• Title/Summary/Keyword: Muscle Model

Search Result 757, Processing Time 0.028 seconds

Development and evaluation of estimation model of ankle joint moment from optimization of muscle parameters (근육 파라미터 최적화를 통한 발목관절 모멘트 추정 모델 개발 및 평가)

  • Son, J.;Hwang, S.;Lee, J.;Kim, Y.H.
    • Journal of Biomedical Engineering Research
    • /
    • v.31 no.4
    • /
    • pp.310-315
    • /
    • 2010
  • Estimation of muscle forces is important in biomechanics, therefore many researchers have tried to build a muscle model. Recently, optimization techniques for adjusting muscle parameters, i.e. EMG-driven model, have been used to estimate muscle forces and predict joint moments. In this study, an EMG-driven model based on the previous studies has been developed and isometric and isokinetic contraction movements were evaluated to validate the developed model. One healthy male participated in this study. The dynamometer tasks were performed for maximum voluntary isometric contractions (MVIC) for ankle dorsi/plantarflexors, isokinetic contraction at both $30^{\circ}/s$ and $60^{\circ}/s$. EMGs were recorded from the tibialis anterior, gastrocnemius medialis, gastrocnemius lateralis and soleus muscles at the sampling rate of 1000 Hz. The MVIC trial was used to customize the EMG-driven model to the specific subject. Once the subject's own model was developed, the model was used to predict the ankle joint moment for the other two dynamic movements. When no optimization was applied to characterize the muscle parameters, weak correlations were observed between the model prediction and the measured joint moment with large RMS error over 100% (r = 0.468 (123%) and r = 0.060 (159%) in $30^{\circ}/s$ and $60^{\circ}/s$ dynamic movements, respectively). However, once optimization was applied to adjust the muscle parameters, the predicted joint moment was highly similar to the measured joint moment with relatively small RMS error below 40% (r = 0.955 (21%) and r = 0.819 (36%) and in $30^{\circ}/s$ and $60^{\circ}/s$ dynamic movements, respectively). We expect that our EMG-driven model will be employed in our future efforts to estimate muscle forces of the elderly.

A Musculoskeletal Model of a Human Lower Extremity and Estimation of Muscle Forces while Rising from a Seated Position (인체 하지부 근골격계 모델 및 의자에서 일어서는 동작 시 근력 예측)

  • Jo, Young-Nam;Yoo, Hong-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.22 no.6
    • /
    • pp.502-508
    • /
    • 2012
  • An analytical model for a human body is important to predict muscle and joint forces. Because it is difficult to estimate muscle or joint forces from a human body, the objective of this study is the development of a reliable analytical model for a human body to evaluate the lower extremity muscle and joint forces. The musculoskeletal system of the human lower extremity is modeled as a multibody system employing the Hill-type muscle model. Muscle forces are determined to minimize energy consumption, and we assume that motion is constrained in the sagittal plane. Muscle forces are calculated through an equilibrium analysis while rising from a seated position. The musculoskeletal model consists of four segments. Each segment is a rigid body and connected by frictionless revolute joints. Muscles of the lower extremity are simplified to seven muscles with those that are not related to the sagittal plane motion are ignored. Muscles that play a similar role are combined together. The results of the present study are compared with experimental results to validate the lower extremity model and the assumptions of the present study.

Estimation of Muscle-tendon Model Parameters Based on a Numeric Optimization (최적화기법에 의한 근육-건 모델 파라미터들의 추정)

  • Nam, Yoon-Su
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.26 no.6
    • /
    • pp.122-130
    • /
    • 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.

Musculotendon Model to Represent Characteristics of Muscle Fatigue due to Functional Electrical Stimulation (기능적 전기자극에 의한 근육피로의 특성을 표현하는 근육 모델)

  • Lim, Jong-Kwang;Son, Jae-Hyun;Nam, Moon-Hyon
    • Proceedings of the KIEE Conference
    • /
    • 1999.07b
    • /
    • 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.

  • PDF

Automatic Estimation of 2D Facial Muscle Parameter Using Neural Network (신경회로망을 이용한 2D 얼굴근육 파라메터의 자동인식)

  • 김동수;남기환;한준희;배철수;권오흥;나상동
    • Proceedings of the IEEK Conference
    • /
    • 1999.06a
    • /
    • pp.1029-1032
    • /
    • 1999
  • Muscle based face image synthesis is one of the most realistic approach to realize life-like agent in computer. Facial muscle model is composed of facial tissue elements and muscles. In this model, forces are calculated effecting facial tissue element by contraction of each muscle strength, so the combination of each muscle parameter decide a specific facial expression. Now each muscle parameter is decided on trial and error procedure comparing the sample photograph and generated image using our Muscle-Editor to generate a specific face image. In this paper, we propose the strategy of automatic estimation of facial muscle parameters from 2D marker movement using neural network. This also 3D motion estimation from 2D point or flow information in captered image under restriction of physics based face model.

  • PDF

Development of a Model for the Estimation of Knee Joint Moment at MVC (MVC 상태에서의 무릎관절 모멘트 추정을 위한 모델 개발)

  • Nam, Yoon-Su;Lee, Woo-Eun
    • Journal of Biomedical Engineering Research
    • /
    • v.29 no.3
    • /
    • pp.222-230
    • /
    • 2008
  • This paper introduces a method of estimating the knee joint moment developed during MVC. By combining the Hill-type muscle model and analytic results on moment arm and musculotendon length change as a function of hip and knee joint angle, the knee joint moment at a specific knee joint angle during MVC is determined. Many differences between the estimated results and the experimental data are noted. It is believed that these differences originate from inaccurate information on the muscle-tendon parameters. The establishment of exact values for the subject's muscle parameters is almost impossible task. However, sensitivity analysis shows that the tendon slack length is the most critical parameter when applying the Hill-type muscle model. The effect of a change of this parameter on the muscle length force relationship is analyzed in detail.

DEVELOPMENT OF FINITE ELEMENT HUMAN NECK MODEL FOR VEHICLE SAFETY SIMULATION

  • Lee, I.H.;Choi, H.Y.;Lee, J.H.;Han, D.C.
    • International Journal of Automotive Technology
    • /
    • v.5 no.1
    • /
    • 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.

facial Expression Animation Using 3D Face Modelling of Anatomy Base (해부학 기반의 3차원 얼굴 모델링을 이용한 얼굴 표정 애니메이션)

  • 김형균;오무송
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.7 no.2
    • /
    • pp.328-333
    • /
    • 2003
  • This paper did to do with 18 muscle pairs that do fetters in anatomy that influence in facial expression change and mix motion of muscle for face facial animation. After set and change mash and make standard model in individual's image, did mapping to mash using individual facial front side and side image to raise truth stuff. Muscle model who become motive power that can do animation used facial expression creation correcting Waters' muscle model. Created deformed face that texture is dressed using these method. Also, 6 facial expression that Ekman proposes did animation.

Trajectory Tracking Control of Pneumatic Artificial Muscle Driving Apparatus based on the Linearized Model (공압 인공근육 구동장치의 선형화 모델 기반 궤적추적제어)

  • Jang, J.S.;Yoo, W.S.
    • Journal of Power System Engineering
    • /
    • v.10 no.3
    • /
    • pp.97-103
    • /
    • 2006
  • In this study, a position trajectory tracking control algorithm is proposed for a pneumatic artificial muscle driving apparatus composed of a actuator which imitates the muscle of human, a position sensor and a control valve. The controller applied to the driving apparatus is composed of a state feedback controller and disturbance observer. The feedback controller which feeds back position, velocity and acceleration is derived from the linear model of pneumatic artificial muscle driving apparatus. The disturbance observer is designed to improve trajectory tracking performance and to reduce the effect of model discrepancy. The effectiveness of the designed controller is proved by experiments and the experimental results show that the pneumatic artificial muscle driving apparatus with the proposed control algorithm tracks given position reference inputs accurately.

  • PDF

Effects of Abdominal Muscle and Pressure on the Spine Stability during Upright Stance Posture - For the Case where Intervertebral Disc Plays the Role of Mechanoreceptor (추간판이 물리적 자극의 수용기 역할을 하는 경우 기립 상태에서 복압 및 복근의 역할이 척추 안전성에 미치는 영향)

  • Choi, Hae-Won;Kim, Young-Eun
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.28 no.1
    • /
    • pp.115-122
    • /
    • 2011
  • Recently, we have proposed a hypothesis that spinal structures have a stress sensor driving feedback mechanism, In the human spine, spinal structure could react to modify muscular action in such a way so as to equalize stress at the disc, therefore reduce the risk of injury, In this analysis, abdominal muscle and abdominal pressure, which were not included in the previous study, were added to identify those effects in spine stability during upright stance posture for the case where the intervertebral disc plays the role of mechanoreceptor, The musculoskeletal FE model was consisted with detailed whole lumbar spine, pelvis, sacrum, coccyx and simplified trunk model. Muscle architecture with 46 local muscles containing paraspinal muscle and 6 rectus abdominal muscles were assigned according to the acting directions. The magnitude of 4kPa was considered for abdominal pressure. Minimization of the nucleus pressure deviation and annulus fiber average tension stress deviation was chosen for cost function. Developed model provide nice coincidence with in-vivo measurement (nucleus pressure). Analysis was conducted according to existence of co-activation of abdominal muscle and abdominal pressure. Antagonistic activity of abdominal muscle produced stability of spinal column with relatively small amount of total muscle force. In contrast to the abdominal muscle, effect of abdominal pressure was not clear that was partly depending on the assumption of constant abdominal pressure.