Unit-Assembly Module Design Enabling Easy Disassembly and Automatic Assembly for Recyclable Robots

This study proposes a unit-assembly architecture for robot modules that enables tool-less disassembly and automated assembly as a design pathway for recyclable robots. The robot module is decomposed into nine separable functional units (drivetrain, cooling, and control groups) connected exclusively via three types of releasable interfaces: magnetic docking, magnetic dowels, and mortise-and-tenon joints. This architecture allows non-destructive disassembly of all functional units in eight pull or slide operations, enables the clean separation of material streams, and facilitates the recovery and reuse of high-value components (motors, sensors, thermoelectric coolers, and printed circuit boards). Experimental validation confirms that the design does not compromise performance: the drivetrain achieves stable positioning (settling time ∼0.9 s, steady-state error ∼1%) and the active cooling system reduces motor temperature to room temperature within 200 s. Furthermore, we demonstrate an automatic assembly system using a 4-DOF robot arm with YOLOv8-based vision (mAP50=0.828), thereby validating that a representative set of releasable interfaces supporting disassembly are also compatible with the robotic assembly. Full nine-unit automatic assembly remains a topic for future investigation.