Browsing by Subject "Material feedback"

Now showing 1 - 3 of 3

Open Access
Artificial heliotropism and nyctinasty based on optomechanical feedback and no electronics
(Mary Ann Liebert, 2018) Baytekin, B.; Cezan, S. D.; Baytekin, H. T.; Grzybowski, B. A.
Although plants are typically not considered an inspiration for designing motile robots, they do perform a variety of intricate motion patterns, including diurnal cycles of sun tracking (heliotropism) and leaf opening (nyctinasty). In real plants, these motions are controlled by complex, feedback-based biological mechanisms that, to date, have been mimicked only in computer-controlled artificial systems. This work demonstrates both heliotropism and nyctinasty in a system in which few simple, but strategically positioned thermo-responsive springs and lenses form a feedback loop controlling these motions and substantiating a behavioral analogy to "plants." In particular, this feedback allows the "artificial plant" to reach and stabilize at a metastable position in which the solar flux on the "plants" and the solar power "leaves" are maximized. Unlike many soft robotic systems, our "plants" are completely autonomous, in that, they do not require any external controls or power sources. Bioinspired designs such as this could be of interest for soft robotic systems in which materials alone - rather than power-consuming electronic circuitry - control the motions.
Open Access
Bio-inspired paper plant robots: artificial heliotropism and nyctinasty through transpiration
(2019-08) Cezan, Süleyman Doruk
Self-regulation is a fundamental feature of all living systems, which maintains their metabolic activities through biochemical feedback loops. Those feedback loops respond to environmental stimuli, and therefore the organism displays ‘embodied intelligence’. Despite the complexity of these feedback loops, using them as a source of inspiration can open new endeavors in soft robotics to design self-regulating systems, and ultimately to fuse embodied intelligence into soft robots. Here we show some simple systems, in which plant-inspired soft robots display heliotropism (tracking the sun) and nyctinasty (opening and closing its leaves) through material feedback and artificial transpiration for self-regulation – all being examples of embodiment of intelligence. First, materials feedback is adapted to a hard robotic system behaving similar to a soft robot, displaying heliotropism and nyctinasty by using the phase transition of shape memory alloy springs. Then, artificial transpiration is integrated into a soft robotic system, using swelling/deswelling of hydrogels on the paper body by using origami/kirigami strategies. Both material and transpiration feedback involve stabilization with cycles of traction and contraction (of shape memory alloys, or hydrogels) events that keep the robots at a metastable state, maximizing of solar flux on the leaves (decorated with solar panels) for higher efficiencies of harvesting light. Moreover, the feedback mechanism of the hydrogel-based system can be advanced by using hybrid hydrogels (e.g. an addition of thermoresponsive hydrogels), or doping the gel with light-absorbing chemicals, or altering the geometrical design of the systems. Finally, achieving self-regulation in soft robots through material/transpiration feedback is important to attain the embodiment of intelligence in them, and this may have implications extending from energy efficiency to adaptability in autonomous soft robots.
Open Access
Self-regulating plant robots: bioinspired heliotropism and nyctinasty
(Mary Ann Liebert, 2020) Cezan, Süleyman Doruk; Baytekin, Hasan Tarık; Baytekin, Bilge
Self-regulation (or so-called homeostasis) is a property of all living organisms to maintain an internal stable state through specialized biofeedback mechanisms under varying external and internal conditions. Although these feedback mechanisms in living organisms are complex networks and hard to implement one-to-one in artificial systems, the new approaches in soft robotics may benefit from the concept of self-regulation—especially in the new endeavors of making untethered, autonomous soft robots. In this study, we show a simple system, in which plant robots display heliotropism (sun tracking) and nyctinasty (leaf opening) through artificial self-regulation attained through a bioinspired transpiration mechanism. The feedback involves dehydration/hydration and transpiration events that keep the stem continuously in a metastable position, which maximizes light on plant leaves and the efficiency of light harvesting when solar panels are attached on leaves. We also demonstrate that this artificial feedback can be regulated by doping with light-absorbing chemicals or by changing the geometry of the system, and it can further be expanded to other lightweight systems. Implementing self-regulation into (soft) robots through bioinspired material feedback is beneficial not only for energy efficiency and harvesting but also for achieving embodied intelligence in autonomous soft robots.