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Animals have the advantage of highly articulated limbs, which allow for subtle sensing, balancing and grasping behaviors as they interact with the world. With this in mind, the MURI team includes experts in programmable materials who can design novel, kirigami-based, shape-shifting structures that will be incorporated into the robotic squirrel’s limbs. The group’s mathematicians will help translate between the body-brain structures that allow animals to place themselves in space, and the engineers’ active materials and mechanisms that drive the robot bodies.
Research Concentration Area (RCA) 3.i: Morphological Design, Computation
Research Concentration Area (RCA) 3.i: Morphological Design, Computation
We are inspired by biological architectures and the abilities of animal tissues to achieve wide and varied functionalities, ranging from motors to brakes to springs and struts. These pluripotent materials are able to adapt based on the animal's locomotory needs at any time. Our goal is to create synthetic materials and metamaterials with comparable versatility so that we can improve robots' mechanical intelligence (ref. RCA 3.ii). Our approach is to combine novel materials with high power densities with new algorithmic approaches to kirigami-inspired design, thus producing new insights in how we can create integrated machines with fully embedded sensing and actuation.
Design of Tubular Auxetic Structures for Universal Robotic Locomotion Modules
Design of Tubular Auxetic Structures for Universal Robotic Locomotion Modules
Lee, Young-Joo, Yuchong Gao, Daniel E. Koditschek, and Shu Yang. “Design of Tubular Auxetic Structures for Universal Robotic Locomotion Modules.” In Symposium on Computational Fabrication (SCF), Pittsburgh, PA, 2019.
Liquid Crystal Elastomer-Carbon Nanotube Composites for Actuation
Liquid Crystal Elastomer-Carbon Nanotube Composites for Actuation
Liu, Jiaqi, Yuchong Gao, Haihuan Wang, Ryan Poling-Skutvik, Chinedum Osuji, and Shu Yang. “Shaping and Locomotion of Soft Robots using Filament Actuators Made from Liquid Crystal Elastomer-Carbon Nanotube Composites.” Adv. Intelligent Systems 2020, accepted. DOI
S6-chicken 8x.MOVS4-8x unicorn.mp4S1-spiral pattern 8x.mp4S5-8x spiral electrothermo.mp4Responsive and Foldable Soft Materials
Responsive and Foldable Soft Materials
Liu, Jiaqi, Yuchong Gao, Young-Joo Lee, and Shu Yang. “Responsive and Foldable Soft Materials.” Trends in Chem. 2020, 2(2), 107-122 (invited review). DOI
Responsive soft materials can be deformed and folded from 2D to 3D in response to external stimuli, including pH, temperature, light, and electric and magnetic fields. In this review, we overview different types of responsive materials (e.g., responsive hydrogels, shape memory polymers, liquid crystal elastomers, and polymer composites) and some of the basic folding mechanisms. We highlight the required material properties, fabrication techniques, and structural designs for desirable folding structures.
General References
General References
Autumn, Kellar, and Jonathan Puthoff. "Properties, principles, and parameters of the gecko adhesive system." In Biological adhesives, pp. 245-280. Springer, Cham, 2016.
Lee, Young-Joo, Seung-Min Lim, Seol-Min Yi, Jeong-Ho Lee, Sung-gyu Kang, Gwang-Mook Choi, Heung Nam Han, Jeong-Yun Sun, In-Suk Choi, and Young-Chang Joo. "Auxetic elastomers: Mechanically programmable meta-elastomers with an unusual Poisson’s ratio overcome the gauge limit of a capacitive type strain sensor." Extreme Mechanics Letters 31 (2019): 100516. doi: 10.1016/j.eml.2019.100516
Kim, Kee‐Bum, Young‐Joo Lee, Avelino Costa, Yu‐Ki Lee, Tae‐Sik Jang, Myoung‐Gyu Lee, Young‐Chang Joo, Kyu Hwan Oh, Juha Song, and In‐Suk Choi. "Extremely Versatile Deformability beyond Materiality: A New Material Platform through Simple Cutting for Rugged Batteries." Advanced Engineering Materials 21, no. 7 (2019): 1900206. doi: 10.1002/adem.201900206
Castle, Toen, Yigil Cho, Xingting Gong, Euiyeon Jung, Daniel M. Sussman, Shu Yang, and Randall D. Kamien. "Making the cut: Lattice kirigami rules." Physical review letters 113, no. 24: 245502, 2014.
Sussman, Daniel M., Yigil Cho, Toen Castle, Xingting Gong, Euiyeon Jung, Shu Yang, and Randall D. Kamien. "Algorithmic lattice kirigami: A route to pluripotent materials." Proceedings of the National Academy of Sciences 112, no. 24, pp. 7449-7453, 2015.
Xia, Yu, Gerardo Cedillo‐Servin, Randall D. Kamien, and Shu Yang. "Guided folding of nematic liquid crystal elastomer sheets into 3D via patterned 1D microchannels." Advanced Materials 28, no. 43, pp. 9637-9643, 2016.
Research Concentration Area (RCA) 3.ii: Morphological Innovation, Control and Behavior
Research Concentration Area (RCA) 3.ii: Morphological Innovation, Control and Behavior
This work utilizes RCA 3.i's result to understand the embodied intelligence of robots by exploring how morphology and mechanical properties of the robot affect the behavior during dynamical tasks. (Lynch et al, 1996) (Topping et al, 2017) The goal is to build dynamic robots capable of managing the kinetic as well as the potential energy of their bodies and environments that can manipulate objects using fewer actuated degree-of-freedoms (DoFs) and negotiate through environments otherwise inaccessible to quasi-statically operated mechanisms. We present several approaches to overcoming challenges in dynamical dexterity for robots through mechanisms with programmable metamaterial compliance properties and unconventional actuation design.
A Tendon-driven Hopper with an Origami Limb
A Tendon-driven Hopper with an Origami Limb
Chen, Wei-Hsi, Shivangi Misra, J. Caporale, Daniel E. Koditschek, Shu Yang, and Cynthia R. Sung. "A Tendon-Driven Origami Hopper Triggered by Proprioceptive Contact Detection." In 3rd IEEE International Conference on Soft Robotics (RoboSoft), 2020.
We report on experiments with a laptop-sized (0.23m, 2.53kg), paper origami robot that exhibits highly dynamic and stable two degree-of-freedom (circular boom) hopping at speeds in excess of 1.5 bl/s (body-lengths per second) at a specific resistance O(1) while achieving aerial phase apex states 25% above the stance height over thousands of cycles. Three conventional brushless DC motors load energy into the folded paper springs through pulley-borne cables whose sudden loss of tension upon touchdown triggers the release of spring potential that accelerates the body back through liftoff to flight with a 20W powerstroke, whereupon the toe angle is adjusted to regulate fore-aft speed. We also demonstrate in the vertical hopping mode the transparency of this actuation scheme by using proprioceptive contact detection with only motor encoder sensing. The combination of actuation and sensing shows potential to lower system complexity for tendon-driven robots.
Using Compliant Origami for Dynamically Dexterous Robots
Using Compliant Origami for Dynamically Dexterous Robots
Chen, Wei-Hsi, Shivangi Misra, Yuchong Gao, Young-Joo Lee, Daniel E. Koditschek, Shu Yang, and Cynthia R. Sung. "A Programmably Compliant Origami Mechanism for Dynamically Dexterous Robots." IEEE Robotics and Automation Letters, vol. 5.2, pp. 2131-2137, 2020.
We present an approach to overcoming challenges in dynamical dexterity for robots through programmably compliant origami mechanisms. Our work leverages a one-parameter family of flat sheet crease patterns that folds into origami bellows, whose axial compliance can be tuned to select desired stiffness. Concentrically arranged cylinder pairs reliably manifest additive stiffness, extending the programmable range by nearly an order of magnitude and achieving bulk axial stiffness spanning 200–1500 N/m using 8 mil thick polyester-coated paper. Accordingly, we design origami energy-storing springs with a stiffness of 1035 N/m each and incorporate them into a three degree-of-freedom (DOF) tendon-driven spatial pointing mechanism that exhibits trajectory tracking accuracy less than 15% rms error within a (2 cm)^3 volume. The origami springs can sustain high power throughput, enabling the robot to achieve asymptotically stable juggling for both highly elastic (1 kg resilient shotput ball) and highly damped (“medicine ball”) collisions in the vertical direction with apex heights approaching 10 cm. The results demonstrate that “soft” robotic mechanisms are able to perform a controlled, dynamically actuated task.
A Study on Coronal Plane Spine Twisting in Animated Objects
A Study on Coronal Plane Spine Twisting in Animated Objects
Caporale, J. Diego, Benjamin McInroe, Chenze Ning, Thomas Libby, Robert J. Full, and Daniel E. Koditschek. “Coronal Plane Spine Twisting Composes Shape To Adjust the Energy Landscape for Grounded Reorientation.” In 2020 International Conference on Robotics and Automation (ICRA), Paris, France, 2020.
Despite substantial evidence for the crucial role played by an active backbone or spine in animal locomotion, its adoption in legged robots remains limited because the added mechanical complexity and resulting dynamical challenges pose daunting obstacles to characterizing even a partial range of potential performance benefits. This paper takes a next step toward such a characterization by exploring the quasistatic terrestrial self-righting mechanics of a model system with coronal plane spine twisting (CPST). Reduction from a full 3D kinematic model of CPST to a two parameter, two degree of freedom coronal plane representation of body shape affordance predicts a substantial benefit to ground righting by lowering the barrier between stable potential energy basins.The reduced model predicts the most advantageous twist angle for several cross-sectional geometries, reducing the required righting torque by up to an order of magnitude depending on constituent shapes. Experiments with a three actuated degree of freedom physical mechanism corroborate the kinematic model predictions using two different quasistatic reorientation maneuvers for both elliptical and rectangular shaped bodies with a range of eccentricities or aspect ratios. More speculative experiments make intuitive use of the kinematic model in a highly dynamic maneuver to suggest still greater benefits of CPST achievable by coordinating kinetic as well as potential energy, for example as in a future multi-appendage system interacting with a contact-rich 3D environment.
General References
General References
Kenneally, Gavin, Wei-Hsi Chen, and Daniel E. Koditschek. “Actuator Transparency and the Energetic Cost of Proprioception.” In 2018 International Symposium on Experimental Robotics (ISER), Buenos Aires, Nov 2018.
Kenneally, Gavin, Avik De, and Daniel E. Koditschek. “Design Principles for a Family of Direct-Drive Legged Robots.” IEEE Robotics and Automation Letters, vol. 1, no. 2, pp. 900–907, Jul. 2016.
Duperret, Jeffrey, Benjamin Kramer, and Daniel E. Koditschek. “Core Actuation Promotes Self-manipulability on a Direct-Drive Quadrupedal Robot.” In 2016 International Symposium on Experimental Robotics (ISER), pp. 147-159. Springer, Cham, 2016.
Lynch, Goran A., Jonathan E. Clark, Pei-Chun Lin, and Daniel E. Koditschek. "A bioinspired dynamical vertical climbing robot." The International Journal of Robotics Research, vol. 31, no. 8, pp. 974-996, Jul. 2012.
Topping, T. Turner, Gavin Kenneally, and Daniel E. Koditschek. “Quasi-static and dynamic mismatch for door opening and stair climbing with a legged robot.” In 2017 IEEE International Conference on Robotics and Automation (ICRA), pp. 1080–1087. IEEE, 2017.
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