Miniaturized 3D Magnetic Force Sensor via Laser-Assisted Folding and Magnetization for Enhanced Robotic Dexterity

Magnetic tactile sensor with centripetally magnetization designs is capable of efficient 3D force decoupling sensing, which is essential for advancing robotic dexterity. Nevertheless, the miniaturization of sensors remains a challenge, primarily due to the complexities associated with precisely fabricating such planar magnetic structures. Here, we present a laser-assisted folding and magnetization (LAFM) method to create centripetally magnetized films. Laser-etched grooves enable controlled folding, achieving accurate magnetization alignment in films as small as 5 × 5 mm², which are verified by root mean square errors (RMSEs) of less than 5 µT between the experimental and theoretical magnetic field values. This breakthrough enabled the compact 3D force sensor featuring high force resolution (tangential 3 mN, normal 9 mN), rapid response (34 ms), and long-term stability (>2500 cycles, <1% deviation). When installed on a mobile manipulator, the sensor enables adaptive grasping of delicate objects during obstacle traversal. Its functionality is further enhanced by deploying an array of 16 units on a dexterous hand, which supports non-destructive stiffness recognition across six representative materials and stable manipulation of variable-mass or irregular objects. This work establishes a robust pathway for miniaturized tactile sensors and embodied intelligence, especially in robotic perception.