Active Fabrics with Controllable Stiffness for Robotic Assistive Interfaces.

Assistive interfaces enable collaborative interactions between humans and robots. In contrast to traditional rigid devices, conformable fabrics with tunable mechanical properties have emerged as compelling alternatives. However, existing assistive fabrics actuated by fluidic or thermal stimuli struggle to adapt to complex body contours and are hindered by challenges such as large volumes after actuation and slow response rates. To overcome these limitations, we draw inspiration from biological protective organisms combining hard and soft phases, and propose active assistive fabrics consisting of architectured rigid tiles interconnected with flexible actuated fibers. Through programmable tessellation of target body shapes into architectured tiles and controlling their interactions by the actuated fibers, our active fabrics can rapidly (within seconds) transition between soft compliant configurations and rigid states conformable to the body (> 350 times stiffness change, loading capacity to weight ratio > 50) while minimizing the device volume after actuation. We demonstrate the versatility of our active fabrics as exosuits for tremor suppression and lifting assistance. We also present its potential as body armors for impact mitigation. Electrothermal actuators are integrated for smart actuation with convenient folding capabilities. Our work offers a practical framework for designing customizable active fabrics with shape adaptivity and controllable stiffness, these active fabrics have wide applications in wearable exosuits, haptic devices, and medical rehabilitation systems. This article is protected by copyright. All rights reserved.