MagGami: An Electromagnetic Origami Actuator With High Stiffness-Switching Density for Lightweight Joint-Space Wearable Haptics.

Kinesthetic feedback gloves play a central role in immersive virtual and augmented reality (VR/AR) by enabling the perception of object shape, stiffness, and spatial constraints. However, key challenges remain: 1) achieving a large stiffness contrast between free-space and constrained-space states, 2) enabling independent actuation on finger joints, and 3) maintaining lightweight, low-power wearable operation. Here, we introduce MagGami, a miniaturized origami-based variable-stiffness actuator weighing 1.2 g for distributed joint-space integration. By combining origami geometric interlocking with an electromagnetic bistable mechanism, it can be triggered by transient current pulses at the flattened 0° configuration of the origami mechanism. MagGami switches from a freely compliant state to a self-locked high-resistance state with a mean locking response time of 102.8 ms, while requiring no coil power to hold the locked state. The mean device-level locked-to-free effective rotational-stiffness ratio is 795.46, corresponding to a module-level stiffness-switching density of 6.63 × 105 kg- 1, and the specified switching cycle consumes 444 mJ. MagGami uses distributed joint-space actuation to deliver lightweight, independently addressable binary constraint cues at individual finger joints, thereby enhancing the perception of virtual spatial constraints and high-resistance contact in VR/AR interactions. This work demonstrates a compact and energy-efficient strategy for next-generation wearable haptic interfaces.