Intelligent Systems


2023


A Versatile Jellyfish-Like Robotic Platform for Effective Underwater Propulsion and Manipulation
A Versatile Jellyfish-Like Robotic Platform for Effective Underwater Propulsion and Manipulation

Wang, T., Joo, H., Song, S., Hu, W., Keplinger, C., Sitti, M.

Science Advances, 9(15), American Association for the Advancement of Science, April 2023, Tianlu Wang and Hyeong-Joon Joo contributed equally to this work. (article)

Abstract
Underwater devices are critical for environmental applications. However, existing prototypes typically use bulky, noisy actuators and limited configurations. Consequently, they struggle to ensure noise-free and gentle interactions with underwater species when realizing practical functions. Therefore, we developed a jellyfish-like robotic platform enabled by a synergy of electrohydraulic actuators and a hybrid structure of rigid and soft components. Our 16-cm-diameter noise-free prototype could control the fluid flow to propel while manipulating objects to be kept beneath its body without physical contact, thereby enabling safer interactions. Its against-gravity speed was up to 6.1 cm/s, substantially quicker than other examples in literature, while only requiring a low input power of around 100 mW. Moreover, using the platform, we demonstrated contact-based object manipulation, fluidic mixing, shape adaptation, steering, wireless swimming, and cooperation of two to three robots. This study introduces a versatile jellyfish-like robotic platform with a wide range of functions for diverse applications.

YouTube video link (url) DOI [BibTex]

2023

YouTube video link (url) DOI [BibTex]


Miniature coiled artificial muscle for wireless soft medical devices
Miniature coiled artificial muscle for wireless soft medical devices

Li, M., Tang, Y., Soon, R. H., Dong, B., Hu, W., Sitti, M.

Science Advances, 8(10):eabm5616, March 2022 (article)

DOI [BibTex]


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Turbulence Modulation and Energy Transfer in Turbulent Channel Flow Coupled with One-Side Porous Media

Chu, X., Wang, W., Müller, J., Schöning, H. V., Liu, Y., Weigand, B.

In High Performance Computing in Science and Engineering’20, pages: 373-386, Springer, 2021 (incollection)

[BibTex]

[BibTex]


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Information transfer between turbulent boundary layers and porous media

Wang, W., Chu, X., Lozano-Durán, A., Helmig, R., Weigand, B.

Journal of Fluid Mechanics, 920, Cambridge University Press, 2021 (article)

[BibTex]

[BibTex]


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Transport of turbulence across permeable interface in a turbulent channel flow: interface-resolved direct numerical simulation

Chu, X., Wang, W., Yang, G., Terzis, A., Helmig, R., Weigand, B.

Transport in Porous Media, 136(1):165-189, Springer, 2021 (article)

[BibTex]

[BibTex]


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Energy transfer structures associated with large-scale motions in a turbulent boundary layer

Wang, W., Pan, C., Wang, J.

Journal of Fluid Mechanics, 906, Cambridge University Press, 2021 (article)

[BibTex]

[BibTex]


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An assessment of turbulence transportation near regular and random permeable interfaces

Wang, W., Yang, G., Evrim, C., Terzis, A., Helmig, R., Chu, X.

Physics of Fluids, 33(11):115103, AIP Publishing LLC, 2021 (article)

[BibTex]

[BibTex]


Method of actuating a shape changeable member, shape changeable member and actuating system
Method of actuating a shape changeable member, shape changeable member and actuating system

Hu, W., Lum, G. Z., Mastrangeli, M., Sitti, M.

Google Patents, January 2020, US Patent App. 16/477,593 (patent)

Abstract
The present invention relates to a method of actuating a shape changeable member of actuatable material. The invention further relates to a shape changeable member and to a system comprising such a shape changeable member and a magnetic field apparatus.

[BibTex]


Ultrasound-guided wireless tubular robotic anchoring system
Ultrasound-guided wireless tubular robotic anchoring system

Wang, T., Hu, W., Ren, Z., Sitti, M.

IEEE Robotics and Automation Letters, 5(3):4859-4866, IEEE, 2020 (article)

link (url) DOI [BibTex]

link (url) DOI [BibTex]


Multifunctional magnetic soft composites: a review
Multifunctional magnetic soft composites: a review

Wu, S., Hu, W., Ze, Q., Sitti, M., Zhao, R.

Multifunctional Materials, 3(4):042003, 2020 (article)

link (url) DOI Project Page [BibTex]

link (url) DOI Project Page [BibTex]


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Turbulence, pseudo-turbulence, and local flow topology in dispersed bubbly flow

Chu, X., Liu, Y., Wang, W., Yang, G., Weigand, B., Nemati, H.

Physics of Fluids, 32(8):083310, AIP Publishing LLC, 2020 (article)

[BibTex]

[BibTex]

2019


A magnetically-actuated untethered jellyfish-inspired soft milliswimmer
A magnetically-actuated untethered jellyfish-inspired soft milliswimmer

(Best Paper Award)

Ziyu Ren, T. W., Hu, W.

Robotics: Science and Systems, June 2019 (conference)

Project Page [BibTex]


Translational prospects of untethered medical microrobots
Translational prospects of untethered medical microrobots

Hakan Ceylan, I. C. Y. U. K. W. H. M. S.

Progress in Biomedical Engineering, 1, pages: 012002, 2019 (article)

DOI [BibTex]

DOI [BibTex]


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Multi-component variational mode decomposition and its application on wall-bounded turbulence

Wang, W., Pan, C., Wang, J.

Experiments in Fluids, 60(6):1-16, Springer, 2019 (article)

[BibTex]

2018


Small-scale soft-bodied robot with multimodal locomotion
Small-scale soft-bodied robot with multimodal locomotion

Hu, W., Lum, G. Z., Mastrangeli, M., Sitti, M.

Nature, 554, pages: 81-85, Nature, January 2018 (article)

Abstract
Untethered small-scale (from several millimetres down to a few micrometres in all dimensions) robots that can non-invasively access confined, enclosed spaces may enable applications in microfactories such as the construction of tissue scaffolds by robotic assembly1, in bioengineering such as single-cell manipulation and biosensing2, and in healthcare3,4,5,6 such as targeted drug delivery4 and minimally invasive surgery3,5. Existing small-scale robots, however, have very limited mobility because they are unable to negotiate obstacles and changes in texture or material in unstructured environments7,8,9,10,11,12,13. Of these small-scale robots, soft robots have greater potential to realize high mobility via multimodal locomotion, because such machines have higher degrees of freedom than their rigid counterparts14,15,16. Here we demonstrate magneto-elastic soft millimetre-scale robots that can swim inside and on the surface of liquids, climb liquid menisci, roll and walk on solid surfaces, jump over obstacles, and crawl within narrow tunnels. These robots can transit reversibly between different liquid and solid terrains, as well as switch between locomotive modes. They can additionally execute pick-and-place and cargo-release tasks. We also present theoretical models to explain how the robots move. Like the large-scale robots that can be used to study locomotion17, these soft small-scale robots could be used to study soft-bodied locomotion produced by small organisms.

link (url) DOI Project Page [BibTex]

2017


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Localized Single-Cell Lysis and Manipulation Using Optothermally-Induced Bubbles
Localized Single-Cell Lysis and Manipulation Using Optothermally-Induced Bubbles

Fan, Q., Hu, W., Ohta, A. T.

Micromachines, 8(4):121, 2017 (article)

[BibTex]

[BibTex]

2016


Shape-programmable magnetic soft matter
Shape-programmable magnetic soft matter

Lum, G. Z., Ye, Z., Dong, X., Marvi, H., Erin, O., Hu, W., Sitti, M.

Proceedings of the National Academy of Sciences, 113(41):E6007–E6015, 2016 (article)

Abstract
Shape-programmable matter is a class of active materials whose geometry can be controlled to potentially achieve mechanical functionalities beyond those of traditional machines. Among these materials, magnetically actuated matter is particularly promising for achieving complex time-varying shapes at small scale (overall dimensions smaller than 1 cm). However, previous work can only program these materials for limited applications, as they rely solely on human intuition to approximate the required magnetization profile and actuating magnetic fields for their materials. Here, we propose a universal programming methodology that can automatically generate the required magnetization profile and actuating fields for soft matter to achieve new time-varying shapes. The universality of the proposed method can therefore inspire a vast number of miniature soft devices that are critical in robotics, smart engineering surfaces and materials, and biomedical devices. Our proposed method includes theoretical formulations, computational strategies, and fabrication procedures for programming magnetic soft matter. The presented theory and computational method are universal for programming 2D or 3D time-varying shapes, whereas the fabrication technique is generic only for creating planar beams. Based on the proposed programming method, we created a jellyfish-like robot, a spermatozoid-like undulating swimmer, and an artificial cilium that could mimic the complex beating patterns of its biological counterpart.

DOI [BibTex]

2016

DOI [BibTex]


Cell patterning in a hydrogel using optically induced dielectrophoresis
Cell patterning in a hydrogel using optically induced dielectrophoresis

Hu, W., Ishii, K., Ohta, A. T.

In Optical MEMS and Nanophotonics (OMN), 2016 International Conference on, pages: 1-2, 2016 (inproceedings)

[BibTex]

[BibTex]

2015


Biomedical applications of untethered mobile milli/microrobots
Biomedical applications of untethered mobile milli/microrobots

Sitti, M., Ceylan, H., Hu, W., Giltinan, J., Turan, M., Yim, S., Diller, E.

Proceedings of the IEEE, 103(2):205-224, IEEE, March 2015 (article)

Abstract
Untethered robots miniaturized to the length scale of millimeter and below attract growing attention for the prospect of transforming many aspects of health care and bioengineering. As the robot size goes down to the order of a single cell, previously inaccessible body sites would become available for high-resolution in situ and in vivo manipulations. This unprecedented direct access would enable an extensive range of minimally invasive medical operations. Here, we provide a comprehensive review of the current advances in biomedical untethered mobile milli/microrobots. We put a special emphasis on the potential impacts of biomedical microrobots in the near future. Finally, we discuss the existing challenges and emerging concepts associated with designing such a miniaturized robot for operation inside a biological environment for biomedical applications.

DOI Project Page [BibTex]

2015

DOI Project Page [BibTex]


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Efficient single-cell poration by microsecond laser pulses

Fan, Q., Hu, W., Ohta, A. T.

Lab on a Chip, 15(2):581-588, Royal Society of Chemistry, 2015 (article)

[BibTex]

[BibTex]

2014


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Continuous electrowetting of non-toxic liquid metal for RF applications

Gough, R. C., Morishita, A. M., Dang, J. H., Hu, W., Shiroma, W. A., Ohta, A. T.

IEEE Access, 2, pages: 874-882, IEEE, 2014 (article)

[BibTex]

2014

[BibTex]


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Laser-induced microbubble poration of localized single cells

Fan, Q., Hu, W., Ohta, A. T.

Lab on a Chip, 14(9):1572-1578, Royal Society of Chemistry, 2014 (article)

[BibTex]

[BibTex]


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Liquid-metal reconfigurable RF components and antennas

Dang, J. H., Morishita, A. M., Gough, R. C., Hu, W., Ohta, A. T., Shiroma, W. A.

In Radio Science Meeting (USNC-URSI NRSM), 2014 United States National Committee of URSI National, pages: 1-1, 2014 (inproceedings)

[BibTex]

[BibTex]


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Molecular delivery and transfection by laser-induced oscillating microbubbles

Fan, Q., Hu, W., Ohta, A. T.

In Nano/Micro Engineered and Molecular Systems (NEMS), 2014 9th IEEE International Conference on, pages: 302-305, 2014 (inproceedings)

[BibTex]

[BibTex]


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Opto-thermal micro-transportation for cellular microbiology

Hu, W.

University of Hawai’i at Manoa, 2014 (phdthesis)

[BibTex]

[BibTex]


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Interactive actuation of multiple opto-thermocapillary flow-addressed bubble microrobots

Hu, W., Fan, Q., Ohta, A. T.

Robotics and biomimetics, 1(1):14, Springer Berlin Heidelberg, 2014 (article)

[BibTex]

[BibTex]

2013


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An opto-thermocapillary cell micromanipulator

Hu, W., Fan, Q., Ohta, A. T.

Lab on a Chip, 13(12):2285-2291, Royal Society of Chemistry, 2013 (article)

[BibTex]

2013

[BibTex]


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Bubble-driven light-absorbing hydrogel microrobot for the assembly of bio-objects

Hu, W., Fan, Q., Tonaki, W., Ohta, A. T.

In Engineering in Medicine and Biology Society (EMBC), 2013 35th Annual International Conference of the IEEE, pages: 5303-5306, 2013 (inproceedings)

[BibTex]

[BibTex]


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Assembly of cell-laden microgels by an optically controlled bubble manipulator

Hu, W., Fan, Q., Ohta, A.

In International Conference on Miniaturized Systems for Chemistry and Life Sciences, Freiburg, Germany, 2013 (inproceedings)

[BibTex]

[BibTex]


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A reconfigurable, liquid-metal-based low-pass filter with reversible tuning

Tonaki, W. G., Hu, W., Ohta, A. T., Shiroma, W. A.

In Wireless Symposium (IWS), 2013 IEEE International, pages: 1-3, 2013 (inproceedings)

[BibTex]

[BibTex]


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Miniaturisation for chemistry, physics, biology, materials science and bioengineering

Lee, T., Shin, Y., Park, M.

Lab Chip, 13, pages: 81-89, 2013 (article)

[BibTex]

[BibTex]

2012


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Cooperative micromanipulation using optically controlled bubble microrobots

Ishii, K. S., Hu, W., Ohta, A. T.

In Robotics and Automation (ICRA), 2012 IEEE International Conference on, pages: 3443-3448, 2012 (inproceedings)

[BibTex]

2012

[BibTex]


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Micro-assembly using optically controlled bubble microrobots in saline solution

Hu, W., Ishii, K. S., Ohta, A. T.

In Robotics and Automation (ICRA), 2012 IEEE International Conference on, pages: 733-738, 2012 (inproceedings)

[BibTex]

[BibTex]