S3E3
Episode 3 (January 24, 2021)
Hedan Bai
Cornell University
Hamed Shahsavan
University of Waterloo
Xudong Liang
Binghamton University
Stretchable Distributed Fiber-Optic Sensor
Abstract of Talk 1
Silica-based distributed fiber-optic sensor (DFOS) systems have been a powerful tool for sensing strain, pressure, vibration, acceleration, temperature, and humidity in inextensible structures. DFOS systems, however, are incompatible with the large strains associated with soft robotics and stretchable electronics. In this talk, I will present a new class of sensor, the distributed fiber-optic sensor, composed of parallel assemblies of elastomeric lightguides that incorporate continuum or discrete chromatic patterns. By exploiting a combination of frustrated total internal reflection and absorption, stretchable DFOSs can distinguish and measure the locations, magnitudes, and modes (stretch, bend, or press) of mechanical deformation. I will further demonstrate multilocation decoupling and multimodal deformation decoupling through a stretchable DFOS–integrated wireless glove that can reconfigure all types of finger joint movements and external presses simultaneously, with only a single sensor in real time.
Biosketch of Speaker 1
Hedan Bai is a Ph.D. candidate in the Sibley School of Mechanical and Aerospace Engineering at Cornell University. She received her B.S. in Mechanical Engineering and Operations Research and Information Engineering from Cornell University in 2016. She is now a Ph.D. candidate at the Organic Robotics Lab led by Prof. Robert Shepherd at Cornell MAE where she works on stretchable optical sensors and completed the Cornell Engineering Commercialization Fellowship. She will join Prof. John Rogers’ group at Northwestern University in 2021 for postdoc research.
Light-fueled Liquid Crystal Gels for Bioinspired Underwater Soft Robots
Abstract of Talk 2
Soft-bodied aquatic invertebrates, such as sea slugs and snails, are capable of diverse locomotion modes under water. We mimic locomotion modes common to these creatures using monolithic liquid crystal gels (LCGs) with inherent light responsiveness and molecular anisotropy. We elicit diverse underwater locomotion modes, such as crawling, walking, jumping, and swimming, by local deformations induced by selective spatiotemporal light illumination. Our results underpin the pivotal role of the physicomechanical properties of LCGs in the realization of diverse modes of light-driven robotic underwater locomotion.
Biosketch of Speaker 2
Hamed Shahsavan is an assistant professor in the Department of Chemical Engineering, and Waterloo Institute for Nanotechnology, at the University of Waterloo. He obtained his PhD in Chemical Engineering - Nanotechnology from the University of Waterloo in 2017. Before his appointment in 2020, he was an NSERC postdoctoral fellow at Max Planck Institute for Intelligent Systems. During his PhD studies, he was a visiting scholar in the Advanced Materials and Liquid Crystal Institute at Kent State University, Ohio, USA. During his post-doctoral fellowship, he was a visiting scientist in the Smart Photonic Materials (SPM) research group at the University of Tampere in Finland. His current research interests revolve around the development of a variety of soft, stimuli-responsive, and programmable materials. In addition, he is interested in emerging fabrication strategies for the manufacturing of small-scale mobile robots and devices, such as direct laser writing, and micro-scale 4D printing.
Programming impulsive deformation with mechanical metamaterials
Abstract of Talk 3
Impulsive deformation is widely observed in biological systems to generate movement with high acceleration and velocity. By storing elastic energy in a quasi-static loading and releasing it through an impulsive elastic recoil, organisms circumvent the intrinsic trade-off between force and velocity and achieve power amplified motion. However, such asymmetry in strain rate in loading and unloading often results in reduced efficiency in converting elastic energy to kinetic energy for homogeneous materials. Here, we demonstrate that specific internal structural designs can offer the ability to tune quasi-static and high-speed recoil independently to control energy storage and conversion processes. Experimental demonstrations with mechanical metamaterials reveal that certain internal structures optimize energy conversion far beyond unstructured materials under the same conditions. Our results provide the first quantitative model and experimental demonstration for tuning energy conversion processes through internal structures of metamaterials. Impulsive deformation is widely observed in biological systems to generate movement with high acceleration and velocity. By storing elastic energy in a quasi-static loading and releasing it through an impulsive elastic recoil, organisms circumvent the intrinsic trade-off between force and velocity and achieve power amplified motion. However, such asymmetry in strain rate in loading and unloading often results in reduced efficiency in converting elastic energy to kinetic energy for homogeneous materials. Here, we demonstrate that specific internal structural designs can offer the ability to tune quasi-static and high-speed recoil independently to control energy storage and conversion processes. Experimental demonstrations with mechanical metamaterials reveal that certain internal structures optimize energy conversion far beyond unstructured materials under the same conditions. Our results provide the first quantitative model and experimental demonstration for tuning energy conversion processes through internal structures of metamaterials.
Biosketch of Speaker 3
Dr. Xudong Liang is an assistant professor in the Department of Mechanical Engineering at the State University of New York at Binghamton. He received his bachelor's degree in Theoretical and Applied Mechanics from Sun Yat-Sen University in 2010, a master's degree in Engineering Mechanics from Tsinghua University in 2013, and a doctoral degree in Mechanical Engineering from the University of California San Diego in 2018. From 2018 to 2020, he was a postdoctoral researcher at the University of Massachusetts Amherst. He worked on soft materials mechanics under high strain rate deformation. His current research interests include mechanics of soft materials, high-speed deformation, and mechanical metamaterials, with applications to energy conversion and absorption, biomechanics and biomaterials, and next-generation advanced materials.
Guest Host: Huichan Zhao
Huichan Zhao started faculty job and led the THU Soft Robotics Lab as an Assistant Professor in the Department of Mechanical Engineering at Tsinghua University from July 2018. Before this, she was a postdoctoral fellow at the Microrobotics Lab at Harvard University, under the supervision of Prof. Robert Wood and Prof. David Clarke. Her research area is soft robotics. She was born in China and got my B.S. in Mechanical Engineering from Tsinghua University in 2012. After that, she came to U.S. and started to pursue her Ph.D. degree at Cornell University, also in Mechanical Engineering. Her doctoral advisor is Prof. Robert Shepherd, who introduced her to the area of soft robotics and guided her through of how to contribute to this area. Her lab, the Organic Robotics Laboratory (ORL), focuses on using synthetic adaptation of natural physiology to improve machine function and autonomy. Her research goal in recent years is to apply her knowledge (mechanics, optics, control theory, electronics) to the design of soft-bodied robots and relevant sensors, controllers to make them stronger, more accurate and smarter. Besides Prof. Shepherd, she has two other doctoral committee members, Prof. Andy Ruina, who is an expert in robotic locomotion and Prof. Eve Donnelly, who is a material scientist devoted to biomaterials.