Muscle-inspired magnetic actuators that push, pull, crawl, and grasp

2026-04-20

AI Summary

This study addresses the longstanding challenge in soft robotics of simultaneously achieving large deformations, high load-bearing capacity, and multifunctional motion with a single actuation material. The authors propose a muscle-inspired magnetic actuator fabricated via laser powder bed fusion (LPBF), which enables concurrent programming of stiffness distribution and magnetization direction within a thermoplastic polyurethane/neodymium–iron–boron composite. Integrated with an anisotropic friction architecture, the resulting lightweight actuator exhibits exceptional fatigue resistance and reconfigurable remote actuation capabilities. It can lift payloads up to 32 times its own mass (50 g), achieves 100% success in locomotion across textured surfaces in a crawling robot configuration, and reliably grasps and anchors heterogeneous objects ranging from soft to rigid.

Technology Category

• Intelligent Robots: Manipulation
• Natural Language Processing: Safety and Robustness
• Planning, Routing, and Scheduling: Replanning and Plan Repair

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Search and Retrieval-Augmented AI: Multilingual and cross-lingual Web search
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments

Abstract

Functional magnetic composites capable of large deformation, load bearing, and multifunctional motion are essential for next-generation adaptive soft robots. Here, we present muscle-inspired magnetic actuators (MMA), additively manufactured from a thermoplastic/permanent magnet polyurethane/Nd2Fe14B (TPU/MQP-S) composite using laser powder bed fusion (LPBF). By tuning the laser-energy scale between 1.0 and 3.0, both mechanical stiffness and magnetic response are precisely controlled: the tensile strength increases from 0.28 to 0.99 MPa while maintaining 30-45% elongation at break. This process enables the creation of 0.5 mm-thick flexural hinges, which reversibly bend and fold under moderate magnetic fields without damage. Two actuator types are reported showing the system versatility. The elongated actuator with self-weight of 1.57 g, magnetized in its contracted state, achieves linear contraction under a 500 mT field, lifting 50 g (32x its own weight) and sustaining performance over at least 50 cycles. Equipped with anisotropic frictional feet, it supports movement of a magnetic crawling robot that achieves up to 100% locomotion success on textured substrates. The expandable actuator exhibits reversible opening and closing under a 300 mT field, reliably grasping and releasing different objects, including soft berries and rigid 3D printed geometries. It can also anchor in a tube while holding suspended 50 g loads. This work demonstrates a LPBF-based strategy to program both stiffness and magnetization within a single material system, enabling remotely driven, reconfigurable, and fatigue-resistant soft actuators. The approach opens new possibilities for force controlled, multifunctional magnetic soft robots for adaptive gripping, locomotion, and minimally invasive manipulation of biomedical tools.

Problem

• soft robotics
• magnetic actuators
• large deformation
• multifunctional motion
• load bearing

Innovation

• magnetic soft actuators
• laser powder bed fusion
• additive manufacturing
• multifunctional locomotion
• programmable stiffness