• Journal of the Korean Society for Precision Engineering
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• v.22 no.11 s.176
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• pp.16-23
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• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.745-746
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.865-866
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• 2008

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.325-326
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• 2011

인체의 질량분포, 부피, 무게중심 등은 운동역학적 변인들을 분석하기위한 중요한 파라미터로 활용된다. 본 연구는 이러한 파라미터, 즉 인체분절계수를 추정하기 위한 분석도구의 개발에 관한 연구이다. 분석은 CT촬영을 통해 얻어진 2차원 의료영상데이터에 대해, 영상정보를 읽어 watershed 알고리즘을 통해 체성분에 따라 지방조직, 뼈조직, 근육조직에 따른 영역경계를 반 자동으로 구분할 수 있다. 분절계수의 추정은 최종적으로 확보한 영상에 대해, 분절경계면을 구분하여 이에 따른 질량, 부피 및 무게중심에 대한 비율을 계산하고 결과는 CSV 타입으로 저장한다. 개발된 분석도구는 연구목적에 따라 다양하게 분절화가 가능할 뿐만 아니라 영상데이터의 확보를 통해 인체분절계수 데이터베이스의 확장 구축에 기여할 수 있다.

• Journal of Internet Computing and Services
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• v.7 no.2
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• pp.23-35
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• 2006

This work presents o novel method which extract facial region und features from motion picture automatically and controls the 3D facial expression in real time. To txtract facial region and facial feature points from each color frame of motion pictures a new nonparametric skin color model is proposed rather than using parametric skin color model. Conventionally used parametric skin color models, which presents facial distribution as gaussian-type, have lack of robustness for varying lighting conditions. Thus it needs additional work to extract exact facial region from face images. To resolve the limitation of current skin color model, we exploit the Hue-Tint chrominance components and represent the skin chrominance distribution as a linear function, which can reduce error for detecting facial region. Moreover, the minimal facial feature positions detected by the proposed skin model are adjusted by using edge information of the detected facial region along with the proportions of the face. To produce the realistic facial expression, we adopt Water's linear muscle model and apply the extended version of Water's muscles to variation of the facial features of the 3D face. The experiments show that the proposed approach efficiently detects facial feature points and naturally controls the facial expression of the 3D face model.

• Journal of Industrial Technology
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• v.28 no.A
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• pp.155-161
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• 2008

Muscle force prediction in forward dynamic analysis of human motion depends many muscle parameters associated with muscle actuation. This research studies the effects of various parameters of Hill type muscle model using the simple hand raising motion. Motion analysis is carried out using motion capture system, and each muscle force is recorded for comparison with muscle model generated muscle force. Using Hill type muscle model, muscle force for generating the same hand rasing motion was setup adjusting 5 activation parameters. The test showed the importance of activation parameters on the accurate generation of muscle force.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.122-130
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• 2009

The analysis of human movement requires the knowledge of the Hill type muscle parameters, the muscle-tendon and moment arm length change as a function of joint angles. However, values of a subject's muscle parameters are very difficult to identify. It turns out from a sensitivity analysis that the tendon slack length and maximum muscle force are the two critical parameters among the Hill-type muscle model. Therefore, it could be claimed that the variation of the tendon slack length and maximum muscle force from the Delp's reference data will change the muscle characteristics of a subject remarkably. A numeric optimization method to search these tendon parameters specific to a subject is proposed, and the accuracy of the developed algorithm is evaluated through a numerical simulation.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.309-312
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• 2004

본 연구에서는 매미가 소형이면서도 광대역의 소리를 낼 수 있는 원리가 무엇인지를 파악하고 이중 음향 발생 장치 제작에 적용할 수 있는 요소를 도출하였다. 매미의 발음기관에서 가장 중요한 부분은 복부 공명실과 진동판이다. 복부 공명실은 위상 반전형 인클로져 시스템으로 모델링 할 수 있으며, 진동판은 돔 형태의 박판으로 볼 수 있다. 근육에서 발생된 입력 신호는 진동판의 곡면에 의해 판에 좌굴을 일으켜 높은 음압의 소리를 발생시킨다. 발생된 소리는 복부를 통해 위상이 반전되어 특정 대역이 강조된다. 진동판의 가장 큰 특징은 곡면구조에 의한 비선형적인 출력이며 이를 통하여 가진 주파수와 상이한 주파수 성분들을 효과적으로 발생시키게 된다. 이러한 구조를 음향 발생장치로 활용하기 위하여 단순한 곡면판의 기하학적 파라미터 변화에 따른 출력 변화 경향을 관찰 하였으며, 이러한 원리를 활용한 음향 발생장치를 구성하였다.

• The Journal of Korea Robotics Society
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• v.17 no.3
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• pp.347-352
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• 2022

The paper presents how to update impedance control parameters for dual-arm manipulators using EMG signals and motions of the operator. Since the hand motions of the dual-arm are modeled to be the mass-spring-damper system in this paper, the impedance parameter update method is an important issue to reflect the operator's force. However, task space inertia to be used as the mass parameter goes to infinity if the manipulator approaches a kinematic singularity. To alleviate this issue, the impedance (stiffness and damping) parameters are divided with a diagonal element of the task space inertia. Also, the stiffness and damping matrices are updated using the normalized EMG signals captured from the operator's forearm. Through this process, the motion of the dual-arm manipulator is more stabilized even though it approaches the kinematic singularity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.8
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• pp.771-782
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• 2017

This paper describes the development of a wearable robot to assist ankle power for the elderly. Previously developed wearable robots have generally used motors and gears to assist muscle power during walking. However, the combination of motor and reduction gear is heavy and has limitations on the simultaneous control of stiffness and torque due to the friction of the gear reducer unlike human muscles. Therefore, in this study, Mckibben pneumatic muscle, which is lighter, safer, and more powerful than an electric motor with gear, was used to assist ankle joint. Antagonistic actuation using a pair of pneumatic muscles assisted the power of the soleus muscles and tibialis anterior muscles used for the pitching motion of the ankle joint, and the model parameters of the antagonistic actuator were experimentally derived using a muscle test platform. To recognize the wearer's walking intention, foot load and ankle torque were calculated by measuring the pressure and the center of pressure of the foot using force and linear displacement sensors, and the stiffness and the torque of the pneumatic muscle joint were then controlled by the calculated ankle torque and foot load. Finally, the performance of the developed ankle power assistive robot was experimentally verified by measuring EMG signals during walking experiments on a treadmill.