A novel robotic knee device with stance control and its kinematic weight optimization for rehabilitation

Pyo, Sanghun,Yoon, Junwon,Oh, Min-Kyun Cambridge University Press 2014 Robotica Vol.32 No.8

<B>SUMMARY</B><P>It is important to develop a robotic orthosis or exoskeleton that can provide back-drivable and good assistive performances with lightweight structures for overground gait rehabilitation of stroke patients. In this paper, we describe a robotic knee device with a five-bar linkage to allow low-impedance voluntary knee motion within a specified rotation range during the swing phase, and to assist knee extension during the stance phase. The device can provide free motion through the five-bar linkage with 2-degree-of-freedom (DOF) actuation via the patient's shank using a linear actuator, and can assist knee extension at any controlled knee angle while bearing weight via a geared five-bar linkage with 1 DOF actuation of the linear actuator. The kinematic transition between the two modes can be implemented by contact with a circular structure and a linear link, and the resultant range of motion can be determined by the linear actuator. The kinematic weight of the device was optimized using the simple genetic algorithm to reduce the mass. The optimization cost function was based on the sum of the total link lengths and the actuator power. The optimization results reduced the total link length and motor power by 47% and 43%, respectively, compared to the initial design. We expect that the device will facilitate rehabilitation of stroke patients by allowing safe and free overground walking while providing support for stumbling.</P>

유전자 알고리즘을 이용한 새로운 무릎 보장구의 최적 설계

표상훈(SangHun Pyo),윤정원(JungWon Yoon) 제어로봇시스템학회 2011 제어·로봇·시스템학회 논문지 Vol.17 No.10

The objective of this paper is to optimize the design parameters of a novel mechanism for a robotic knee orthosis. The feature of the proposed knee othosis is to drive a knee joint with independent actuation during swing and stance phases, which can allow an actuator with fast rotation to control swing motions and an actuator with high torque to control stance motions, respectively. The quadriceps device operates in five-bar links with 2-DOF motions during swing phase and is changed to six-bar links during stance phase by the contact motion to the patella device. The hamstring device operates in a slider-crank mechanism for entire gait cycle. The suggested kinematic model will allow a robotic knee orthosis to use compact and light actuators with full support during walking. However, the proposed orthosis must use additional linkages than a simple four-bar mechanism. To maximize the benefit of reducing the actuators power by using the developed kinematic design, it is necessary to minimize total weight of the device, while keeping necessary actuator performances of torques and angular velocities for support. In this paper, we use a SGA (Simple Genetic Algorithm) to minimize sum of total link lengths and motor power by reducing the weight of the novel knee orthosis. To find feasible parameters, kinematic constraints of the hamstring and quadriceps mechanisms have been applied to the algorithm. The proposed optimization scheme could reduce sum of total link lengths to half of the initial value. The proposed optimization scheme can be applied to reduce total weight of general multi-linkages while keeping necessary actuator specifications.

고속 및 고가속 성능의 전방향 트레드밀 시스템 개발

표상훈(Sanghun Pyo),이호수(Hosu Lee),박상준(Sangjoon Park),윤정원(Jungwon Yoon) 한국HCI학회 2018 한국HCI학회 학술대회 Vol.2018 No.1

몰입감 있는 가상현실(VR)과의 상호작용을 위하여, 인체를 구속하지 않으면서 보행 인터페이스가 가능한 여러가지 타입의 장치가 개발되고 있다. 전방향 트레드밀 (Omni-Directional Treadmill)은, 기존 1 차원 트레드밀과 달리, 2 차원 무한지면을 생성할 수 있으므로 사용자에게 지면과 같은 자유로운 보행 자유도를 허락할 수 있고 가상환경에 대한 몰입감을 증대할 수 있다. 그러나 기존에 개발된 2D 트레드밀은 시스템의 복잡하고 동력전달의 효율성이 낮으며 상대 운동하는 부분이 무겁기 때문에, 느린 보행속도의 인터페이스만 가능하다. 본 논문에서는 기존 2D 트레드밀 시스템의 문제점을 개선한 새로운 2D 트레드밀 시스템을 소개한다. 개발된 시스템의 증진된 속도 및 가속도 성능은 인간의 도약까지 안정적으로 인터페이스 할 수 있으므로, 사용자에게 더욱 몰입감 있는 VR 상호작용을 공급할 수 있다.

스마트폰을 이용한 산업용 로봇의 사용자 친화적 및 직관적인 교시 기법 설계

표상훈(Sanghun Pyo),윤정원(Jungwon Yoon) 한국HCI학회 2013 한국HCI학회 학술대회 Vol.2013 No.1

기존의 산업용 로봇의 교시(teaching)는 티칭 펜던트에 의하여 이루어지고 있으나 효율적인 교시작업을 위해선 로봇 끝단 조종의 직관성과 사용자 친화적인 인터페이스가 요구되며, 장소의 제약으로부터 독립적인 교시를 위해선 원격조종이 가능하면서 기동성도 확보된 장치가 필요하다. 이를 위하여 현재 보급이 활발히 진행되고 있는 스마트폰을 이용한 산업용 로봇의 직관적인 교시 기법을 제시하고자 한다. 본 논문에서 제시하는 방법의 기본 아이디어는 스마트 폰의 기울기 정보를 universal 조인트를 기저(base)로 가지는 조종 장치로 가정하여 로봇의 끝단과 스마트 폰의 기울기 정보를 매칭 하는 방법을 사용한다. 이어서 전용 어플리케이션을 통하여 스마트 폰의 orientation 정보에 따라 로봇 끝단의 translation과 orientation을 직관적으로 교시할 수 있는 기법을 제시하고, 제시된 로봇 티칭 시스템이 적용된 가상환경을 통한 사용자 평가를 실시하여 제시된 방법이 기존의 티칭 펜던트만 이용한 교시작업에 비해 시간적인 효율성이 개선됨을 보이고자 한다. Industrial robot control widely utilizes conventional teaching pendant for task manipulations. The conventional teaching pendants lack features like smart control, robust design and visualizations and there is an urge to equip them with modern mobility and user friendly features. A pendant device that is capable of conventional features as well as tele-operations and mobility from remote locations. In this regard, this research proposes smart phone based intuitive teaching pendant. Since smart phone is capable of motion sensors, therefore, its sensory information is utilized to control the robot. Smartphone orientation information based on universal joint is utilized for the robot end effector translations and orientations. Furthermore, a user study is performed to compare the proposed smart teaching pendant with conventional approach in a given scenario.

회전기 및 착지기 분리 구동을 가능케 하는 새로운 무릎 보장구의 기구부 설계

표상훈(SangHun Pyo),김갑순(Gab-Soon Kim),윤정원(JungWon Yoon) 제어로봇시스템학회 2011 제어·로봇·시스템학회 논문지 Vol.17 No.8

Nowadays many neurological diseases such as stroke and Parkinson diseases are continually increasing. Orthotic devices as well as exoskeletons have been widely developed for supporting movement assistance and therapy of patients. Robotic knee orthosis can compensate stiff-knee gait of the paralyzed limb and can provide patients consistent assistance at wearable environments. With keeping a robotic orthosis wearable, however, it is not easy to develop a compact and safe actuator with fast rotation and high torque for consistent supports of patients during walking. In this paper, we propose a novel kinematic model for a robotic knee orthosis to drive a knee joint with independent actuation during swing and stance phases, which can allow an actuator with fast rotation to control swing motions and an actuator with high torque to control stance motions, respectively. The suggested kinematic model is composed of a hamstring device with a slide-crank mechanism, a quadriceps device with five-bar/six-bar links, and a patella device for knee covering. The quadriceps device operates in five-bar links with 2-dof motions during swing phase and is changed to six-bar links during stance phase by the contact motion to the patella device. The hamstring device operates in a slider-crank mechanism for entire gait cycle. The kinematics and velocity/force relations are analyzed for the quadriceps and hamstring devices. Finally, the adequate actuators for the suggested kinematic model are designed based on normal gait requirements. The suggested kinematic model will allow a robotic knee orthosis to use compact and light actuators with full support during walking.

뇌졸중 환자의 보행 재활에 동기를 부여와 보행 안정성의 확보가 동시에 고려된 하지 보장구의 개발 : 보행 안정성만을 제공함으로써 환자의 보행훈련 및 보행동작의 의지를 고취할 수 있는 로봇의 기구 설계와 제어방법

표상훈(Sanghun Pyo),윤정원(Jungwon Yoon) 한국HCI학회 2012 한국HCI학회 학술대회 Vol.2012 No.1

고전적 보장구인 RGO(Reciprocating Gait Orthosis)는 옷을 입는 것처럼 착용이 가능한 보장구로써 반신불수(hemiplegia) 환자의 보행 능력 보조을 위한 통상적 보조 장치로 쓰여지고 있다. 하지만 RGO 를 통한 인체의 단순한 구속은 환자에게 또 다른 신체적 문제를 야기 할 수 있는 단점이 있다. 그리고 다른 로봇의 경우 환자가 로봇장치에 정상적인 물리적 신호를 제공하기 어려운 상황이므로 제어가 쉽지 않은 단점이 있으며 일정한 패턴을 발생으로 환자의 하지를 운동시키는 방법은 환자 스스로의 의지가 들어간 상태가 아니므로 진정한 재활을 효과를 얻기가 힘들다는 단점이 있다. 본 논문에서는 환자가 RGO 와 호환이 가능하고 착용성 및 이동성이 보장 되면서 환자의 의지를 최대한 이끌어냄과 동시에 자세 안정성 및 보행안정성을 동시에 보장할 수 있는 5 절 링크장치를 이용한 하지 보장구를 개발하고자 한다. 이들 5 절 링크장치는 상황에 따라 각각 4 절 링크장치 및 6 절 링크장치로 변환되는 특징을 가지게 되는데 이러한 기구학적 특징으로 인해 환자의 의도를 파악하는 과정 없이 안정성 보조와 보행보조를 동시에 수행 할 수 있고 환자의 의지를 자극하여 훈련 효과를 높일 수 있는 특징을 가진다. Recently, Reciprocating Gait Orthoses (RGO) are commonly used to support hemiplegia patient's gait and posture. However, such devices can cause asymmetry during gait as a result of the irregular and sudden impulsive compulsion support. In case of existing rehabilitation robots it's difficult for patients to generate normal signal to the robot sensors. Therefore, it's not easy for robot to support the wearer properly. Moreover, in pattern generator a supportive method of gait is also found to be difficult to get effective result of rehabilitation because the patient doesn't stimulate the motivation by oneself. In this paper, we proposed the 5 linkage mechanism robot which is compatible with RGO. This robot is capable of transforming between 1DOF to 2 DOF providing flexibility, control stability support, and gait assistance. Furthermore, robot at the same time without grasping the patient's intention it has the feature which can heighten the intensity rehabilitation training effect by stimulating the patient's motivation utilizing 5 linkage mechanisms.

GERAN에서의 향상된 셀 재탐색에 관한 연구

표상훈 ( Sanghun Pyo ),함형민 ( Hyoungmin Ham ),송주석 ( Jooseok Song ) 한국정보처리학회 2009 한국정보처리학회 학술대회논문집 Vol.16 No.1

본 연구에서는 GERAN (GSM EDGE Radio Access Network) 망에서 다양한 무선환경에 따른 셀 재탐색을 연구하였으며, 시계열분석을 통하여 재탐색 이후의 RSS (Received Signal Strength)를 예측하여 개선된 재탐색 알고리즘을 연구하였다. Field 데이터를 통해 제안된 알고리즘을 분석하였으며, 이를 통하여 다양한 조건에 적합한 기법을 제안코저 한다.

EU REACH 이행에 사용되는 노출평가 툴의 현황과 전망

김상헌(Sanghun Kim),김동현(Dong Hyeon Kim),최은경(Eun Kyung Choe),전현표(Hyun Pyo Jeon) 한국환경보건학회 2024 한국환경보건학회지 Vol.50 No.4

Background: Human health and environment exposure assessments of chemicals are essential part for REACH and BPR as well as K-REACH and K-BPR. Several useful exposure assessment tools have been developed and updated to become extensively used during more than fifteen years of chemical registrations under REACH and their updates are still going on. Objectives: Evolution of regulatory tools for environment, workers and consumers exposure assessments under REACH is investigated focusing on why and how tools have been developed and updated for the future regulatory tools in Korea. Methods: REACH regulatory tools including EUSES, ECETOC TRA and CHESAR as well as built-in models SimpleTreat and SimpleBox were chosen with other frequently used Tier 1 and 2 tools. Available resources such as homepage information, background documents, related scientific reports, relevant journal publications, up-to-date lists of new version publications, release notes and user guides were reviewed extensively and summarized using easy-readable Tables and Figures. Results: SimpleTreat and SimpleBox are built-in models both for EUSES and ECETOC TRA (Environment). ECHA’s CHESAR contains ECETOC TRA (Workers) and ECETOC TRA (Consumers) as well as EUSES and ECETOC TRA (Environment) for environment exposure assessment while results of Tier 2 Stoffenmanager and ConsExpoWeb can be imported. Evolution of CHESAR from version 1 (2010) to 3.8 (2023) has focused on the compatibility of frequent updates of IUCLID, importing functionality, editability, updated use maps, harmonised conditions of use as well as updates of the built-in tools evolved according to scientific development, refinements of the tool, increased conservatism and user-friendliness. CHESAR Platform 1.0 will soon be published to serve both for REACH and BPR. Conclusions: Updates of the tools can be successfully continued by transparency of the tools, participation of industry sectors for tool refinements and tool developers’/authorities’ encouragements of partners/users to jointly innovate tools through scientific researches, tool validations and user feedback.

PVDF-HFP 전기방사막의 수처리 성능향상을 위한 열압연 후처리에 관한 연구

표민수(Minsu Pyo),이상훈(Sanghun Lee),이의종(Eui-Jong Lee) 대한환경공학회 2022 대한환경공학회 학술발표논문집 Vol.2022 No.11

A 2-GS/s 6-bit Single-channel Speculative Loop-unrolled SAR ADC with Low-overhead Comparator Offset Calibration in 28-nm CMOS

Eunsang Lee,Sanghun Lee,Changhyun Pyo,Hyunseok Kim,Jaeduk Han 대한전자공학회 2024 Journal of semiconductor technology and science Vol.24 No.4

This paper presents a 2-GS/s 6-bit single-channel speculative loop-unrolled successive approximation register (SAR) analog-to-digital converter (ADC) with comparator offset calibration. The proposed loop-unrolled SAR ADC speeds up its conversion speed by selecting one of the pre-determined capacitive digital-to-analog converters (CDACs) speculatively. A foreground comparator offset calibration for the speculative loop-unrolled SAR ADC is introduced to improve the ADC performance by reducing the input parasitic capacitance and minimizing the logic fan-out in comparator internal clock path. The CDAC switching method that minimizes the variation of the output common-mode (CM) voltage is applied to be compatible with the proposed foreground comparator offset calibration. In addition, the modified double-tail comparator structure is adopted for reducing the kickback noise without the speed overhead. The proposed SAR ADC achieves a 2-GS/s sampling rate with only a single-channel without a time-interleaving technique. The ADC is fabricated in 28-nm CMOS and has a 33.1-dB SNDR at a low input frequency and a 29.9-dB SNDR at the Nyquist frequency with a 6.2- mW power consumption from 1.2-V supply voltage.