• 대한전기학회논문지:전력기술부문A
• /
• 제48권11호
• /
• pp.1476-1478
• /
• 1999

A musculotendon model is proposed to predict muscle force during muscle fatigue due to the continuous functional electrical stimulation(FES). Muscle fatigue dynamics can be modeled as the electrical admittance of muscle fibers and included in activation dynamics based on the{{{{ { Ca}^{2+ } }}}} kinetics. The admittance depends on the fatigue variable that monotonically increase or decrease if electrical pulse exists or not, and on the stimulation parameters and the number of applied pulses. In the response of the change in activation the normalized Hill-type contraction dynamics connected with activation dynamics decline the muscle shortening velocity and thus its force under muscle fatigue. The computer simulation shows that the proposed model can express the muscle fatigue and its recovery without changing any stimulation parameters.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 B
• /
• pp.656-658
• /
• 1999

This paper presents musculotendon model to show the decline in muscle force during functional electrical stimulation (FES). It represent muscle activation and contraction concepts including muscle fatigue. A muscle fatigue term in activation dynamics as a function of the intracellular acidification and the pulsewidth of stimulation pulses change activation to decline muscle force. The computer simulation shows that muscle force decline in stimulation time.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권8호
• /
• pp.1046-1053
• /
• 1999

The musculotendon model is presented to show the declines in muscle force and shortening velocity during muscle fatigue due to the repeated functional electrical stimulation (FES). It consists of the nonlinear activation and contraction dynamics including physiological concepts of muscle fatigue. The activation dynamics represents $Ca^{2+}$ binding and unbinding mechanism with troponins of cross-bridges in sarcoplasm. It has the constant binding rate or activation time constant and two step nonlinear unbinding rate or inactivation time constant. The contraction dynamics is the modified Hill type model to represent muscle force - length and muscle force - velocity relations. A muscle fatigue profile as a function of the intracellular acidification, pH is applied into the contraction dynamics to represent the force decline. The computer simulation shows that muscle force and shortening velocity decline in stimulation time. And we validate the model. The model can predicts the proper muscle force without changing its parameters even when existing the estimation errors of the optimal fiber length. The change in the estimate of the optimal fiber length has an effect only on muscle time constant in transient period not on the tetanic force in the steady-state and relaxation periods.

• 산업기술연구
• /
• 제28권A호
• /
• pp.155-161
• /
• 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.

• 대한기관식도과학회:학술대회논문집
• /
• 대한기관식도과학회 1993년도 제27차 학술대회 초록집
• /
• pp.70-70
• /
• 1993

발성시 기본주파수의 조절은 윤상갑상근과 갑상피열근의 적절한 수축 작용에 의한다는 사실은 잘 알려져 있다. 윤상갑상근의 기능은 자세히 알려져 있는데 반하여, 갑상피열근의 기능은 현재까지 생체 발성 모형이 개발되지 않아 자세한 내용을 알 수 없었기에, 저자들은 갑상피열근 기능 검사를 위한 생체 발성 모형을 고안하였다. 개의 갑상연골에 창문을 만들어서, 반회신경의 마지막 분지인 갑상피열 분지를 확인, 절단하고 전극으로 자극하도록 하였다. 유발된 음성에 대한 갑상피열근 수축의 효과는 성역의 결정에 중요한 결정 요소로 작용되며, 가성 (falsetto) 영역에서 갑상피열근의 수축은 기본주파수 하강을 초래하고, 지성 (modal) 영역에서는 반대로 기본주파수가 상승되었다. 한편, 갑상피열근의 자극에 따라 성문하압은 증가되고 성문개대율 (OQ) 은 감소되었다.

• 한국정밀공학회지
• /
• 제30권6호
• /
• pp.650-657
• /
• 2013

This study uses a muscle activation sensor and elbow joint model to develop an estimation algorithm for human elbow joint torque for use in a human-robot interface. A modular-type MVS (Muscle Volume Sensor) and calibration algorithm are developed to measure the muscle activation signal, which is represented through the normalization of the calibrated signal of the MVS. A Hill-type model is applied to the muscle activation signal and the kinematic model of the muscle can be used to estimate the joint torques. Experiments were performed to evaluate the performance of the proposed algorithm by isotonic contraction motion using the KIN-COM$^{(R)}$ equipment at 5, 10, and 15Nm. The algorithm and its feasibility for use as a human-robot interface are verified by comparing the joint load condition and the torque estimated by the algorithm.

• International Journal of Automotive Technology
• /
• 제5권1호
• /
• pp.33-46
• /
• 2004

A finite element model development of a 50th percentile male cervical spine is presented in this paper. The model consists of rigid, geometrically accurate vertebrae held together with deformable intervertibral disks, facet joints, and ligaments modeled as a series of nonlinear springs. These deformable structures were rigorously tuned, through failure, to mimic existing experimental data; first as functional unit characterizations at three cervical levels and then as a fully assembled c-spine using the experimental data from Duke University and other data in the NHTSA database. After obtaining satisfactory validation of the performance of the assembled ligamentous cervical spine against available experimental data, 22 cervical muscle pairs, representing the majority of the neck's musculature, were added to the model. Hill's muscle model was utilized to generate muscle forces within the assembled cervical model. The muscle activation level was assumed to be the same for all modeled muscles and the degree of activation was set to correctly predict available human volunteer experimental data from NBDL. The validated model is intended for use as a post processor of dummy measurement within the simulated injury monitor (SIMon) concept being developed by NHTSA where measured kinematics and kinetic data obtained from a dummy during a crash test will serve as the boundary conditions to "drive" the finite element model of the neck. The post-processor will then interrogate the model to determine whether any ligament have exceeded its known failure limit. The model will allow a direct assessment of potential injury, its degree and location thus eliminating the need for global correlates such as Nij.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
• /
• pp.352-355
• /
• 1998

A musculotendon model is investigated to show muscle fatigue under the repeated functional electrical stimulation (FES). The normalized Hill-type model can predict the decline in muscle force. It consists of nonlinear activation and contraction dynamics including physiological concepts of muscle fatigue. A muscle fatigue as a function of the intracellular acidification, pHi is inserted into contraction dynamics to estimate the force decline. The computer simulation shows that muscle force declines in stimulation time and the change in the estimate of the optimal fiber length has an effect only on muscle time constant not on the steady-state tetanic force.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제52권9호
• /
• pp.560-567
• /
• 2003

EMG recordings of the electrical activity of muscle have proved to be a valuable tool in studying muscle function and reflex activity. SP(silent period) is elicited by a electrical stimulation on the chin during isometric contraction of jaw muscle. This paper proposes a model of the inhibitory reflex mechanism of jaw muscle after electrical stimulation. The SPs of jaw muscle after a electrical stimulation to the chin were divided into SP1 and SP2. SP1 is produced by the activation of periodontal receptors. The activation of nociceptors contributes to the SP2. As a result, the EMG signal generated by a proposed a model of inhibitory reflex mechanism is similar to real both EMG signal including SP1 and SP2. The present study have shown differences of SP1 and SP2 induced by inhibitory reflex mechanism.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 추계학술대회 논문집
• /
• pp.1015-1016
• /
• 2010