• 한국정밀공학회지
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• 제31권10호
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• pp.913-922
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• 2014

This paper describes design of a robotic above-knee prosthetic leg which is powered by electrical motors. As a special feature, the robotic prosthetic leg has enough D.O.F.s. For mimicking the human leg, the robotic prosthetic leg is composed of five joints. Three of them are called 'active joint' which is driven by electrical motors. They are placed at the knee-pitch-axis, the ankle-pitch-axis, and the an! kle-roll-axis. Every 'active joint' has enough torque capacity to overcome ground reaction forces for walking and is backlashless for accurate motion generation and high-performance balance control. Other two joints are called 'passive joint' which is activating by torsion spring. They are placed at the toe part and designed by Crank-rocker mechanism using kinematic design approach. In order to verify working performance of the robotic prosthetic leg, we designed a gait trajectory through motion capture technique and experimentally applied it to the robot.

• 제어로봇시스템학회논문지
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• 제21권10호
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• pp.944-950
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• 2015

Recent studies on ankle-foot prostheses used for transtibial amputees have focused on the adaptation of the ankle angle of the prosthesis according to ground conditions. For adaptation to various ground conditions (e.g., incline, decline, and step conditions), ankle-foot prostheses should first recognize the ground conditions as well as the current human motion pattern. For this purpose, the ground reaction forces and orientation angle of the tibia provide fundamental information. The measurement of the orientation angle, however, creates a challenge in practice. Although various sensors, such as accelerometers and gyroscopes, can be utilized to measure the orientation angles of the prosthesis, none of these sensors can be solely used due to their intrinsic drawbacks. In this paper, a time-varying complementary filtering (TVCF) method is proposed to incorporate the measurements from an accelerometer and a gyroscope to obtain a precise orientation angle. The cut-off frequency of TVCF is adaptively determined according to the human gait phase detected by a fuzzy logic algorithm. The performance of the proposed method is verified through experiments.

• 제어로봇시스템학회논문지
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• 제17권12호
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• pp.1248-1255
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• 2011

In daily life, another major role of human hand is a communicative function using hand gestures besides grasp function. Therefore, if amputees can express their intention by the prosthetic hand, they can much actively participate in social activities. Thus, this paper propose myoelectric multi-function prosthetic hand which can express 6 useful hand gestures such as Rock, Scissors, Paper, Indexing, Ok and Thumb-up. It was designed as under-actuated structure to minimize volume and weight of the prosthetic hand. Moreover, in order to effectively control various hand gestures by only two EMG sensors, we propose a control strategy that the signal type are expanded as "Strong" and "Light", and hand gestures are hierarchically classified for the intuitive control. Finally, we prove the validity of the developed prosthetic hand with the experiment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1373-1377
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• 2003

Current prostheses for amputees are generally extrinsic wearing socket type that the coupling between body stump and appliance wraps the soft tissue and this structure causes several problems :applying direct weight to soft tissue such as skin and muscle, skin trouble of contacting area and pain. In this study, osseointegration implant is a method to directly connect prosthesis to the residual stump skeletal tissue of arm, finger and leg through surgical operation. Technology presented in this paper essentially solves the problems of pain and abnormal weight transfer system indicated above and recovers the functions of the amputated arm and leg. In this paper, implant shape was designed for the first step for the development of osseointegration implant and then we studied the possibility to apply this osseointegration implant to human body by performing implant insertion operation to beagle tibia for the clinical animal test and normal beagle's gait analysis was executed in order to quantitatively verify the beagle's skeletal functions after the implant insertion.

• 대한의용생체공학회:의공학회지
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• 제30권3호
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• pp.205-212
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• 2009

This paper proposes a biomimetic hand prosthesis with tendon-driven five fingers. Each finger is composed of a distal-middle phalange, a proximal phalange and a metacarpal bone, which are connected to a link mechanism. The finger flexion is a resultant motion by pulling a wire to serve as a tendon, but the finger extension is performed by an elastic mechanism composed of a restoration spring. The designed hand prosthesis with tendon-driven five fingers has totally six degrees of freedom. But its weight is merely 400.73g. The hand can perform various hand functions such as the grasping and the hand postures. From experimental results, we show that the proposed hand prosthesis is useful to amputees as a prosthetic hand.

• 한국전문물리치료학회지
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• 제9권4호
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• pp.61-68
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• 2002

본 연구는 하퇴의지 착용자와 정상 성인간의 시간-거리, 운동형상학 변수를 조사하고 비교하기 위하여 실시하였다. 연구 대상자는 외상으로 인한 하퇴 절단자로서 내골격식 하퇴의지를 착용하고 독립적으로 보행이 가능한 20명과 연령, 신장으로 짝짓기한 대조군(matched control group) 20명이 참여하였다. 보행분석은 Vicon Clinical Manager Software (VCM)를 내장한 PC에 5개의 카메라가 연결되어 있는 Vicon 512 Motion Analysis System (MAS, Oxford Metrics Inc.)을 이용하였다. 하퇴의지 착용군의 단하지 지지시간이 정상 성인군에 비해 유의하게 짧았으며(p<.05), 하퇴의지 착용군에서 슬관절의 선전이 증가되었으며 족관절의 저측굴곡이 감소되었다(p<.05). 하퇴절단자들의 보행개선을 위해서는 하퇴절단자 개인의 보행능력에 알맞은 부품의 선택, 체계적인 보행훈련 및 평가, 보행능력 향상을 위한 근력강화 프로그램 등 체계적인 재활훈련 프로그램이 필요한 것으로 사료된다. 본 연구는 연구대상자의 수가 제한되어 있으므로 연구의 결과를 일반화하기에는 제한점이 있으나, 향후 편측 하퇴절단자의 보행연구에 대한 기초 자료로 사용될 수 있을 것이라고 생각된다.

• 대한족부족관절학회지
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• 제12권1호
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• pp.41-46
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• 2008

Purpose: This study was designed to evaluate characteristics of foot pressure distribution with or without partial prosthetic foot in transmetatarsal amputee. Materials and Methods: The subjects were 9 transmetatarsal amputees. Foot pressures were measured at hallux, the $1^{st}-5^{th}$ metatarsal head (MTH), mid-foot, condyle area by F-scan system in amputated or contralateral foot during active walking. Results: In amputated foot, mean peak pressure was greatest in midfoot without prosthetic foot but it was greatest in hindfoot with prosthetic foot. In unaffected foot, although mean peak pressure was higher in hallux, and $1-5^{th}$ MTH compared to amputated foot, it was greatest in hind foot both with and without prosthetic foot. However, in unaffected foot, mean peak pressure significantly decreased in hallux and $5^{th}$ MTH after wearing the prosthetic foot. There was a significant difference in mean peak pressure in hallux and $5^{th}$ MTH between amputated and unaffected foot after wearing prosthetic foot. However, other region had no significant difference with or without prosthetic foot between feet. Conclusions: The use of partial prosthetic foot tends to shift weight bearing from the heel area to forefoot and could significantly reduce hind foot peak pressure and redistributed to peak pressure. The partial prosthetic foot can also offer the peak pressure to reduction both amputated foot and unaffected foot and help to toe off during walking.

• The Korean Journal of Pain
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• 제33권3호
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• pp.267-274
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• 2020

Background: General anesthesia (GA) has been considered the anesthetic technique which most frequent leads to phantom limb pain (PLP) after a limb amputation. However, these prior reports were limited by small sample sizes. The aims of this study were to evaluate the incidence of PLP according to the various anesthetic techniques used for limb amputation and also to compare the occurrence of PLP according to amputation etiology using the Korean Health Insurance Review and Assessment Service for large-scale demographic information. Methods: The claims of patients who underwent limb amputation were reviewed by analyzing the codes used to classify standardized medical behaviors. The patients were categorized into three groups-GA, neuraxial anesthesia (NA), and peripheral nerve block (PNB)-in accordance with the anesthetic technique. The recorded diagnosis was confirmed using the diagnostic codes for PLP registered within one year after the limb amputation. Results: Finally, 7,613 individuals were analyzed. According to the recorded diagnoses, 362 patients (4.8%) developed PLP after amputation. Among the 2,992 patients exposed to GA, 191 (6.4%) were diagnosed with PLP, whereas 121 (4.3%) of the 2,840 patients anesthetized with NA, and 50 (2.8%) of the 1,781 patients anesthetized under PNB developed PLP. The relative risks were 0.67 (95% confidence interval [CI], 0.53-0.84; P < 0.001) for NA and 0.43 (95% CI, 0.32-0.59; P < 0.001) for PNB. Conclusions: In this retrospective cohort study, using large-scale population-based databases, the incidence rates of PLP after limb amputations were, in the order of frequency, GA, NA, and PNB.

• 대한의용생체공학회:의공학회지
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• 제40권6호
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• pp.242-249
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• 2019

Forearm electromyography (EMG) generated by wrist movements has been widely used to develop an electrical prosthetic hand, but EMG generated by finger movements has been rarely used even though 20% of amputees lose fingers. The goal of this study is to improve the classification performance of different finger movements using a deep learning algorithm, and thereby contributing to the development of a high-performance finger-based prosthetic hand. Ten participants took part in this study, and they performed seven different finger movements forty times each (thumb, index, middle, ring, little, fist and rest) during which EMG was measured from the back of the right hand using four bipolar electrodes. We extracted mean absolute value (MAV), root mean square (RMS), and mean (MEAN) from the measured EMGs for each trial as features, and a 5x5-fold cross-validation was performed to estimate the classification performance of seven different finger movements. A long short-term memory (LSTM) model was used as a classifier, and linear discriminant analysis (LDA) that is a widely used classifier in previous studies was also used for comparison. The best performance of the LSTM model (sensitivity: 91.46 ± 6.72%; specificity: 91.27 ± 4.18%; accuracy: 91.26 ± 4.09%) significantly outperformed that of LDA (sensitivity: 84.55 ± 9.61%; specificity: 84.02 ± 6.00%; accuracy: 84.00 ± 5.87%). Our result demonstrates the feasibility of a deep learning algorithm (LSTM) to improve the performance of classifying different finger movements using EMG.

• 대한의용생체공학회:의공학회지
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• 제21권4호
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• pp.385-390
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• 2000

의족착용자의 보행에 있어서 의족의 정렬은 매우 중요하나, 정량적이고 다양한 의족에 공통적으로 적용할 수 있는 정렬방법이 아직 소개되지 않고 있다. 본 연구를 통해서 load cell, 레이저, 이송 가이드로 구성되는 정적 의족정렬시스템을 개발되었다. 개발된 시스템을 24명의 남자성인과 4명의 하퇴의족착용자에게 적용하여 직립자세와 전방, 후방ㅇ로 기운 자세에서 족관절, 슬관절, 대전자, 어깨관절등과 하중선과의 상대적 위치를 측정하였다. 정상인의 중립자세에서 하중선의 위치는 외과, 슬관절, 견관절에서는 앞쪽에 그러나 대전자에서는 뒤쪽에 있었다. 정상인이 앞쪽으로 최대한 기운 자세에서 외과와 슬관절, 대전자는 하중선의 뒤쪽에 위치하였으나 견관절은 앞쪽에 위치하였다. 그러나 뒤쪽으로 기운 자세의 경우, 하중선은 견관절을 제외한 모든 곳의 뒤쪽에 위치하였다. 의족착용자의 환측의 하중선은 족관절, 슬관절, 대전자, 견관절 모두의 전방에 위치하였으며, 의족착용자의 건측에서의 하중선의 위치는 정상인의 경우와 통계적으로 유사하였다. 본 연구를 통해서 개발된 정적 의족정렬시스템은 의족 착용자는 물론, 정상인들의 하중선과 주요 관절과의 상대적 위치를 파악하는데 매우 유용하게 사용될 수 있을 것으로 기대된다.