Bifurcation-based embodied logic and autonomous actuation

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.

3D Printing of Amylopectin‐Based Natural Fiber Composites

“…These natural fibers have a high strain of failure and have a strength similar to other natural fibers . The cotton forms a network of primary fibers (with diameters of ≈11 µm), which are nominally aligned along the print path due to shearing of the material during extrusion, and secondary (submicron) fibers that emerge from the surfaces of the primary fibers. We investigate the effect of processing parameters on the microstructure and the mechanical properties using formal design of experiments (DOE).…”

3D and 4D printing for optics and metaphotonics

“…Multi-material printing can provide a venue for realizing various active structures. Based on multi-material 3D printing, there have been various studies on multi-functional structures and sequentially deforming or actuating structures [15][16][17][18]. For example, Le Duigou et al fabricated a bio-inspired electro-thermo-hygro reversible shape-changing structure using a hygroscopic polyamide matrix and continuous carbon fibers [19].…”

Electrochemical reactions drive morphing of materials

“…Solving such large structures -finding the location of each atom -is a great technical challenge. Nevertheless, studies in the past couple of years have described partial structures of Piezo1 at near-atomic resolution [6][7][8] .…”