A Disk-Shaped Magnetoelastic Torque Sensor for Robotic Joints Using Permanent Magnetization
This study addresses the limited accuracy of joint motor torque estimation in robotic systems by proposing a compact, disc-shaped magnetoelastic torque sensor. The device employs a four-magnetometer differential architecture to suppress parasitic force interference, combined with a custom magnetic shielding structure that enhances sensitivity and mitigates stray field effects. Non-contact torque sensing is achieved through permanent magnetization coupled with the magnetoelastic effect. Experimental results demonstrate a measurement accuracy of 1.34% full scale over a 50 Nm range, with an axial envelope of approximately one centimeter. This work provides an effective solution for embedding high-precision, miniaturized torque sensing within robotic joints.