• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.3
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• pp.196-201
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• 2016

This paper analyses the characteristics of a stiffness-based rehabilitation mechanism for improving the function of the elbow joint of a human. We consider an elastic string as a tool for the elbow joint rehabilitation, where the string has been modeled as a linear spring with a stiffness. For effective rehabilitation training by using such a mechanism, we need to analyse the available torque characteristics of the elbow joint according to the stiffness of the string. Through various simulations, the torque pattern and its range of the elbow joint by assigning the stiffness of the string have been identified for a pre-defined trajectory of motion of the elbow joint. Finally, we show that the specified stiffness-based rehabilitation scheme can be used for effective rehabilitation of the elbow joint.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.411-411
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• 2000

본 논문에서는 새로운 형태의 정밀위치제어용 3자유도 매니플레이터를 제안하고, 기구학 해석을 수행하며, FEM과 수치해석적인 방법을 비교하여 메카니즘에 대한 모델링 방법이 크게 틀리지 않음을 확인 하고자 한다. 회전관절과 구형관절은 비구동관절로써 미소움직임이 가능하도록 하나의 모듈로 이루어진 flexure hinge들로 만들어진다. 따라서, 비구동관절에 대한 강성해석을 수행하며 구동관절의 토오크 벡터를 비구동관절의 강성과 변위로 표현하여 액추에이터의 구동용량을 결정한다.

• Transactions of the KSME C: Technology and Education
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• v.1 no.2
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• pp.153-165
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• 2013

The established gait analysis studies have regarded leg as one single spring. If we can design a knee-ankle actuating mechanism as a primary actuator for supporting knee extension, it might be possible to revolutionary store or release elastic strain energy, which is consumed during the gait cycle, and as a result leg stiffness is expected to increase. An ankle joint actuating mechanism that stores and releases the energy in ankle joint is expected to support and solve excessive artificial leg stiffness caused by the knee actuator (primary actuator) to a reasonable extent. If unnecessary kinematic energy is released with the artificial speed reduction control designed to prevent increase in gait speed caused by increase in time passed, it naturally brings question to the effectiveness of the actuator. As opposed to the already established studies, the authors are currently developing knee-ankle two actuator system under the concept of increasing lower limb stiffness by controlling the speed of gait in relative angular velocity of the two segments. Therefore, the author is convinced that compensatory mechanism caused by knee actuating must exist only in ankle joint. Ankle joint compensatory mechanism can be solved by reverse-examining the change in metatarso-phalangeal joint (MTPJ) tilt angle (${\theta}_1=0^{\circ}$, ${\theta}_2=17^{\circ}$, ${\theta}_3=30^{\circ}$) and the effect of change in gait speed on knee activity.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.7
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• pp.723-729
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• 2012

Spring-like leg models have been employed to explain various dynamic characteristics in human walking. However, this leg stiffness model has limitations to represent complex motion of actual human gait, especially the behaviors of each lower limb joint. The purpose of this research was to determine changes of total leg stiffness and lower limb joint stiffness with gait speed in knee osteoarthritis. Joint stiffness defined as the ratio of the joint torque change to the angular displacement change. Eight subjects with knee osteoarthritis participated to this study. The subject walked on a 12 m long and 1 m wide walkway with three sets of four different randomly ordered gait speeds, ranging from their self-selected speed to maximum speed. Kinetic and kinematic data were measured using three force plates and an optical marker system, respectively. Joint torques of lower limb joints calculated by a multi-segment inverse dynamics model. Total leg and each lower limb joint had constant stiffness during single support phase. The leg and hip joint stiffness increased with gait speed. The correlation between knee joint angles and torques had significant changed by the degree of severity of knee osteoarthritis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1311-1312
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1627-1628
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• 2013

• 대한관절경학회:학술대회논문집
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• 2009.10a
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• pp.149-150
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• 2009

• Journal of Veterinary Clinics
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• v.18 no.2
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• pp.133-138
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• 2001

본 연구는 랫드에서 Freund's complete adjuvant를 랫드의 후지에 투여하여 인의적으로 유발된 관절염을 진단하기 위한 방법으로 $^{99m}Technetium-MDP (^{99m}Tc_MDP$)을 이용한 골 스캔의 임상적 의의를 찾고자 하였다. 성숙 Sprague-Dawley 암컷 랫드를 대조군과 실험군으로 분리하고, 골의 스캔은 0.05mCi의 $^{99m}Tc_MDP$를 정맥 주사하여 3시간 후에 전신 영상을 얻었다. 골의 스캔과 방사선학적 평가를 비교한 겨과 관절염 유발 7일 후부터 관절염의 병변이 관찰되었지만, 방사선학적 소견에서는 14일 후부터 병변이 관찰되었다. 골의 스캔에서 관절염 유발 7일 후에 유의적으로 골의 이상적 섭취 증각가 관찰되었고(p<0.05), 21일 후에는 전지와 후지의 모든 부위에서 골의 이상적 섭취 증가가 관찰되었지만, 방사선학적 소견에서는 후지에서만 병변 부위가 관찰되었다. 이상의 결과에서 $^{99m}Tc_MDP$을 이용한 골의 스캔은 류마티스 관절염을 임상적으로 진단하는데 방사선학적 진단보다 효과적인 방법임을 알 수가 있었고, 골의 스캔은 류마티스 관절염을 초기에 진단하는데 유효한 진단방법임을 확인하였다.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.128-134
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• 2009

This paper aims to design a variable-stiffness type economical safety joint for service robots. The safety joint was designed to have a passive shock absorbing mechanism for protecting human from a catastrophic collision under service condition of robots. A simple mechanism composed of two action disks for switching the load transfer, a spring and a screw for pre-load was proposed. In order to evaluate the performance of the safety joint a testing platform which can carry out the static and impact tests was also designed and fabricated. From the test results, the designed safety joint was proved to have a variable load-carrying capacity and about 42% impact absorption capacity with simple manipulation of the control screw.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1093-1094
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• 2010