Effect of Elastic Layer Geometry on the Range and Sensitivity of Flexible Magnetic Tactile Sensor

Tactile sensing is a foundational technology for advancing artificial intelligence and flexible electronics. Magnetically based tactile sensors show considerable promise; however, prior research has predominantly focused on magnetic films, overlooking the optimization of the non-magnetic elastic layer. This study introduces a complementary design strategy that enhances performance through geometric optimization of the non-magnetic elastic layer. A flexible magnetic tactile sensor (FMTS) with a sandwich architecture is presented, and a systematic quantitative analysis is conducted to show how elastic-layer geometry affects sensitivity and measurement range. A clear geometry-performance relationship is established by comparing planar, hemispherical, and directionally anisotropic pyramidal microstructures and integrating magnetic field modeling with mechanical analysis. Relative to the planar baseline, hemispherical and pyramidal microstructures improve normal-force sensitivity by factors of 2.47 and 5.34, and shear-force sensitivity by factors of 2.12 and 4.28, respectively, while the normal-force measurement range can be tuned from 1700 gf (planar) down to 380 gf (pyramidal). The FMTS achieves triaxial decoupling with quantified crosstalk, exhibits long-term stability (as validated by stress-relaxation and creep tests) and environmental robustness (under thermal and humidity tests), and demonstrates practical utility in grip-force monitoring. In summary, this work establishes a new design dimension for high-performance flexible magnetic sensors by tailoring elastic microstructures—an approach conceptually distinct from, yet functionally complementary to, prevailing magnetization strategies.