Magnetoelastic Sensing: A Study of Flexible Magnetoelastic Strain Sensors for Highly Deformed Posture Perception

Abstract This study proposes a magnetoelastic strain sensor for highly deformed posture perception. The sensor can maintain stable sensing signal output under significant strain (200%) and at varying stretch rates (ranging from 1000 to 8000 mm min −1 ). The sensor design is simple and can be applied to soft robots and wearable devices. The characteristics of the magnetoelastic sensor can be adjusted by varying the weight ratio of the magnetic powders, which were evaluated experimentally to determine their influence on the mechanical properties and sensing characteristics of the sensors. The experimental results indicate that while the stiffness, sensing signal response, and signal‐to‐noise ratio of the sensor increase with the weight ratio of the magnetic powder, there is a concomitant decrease in mechanical stability. Therefore, the weight ratio of the magnetic powder may require optimization for different scenarios. Notably, the sensing signal remained consistent across different stretching rates. Practical applications of the magnetoelastic sensors were demonstrated through integration with a soft actuator, achieving an root‐mean‐square error (RMSE) of 2.27° over a 90° bending range for bending angle estimation, and onto a knee brace, achieving an RMSE of 3.25° over a 50° range for knee flexion/extension angle measurements at normal walking speeds.