Cyber-Physical AI: Systematic Research Domain for Integrating AI and Cyber-Physical Systems

The integration of Cyber-Physical Systems (CPS) and AI presents both opportunities and challenges. AI operates on the principle that "good things happen probabilistically," while CPS adheres to the principle that "all bad things must not happen," requiring uncertainty-awareness. Furthermore, the difference between AI's resource accessibility assumption and CPS's resource limitations highlights the need for resource-awareness. We introduce Cyber-Physical AI (CPAI), an interdisciplinary sub-field of AI and CPS research, to address these constraints. To the best of our knowledge, CPAI is the first research domain on CPS-AI integration. We propose a 3D classification schema of CPAI: Constraint (C), Purpose (P), and Approach (A). We also systematize the CPS-AI integration process into three phases and nine steps. By analyzing 104 studies, we highlight nine key challenges and insights from a CPAI perspective. CPAI aims to unify fragmented studies and provide guidance for reliable and resource-efficient integration of AI as a component of CPS.