Fueling Soft Actuators Directly with Small Molecule Fuels for Operational Versatility
Abstract
Muscle tissue combines high power density (~250 W/kg), rapid actuation (up to ~100 Hz), and fuel-source versatility (glucose, fat, etc.) in ways that remain unrivaled by synthetic systems. Due to an increase in the amount of potential applications for so-called ÒsoftÓ robotic devices, the need for actuation systems that approach the characteristics found in biology has never been greater. The goal of this research program is to deliver synthetic actuators that operate using a range of molecular fuels following design principles inspired by biological muscle. Pursuant this goal, this program includes the following specific research objectives: i. Fabricate soft actuators that are powered by small-molecule fuels; ii. Evaluate the performance of small-molecule-powered microgel actuators; and iii. Demonstrate multi-responsive microgel soft actuators. Inspired by biological systems, the technical approach of this research proposal relies on two core concepts: divisional microarchitecture and colocation. Specifically, a scalable procedure pioneered by the research teamÑsurface molding, which uses chemical patterns for directly producing microstructured polymer materialsÑwill be used to generate hydrogel-based actuators that feature tailored catalytic properties which render them responsive to various aqueous fuel formulations. The empirical activities, which center around designing, fabricating, and testing the fundamental performance characteristics (power, force, speed, and fuel flexibility), will be guided by physicochemical simulations, fluid dynamic modeling, and finite element analysis. This theoretical/experimental loop will enable the generation of actuation systems with tailored motions and performance characteristics suitable for future applications in the fabrication of, for example, soft microrobotic systems. This research will enable a new variety of chemically-programmable soft actuators that transform chemical energy into controlled motion, contributing to the mission of the Embodied and Distributed Control, Sensing, and Actuation thrust within the Complex Dynamics and Systems Program. By coupling the morphological transformations of rationally structured microgel actuators to the catalytic decomposition of fuels following a generalizable set of reaction motifs, these efforts present many new opportunities: i. Design flexibility: converting chemical potential to mechanical motion within one system (not separate devices connected through transmission systems) will maximize space-filling efficiency and enable new biomorphic architectures in machines/robots; ii. Adaptable operation: rational selection of general chemical decomposition pathways will lead to devices that can operate using a diverse range of fuel sources; and iii. Damage tolerance: these devices (i.e., microgel actuators) will not rely on one another to maintain operation and thus damage to one unit will not affect the operation of the system. Furthermore, the resulting soft actuation systems will feature speed, control, and power characteristics that surpass that currently possible using stimuli-responsive polymers: miniaturizing and arraying microgels will dramatically improve response time and enable chemically-programmed cooperative assemblies with sophisticated motions and power densities which begin to approach those found in biological systems.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 28, 2022
- Source ID
- W911NF2210262
Entities
People
- Stephen Morin
Organizations
- Army Contracting Command
- United States Army
- University of Nebraska–Lincoln