Harnessing bistability for directional propulsion of soft, untethered robots

Chen, Tian and Bilal, Osama R. and Shea, Kristina and Daraio, Chiara (2018) Harnessing bistability for directional propulsion of soft, untethered robots. Proceedings of the National Academy of Sciences of the United States of America, 115 (22). pp. 5698-5702. ISSN 0027-8424. PMCID PMC5984517. doi:10.1073/pnas.1800386115. https://resolver.caltech.edu/CaltechAUTHORS:20180515-101708023

	PDF - Published Version See Usage Policy. 2MB
	PDF (Appendix) - Supplemental Material See Usage Policy. 4MB
	Video (MPEG) (Movie S1. Propulsion of a single stroke swimmer. The distance travelled is approximately 1.15l where l is the body length of the swimmer.) - Supplemental Material See Usage Policy. 161kB
	Video (MPEG) (Movie S2. Shape memory muscle of different thickness exhibiting different time to activation.) - Supplemental Material See Usage Policy. 1MB
	Video (MPEG) (Movie S3. Propulsion of a two-stroke swimmer. The sequence of activation is controlled by the thickness of the shape memory muscle. The distance traveled is approximately 1.9l (where l is the length of the single actuator swimmer).) - Supplemental Material See Usage Policy. 966kB
	Video (MPEG) (Movie S4. Propulsion of a two-stroke directional swimmer. The programmed path is straight followed by a left turn. The distance traveled is approximately 0.5l after the first stroke, and a turn of 23.85° after the second stroke.) - Supplemental Material See Usage Policy. 551kB
	Video (MPEG) (Movie S5. Propulsion of a two-stroke directional swimmer. The programmed path includes a left turn followed by a right turn. The rotation is approximately 21.64° after the first stroke, and −21.45° after the second stroke.) - Supplemental Material See Usage Policy. 587kB
	Video (MPEG) (Movie S6. Shape memory muscle of different material exhibiting controlled activation depending on the surrounding temperature.) - Supplemental Material See Usage Policy. 1MB
	Video (MPEG) (Movie S7. Propulsion of a reversing swimmer. The programmed operation includes a forward stroke, deployment of cargo, and a reverse stroke. The sequence of activation is controlled by the temperature of the surrounding environment. The first stroke ...) - Supplemental Material See Usage Policy. 683kB
	Video (MPEG) (Movie S8. Internal mechanism of the actuator showing the shape memory muscle pushing the bistable mechanism from one equilibrium state to the next.) - Supplemental Material See Usage Policy. 904kB

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20180515-101708023

Abstract

In most macroscale robotic systems, propulsion and controls are enabled through a physical tether or complex onboard electronics and batteries. A tether simplifies the design process but limits the range of motion of the robot, while onboard controls and power supplies are heavy and complicate the design process. Here, we present a simple design principle for an untethered, soft swimming robot with preprogrammed, directional propulsion without a battery or onboard electronics. Locomotion is achieved by using actuators that harness the large displacements of bistable elements triggered by surrounding temperature changes. Powered by shape memory polymer (SMP) muscles, the bistable elements in turn actuate the robot’s fins. Our robots are fabricated using a commercially available 3D printer in a single print. As a proof of concept, we show the ability to program a vessel, which can autonomously deliver a cargo and navigate back to the deployment point.

Item Type:

Article

Related URLs:

URL	URL Type	Description
https://doi.org/10.1073/pnas.1800386115	DOI	Article
http://www.pnas.org/lookup/suppl/doi:10.1073/pnas.1800386115/-/DCSupplemental	Publisher	Supplemental material
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5984517/	PubMed Central	Article

ORCID:

Author	ORCID
Bilal, Osama R.	0000-0003-3803-5084
Shea, Kristina	0000-0003-3921-2214
Daraio, Chiara	0000-0001-5296-4440

Additional Information:

© 2018 National Academy of Sciences. Published under the PNAS license. Edited by John A. Rogers, Northwestern University, Evanston, IL, and approved April 23, 2018 (received for review January 9, 2018). Published ahead of print May 15, 2018. We thank Jung-Chew Tse for fabrication support and Connor McMahan and Ethan Pickering for support in experiments. This work was supported by Army Research Office Grant W911NF-17-1-0147 and Eidgenössische Technische Hochschule (ETH) Postdoctoral Fellowship FEL-26 15-2 (to O.R.B.). Author contributions: O.R.B. and C.D. designed research; T.C. and O.R.B. performed research; T.C., O.R.B., K.S., and C.D. analyzed data; and T.C., O.R.B., K.S., and C.D. wrote the paper. The authors declare no conflict of interest. This article is a PNAS Direct Submission. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1800386115/-/DCSupplemental.

Funders:

Funding Agency	Grant Number
Army Research Office (ARO)	W911NF-17-1-0147
ETH Zurich	FEL-26 15-2

Subject Keywords:

soft robots; programmable materials; mechanical bistability; shape memory polymer; autonomous propulsion

Issue or Number:

PubMed Central ID:

PMC5984517

DOI:

10.1073/pnas.1800386115

Record Number:

CaltechAUTHORS:20180515-101708023

Persistent URL:

https://resolver.caltech.edu/CaltechAUTHORS:20180515-101708023

Official Citation:

Harnessing bistability for directional propulsion of soft, untethered robots Tian Chen, Osama R. Bilal, Kristina Shea, Chiara Daraio Proceedings of the National Academy of Sciences May 2018, 115 (22) 5698-5702; DOI: 10.1073/pnas.1800386115

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No commercial reproduction, distribution, display or performance rights in this work are provided.

ID Code:

86403

Collection:

CaltechAUTHORS

Deposited By:

Katherine Johnson

Deposited On:

15 May 2018 17:37

Last Modified:

10 Mar 2022 17:13

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