A High-Sensitivity Magnetic Tactile Sensor with a Structure-Optimized Hall Sensor and a Flexible Magnetic Film

This article presents a high-sensitivity magnetic tactile sensor comprising a dipole magnetic film and a z-axis Hall sensor. The tactile sensor primarily focuses on pressure response along the z-axis, minimizing interference from magnetic fields in other axes and thereby simplifying signal processing complexity. To enhance the overall performance of the tactile sensor, a qualitative analysis and structural optimization are conducted on both the magnetic film and the Hall sensor. The magnetic film is optimized by comparing different thicknesses and magnetic powder mass fractions, and the Hall sensor undergoes structural optimization through a comparative analysis of different length-to-width (L/W) ratios. By embedding the Hall sensor into the PCB (Printed circuit board), we can ensure a snug fit with the ultra-thin flat magnetic film, resulting in an advantageous packaging effect. Employing these approaches, we substantially improve sensitivity, measuring at 5.92 Gs/N, surpassing the sensitivity level (about 0.17 Gs/N) reported in previous works by one order of magnitude. Finally, the device performs comprehensive characterizations, revealing excellent properties, including low hysteresis (6.82%), rapid response time (<2 ms), remarkable stability (0.09%), and high repeatability (0.48%). This research will actively promote the development of tactile sensors, which offer substantial applications in robotics, health monitoring, and electronic skin devices.