• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.858-863
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• 2004

In this study, the new prosthetic hand which can perform sensory feedback is developed. Although the continuous development of current prosthetic hands, they have some drawbacks. The drawbacks are the low grasping capabilities, the lack of sensory information given to the user, and so on. Despite the improvement of the function of fingers, the sensory information problem still remains undeveloped. By using differential gear and underactuated mechanical design, it can be solved with the minimum additional weight. And it will be applied to all of the prosthetic hands.

• 대한기계학회논문집A
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• 제41권5호
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• pp.415-420
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• 2017

과소 구동 전동의수는 가벼우며 비교적 경제적이라는 장점이 있다. 본 연구에서는 적응파지가 가능한 과소 구동 전동의수를 대상으로 경제적인 파지력 제어 시스템을 제안하였다. 근전도 신호로 구동되는 메인 케이블의 장력으로 파지력이 결정되므로 장력에 따라 사용자의 피부에 부착된 진동모터를 구동하는 촉감기반 피드백 시스템을 구성하였다. 진동 신호에 대한 사용자의 감각적 판단을 기반으로 파지력을 추정하고 제어하기 위하여 파지력과 진동 신호 간의 적절한 변환 관계를 수립하고 시제품 성능시험을 하였다. 최소한의 훈련으로 사용자들은 비교적 정확하게 파지력을 제어할 수 있었다.

• Advances in nano research
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• 제17권4호
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• pp.369-383
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• 2024

Annular nano-electromechanical systems (NEMS) in intelligent prosthetic hands enhance precision by serving as highly sensitive sensors for detecting pressure, vibrations, and deformations. This improves feedback and control, enabling users to modulate grip strength and tactile interaction with objects more effectively, enhancing prosthetic functionality. This research focuses on the electro-thermal buckling behavior of multi-directional poroelastic annular NEMS used as temperature sensors in airplanes. In the present study, thermal buckling performance of nano-scale annular functionally graded plate structures integrated with piezoelectric layers under electrical and extreme thermal loadings is investigated. In this regard, piezoelectric layers are placed on a disk made of metal matrix composite with graded properties in three radials, thickness and circumferential directions. The grading properties obey the power-law distribution. The whole structure is embedded in thermal environment. To model the mechanical behavior of the structure, a novel four-variable refined quasi-3D sinusoidal shear deformation theory (RQ-3DSSDT) is engaged in obtaining displacement field in the whole structure. The validity of the results is examined by comparing to a similar problem published in literature. The results of the buckling behavior of the structure in different boundary conditions are presented based on the critical temperature rise and critical external voltage. It is demonstrated that increase in the nonlocal and gradient length scale factor have contradicting effects on the critical temperature rise. On the other hand, increase in the applied external voltage cause increase in the critical temperature. Effects of other parameters like geometrical parameters and grading indices are presented and discussed in details.

• Advances in nano research
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• 제17권4호
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• pp.385-399
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• 2024

NEMS (Nano-Electro-Mechanical Systems) devices play a significant role in the advancement of prosthetic hands due to their unique properties at the nanoscale. Their integration enhances the functionality, sensitivity, and performance of prosthetic limbs. Understanding the electro-thermal buckling behavior of such structures is crucial since they may be subjected to extreme heat. So, in this paper, the two-dimensional hyperbolic differential quadrature method (2D-HDQM) integrated with a four-variable refined quasi-3D tangential shear deformation theory (RQ-3DTSDT) in view of the trace of thickness stretching is extended to study electro-thermal buckling response of three-directional poroelastic FG (3D-PFG) circular sector nanoplate patched with piezoelectric layer. Aimed at discovering the real governing equations, coupled equations with the aid of compatibility conditions are employed. Regarding modeling the size-impacts, nonlocal refined logarithmic strain gradient theory (NRLSGT) with two variables called nonlocal and length scale factors is examined. Numerical experimentation and comparison are used to indicate the precision and proficiency related to the created procedure. After obtaining the outputs of the mathematics, an appropriate dataset is used for testing, training and validating of the artificial intelligence. In the results section will be discussed the trace associated with multiple geometrical and physical factors on the electro-thermal buckling performance of the current nanostructure. These findings are essential for the design and optimization of NEMS applications in various fields, including sensing, actuation, and electronics, where thermal stability is paramount. The study's insights contribute to the development of more reliable and efficient NEMS devices, ensuring their robust performance under varying thermal conditions.

• 문화기술의 융합
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• 제10권1호
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• pp.19-23
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• 2024

양손 절단 환자들에게 미용적 목적과 함께 기능적 목적을 갖춘 의수가 필요하며 잔존 근육의 근전도를 이용한 인공 의수에 대한 연구가 활발하나 아직도 비싼 비용의 문제가 있다. 본 연구에서는 저비용의 부품과 소프트웨어인 표면 근전도 센서, 머신러닝 소프트웨어 Edge Impulse, Arduino Nano 33 BLE, 그리고 3D 프린팅을 이용하여 인공의수를 제작하고 성능을 평가하였다. 표면 근전도 센서로 획득하고 Edge Impulse에서 디지털 시그널 프로세싱 과정을 거친 신호들을 이용하여 머신러닝으로 손가락 운동의 종류를 판단하는 훈련을 통해 각 손가락의 굽힘 운동신호를 의수 모델의 손가락들에 전달하였다. 디지털 시그널 프로세싱 조건을 노치 필터 60 Hz, 대역필터 10-300 Hz, 그리고 샘플링 주파수 1,000 Hz로 했을 때, 머신 러닝의 정확도가 82.1%로 가장 높았다. 각 손가락 굴곡 운동간에 혼동될 수 있는 가능성은 약지가 가장 높아서 검지의 운동으로 혼동될 가능성이 44.7 %이었다. 저비용 인공의수의 성공적인 개발을 위해서는 더 많은 연구가 필요하다.

• 문화기술의 융합
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• 제9권4호
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• pp.393-399
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• 2023

상지 절단 장애인은 미관 목적과 기능적 필요성에 의하여 상지 의지를 착용하며, 특히 양손 절단자인 경우 잡는 동작 즉 파지동작이 가능한 근전 전동의수의 착용이 필수적이다. 잔존 근육의 근전도 신호에 의하여 작동하는 근전 전동의수는 산업재해보상보험의 공적보험 급여 품목이며, 사용자의 안전과 제품 성능의 유효성에 대한 시험 방법 표준의 개발이 필요하다. 본 연구에서는 상지 전동의수의 잡는 힘 즉 파지력을 로드셀을 이용하여 측정하고 반복 동작으로 인한 내구성을 근접센서를 이용하여 시험하기 위한 내구성 시험 장치를 개발하고 그 시험 방법의 표준을 제안한다. 아직까지 국제 표준화 기구 ISO(International Standardization Organization)의 시험 표준이 제정되지 않은 상태이므로 향후 전동의수 시험 표준 분야에서 한국의 선도적인 역할을 할 수 있을 것으로 기대된다.

• 로봇학회논문지
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• 제18권4호
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• pp.367-375
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• 2023

Most partial hand amputees experience limited wrist movement, which hinders the efficient functioning of upper limb, affecting hand-to-use coordination and the usability of the prosthetic hand. This limitation can lead to secondary musculoskeletal issues due to repetitive compensatory movement patterns. However, current partial hand prosthetic lack rotational wrist movement due to challenges in accommodating various hand shapes and limited space. In our study, we proposed a prosthetic hand with a wrist rotation module for partial hand amputees, aiming to reduce compensatory movement. To validate the proposed wrist rotation module, we conducted motion analysis during reach-to-grasp task. Furthermore, during the Jebsen-Taylor hand function test, we evaluated both the effect on upper limb movement and the usability of the prosthetic hand, comparing configurations with and without the wrist rotation module. The results showed that the prosthetic hand equipped with rotational wrist movements reduces compensatory movements and promotes efficient upper limb movement patterns. This finding highlights the value of incorporating a wrist rotation module in prosthetic hands to improve upper limb movement for partial hand amputees.

• 한국정밀공학회지
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• 제32권10호
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• pp.851-856
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• 2015

This study aimed to develop a sensory feedback system which could measure force and temperature for the user of myoelectric prosthetic hands. The Sensory measurement module consisted of a force sensing resistor to measure forces and non-contact infrared temperature sensor. These sensors were attached on the fingertips of the myoelectric prosthetic hand. The module was validated by using standard weights corresponding to external force and a Peltier module. Sensory transmission module consisted of four vibration motors. Eight vibration patterns were generated by combining motion of each vibration motor and were dependent on kinds and/or magnitude. The module was verified by using standard weigts and water at varying temperatures. There were correlations of force and temperature between the sensory measurement module and standard weight and water. Additionally, exact vibration patterns were generated, indicating the efficacy of the sensory feedback system for the myoelectric prosthetic hand.

• 대한기계학회논문집A
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• 제40권10호
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• pp.843-849
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• 2016

과소 구동기구 로봇 핸드에서 최소한의 구동기만으로 적응 파지 기능을 구현할 수 있는 것으로 알려져 있다. 이러한 연구결과를 기반으로 새로운 의수의 설계를 제안하였다. 또한 다양한 크기의 원통형, 구형, 사각 기둥 형 물체에 대한 의수의 파지 성능을 평가하는 방법을 제시하였다. 중요 설계 인자들이 파지 성능에 미치는 영향을 실험계획법으로 평가하고 개선된 설계 방안을 제시하였다.

• 로봇학회논문지
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• 제17권4호
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• pp.484-492
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• 2022

This paper presents a simple and robust under-actuated robotic finger mechanism that enables self-adaptive grip, fingertip pinch, and caging grasp functions. In order to perform daily activities using hands, the fingers should be able to perform adaptive gripping and pinching motion, and the caging grasp function is required to realize natural gripping motions and improve grip reliability. However, general commercial prosthetic hands cannot implement all three functions because they use under-actuation mechanism and simple mechanical structure to achieve light-weight and high robustness characteristic. In this paper, new mechanism is proposed that maintains structural simplicity and implements all the three finger functions with simple one degree-of-freedom control through a combination of a four-bar linkage mechanism and a wire-driven mechanism. The basic structure and operating principle of the proposed finger mechanism were explained, and simulation and experiments using the prototype were conducted to verify the gripping performance of the proposed finger mechanism.