🤖 AI Summary
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.
📝 Abstract
Direct torque sensing is a growing need in the robotics community to enable precise control and interactions where torque estimation from motor current is not sufficient. This paper presents a novel disk-shaped magnetoelastic torque sensor with a compact axial envelope of about 1 cm, suitable for integration in robotic joints. A four-magnetometer architecture is used to measure the field modulated by the stress affecting a narrow magnetized region while rejecting the effects of parasitic cross forces. A custom-designed magnetic shield enhances the torque sensitivity while reducing the external stray fields by a factor 7x. The device measures the torque with an accuracy of 1.34 %FS relative to the 50 Nm full scale (FS). The paper details the development of the sensor through the mechanical design, the magnetization procedure, and the experimental validation. The results demonstrate the potential of the proposed sensor for robotic applications.