: Bridging Legal Accountability and Cognitive Autonomy in Elderly Care

As assistive robots move into home-based rehabilitation and elderly care, technical autonomy must be reconciled with legal accountability, data protection, privacy, and safety. This paper proposes an ontology-centered normative decision architecture that embeds compliance-by-design into robot planning and monitoring. The approach combines a precedence-aware constraint lattice with a multi-layer reasoning stack to operationalize legal requirements alongside clinical workflows. The ontology is modular and adopts IEEE 7007 concepts to structure explanation artifacts and responsibility attributions for automated decisions. Two execution primitives translate norms into behavior to enable, block, or mitigate actions and generate audience-appropriate explanations. Through illustrative scenarios grounded in the Italian regulatory context and a post-stroke telerehabilitation setting, the architecture shows how explicit normative precedence supports gated compliance and traceable accountability. Limitations are discussed and future directions are outlined on multi-jurisdictional profiles, interoperable evidence exchange, and governance tooling, advancing a portable, auditable substrate for safe, explainable, and norm-adaptive assistive robotics in home rehabilitation.