@conference{misra2023design,

title = {Design and Control of a Tunable-Stiffness Coiled-Spring Actuator},

author = {Shivangi Misra and Mason Mitchell and Rongqian Chen and Cynthia Sung},

url = {https://repository.upenn.edu/grasp_papers/72/

https://youtu.be/52WVMEeGxUk

},

year  = {2023},

date = {2023-00-00},

urldate = {2023-00-00},

booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},

abstract = {We propose a novel design for a lightweight and compact tunable stiffness actuator capable of stiffness changes up to 20x. The design is based on the concept of a coiled spring, where changes in the number of layers in the spring change the bulk stiffness in a near-linear fashion. We present an elastica nested rings model for the deformation of the proposed actuator and empirically verify that the designed stiffness-changing spring abides by this model. Using the resulting model, we design a physical prototype of the tunable-stiffness coiled spring actuator and discuss the effect of design choices on the resulting achievable stiffness range and resolution. In the future, this actuator design could be useful in a wide variety of soft robotics applications, where fast, controllable, and local stiffness change is required over a large range of stiffnesses.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{huang2022evorobogami,

title = {EvoRobogami: Co-designing with Humans in Evolutionary Robotics Experiments},

author = {Zonghao Huang and Quinn Wu and David Howard and Cynthia Sung},

url = {https://arxiv.org/abs/2205.08086

https://sung.seas.upenn.edu/publications/evorobogami-gecco-2022/},

doi = {10.1145/3512290.3528867},

year  = {2022},

date = {2022-07-09},

urldate = {2022-07-09},

booktitle = {Genetic and Evolutionary Computation Conference (GECCO)},

abstract = {We study the effects of injecting human-generated designs into the initial population of an evolutionary robotics experiment, where subsequent population of robots are optimised via a Genetic Algorithm and MAP-Elites. First, human participants interact via a graphical front-end to explore a directly-parameterised legged robot design space and attempt to produce robots via a combination of intuition and trial-and-error that perform well in a range of environments. Environments are generated whose corresponding high-performance robot designs range from intuitive to complex and hard to grasp. Once the human designs have been collected, their impact on the evolutionary process is assessed by replacing a varying number of designs in the initial population with human designs and subsequently running the evolutionary algorithm. Our results suggest that a balance of random and hand-designed initial solutions provides the best performance for the problems considered, and that human designs are most valuable when the problem is intuitive. The influence of human design in an evolutionary algorithm is a highly understudied area, and the insights in this paper may be valuable to the area of AI-based design more generally. },

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{misra2022forward,

title = {Forward kinematics and control of a segmented tunable-stiffness 3-D continuum manipulator},

author = {Shivangi Misra and Cynthia Sung},

url = {https://repository.upenn.edu/grasp_papers/69/

https://youtu.be/P-vg3Hiuk4M

https://youtu.be/lc6W61xCWuQ},

doi = {10.1109/ICRA46639.2022.9812098},

year  = {2022},

date = {2022-05-23},

urldate = {2022-05-23},

booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},

abstract = {In this work, we consider the problem of controlling the end effector position of a continuum manipulator through local stiffness changes. Continuum manipulators offer the advantage of continuous deformation along their lengths, and recent advances in smart material actuators further enable local compliance changes, which can affect the manipulator's bulk motion. However, leveraging local stiffness change to control motion remains lightly explored. We build a kinematic model of a continuum manipulator as a sequence of segments consisting of symmetrically arranged springs around the perimeter of every segment, and we show that this system has a closed form solution to its forward kinematics. The model includes common constraints such as restriction of torsional or shearing movement. Based on this model, we propose a controller on the spring stiffnesses for a single segment and provide provable guarantees on convergence to a desired goal position. The results are verified in simulation and compared to physical hardware.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{sun2022repeated,

title = {Repeated jumping with the REBOund: Self-righting jumping robot leveraging bistable origami-inspired design},

author = {Yuchen Sun* and Joanna Wang* and Cynthia Sung},

url = {https://repository.upenn.edu/grasp_papers/70/

https://youtu.be/LoCXcwIxCgU

https://youtu.be/JXWAp-rVOxg},

doi = {10.1109/ICRA46639.2022.9812232},

year  = {2022},

date = {2022-05-23},

urldate = {2022-05-23},

booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},

abstract = {Repeated jumping is crucial to the mobility of jumping robots. In this paper, we extend upon the REBOund jumping robot design, an origami-inspired jumping robot that uses the Reconfigurable Expanding Bistable Origami (REBO) pattern as its body. The robot design takes advantage of the pattern's bistability to jump with controllable timing. For jump repeatedly, we also add self-righting legs that utilize a single motor actuation mechanism. We describe a dynamic model that captures the compression of the REBO pattern and the REBOund self-righting process and compared it to the physical robot. Our experiments show that the REBOund is able to successfully self-right and jump repeatedly over tens of jumps.},

note = {* = co-first author},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{qin2022trussbot,

title = {TrussBot: Modeling, design and control of a compliant, helical truss of tetrahedral modules},

author = {Yuhong Qin* and Linda Ting* and Celestina Saven* and Yumika Amemiya and Michael Tanis and Randall Kamien and Cynthia Sung},

url = {https://repository.upenn.edu/grasp_papers/71/

https://youtu.be/bcvFMq40EzI

https://youtu.be/mGf1qmQVNmg},

doi = {10.1109/ICRA46639.2022.9812295},

year  = {2022},

date = {2022-05-23},

urldate = {2022-05-23},

booktitle = {IEEE International Conference on Robotics and Automation},

abstract = {Modular and truss robots offer the potential of high reconfigurability and great functional flexibility, but common implementations relying on rigid components often lead to highly complex actuation and control requirements. This paper introduces a new type of modular, compliant robot: TrussBot. TrussBot is composed of 3D-printed tetrahedral modules connected at the corners with compliant joints. We propose a truss geometry, analyze its deformation modes, and provide a simulation framework for predicting its behavior under applied loads and actuation. The TrussBot is geometrically constrained, thus requiring compliant joints to move. The TrussBot can be actuated through a network of tendons which pinch vertices together and apply a twisting motion due to the structure's connectivity. The truss was demonstrated in a physical prototype and compared to simulation results. },

note = {*=co-first author},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{yuan2021programmable,

title = {Programmable Stiffness and Applications of 3D Printed TPU Diamond Lattices},

author = {Yifan Yuan and Cynthia Sung},

doi = {10.1115/DETC2021-69826},

year  = {2021},

date = {2021-11-17},

urldate = {2021-11-17},

booktitle = {International Design Engineering Technical Conferences & Computers and Information in Engineering Conference},

number = {DETC2021-69826, V08AT08A016},

abstract = {Additive manufacturing provides a rapid manufacturing method for a variety of materials with different applications. Thermoplastic Polyurethane (TPU) is a soft polymer material that can be 3D printed. In this work, we explore the mechanical properties of a 3D printed grid pattern structure with TPU. By changing the pattern's cell size and wall thickness parameters, we control the density of the grid lattice and, as a result, the bulk elastic modulus of the structure. We compare simulation and physical compression tests and conclude that the bulk elastic modulus of a print is related to the infill percentage according to a cubic relationship, with higher infill percentage samples resulting in higher elastic moduli. The precise cell size and wall thickness parameter values are minor influences comparatively. The elastic moduli of the resulting samples span from 0.36 MPa with 23.44% infill to 21.83 MPa with 75% infill, compared to an elastic modulus of 64.31 MPa when printing at 100% density. We also explore other factors such as the sample size, the printer, the build orientation, and the sample geometry. The results have uses in a variety of applications, including a custom linear spring, a bistable gripper, or a soft robot finger. },

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{li2021hav,

title = {Soft hybrid aerial vehicle via bistable mechanism},

author = {Xuan Li* and Jessica McWilliams* and Minchen Li and Cynthia Sung and Chenfanfu Jiang},

url = {https://arxiv.org/abs/2011.00426

https://www.youtube.com/watch?v=fnTyAVVzJMc},

doi = {10.1109/ICRA48506.2021.9561434},

year  = {2021},

date = {2021-05-01},

urldate = {2021-05-01},

booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},

abstract = {Unmanned aerial vehicles have been demonstrated successfully in a variety of tasks, including surveying and sampling tasks over large areas. These vehicles can take many forms. Quadrotors' agility and ability to hover makes them well suited for navigating potentially tight spaces, while fixed wing aircraft are capable of efficient flight over long distances. Hybrid aerial vehicles (HAVs) attempt to achieve both of these benefits by exhibiting multiple modes; however, morphing HAVs typically require extra actuators which add mass, reducing both agility and efficiency. We propose a morphing HAV with folding wings that exhibits both a quadrotor and a fixed wing mode without requiring any extra actuation. This is achieved by leveraging the motion of a bistable mechanism at the center of the aircraft to drive folding of the wing using only the existing motors and the inertia of the system. We optimize both the bistable mechanism and the folding wing using a topology optimization approach. The resulting mechanisms were fabricated on a 3D printer and replaced the frame of an existing quadrotor. Our prototype successfully transitions between both modes and our experiments demonstrate that the behavior of the fabricated prototype is consistent with that of the simulation.},

note = {*=co-first author, best paper in mechanisms and design},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{mcwilliams2021push,

title = {Push On, Push Off: A compliant bistable gripper with mechanical sensing and actuation},

author = {Jessica McWilliams and Yifan Yuan and Jason Friedman and Cynthia Sung},

url = {https://www.youtube.com/watch?v=z50dYYzYvls

https://repository.upenn.edu/meam_papers/307/},

doi = {10.1109/RoboSoft51838.2021.9479209},

year  = {2021},

date = {2021-04-01},

urldate = {2021-04-01},

booktitle = {IEEE International Conference on Soft Robotics (RoboSoft)},

pages = {622-629},

abstract = {Grasping is an essential task in robotic applications and is an open challenge due to the complexity and uncertainty of contact interactions. In order to achieve robust grasping, systems typically rely on precise actuators and reliable sensing in order to control the contact state. We propose an alternative design paradigm that leverages contact and a compliant bistable mechanism in order to achieve "sensing" and "actuation" purely mechanically. To grasp an object, the manipulator holding our end effector presses the bistable mechanism into the object until snap-through causes the gripper to enclose it. To release the object, the tips of the gripper are pushed against the ground, until rotation of the linkages causes snap-through in the other direction. This push-on push-off scheme reduces the complexity of the grasping task by allowing the manipulator to automatically achieve the correct grasping behavior as long as it can get the end effector to the correct location and apply sufficient force. We present our dynamic model for the bistable gripping mechanism, propose an optimized result, and demonstrate the functionality of the concept on a fabricated prototype. We discuss our stiffness tuning strategy for the 3D printed springs, and verify the snap-through behavior of the system using compression tests on an MTS machine. },

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{kim2021sma,

title = {Fabrication and characterization of I-cord knitted SMA actuators},

author = {Christopher Kim and Athena Chien and Megha Tippur and Cynthia Sung},

url = {https://www.youtube.com/watch?v=Czoy5NctBtY

https://repository.upenn.edu/meam_papers/308/

},

doi = {10.1109/RoboSoft51838.2021.9479207},

year  = {2021},

date = {2021-04-01},

urldate = {2021-04-01},

booktitle = {IEEE International Conference on Soft Robotics (RoboSoft)},

pages = {379-386},

abstract = {Knitted SMA actuators provide greater actuation stroke than single-strand SMA wire actuators by leveraging its knitted structure. However, due to short-circuiting through interlacing knit loops, existing knitted SMA sheet actuators are unsuitable for joule-heating actuation when uniform contractile actuation is desired. We explore an axially symmetric tubular i-cord knitted actuator as a possible solution. The fabrication process of an i-cord knitted SMA actuator and its electrical, thermal, and mechanics models are presented. After modifying existing models for single-strand SMA wire and adjusting their parameters, the proposed electrical, thermal, and mechanics models were verified with experimental results.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{carlson2020rebound,

title = {REBOund: Untethered origami jumping robot with controllable jump height},

author = {Jaimie Carlson and Jason Friedman and Christopher Kim and Cynthia Sung},

url = {https://sung.seas.upenn.edu/wp-content/publications/carlsonICRA2020_jumper.pdf},

doi = {10.1109/ICRA40945.2020.9196534},

year  = {2020},

date = {2020-06-01},

urldate = {2020-06-01},

booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},

pages = {10089-10095},

abstract = {Origami robots are well-suited for jumping maneuvers because of their light weight and ability to incorporate actuation and control strategies directly into the robot body. However, existing origami robots often model fold patterns as rigidly foldable and fail to take advantage of deformation in an origami sheet for potential energy storage. In this paper, we consider a parametric origami tessellation, the Reconfigurable Expanding Bistable Origami (REBO) pattern, which leverages face deformations to act as a nonlinear spring. We present a pseudo-rigid-body model for the REBO for computing its energy stored when compressed to a given displacement and compare that model to experimental measurements taken on a mechanical testing system. This stored potential energy, when released quickly, can cause the pattern to jump. Using our model and experimental data, we design and fabricate a jumping robot, REBOund, that uses the spring-like REBO pattern as its body. Four lightweight servo motors with custom release mechanisms allow for quick compression and release of the origami pattern, allowing the fold pattern to jump over its own height even when carrying 5 times its own weight in electronics and power. We further demonstrate that small geometric changes to the pattern allow us to change the jump height without changing the actuation or control mechanism.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{chen2020tendon,

title = {A tendon-driven origami hopper triggered by proprioceptive contact detection},

author = {Wei-Hsi Chen and Shivangi Misra and J. Diego Caporale and Daniel E. Koditschek and Shu Yang and Cynthia Sung},

url = {https://repository.upenn.edu/ese_papers/866/

https://youtu.be/3fx-vVZki5c},

doi = {10.1109/RoboSoft48309.2020.9116040},

year  = {2020},

date = {2020-05-26},

urldate = {2020-05-26},

booktitle = {IEEE International Conference on Soft Robotics (RoboSoft)},

abstract = {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.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{yuan2018programmable,

title = {Programmable 3-D surfaces using origami tessellations},

author = {Hang Yuan and James Pikul and Cynthia Sung},

url = {https://sung.seas.upenn.edu/wp-content/publications/yuan_7OSME_2018_programmable.pdf},

year  = {2018},

date = {2018-09-19},

urldate = {2018-09-19},

booktitle = {7th International Meeting on Origami in Science, Mathematics, and Education},

pages = {893-906},

abstract = {We present an origami-inspired approach to reconfigurable surfaces. A circular origami tessellation with the ability to extend and flatten was designed to approximate radially symmetric 3-D surfaces. The pattern exhibits snap-through effects, allowing desired 3-D shapes to be maintained indefinitely without additional infrastructure or energy input. We characterize the geometry of the fold pattern and its resulting 3-D shape, present a strategy for reconfiguration, and demonstrate this strategy for surfaces with positive, negative, and zero Gaussian curvature.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{deng2018leveraging,

title = {Leveraging compliance in origami robot legs for robust and natural locomotion},

author = {Xiang Deng and Cynthia Sung},

url = {https://sung.seas.upenn.edu/wp-content/publications/deng_7OSME_2018_leveraging.pdf},

year  = {2018},

date = {2018-09-12},

urldate = {2018-09-12},

booktitle = {7th International Meeting on Origami in Science, Mathematics, and Education},

pages = {965-980},

abstract = {We present an origami-inspired compliant robot leg design with three degree of freedom compliance. Using the proposed leg, we created a full quadrupedal robot that can walk robustly with adaption to non-flat terrains and external perturbations. We can reconfigure the design to change the stiffness. According to systematic locomotion tests, we demonstrate unique advantages of the proposed leg design over a rigid counterpart of the same dimension and weight in terms of enhancing locomotion stability},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{sung2017self,

title = {Self-folded soft robotic structures with controllable joints},

author = {Cynthia Sung and Rhea Lin and Shuhei Miyashita and Sehyuk Yim and Sangbae Kim and Daniela Rus},

doi = {10.1109/ICRA.2017.7989072},

year  = {2017},

date = {2017-05-29},

urldate = {2017-05-29},

booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},

pages = {580-587},

abstract = {This paper describes additive self-folding, an origami-inspired rapid fabrication approach for creating actuatable compliant structures. Recent work in 3-D printing and other rapid fabrication processes have mostly focused on rigid objects or objects that can achieve small deformations. In contrast, soft robots often require elastic materials and large amounts of movement. Additive self-folding is a process that involves cutting slices of a 3-D object in a long strip and then pleat folding them into a likeness of the original model. The zigzag pattern for folding enables large bending movements that can be actuated and controlled. Gaps between slices in the folded model can be designed to provide larger deformations or higher shape accuracy. We advance existing planar fabrication and self-folding techniques to automate the fabrication process, enabling highly compliant structures with complex 3-D geometries to be designed and fabricated within a few hours. We describe this process in this paper and provide algorithms for converting 3-D meshes into additive self-folding designs. The designs can be rapidly instrumented for global control using magnetic fields or tendon-driven for local bending. We also describe how the resulting structures can be modeled and their responses to tendon-driven control predicted. We test our design and fabrication methods on three models (a bunny, a tuna fish, and a starfish) and demonstrate the method's potential for actuation by actuating the tuna fish and starfish models using tendons and magnetic control.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{spielberg2017functional,

title = {Functional co-optimization of articulated robots},

author = {Andrew Spielberg and Brandon Araki and Cynthia Sung and Russ Tedrake and Daniela Rus},

doi = {10.1109/ICRA.2017.7989587},

year  = {2017},

date = {2017-05-29},

urldate = {2017-05-29},

booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},

pages = {5035-5042},

abstract = {We present parametric trajectory optimization, a method for simultaneously computing physical parameters, actuation requirements, and robot motions for more efficient robot designs. In this scheme, robot dimensions, masses, and other physical parameters are solved for concurrently with traditional motion planning variables, including dynamically consistent robot states, actuation inputs, and contact forces. Our method requires minimal user domain knowledge, requiring only a coarse guess of the target robot configuration sequence and a parameterized robot topology as input. We demonstrate our results on four simulated robots, one of which we physically fabricated in order to demonstrate physical consistency. We demonstrate that by optimizing robot body parameters alongside robot trajectories, motion planning problems which would otherwise be infeasible can be made feasible, and actuation requirements can be significantly reduced.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{sung2015automated,

title = {Automated fabrication of foldable robots using thick materials},

author = {Cynthia Sung and Daniela Rus},

doi = {10.1007/978-3-319-51532-8_16},

year  = {2015},

date = {2015-09-09},

booktitle = {International Symposium on Robotics Research},

pages = {253-266},

abstract = {Designing complex machines such as robots often requires multiple iterations of design and prototyping. Folding has recently emerged as a method to both simplify fabrication and accelerate assembly of such machines. However, the robots so far produced by folding have often been made of thin, flexible materials that limit their size and strength. We introduce a folding-based fabrication process that uses thick materials layered with flexible film to enable folding while maintaining high stiffness in the folded structure. We use this process to fabricate multiple solid bodies, as well as two hexapods, one of which can carry up to 2.50 kg payloads. Each folded structure took less than 3 h to construct. Our results indicate that folding using thick materials can be a viable method for rapidly fabricating and prototyping larger and sturdier robots.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{sung2015reconfiguration,

title = {Reconfiguration planning for pivoting cube modular robots},

author = {Cynthia Sung and James Bern and James Romanishin and Daniela Rus},

doi = {10.1109/ICRA.2015.7139451},

year  = {2015},

date = {2015-05-26},

booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},

pages = {1933-1940},

abstract = {In this paper, we present algorithms for self-reconfiguration of modular robots that move by pivoting. The modules are cubes that can pivot about their edges along the x̂, ŷ, or ẑ axes to move on a 3-dimensional substrate. This is a different model from prior work, which usually considers modules that slide along their faces. We analyze the pivoting cube model and give sufficient conditions for reconfiguration to be feasible. In particular, we show that if an initial configuration does not contain any of three subconfigurations, which we call rules, then it can reconfigure into a line. We provide provably correct algorithms for reconfiguration for both 2-D and 3-D systems, and we verify our algorithms via simulation on randomly generated 2-D and 3-D configurations.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{miyashita2015untethered,

title = {An untethered miniature origami robot that self-folds, walks, swims, and degrades},

author = {Shuhei Miyashita and Steven Guitron and Marvin Ludersdorfer and Cynthia Sung and Daniela Rus},

doi = {10.1109/ICRA.2015.7139386},

year  = {2015},

date = {2015-05-26},

booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},

pages = {1490-1496},

publisher = {IEEE},

abstract = {A miniature robotic device that can fold-up on the spot, accomplish tasks, and disappear by degradation into the environment promises a range of medical applications but has so far been a challenge in engineering. This work presents a sheet that can self-fold into a functional 3D robot, actuate immediately for untethered walking and swimming, and subsequently dissolve in liquid. The developed sheet weighs 0.31 g, spans 1.7 cm square in size, features a cubic neodymium magnet, and can be thermally activated to self-fold. Since the robot has asymmetric body balance along the sagittal axis, the robot can walk at a speed of 3.8 body-length/s being remotely controlled by an alternating external magnetic field. We further show that the robot is capable of conducting basic tasks and behaviors, including swimming, delivering/carrying blocks, climbing a slope, and digging. The developed models include an acetone-degradable version, which allows the entire robot's body to vanish in a liquid. We thus experimentally demonstrate the complete life cycle of our robot: self-folding, actuation, and degrading.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{Sung2014,

title = {Foldable joints for foldable robots},

author = {Cynthia Sung and Daniela Rus},

doi = {10.1007/978-3-319-23778-7_28},

year  = {2014},

date = {2014-06-15},

booktitle = {International Symposium on Experimental Robotics (ISER)},

pages = {421-433},

abstract = {Print-and-fold approaches to robot fabrication allow entire

robots to be produced using a single uniform process: fabricating them

in-plane and then folding them into their 3-D forms. Current efforts to

design print-and-fold robots have been limited by a lack of understanding

of what motions can be achieved by folding. In this paper, we introduce

fold patterns for three basic joints commonly used in robots, and we

show how the patterns can be changed to accommodate user-specified

ranges of motion. The joints are composed with each other to produce

joints with higher degrees of freedom and with rigid bodies to produce

entire foldable linkage mechanisms. We have folded our basic joints and

composed mechanisms, and they achieve the expected kinematics. We

have also printed control circuitry on and attached actuators directly

to three of our designs, demonstrating that it possible to print and fold

robots with many different kinematics.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{feldman2013idiary,

title = {iDiary: From GPS signals to a text-searchable diary},

author = {Dan Feldman and Andrew Sugaya and Cynthia Sung and Daniela Rus},

doi = {10.1145/2517351.2517366},

year  = {2013},

date = {2013-11-11},

booktitle = {11th ACM Conference on Embedded Networked Sensor Systems (SenSys)},

pages = {6},

publisher = {ACM},

abstract = {This paper describes a system that takes as input GPS data streams generated by users' phones and creates a searchable database of locations and activities. The system is called iDiary and turns large GPS signals collected from smartphones into textual descriptions of the trajectories. The system features a user interface similar to Google Search that allows users to type text queries on their activities (e.g., "Where did I buy books?") and receive textual answers based on their GPS signals.



iDiary uses novel algorithms for semantic compression (known as coresets) and trajectory clustering of massive GPS signals in parallel to compute the critical locations of a user. Using an external database, we then map these locations to textual descriptions and activities so that we can apply text mining techniques on the resulting data (e.g. LSA or transportation mode recognition).



We provide experimental results for both the system and algorithms and compare them to existing commercial and academic state-of-the-art. This is the first GPS system that enables text-searchable activities from GPS data.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{sung2013joining,

title = {Joining unfoldings of 3-D surfaces},

author = {Cynthia Sung and Erik D. Demaine and Martin L. Demaine and Daniela Rus},

doi = {10.1115/DETC2013-12692},

year  = {2013},

date = {2013-08-04},

booktitle = {ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference (IDETC/CIE)},

pages = {DETC2013-12692},

publisher = {ASME},

abstract = {Origami-based design methods enable complex devices to be fabricated quickly in plane and then folded into their final 3-D shapes. So far, these folded structures have been designed manually. This paper presents a geometric approach to automatic composition of folded surfaces, which will allow existing designs to be combined and complex functionality to be produced with minimal human input. We show that given two surfaces in 3-D and their 2-D unfoldings, a surface consisting of the two originals joined along an arbitrary edge can always be achieved by connecting the two original unfoldings with some additional linking material, and we provide an algorithm to generate this composite unfolding. The algorithm is verified using various surfaces, as well as a walking and gripping robot design.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{sung2013improving,

title = {Improving the performance of multi-robot systems by task switching},

author = {Cynthia Sung and Nora Ayanian and Daniela Rus},

doi = {10.1109/ICRA.2013.6630993},

year  = {2013},

date = {2013-05-06},

booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},

pages = {2999-3006},

publisher = {IEEE},

abstract = {We consider the problem of task assignment for a multi-robot system where each robot must attend to one or more queues of tasks. We assume that individual robots have no knowledge of tasks in the environment that are not in their queue. Robots in communication with each other may share information about active tasks and exchange queues to achieve lower cost for the system. We show that allowing this kind of task switching causes tasks to be completed more efficiently. In addition, we present conditions under which queues can be guaranteed to make progress, and we support these claims with simulation and experimental results. This work has potential applications in manufacturing, environmental exploration, and pickup-delivery tasks.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{feldman2012single,

title = {The single pixel GPS: Learning big data signals from tiny coresets},

author = {Dan Feldman and Cynthia Sung and Daniela Rus},

doi = {10.1145/2424321.2424325},

year  = {2012},

date = {2012-11-06},

booktitle = {20th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems (GIS 2012)},

pages = {23-32},

publisher = {ACM},

abstract = {We present algorithms for simplifying and clustering patterns from sensors such as GPS, LiDAR, and other devices that can produce high-dimensional signals. The algorithms are suitable for handling very large (e.g. terabytes) streaming data and can be run in parallel on networks or clouds. Applications include compression, denoising, activity recognition, road matching, and map generation.



We encode these problems as (k, m)-segment mean problems. Formally, we provide (1 + ε)-approximations to the k-segment and (k, m)-segment mean of a d-dimensional discrete-time signal. The k-segment mean is a k-piecewise linear function that minimizes the regression distance to the signal. The (k,m)-segment mean has an additional constraint that the projection of the k segments on Rd consists of only m ≤ k segments. Existing algorithms for these problems take O(kn2) and nO(mk) time respectively and O(kn2) space, where n is the length of the signal.



Our main tool is a new coreset for discrete-time signals. The coreset is a smart compression of the input signal that allows computation of a (1 + ε)-approximation to the k-segment or (k,m)-segment mean in O(n log n) time for arbitrary constants ε,k, and m. We use coresets to obtain a parallel algorithm that scans the signal in one pass, using space and update time per point that is polynomial in log n. We provide empirical evaluations of the quality of our coreset and experimental results that show how our coreset boosts both inefficient optimal algorithms and existing heuristics. We demonstrate our results for extracting signals from GPS traces. However, the results are more general and applicable to other types of sensors.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}

@conference{sung2012trajectory,

title = {Trajectory clustering for motion prediction},

author = {Cynthia Sung and Dan Feldman and Daniela Rus},

doi = {10.1109/IROS.2012.6386017},

year  = {2012},

date = {2012-10-07},

booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},

pages = {1547-1552},

publisher = {IEEE},

abstract = {We investigate a data-driven approach to robotic path planning and analyze its performance in the context of interception tasks. Trajectories of moving objects often contain repeated patterns of motion, and learning those patterns can yield interception paths that succeed more often. We therefore propose an original trajectory clustering algorithm for extracting motion patterns from trajectory data and demonstrate its effectiveness over the more common clustering approach of using k-means. We use the results to build a Hidden Markov Model of a target's motion and predict movement. Our simulations show that these predictions lead to more effective interception. The results of this work have potential applications in coordination of multi-robot systems, tracking and surveillance tasks, and dynamic obstacle avoidance.},

keywords = {},

pubstate = {published},

tppubtype = {conference}

}