Publications

3D-printed semi-soft mechanisms inspired by origami twisted tower

Yanzhou Wang and Kiju Lee

NASA/ESA Conference on Adaptive Hardware and Systems (AHS)

24-27 July 2017

DOI: 10.1109/AHS.2017.8046373

This paper presents a novel modeling and fabrication technique of semi-soft mechanisms inspired by the origami twisted tower. The twisted tower is a modular origami structure consisting of multiple octagon-shaped layers. This structure can generate linear contraction, extension, and bending. A special geometric construct of this design allows each layer to fully collapse by twisting π/4°. Inspired by this unique feature, the design was further diversified to use any regular polygon with m sides, where m ≥ 3 and resulting maximum twisting within a single layer is 2π/m. This design diversification broadens potential applications of this mechanism. Such complex origami designs, however, faces one fundamental problem, i.e. manufacturability. There is no current manufacturing technique available for automating complex sequences of paper folding and assembling. To address this challenge, the twisted tower design was converted into a 3D printable model. 2-layer towers based on a triangle, square, pentagon, hexagon, and octagon were printed using the PolyJet ^™ 3D printing technology. For the octagon-based design, an additional 10-layer tower was printed to demonstrate the range of motions preserved from the hand-folded origami tower.

SIG-Blocks: Tangible game technology for automated cognitive assessment

Kiju Lee, Donghwa Jeong, Rachael C. Schindler, and Elizabeth J. Short

Computers in Human Behavior

December 2016

DOI: 10.1016/j.chb.2016.08.023

This paper presents the SIG-Blocks system developed for automated cognitive assessment via tangible geometric games (TAG-Games). Computerized game administration and real-time cognitive and behavior assessments were realized by wireless self-synchronization in communication, decentralized hybrid-sensing, assembly and motion detection, and graphical visualization. The measurable performance data included time and accuracy at each manipulation step, overall speed of manipulative motions, and the total number of rotational motions. For preliminary evaluation, three types of TAG-Games were designed: TAG-Game^A for assembly, TAG-Game^S for shape matching, and TAG-Game^M for memory. As a part of the game design, a computational measure of play complexity was defined for each TAG-Game based on the geometric properties and the number of blocks in the item. An evaluation with 86 participants assessed both reliability of the TAG-Game items using split-half and test-retest reliability tests and validity of the proposed complexity measures by comparing the results with three subtests of the Wechsler Adults Intelligence Scale 4th Edition (WAIS-IV), i.e. Block Design (BD), Matrix Reasoning (MR), and Digit Span (DS). The high reliability coefficients showed that TAG-Games were reliable. Regarding validity, correlations were found between TAG-Game^A and BD and between TAG-Game^S and MR. Behavioral analysis also showed that the TAG-Game performance was positively correlated with the manipulation speed, but not correlated with the total number of rotations applied to the blocks.

Distributed Communication and Localization Algorithms for Homogeneous Robotic Swarm

Donghwa Jeong and Kiju Lee

Distributed Autonomous Robotic Systems (DARS)

15 January 2016

DOI: 10.1007/978-4-431-55879-8_28

Swarm robotics aims to achieve physical flexibility, overall system robustness, and enhanced reliability and efficiency by employing a group of autonomous robots for collective task performance. Achieving collective performance by individual robots with limited sensing, processing, and communication capabilities, however, faces several technical challenges, such as difficulties in establishing reliable communication and decentralized control among the robots. This paper presents the following wireless communication algorithms that can be applied to homogeneous swarm robots: (1) infrared-based short-distance communication between the adjacent robots using a self-synchronization technique; and (2) long-distance communication and localization based on distance measurement using radio signals. In addition, two decentralized global shape formation algorithms for homogeneous swarm robots are presented for simulating dispersion and line formation collectively achieved by homogeneous swarm robots.

OrigamiBot-II: An Amphibious Robot With Reconfigurable Origami Wheels for Locomotion in Dynamic Environments

Donghwa Jeong and Kiju Lee

International Mechanical Engineering Congress & Exposition (IMECE)

March 7, 2016

DOI: 10.1115/IMECE2015-53081

This paper presents a mobile robot with reconfigurable origami wheels, called OrigamiBot-II. The origami wheels, based on the twisted tower design, can contract and extend the width and therefore suitable for amphibious locomotion in an unknown, possibly dynamic, environment. The mechanical design focused on achieving locomotion on various types of ground and water surfaces. To establish wireless communication between the robot and a remote base or another robot, radio frequency (RF) based techniques were investigated and tested for both ground and water environments. The locomotion performance of Origamibot-II was evaluated in two ways: simulations using Gazebo integrated with Robot Operating System (ROS) and physical experiments on various types of surfaces. The simulations showed that the robot moves faster with contracted wheels on a smooth surface than with extend wheels, while expanded wheels provides more traction on a rugged terrain, such as asphalt, than contracted wheels. Physical experiments supported the simulation results and further demonstrated the robot’s amphibious locomotion capability by successfully maneuvering on a variety of ground environments and water surfaces.

Design and Evaluation of a Multi-Sensor Unit for Measuring Physiological Stressors of Medical Transport

Georgios Kaloutsakis, Andrew Reimer, Donghwa Jeong, and Kiju Lee

International Mechanical Engineering Congress and Exposition (IMECE)

November 15-21, 2013

DOI: 10.1115/IMECE2013-65435

Patients who undergo inter-hospital transfer experience increased relative mortality, ranging from 10 to 100% higher than non-transferred patients. The high-cost, increased risk of complications and poor outcomes of transferred patients warrant the critical examination of potential causes. One of the major causes may be the external stressors that patients are exposed to during medical transport. To realize simultaneous measurements of external stressors, we developed a multi-sensor unit for measuring vibration, noise, ambient temperature, and barometric pressure. For preliminary evaluation, the sensor unit was tested on 29 medical transports, 11 air transports by a helicopter and 18 ground missions by an ambulance. The average whole-body vibration for each air and ground transport was calculated at 0.3510m/s² and 0.5871m/s² respectively. Air transports produced much higher level of noise than the ground transports. We found no significant difference between two modes in terms of average temperature and the temperature changes. Barometric pressure drops significantly during air transport, indicating potential use of this data for automatic mode classification.

Implementation of Vision-based Object Tracking Algorithms for Motor Skill Assessments

Beatrice Floyd and Kiju Lee

International Journal of Advanced Computer Science and Applications

2015

DOI: 10.14569/IJACSA.2015.060639

Assessment of upper extremity motor skills often involves object manipulation, drawing or writing using a pencil, or performing specific gestures. Traditional assessment of such skills usually requires a trained person to record the time and accuracy resulting in a process that can be labor intensive and costly. Automating the entire assessment process will potentially lower the cost, produce electronically recorded data, broaden the implementations, and provide additional assessment infor-mation. This paper presents a low-cost, versatile, and easy-to-use algorithm to automatically detect and track single or multiple well-defined geometric shapes or markers. It therefore can be applied to a wide range of assessment protocols that involve object manipulation or hand and arm gestures. The algorithm localizes the objects using color thresholding and morphological operations and then estimates their 3-dimensional pose. The utility of the algorithm is demonstrated by implementing it for automating the following five protocols: the sport of Cup Stacking, the Soda Pop Coordination test, the Wechsler Block Design test, the visual-motor integration test, and gesture recognition.

iSIG-Blocks: interactive creation blocks for tangible geometric games

Donghwa Jeong and Kiju Lee

IEEE Transactions on Consumer Electronics

November 2015

DOI: 10.1109/TCE.2015.7389795

This paper presents interactive creation blocks, called iSIG-Blocks (interactive SIG-Blocks), for automated tangible geometric games. iSIG-Blocks can detect physical motions and assembly configurations using embedded sensors. Each block features programmable LED display, a buzzer, and a vibration motor to provide sensory feedback to the player. A graphical user interface and tangible pattern design software (TAPware) were also developed for game administration, performance monitoring, and game customization. TAPware incorporates a computational measure of geometric complexity for generating game items of varying difficulty levels. For preliminary evaluation, a tangible memory game, Memorix, was developed and tested on a small group of young adults (N=12). The test results revealed that accuracy in correctness and in manipulation speed measurements was over 98%. Also, high correlation was found between the game performance and the complexity measure (r=0.84, p<0.01). Parameter sensitivity analysis revealed that the participants’ failure rate was more sensitive to color than to length or geometric shape, used in the game pattern.

Dispersion and Line Formation in Artificial Swarm Intelligence

Donghwa Jeong and Kiju Lee

Collective Intelligence

June 2014

arXiv: 1407.0014 [cs. NE]

One of the major motifs in collective or swarm intelligence is that, even though individuals follow simple rules, the resulting global behavior can be complex and intelligent. In artificial swarm systems, such as swarm robots, the goal is to use systems that are as simple and cheap as possible, deploy many of them, and coordinate them to conduct complex tasks that each individual cannot accomplish. Shape formation in artificial intelligence systems is usually required for specific task-oriented performance, including 1) forming sensing grids, 2) exploring and mapping in space, underwater, or hazardous environments, and 3) forming a barricade for surveillance or protecting an area or a person. This paper presents a dynamic model of an artificial swarm system based on a virtual spring damper model and algorithms for dispersion without a leader and line formation with an interim leader using only the distance estimation among the neighbors.

OrigamiBot-I: A thread-actuated origami robot for manipulation and locomotion

Evan Vender-Hoff, Donghwa Jeong, and Kiju Lee

IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

14-18 Sept. 2014

DOI: 10.1109/IROS.2014.6942743

This paper presents OrigamiBot-I, a thread-actuated origami robot, to demonstrate a physical application of an origami design for robotic manipulation and locomotion. The selected design can generate twisting and bending motions by pulling, pushing, or torsional force applied to the origami structure. Thread-based actuation also enables various shapes and motions by using different numbers of threads and routing them through different paths. The kinematics for each twisting and bending motions based on estimated parameters is derived. To evaluate potential use of origami for real-world applications and identify structural weaknesses, preliminary stiffness and durability testing was conducted. For physical demonstrations of robotic manipulation and locomotion, OrigamiBot-I was equipped with four independently-routed threads, where each thread is controlled by a geared DC motor. The robot successfully demonstrated its simple manipulation and locomotion capabilities.