Robot hardware is the academic and engineering domain focused on the design, construction, and integration of the physical components that constitute robotic systems, encompassing mechanical structures, actuation mechanisms, sensing modalities, power systems, and electronic interfaces. This research area investigates principles from mechanics, materials science, and electrical engineering to develop novel and optimized physical embodiments, enabling robots to perceive, interact with, and operate within their environments, thereby serving as the foundational platform for robotic capabilities.