Skin‐Inspired Hierarchical Structure Sensor for Ultrafast Active Human–Robot Interaction

Biomimetic sensors that mimic human skin perception have received enormous attention in human motion detection and human–robot interaction. However, the narrow working range limits the response linearity of mechanical stimuli. Especially the ultrafast active response is needed to detect and react to the potential collision. Inspired by the skin structure, a hierarchical structure with poly(ethylene oxide)‐based ionic conductive polymer electrolytes and polyurethane is designed. The observable synergistic sensing mechanism works throughout the compression process, providing the device with a continuous change in electrical response with excellent linearity (R2 = 0.998) over a broad range (100 Pa–500 kPa). The compressive deformation and corresponding mechanical behavior of hierarchical structures are dynamically and simultaneously observed by using in situ electron microscopy at the atomistic scale. Furthermore, a biomimetic skin is established in the human–robot interaction system, which can provide active and efficient collision avoidance. The electrolyte‐elastomer‐based biomimetic hierarchical structure sensor exhibits a wide linear operating range from 100 Pa to 500 kPa. In situ scanning electron microscopy experiments have dynamically characterized the stress concentration relationship of the hierarchical structure under 0–80% compressive deformation. The multi‐stage cooperative working mechanism of hierarchical structure sensors is revealed.