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Gravert SD, Varini E, Kazemipour A, Michelis MY, Buchner T, Hinchet R, Katzschmann RK. Low-voltage electrohydraulic actuators for untethered robotics. SCIENCE ADVANCES 2024; 10:eadi9319. [PMID: 38181082 PMCID: PMC10775996 DOI: 10.1126/sciadv.adi9319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 12/05/2023] [Indexed: 01/07/2024]
Abstract
Rigid robots can be precise but struggle in environments where compliance, robustness to disturbances, or energy efficiency is crucial. This has led researchers to develop biomimetic robots incorporating soft artificial muscles. Electrohydraulic actuators are promising artificial muscles that perform comparably to mammalian muscles in speed and power density. However, their operation requires several thousand volts. The high voltage leads to bulky and inefficient driving electronics. Here, we present hydraulically amplified low-voltage electrostatic (HALVE) actuators that match mammalian skeletal muscles in average power density (50.5 watts per kilogram) and peak strain rate (971% per second) at a 4.9 times lower driving voltage (1100 volts) compared to the state of the art. HALVE actuators are safe to touch, are waterproof, and exhibit self-clearing properties. We characterize, model, and validate key performance metrics of our actuator. Last, we demonstrate the utility of HALVE actuators on a robotic gripper and a soft robotic swimmer.
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Affiliation(s)
| | - Elia Varini
- Soft Robotics Lab, D-MAVT, ETH, Zurich, Switzerland
| | | | | | | | - Ronan Hinchet
- Computational Robotics Lab, D-INFK, ETH, Zurich, Switzerland
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Yang Y, Wang Y. Snapping for 4D-Printed Insect-Scale Metal-Jumper. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307088. [PMID: 37997200 PMCID: PMC10797476 DOI: 10.1002/advs.202307088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Indexed: 11/25/2023]
Abstract
The replication of jumping motions observed in small organisms poses a significant challenge due to size-related effects. Shape memory alloys (SMAs) exhibit a superior work-to-weight ratio, making them suitable for jumping actuators. However, the SMAs advantages are hindered by the limitations imposed by their single actuator configuration and slow response speed. This study proposes a novel design approach for an insect-scale shape memory alloy jumper (net-shell) using 4D printing technology and the bistable power amplification mechanism. The energy variations of the SMA net-shell under different states and loads are qualitatively elucidated through a spring-mass model. To optimize the performance of the SMA net-shell, a non-contact photo-driven technique is employed to induce its shape transition. Experimental investigations explore the deformation response, energy release of the net-shell, and the relationship between the light power density. The results demonstrate that the SMA net-shell exhibits remarkable jumping capabilities, achieving a jump height of 60 body lengths and takeoff speeds of up to 300 body lengths per second. Furthermore, two illustrative cases highlight the potential of net-shells for applications in unstructured terrains. This research contributes to miniaturized jumping mechanisms by providing a new design approach integrating smart materials and advanced structures.
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Affiliation(s)
- Yang Yang
- School of Mechanical EngineeringXi'an Jiaotong UniversityXi'an710049P. R. China
| | - Yongquan Wang
- School of Mechanical EngineeringXi'an Jiaotong UniversityXi'an710049P. R. China
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Villeda-Hernandez M, Baker BC, Romero C, Rossiter JM, Dicker MPM, Faul CFJ. Chemically Driven Oscillating Soft Pneumatic Actuation. Soft Robot 2023; 10:1159-1170. [PMID: 37384917 DOI: 10.1089/soro.2022.0168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023] Open
Abstract
Pneumatic actuators are widely studied in soft robotics as they are facile, low cost, scalable, and robust and exhibit compliance similar to many systems found in nature. The challenge is to harness high energy density chemical and biochemical reactions that can generate sufficient pneumatic pressure to actuate soft systems in a controlled and ecologically compatible manner. This investigation evaluates the potential of chemical reactions as both positive and negative pressure sources for use in soft robotic pneumatic actuators. Considering the pneumatic actuation demands, the chemical mechanisms of the pressure sources, and the safety of the system, several gas evolution/consumption reactions are evaluated and compared. Furthermore, the novel coupling of both gas evolution and gas consumption reactions is discussed and evaluated for the design of oscillating systems, driven by the complementary evolution and consumption of carbon dioxide. Control over the speed of gas generation and consumption is achieved by adjusting the initial ratios of feed materials. Coupling the appropriate reactions with pneumatic soft-matter actuators has delivered autonomous cyclic actuation. The reversibility of these systems is demonstrated in a range of displacement experiments, and practical application is shown through a soft gripper that can move, pick up, and let go of objects. Our approach presents a significant step toward more autonomous, versatile soft robots driven by chemo-pneumatic actuators.
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Affiliation(s)
- Marcos Villeda-Hernandez
- School of Chemistry, University of Bristol, Bristol, United Kingdom
- School of Civil, Aerospace and Mechanical Engineering, University of Bristol, Bristol, United Kingdom
- Bristol Centre of Functional Nanomaterials, University of Bristol, Bristol, United Kingdom
| | - Benjamin C Baker
- School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Christian Romero
- Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom
- Bristol Robotics Laboratory, University of Bristol, Bristol, United Kingdom
| | - Jonathan M Rossiter
- Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom
- Bristol Robotics Laboratory, University of Bristol, Bristol, United Kingdom
| | - Michael P M Dicker
- School of Civil, Aerospace and Mechanical Engineering, University of Bristol, Bristol, United Kingdom
| | - Charl F J Faul
- School of Chemistry, University of Bristol, Bristol, United Kingdom
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Johnson K, Arroyos V, Ferran A, Villanueva R, Yin D, Elberier T, Aliseda A, Fuller S, Iyer V, Gollakota S. Solar-powered shape-changing origami microfliers. Sci Robot 2023; 8:eadg4276. [PMID: 37703382 DOI: 10.1126/scirobotics.adg4276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 08/17/2023] [Indexed: 09/15/2023]
Abstract
Using wind to disperse microfliers that fall like seeds and leaves can help automate large-scale sensor deployments. Here, we present battery-free microfliers that can change shape in mid-air to vary their dispersal distance. We designed origami microfliers using bistable leaf-out structures and uncovered an important property: A simple change in the shape of these origami structures causes two dramatically different falling behaviors. When unfolded and flat, the microfliers exhibit a tumbling behavior that increases lateral displacement in the wind. When folded inward, their orientation is stabilized, resulting in a downward descent that is less influenced by wind. To electronically transition between these two shapes, we designed a low-power electromagnetic actuator that produces peak forces of up to 200 millinewtons within 25 milliseconds while powered by solar cells. We fabricated a circuit directly on the folded origami structure that includes a programmable microcontroller, a Bluetooth radio, a solar power-harvesting circuit, a pressure sensor to estimate altitude, and a temperature sensor. Outdoor evaluations show that our 414-milligram origami microfliers were able to electronically change their shape mid-air, travel up to 98 meters in a light breeze, and wirelessly transmit data via Bluetooth up to 60 meters away, using only power collected from the sun.
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Affiliation(s)
- Kyle Johnson
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, USA
| | - Vicente Arroyos
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, USA
| | - Amélie Ferran
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
- LEGI Laboratory, Université Grenoble Alpes, CNRS, Grenoble, France
| | - Raul Villanueva
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
| | - Dennis Yin
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
| | - Tilboon Elberier
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
| | - Alberto Aliseda
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Sawyer Fuller
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, USA
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Vikram Iyer
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, USA
| | - Shyamnath Gollakota
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, USA
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Chi Y, Hong Y, Zhao Y, Li Y, Yin J. Snapping for high-speed and high-efficient butterfly stroke-like soft swimmer. SCIENCE ADVANCES 2022; 8:eadd3788. [PMID: 36399554 PMCID: PMC9674291 DOI: 10.1126/sciadv.add3788] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Natural selection has tuned many flying and swimming animals to share the same narrow design space for high power efficiency, e.g., their dimensionless Strouhal numbers St that relate flapping frequency and amplitude and forward speed fall within the range of 0.2 < St < 0.4 for peak propulsive efficiency. It is rather challenging to achieve both comparably fast-speed and high-efficient soft swimmers to marine animals due to the naturally selected narrow design space and soft body compliance. Here, bioinspired by the flapping motion in swimming animals, we report leveraging snapping instabilities for soft flapping-wing swimmers with comparable high performance to biological counterparts. The lightweight, butterfly stroke-like soft swimmer (2.8 g) demonstrates a record-high speed of 3.74 body length/s (4.8 times faster than the reported fastest flapping soft swimmer), high power efficiency (0.2 < St = 0.25 < 0.4), low energy consumption cost, and high maneuverability (a high turning speed of 157°/s).
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Song X, Sun R, Wang R, Zhou K, Xie R, Lin J, Georgiev D, Paraschiv AA, Zhao R, Stevens MM. Puffball-Inspired Microrobotic Systems with Robust Payload, Strong Protection, and Targeted Locomotion for On-Demand Drug Delivery. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2204791. [PMID: 36066311 DOI: 10.1002/adma.202204791] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 08/30/2022] [Indexed: 06/15/2023]
Abstract
Microrobots are recognized as transformative solutions for drug delivery systems (DDSs) because they can navigate through the body to specific locations and enable targeted drug release. However, their realization is substantially limited by insufficient payload capacity, unavoidable drug leakage/deactivation, and strict modification/stability criteria for drugs. Natural puffballs possess fascinating features that are highly desirable for DDSs, including a large fruitbody for storing spores, a flexible protective cap, and environmentally triggered release mechanisms. This report presents a puffball-inspired microrobotic system which incorporates an internal chamber for loading large drug quantities and spatial drug separation, and a near-infrared-responsive top-sealing layer offering strong drug protection and on-demand release. These puffball-inspired microrobots (PIMs) display tunable loading capacities up to high concentrations and enhanced drug protection with minimal drug leakage. Upon near-infrared laser irradiation, on-demand drug delivery with rapid release efficiency is achieved. The PIMs also demonstrate translational motion velocities, switchable motion modes, and precise locomotion under a rotating magnetic field. This work provides strong proof-of-concept for a DDS that combines the superior locomotion capability of microrobots with the unique characteristics of puffballs, thereby illustrating a versatile avenue for development of a new generation of microrobots for targeted drug delivery.
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Affiliation(s)
- Xin Song
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Rujie Sun
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Richard Wang
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Kun Zhou
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Ruoxiao Xie
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Junliang Lin
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Dimitar Georgiev
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
- Department of Computing, UKRI Centre for Doctoral Training in AI for Healthcare, Imperial College London, London, SW7 2AZ, UK
| | - Andrei-Alexandru Paraschiv
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
- Department of Chemistry, Imperial College London, London, SW7 2AZ, UK
| | - Ruibo Zhao
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
- Institute of Smart Biomaterials, School of Materials Science and Engineering, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, 310018, China
| | - Molly M Stevens
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
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Li AL, Lee S, Shahsa H, Duduta M. Real time high voltage capacitance for rapid evaluation of dielectric elastomer actuators. SOFT MATTER 2022; 18:7123-7130. [PMID: 36082902 DOI: 10.1039/d2sm00690a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Dielectric elastomer actuators (DEAs) are soft electromechanical transducers that have enabled robotic, haptic, and optical applications. Despite their advantages in high specific energy, large bandwidth, and simple fabrication, their widespread adoption is limited by poor long-term performance. While the mechanical work output has been studied extensively, the electrical energy input has rarely been characterized. Here we report a method to continuously monitor high voltage capacitance during DEA actuation to directly measure the electrical energy consumption. Our approach can track energy conversion efficiency, but also show changes in the device's properties in real-time. This unprecedented insight enables a novel way to study DEAs, evaluate degradation mechanisms, and correlate material structure to device performance. Moreover, it provides a data acquisition platform for data-driven optimization and prediction of long-term actuator performance. This work is a necessary step towards developing ultra-resilient DEAs and enabling a wide range of applications, from wearable devices to soft machines across different scales.
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Affiliation(s)
- Ang Leo Li
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8, Canada.
| | - Siyoung Lee
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8, Canada.
| | - Haleh Shahsa
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8, Canada.
| | - Mihai Duduta
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, Ontario M5S 3G8, Canada.
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Zadeh MN, Garrad M, Romero C, Conn A, Scarpa F, Rossiter J. RoboHeart: A Bi-Directional Zipping Actuator. IEEE Robot Autom Lett 2022. [DOI: 10.1109/lra.2022.3193249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
| | - Martin Garrad
- Department of Engineering Mathematics, University of Bristol, U.K
| | - Christian Romero
- Department of Engineering Mathematics, University of Bristol, U.K
| | - Andrew Conn
- Department of Mechanical Engineering, University of Bristol, U.K
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