Soft Magnetic Skin for Continuous Deformation Sensing

Recent progress in soft-matter sensors has shown improved fabrication techniques, resolution, and range. However, scaling up these sensors into an information-rich tactile skin remains largely limited by designs that require a corresponding increase in the number of wires to support each new sensing node. To address this, a soft tactile skin that can estimate force and localize contact over a continuous 15mm(2) area with a single integrated circuit and four output wires is introduced. The skin is composed of silicone elastomer loaded with randomly distributed magnetic microparticles. Upon deformation, the magnetic particles change position and orientation with respect to an embedded magnetometer, resulting in a change in the net measured magnetic field. Two experiments are reported to calibrate and estimate both location and force of surface contact. The classification algorithms can localize pressure with an accuracy of >98% on both grid and circle pattern. Regression algorithms can localize pressure to a 3mm(2) area on average. This proof-of-concept sensing skin addresses the increasing need for a simple-to-fabricate, quick-to-integrate, and information-rich tactile surface for use in robotic manipulation, soft systems, and biomonitoring.