Snake‐Scale‐Inspired Serrated Structures With Frictional Anisotropy for Tunable Bidirectional Shear‐Force Sensing

ABSTRACT

Flexible tactile sensors are essential components of intelligent robotics, wearable healthcare systems, and human‐machine interfaces. However, most existing tactile sensors have limited capability to discriminate the direction of tangential forces, restricting multidimensional tactile perception under complex loading conditions. Herein, inspired by the serrated unidirectional compliant architecture of snake ventral scales, we develop a bioinspired serrated anisotropic tactile sensor (BSATS) for normal‐pressure sensing and bidirectional shear‐force discrimination. Moreover, modulation of the serration angle enables effective tuning of the sensing sensitivity and detection range, establishing a direct structure‐property relationship for adaptable tactile sensing. Finite element analysis elucidates the direction‐dependent deformation and contact‐area evolution of the serrated friction‐anisotropic structure under normal and bidirectional shear loading, revealing the underlying angle‐dependent anisotropic sensing mechanism. The optimized BSATS exhibits a high pressure sensitivity of 1.832 kPa ⁻¹ , a rapid response time of 50 ms, and robust durability over 2000 loading‐unloading cycles, while reliably distinguishing oppositely directed shear forces. The BSATS further demonstrates versatile functionality in wearable physiological monitoring, human‐motion tracking, surface‐texture recognition, and real‐time robotic grasp‐state perception. This work establishes bioinspired friction anisotropy as an effective structural strategy for tunable multidimensional tactile sensing in wearable healthcare and intelligent robotics.