A three-dimensionally architected biomimetic magnetic sensor with gradient structure and wide detection range for versatile applications

Conventional tactile sensors often encounter challenges in simultaneously achieving a wide detection range and high sensitivity, which significantly limits their applicability in various practical scenarios. Drawing inspiration from the structural characteristics of human skin, we design a magnetic tactile sensor composed of three layers with distinct elastic moduli and a three-dimensional distribution of magnetic particles. Compression-assisted magnetization is employed to optimize the orientation of magnetic moments. This structural strategy enables the sensor to detect subtle stimuli, such as the placement and removal of a 50 mg metal foil, while supporting pressures up to 50 kPa and maintaining a sensitivity of 0.148 kPa⁻¹ above 30 kPa, representing a 202 % improvement over the un-optimized configuration. In addition to pressure sensing, the sensor also exhibits high sensitivity to shear forces, with measured sensitivities of 0.13 N⁻¹ in the range of 0–1.13 N and 0.33 N⁻¹ in the range of 1.13–3 N. Experimental results confirm the potential of this magnetic tactile sensor for applications in grasp motion perception, slip detection, and human–machine interface systems.