Rapid state-switching systems based on magnetic-actuated bistable 4R Mechanisms

Bistable mechanisms enable rapid switching between two stable states while maintaining either state without continuous energy input, making them a viable solution for driving rapid state-switching systems. However, bistability in most existing designs is realized via material elastic potential, tuning usually requires geometry changes and performance degrades over time under viscoelasticity and fatigue, limiting generalizability across applications. To address this challenge, we propose a 4R mechanism that achieves bistability via embedded permanent magnets. By shaping the magnetic potential landscape, the mechanism creates two energy minima corresponding to stable states and switches in tens of milliseconds. Prototypes fabricated via 3D printing verified tunable bistable properties by adjusting magnetic strength. The mechanism's bistable performance remained reliable under varying speeds and after 1000 cycles. We further demonstrate cross-scenario applicability by integrating the proposed mechanism into two representative systems, a bistable deployable structure and a bistable gripper. The bistable deployable structure has configuration keeping capability in both folded and deployed states, eliminating the need for locking mechanisms. Moreover, owing to its bistability, it requires a shorter actuation stroke and achieves faster deployment. The bistable gripper achieves adaptive, rapid, and stable grasping, switching within tens of milliseconds while securely holding diverse objects without continuous power. In addition to active grasping, it supports passive interception, capturing moving targets such as a ball moving up to 2 m/s within 10 ms. In summary, this study presents a novel bistable mechanism, providing significant technical support for the development and application of rapid state-switching systems.