• Title, Summary, Keyword: Surface EMG

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Intramuscular EMG signal estimation using surface EMG signal analysis (표면 근전도 신호 해석에 의한 내부 근육 근전도 신호의 추정)

  • 왕문성;변윤식;박상희
    • 제어로봇시스템학회:학술대회논문집
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    • pp.641-642
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    • 1986
  • We present a method for the estimation of intramuscular electromyographic(EMG) signals from the given surface EMG signals. This method is based on representing the surface EMG signal as an autoregressive(AR) time model with a delayed intramuscular EMG signal as an input. The parameters of the time series model that transforms the intramuscular signal to the surface signal are identified. The identified model is then used in estimating the intramuscular signal from the surface signal.

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Quantitative Analysis of EMG Amplitude Estimator for Surface EMG Signal Recorded during Isometric Constant Voluntary Contraction (등척성 일정 자의 수축 시에 기록한 표면근전도 신호에 대한 근전도 진폭 추정기의 정량적 분석)

  • Lee, Jin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.5
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    • pp.843-850
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    • 2017
  • The EMG amplitude estimator, which has been investigated as an indicator of muscle force, is utilized as the control input to artificial prosthetic limbs. This paper describes an application of the optimal EMG amplitude estimator to the surface EMG signals recorded during constant isometric %MVC (maximum voluntary contraction) for 30 seconds and reports on assessing performance of the amplitude estimator from the application. Surface EMG signals, a total of 198 signals, were recorded from biceps brachii muscle over the range of 20-80%MVC isometric contraction. To examine the estimator performance, a SNR(signal-to-noise ratio) was computed from each amplitude estimate. The results of the study indicate that ARV(average rectified value) and RMS(root mean square) amplitude estimation with forth order whitening filter and 250[ms] moving average window length are optimal and showed the mean SNR improvement of about 50%, 40% and 20% for each 20%MVC, 50%MVC and 80%MVC surface EMG signals, respectively.

An Accuracy Analysis of Run-test and RA(Reverse Arrangement)-test for Assessing Surface EMG Signal Stationarity (표면근전도 신호의 정상성 검사를 위한 Run-검증과 RA-검증의 정확도 분석)

  • Lee, Jin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.2
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    • pp.291-296
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    • 2014
  • Most of the statistical signal analysis processed in the time domain and the frequency domain are based on the assumption that the signal is weakly stationary(wide sense stationary). Therefore, it is necessary to know whether the surface EMG signals processed in the statistical basis satisfy the condition of weak stationarity. The purpose of this study is to analyze the accuracy of the Run-test, modified Run-test, RA(reverse arrangement)-test, and modified RA-test for assessing surface EMG signal stationarity. Six stationary and three non-stationary signals were simulated by using sine wave, AR(autoregressive) modeling, and real surface EMG. The simulated signals were tested for stationarity using nine different methods of Run-test and RA-test. The results showed that the modified Run-test method2 (mRT2) classified exactly the surface EMG signals by stationarity with 100% accuracy. This finding indicates that the mRT2 may be the best way for assessing stationarity in surface EMG signals.

Optimal Signal Segment Length for Modified Run-test and RA(reverse arrangement)-test for Assessing Surface EMG Signal Stationarity (표면근전도 신호의 정상성 검사를 위한 수정된 Run-검증과 RA-검증에 최적인 신호분할 길이)

  • Lee, Jin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.8
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    • pp.1128-1133
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    • 2014
  • Most of the statistical signal analysis processed in the time domain and the frequency domain are based on the assumption that the signal is weakly stationary(wide sense stationary). Therefore, it is necessary to know whether the surface EMG signals processed in the statistical basis satisfy the condition of the weak stationarity. The purpose of this study is to find optimal segment length of surface EMG signal for assessing stationarity with the modified Run-test and RA-test. Ten stationary surface EMG signals were simulated by AR(autoregressive) modeling, and ten real surface EMG signals were recorded from biceps brachii muscle and then modified to have non-stationary structures. In condition of varying segment length from 20ms to 100ms, stationarity of the signals was tested by using six different methods of modified Run-test and RA-test. The results indicate that the optimal segment length for the surface EMG is 30ms~35ms, and the best way for assessing surface EMG signal stationarity is the modified Run-test (Run2) method using this optimal length.

Digital Fractional Order Low-pass Differentiators for Detecting Peaks of Surface EMG Signal (표면 근전도 신호 피이크 검출을 위한 디지털 분수 차수 저역통과 미분기)

  • Lee, Jin;Kim, Sung-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.7
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    • pp.1014-1019
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    • 2013
  • Signal processing techniques based on fractional order calculus have been successfully applied in analyzing heavy-tailed non-Gaussian signals. It was found that the surface EMG signals from the muscles having nuero-muscular disease are best modeled by using the heavy-tailed non-gaussian random processes. In this regard, this paper describes an application of digital fractional order lowpass differentiators(FOLPD, weighted FOLPD) based on the fractional order calculus in detecting peaks of surface EMG signal. The performances of the FOLPD and WFOLPD are analyzed based on different filter length and varying MUAP wave shape from recorded and simulated surface EMG signals. As a results, the WFOLPD showed better SNR improving factors than the existing WLPD and to be more robust under the various surface EMG signals.

The Difference of Trunk Muscle Activities In Trunk Stabilization on the Stable and Unstable Surface. (안정한 지지면과 불안정한 지지면에서의 자세에 따른 체간안정화 근육 활성도 비교)

  • Kim, Suhyon
    • Journal of The Korean Society of Integrative Medicine
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    • v.6 no.2
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    • pp.37-44
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    • 2018
  • Purpose : The aim of this study is to compare the trunk muscle activities in trunk stabilization on the stable and unstable supporting surfaces using by sEMG. Methods : The subjects of this study include seventeen male. We measured sEMG activities of rectus abdominis and erector spine in subjects during trunk stabilization such as plank exercise, quadruped position, quadruped position with rising hand and foot on the stable and unstable surface. Results : sEMG activities in plank exercise was significantly higher in left rectus abdominis and left erector spine on unstable surface then stable surface (p<.05). sEMG activities of left rectus abdominis and left erector spine in quadruped position was significantly higher in unstable surface than stable surface (p<.05). In comparison with posture, Plank exercise showed a significant difference increase other postures (p<.05). Conclusion : sEMG activities of muscle in trunk stabilization was significantly higher in unstable surface than stable surface and plank exercise. So, we suggest that trunk stabilization on the unstable supporting surface and plank exercise were more effective method than stable surface to improve trunk muscles activities.

Surface EMG Amplitude Estimation by using Spike and Turn Variables (Spike와 Turn 변수를 이용한 표면근전도 신호의 진폭 추정)

  • Lee, Jin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.1
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    • pp.124-130
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    • 2018
  • The EMG amplitude estimator, which has been investigated as an indicator of muscle force, is of high relevance not only in biomechanical studies but also more and more in clinical applications. This paper presents a new approach to estimate surface EMG amplitude by using the mean spike and mean turn amplitude(MSA and MTA) variables. Surface EMG signals, a total of 198 signals, were recorded from biceps brachii muscle over the range of 20-80%MVC isometric contraction and performance of the MSA and MTA variables applied to amplitude estimation of the EMG signals were investigated. To examine the performance, a SNR(signal-to-noise ratio) was computed from each amplitude estimate. The results of the study indicate that MSA and MTA amplitude estimations with first order whitening filter and 300[ms]-350[ms] moving average window length are optimal and show better performance(mean SNR improvement of 6%-15%) than the most frequently used variables(ARV and RMS).

Surface EMG Activity of the Suprahyoid and Infrahyoid Muscles along the Pitch Changes in Trained and Untrained Singers (성악전공자와 비전공자에서의 음도에 따른 성대외근의 표면근전도 변화)

  • 윤영선;손영익;추광철;김선일
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.10 no.1
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    • pp.24-29
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    • 1999
  • Extrinsic laryngeal muscles are well known to be important for the classical singers. We tried to elucidate any differences in the function of above muscles between trained and untrained singers by non-invasive surface electromyography(EMG). Four trained sopranos and four untrained singers sang vowel /i/ at different pitch(E3, G3, C4, E4, G4, C5, E5, G5, C6). The EMG activities of the suprahyoid, infrahyoid and omohyoid muscles were measured using surface electrodes. In trained singers, infrahyoid muscle activities increased more than those of suprahyoid in most of pitch. To the contrary, in untrained singers, the pattern of EMG activities were variable among each subjects and the EMG activities of suprahyoid muscles were relatively greater than those of infrahyoid.

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Development of Surface EMG Sensor Prototype and Its Application for Human Elbow Joint Angle Extraction (표면 근전도 센서 프로토타입 개발 및 인간의 팔꿈치 관절 각도 추출 응용)

  • Yu, Hyeon-Jae;Lee, Hyun-Chul;Choi, Young-Jin
    • The Journal of Korea Robotics Society
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    • v.2 no.3
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    • pp.205-211
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    • 2007
  • In this paper, the prototype of surface EMG (ElectroMyoGram) sensor is developed for the robotic rehabilitation applications, and the developed sensor is composed of the electrodes, analog signal amplifiers, analog filters, ADC (analog to digital converter), and DSP (digital signal processor) for coding the application example. Since the raw EMG signal is very low voltage, it is amplified by about one thousand times. The artifacts of amplified EMG signal are removed by using the band-pass filter. Also, the processed analog EMG signal is converted into the digital form by using ADC embedded in DSP. The developed sensor shows approximately the linear characteristics between the amplitude values of the sensor signals measured from the biceps brachii of human upper arm and the joint angles of human elbow. Finally, to show the performance of the developed EMG sensor, we suggest the application example about the real-time human elbow motion acquisition by using the developed sensor.

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The study on the asymmetry ratio of surface EMG in low back pain groups - before and after flexion-distraction technique (요통환자에게 굴곡신연기법을 시술한 전후의 표면근전도 비교 연구)

  • Hwang, Eui-Hyoung;Kim, Jeong-Yun
    • The Journal of Korea CHUNA Manual Medicine
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    • v.5 no.1
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    • pp.243-249
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    • 2004
  • Objectives : This study is to evaluate the effect of flexion-distraction technique by measuring surface EMG in low back pain groups. Methods : 5 low back pain patients' constact time, power, fatigue, recovery of muscle were measured before and after flexion-distraction technique. Results : The asymmetry ratio of surface EMG in low back pain groups were Increased, but decreased after flexion-distraction technique. Conclusions : Surface EMG might be used for evaluating the effect of flexion-distraction technique.

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