Fish-Scale-Inspired Giant Piezocapacitive Sensors for Human-Level Touch Perception.

Abstract

Achieving human-level touch perception in robotics requires flexible sensors that combine a low detection limit, rapid response, robust reliability, and ease of fabrication. Yet, integrating these diverse characteristics into a single device remains a formidable challenge. This work presents a giant piezocapacitive sensor (GPCS) that matches human touch perception capabilities, based on a fish-scale-inspired electric-field gating film. This mechanically compliant and robust biomimetic film consists of high-permittivity rigid scales separated by air gaps within an elastomer matrix, resulting in a high bulk permittivity. These gaps act as electric-field gates that modulate the fringing electric field between electrode pairs, translating subtle mechanical deformations into substantial capacitance changes. Consequently, the GPCS achieves an exceptional bidirectional bending resolution of 0.005° over a range of ± 90° with a response time of 0.6 ms, showing no performance degradation in a 100 000-cycle bending test. This performance enables the precise discrimination of 16 fabric textures and the detection of surface topographies as fine as 1.8 µm-sufficient to resolve printed toner lines on paper. Finally, a GPCS array is integrated onto a robotic gripper, demonstrating in situ ripeness evaluation of kiwis during grasping, automated fruit sorting, and intuitive human-robot interactions.