Bifurcation-based embodied logic and autonomous actuation

TLDR

Natural systems embed sensing, actuation, and control within their structure, allowing plants to autonomously alter morphology in response to environmental stimuli, unlike electronically integrated mechatronics. The study aims to embody logic in autonomous systems so they can respond to multiple stimuli without electronics. By fabricating 3D‑printable fibrous composites with geometries near a bistability–monostability bifurcation, anisotropic swelling under stimuli drives a key geometric parameter across the bifurcation, producing rapid, large‑amplitude self‑actuation and enabling bioinspired control without external electronics. Actuation time can be tuned by structural design, ranging from 0.6 to 108 s for millimeter‑scale structures.

Abstract

Many plants autonomously change morphology and function in response to environmental stimuli or sequences of stimuli. In contrast with the electronically-integrated sensors, actuators, and microprocessors in traditional mechatronic systems, natural systems embody these sensing, actuation, and control functions within their compositional and structural features. Inspired by nature, we embody logic in autonomous systems to enable them to respond to multiple stimuli. Using 3D printable fibrous composites, we fabricate structures with geometries near bifurcation points associated with a transition between bistability and monostability. When suitable stimuli are present, the materials swell anisotropically. This forces a key geometric parameter to pass through a bifurcation, triggering rapid and large-amplitude self-actuation. The actuation time can be programmed by varying structural parameters (from 0.6 to 108 s for millimeter-scale structures). We demonstrate this bioinspired control strategy with examples that respond to their environment according to their embodied logic, without electronics, external control, or tethering.