• 제목/요약/키워드: dominant arm

검색결과 90건 처리시간 0.03초

자동차 제어장치의 져더 진동 측정 및 진단 방법 (Test and Diagnostics Methods for Judder Vibration of the Brake System)

  • 강태원;임상규
    • 소음진동
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    • 제9권3호
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    • pp.613-620
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    • 1999
  • 디스크 두께 변화(DTV)에 의해 야기되는 져더현상은 일반적으로 차체진동, 브레이크 페달 떨림, 그리고 스티어링 휠의 떨림에 의해 감지된다. 이번 연구에서는, 차수분석 및 Operational Vibration Analysis(OVA)를 통해 차체진동이 DTV profile에 의해 어떻게 영향을 받는지를 중점적으로 조사하였다. 진동 측정위치는 knuckle, lower arm, lower arm 연결 차체부위이고, 져더 발생 DTV profile도 실측하였다. 시험 분석 결과, DTV는 져더현상에 차수별 상대적인 방향 기여도를 나타내며 특히 디스크 회전 2차 성분은 차량진행 방향으로의 lower arm 진동을 현저하게 야기시키는 것으로 나타났다. 이러한 시험 및 분석 기술은 져더 현상을 진단하고 문제를 개선하는데 유효하리라고 예측된다.

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그라인딩 작업시 손목자세별 국소진동 전달특성 분석 (An Analysis of Transmitted-Vibration Characteristics by Different Wrist Posture during Grinding Tasks)

  • 황성환;이동춘
    • 대한인간공학회지
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    • 제26권1호
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    • pp.29-37
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    • 2007
  • This study was performed to evaluate the characteristics of transmitted vibration to hand-arm system under different work posture while operating a light-weighted powered hand grinder. For the experiment, 8 different types of wrist posture (natural, unlar-flexion, radual-flexion, flexion, extension, complex posture, and etc.) and 3 types of feed force (20[N], 50[N], 70[N]) were considered. 10 male subjects were employed to polish metal plate with a hand grinder. All of them were normal and healthy with no history and symptom of the work related musculoskeletal disorders in the dominant hand. Vibration acceleration data were recorded with sampling rate, 2048[Hz]. In addition, unweighted overall R.M.S. acceleration at the tool and wrist, and transmissibility between them were used to evaluate factors from the recorded tri-axial vibration acceleration. The results indicate that transmissibility of natural wrist posture was significantly higher than others. In addition, as the feed force becomes larger, the vibration was transmitted in large quantities to hand-arm system through radius.

그라인딩 작업에 의한 수완계 진동 계측 및 평가 (Measurement and Assessment of Hand-arm Vibration due to Grinders)

  • 이종문;박진화
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 추계학술대회논문집
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    • pp.1032-1037
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    • 2003
  • This work measured the hand-transmitted vibration due to shipyard worker's grinding and assessed the vibration exposure for predicted 10% prevalence of vibration-induced white finger in a group of exposed persons according to test procedure of ISO 5349-1. And also the transmissibility performance of resilient material, mainly applied to anti-vibration gloves in present market was measured on the basis of ISO 13753 and confirmed that the material would Probably not provide greater attenuation below 30㎐, the dominant frequency range of hand-transmitted vibration due to grinder.

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자동차 조립라인에서 이중-헴머형(Double-hammer type) 임펙트 렌치와 오일-펄스형(Oil-pulse type)임펙트 렌치 에어공구의 국소진동가속도 및 소음수준 (Hand-Arm Vibration and Noise Levels of Double-Hammer Type and Oil-Pulse Type Impact Wrenches in Automobile Assembly Lines)

  • 정재열;김정만
    • 한국산업보건학회지
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    • 제5권2호
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    • pp.147-159
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    • 1995
  • This study was conducted to introduce fundamental data of hand-arm vibration and noise exposure levels with impact wrenches(double-hammer impact wrenches and oil-pulse impact wrenches) used in automobile assembly lines considering the process variables and tool variables. In studing, products per day, required time screwing the bolts or nuts per bolts or nut were considered as process variables, and capacity of bolts or nuts, air consumptions per minute, tool weights, RPM were considered as tool variables. Hand-arm vibration levels of 3 axis in each hand were measured using the instruments compling with ISO/DIS 5349 and noise levels were measured using a noise logging dosimeter. The results were as follows : 1. Required time to screwing the bolt or nut by oil-pulse impact wrenches is shorter than double-hammer impact wrenches but total daily exposure time of oil-pulse impact wrenches was higher than double-hammer impact wrenches because the number of bolts or nuts per cycle was many. 2. Oil-pulse impact wrenches have been used to screwing the large bolt or nut in comparing with double-hammer impact wrenches and required time to screwing the bolts or nuts were shorter than double-hammer impact wrenches because oil-pulse impact wrenches were using high RPM and large air consumption per minute. Noise level of oil-pulse impact wrenches was 8 dB(A) lower than double-hammer impact wrenches. 3. Dominant hand-arm vibration levels of double-hammer impact wrenches in each hand were $8.24m/sec^2$ of Zh axis in right hand and $9.60m/sec^2$ of Xh axis in left hand. Dominant hand-arm vibration level of oil-pulse impact wrenches in each hand was $2.59m/sec^2$ of Xh axis in right hand and $3.23m/sec^2$ of Yh axis in left hand. 4. In double-hammer impact wrenches, corresponding hand-arm vibration levels of Xh, Yh, Zh axis in left hand were higher than hand-arm vibration levels of right hand in 3 axis. In oil-pulse impact wrenches, Xh axis of right, Yh axis of left, Zh axis of left were higher than the corresponding hand-arm vibration levels of Xh, Yh, Zh axis in right and left hand. 5. Correlation coefficients among Xh, Yh. Zh axis of right and left hand hand-arm vibration levels in double-hammer impact wrenches and oil-pulse impact wrenches were commonly high in Yh axis and correlation coefficients of Yh axis in double-hammer impact wrenches and oil-pulse impact wrenches were 0.76 and 0.86,respectively. 6. As a measure repetitiveness, plotting total daily exposure time with the number of bolts or nut per cycle, direct correlation was shown between repetitiveness and hand-arn vibration exposure, and correlation coefficient between the number of bolts or nut per cycle and total daily exposure time in double-hammer impact wrenches, oil-pulse impact wrenches were 0.84 and 0.50, respectively. 7. Considering the total acceleration level and tool variables in double-hammer impact wrenches and oil-pulse impact wrenches, air consumption in right hand, and bolt or nut capacity in left hand were commonly the variable that explainability was high. Considering the noise and tool variables in double-hammer impact wrenches and oil-pulse impact wrenches, air consumption per minute was commonly the variable that explainability was high.

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운동감의 정량화를 위한 감성공학적 기법 개발에 관한 연구 (A Study on Quantification of Kinesthetic Sense Using Human Sensibility Ergonomics Approach)

  • 신동윤;이세한;송재복;김용일
    • 대한인간공학회지
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    • 제17권1호
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    • pp.11-22
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    • 1998
  • When grasping a movable object or making an object move, humans feel kinesthetic sense. The kinesthetic sense is the human sense that the human feels in response to the motion acted on him. The objective of the paper is to transform the kinesthetic sense associated with the human arm into the quantified data that are useful from the engineering viewpoint. A 2-dimensional motion generator composed of two linear motors was developed to provide various motion patterns. It can change its stiffness and damping values on the real-time basis by properly regulating the force generated by the linear motors. Based on Taguchi method, the most dominant factors to affect the kinesthetic sense were investigated. Also, a reference function adequate to quantify the kinesthetic sense was found. Based on this function, the effects of changes in stiffness and damping on the kinesthetic sense were investigated. Various tests show that the damping is a more dominant factor than the stiffness in forming the kinesthetic sense.

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환경 온도가 개구부를 통한 의복의 환기 양상에 미치는 영향 (Effect of Ambient Air Temperature on the Pattern of Clothing Ventilation through Openings)

  • 추미선
    • 복식문화연구
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    • 제10권6호
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    • pp.793-801
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    • 2002
  • The effects of ambient air temperature on the clothing ventilation were investigated numerically by a finite difference method. Numerical analysis using a 2-dimensional model comprising the air space between the skin and the clothing was conducted under the assumption that the clothing ventilation occurred only through the openings not through the fabric. The larger the temperature difference between the skin and the surroundings, the more apparent the thermal boundary layer As the ambient air temperature decreased, the air flow and the rate of the return of oxygen concentration to the atmosphere level in the clothing increased. Convection was dominant under low ambient air temperature, whereas conduction was dominant under high ambient air temperature. The ventilation rate was faster in the clothing microenvironment of the body part than that of the arm part.

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강도조건을 고려한 벽걸이 모니터 브라켓 암의 다중목적 근사최적설계 (Approximate Multi-Objective Optimization of A Wall-mounted Monitor Bracket Arm Considering Strength Design Conditions)

  • 도재혁;이종수
    • 대한기계학회논문집A
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    • 제39권5호
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    • pp.535-541
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    • 2015
  • 본 연구에서는 벽걸이 모니터 브라켓 암의 다중목적 근사최적설계를 수행하였다. 이를 위해 브라켓 암의 자유도를 고려하여 평면내의 회전 각도를 선정해 응력과 처짐량이 크게 발생하는 경우에 대한 최적화 문제를 정식화 하였다. 직교배열표와 반응표면법을 사용하여 평균 및 파라미터 분석을 통해 성능지수에 대한 설계변수 민감도를 확인하였으며, 중심합성계획법과 D-최적 계획법을 사용하여 목적함수와 제한조건함수에 대하여 반응표면 근사모델을 생성하고 $R^2$ 값을 통해 정확도를 평가하였다. 이를 비지배 분류 유전알고리즘에 적용하여 최적화를 수행하고 유한요소해석을 통해 검증하였다. 또한, 중심합성 계획법과 D-최적 계획법을 이용한 최적해를 비교 분석하였다.

견관절 운동 분율의 측정 (Measurement of shoulder motion fraction and motion ratio)

  • 강영한
    • 대한방사선기술학회지:방사선기술과학
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    • 제29권2호
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    • pp.57-62
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    • 2006
  • 연구 목적: 견관절 운동분율과 운동비의 측정과정을 이해하고, 견갑 흉곽관절과 관절와 상완관절의 운동비의 기준을 제시하고자 함이다. 연구대상 및 방법: 100명의 건강한 대상자를 연령대별(20, 30, 40, 50, 60대)로 20명씩 나누어 각각의 견관절 촬영과 분율을 계산하였다. 견갑극에 수직이고 관절와 면에 평행인 상을 재현하기 위하여 상완이 자연지위일 때 머리 방향 $15^{\circ}$, 90도 거상 시 $19^{\circ}$, 최대 거상 시 $22^{\circ}$로 입사각을 적용하였고, 몸의 회전 각도는 $40^{\circ},\;36^{\circ},\;22^{\circ}$로 시상면에서 외전시키며 촬영하였다. 관절운동 방향에 따른 운동 범위를 확인하기 위해, 측각도계(goniometer)를 이용하여 양측 견관절의 운동범위를 측정하였다. 전운동의 팔의 각도와 방사선 영상의 팔의 각도를 측정하여 상완관절 운동 각도와 견갑 흉곽관절의 운동 각도를 계산하였다. 결 과: 오른팔의 운동 분율은 $90^{\circ}$에서 남자 1.22, 여자 1.70 이었고, 최대 거상 시 1.63, 1.84였다. 왼팔은 $90^{\circ}$에서 1.31, 1.54, 최대 거상 시 각각 1.57, 1.32였다. 오른 우세팔은 $90^{\circ}$에서 1.58, 최대 거상 시 1.43이었고, 왼쪽 우세팔 각각 1.82, 1.94였다. 20대에서는 $90^{\circ}$ 거상 시 1.56, 최대 거상 시 1.52였고, 30대는 1.82, 1.43, 40대는 1.23, 1.16, 50대는 1.80, 1.28, 60대는 1.24, 1.75로 나타났다. 견관절의 운동 특성상 남녀에 따른 운동비, 우세팔과 비우세팔, 연령대에 따른 운동비를 측정하여 비교해 본 결과 유의한 차이가 없었다. 결 론: 견관절 운동 분율의 기준은 견관절의 운동장애를 확인하고 견관절 질환의 치료 후 정상적인 견관절 기능회복 여부를 확인하는데 도움을 줄 수 있을 것이다. 견관절 운동비 측정을 위한 운동 각도를 정확하게 측정할 수 있고, 실제 운동비를 계산할 수 있으면 방사선학적 자세와 입사각 설정에도 유용할 것이다.

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Ultrasound-guided needle decompression and steroid injection for calcific tendinitis of the shoulder: risk factors for repeat procedures and outcome analysis

  • Kim, Su Cheol;Lee, Sang Min;Park, Gun Tae;Jang, Min Chang;Yoo, Jae Chul
    • Clinics in Shoulder and Elbow
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    • 제24권2호
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    • pp.55-65
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    • 2021
  • Background: Although ultrasound-guided needle decompression (US-GND) can treat calcific tendinitis of the shoulder effectively, repeat procedures might be required for unresolved symptoms. We evaluated the overall clinical outcomes of US-GND with subacromial steroid injection and the final results and factors predisposing toward repeat procedures. Methods: Ninety-eight patients who underwent US-GND for calcific tendinitis of the supraspinatus/infraspinatus were analyzed between March 2017 and December 2018. The clinical outcomes (pain visual analog scale, functional visual analog scale [FVAS], and American Shoulder and Elbow Surgeons [ASES] score) and final subjective satisfaction were compared between groups A (single US-GND) and B (repeat US-GND). The factors predisposing toward repeated US-GNDs were analyzed. Results: We found that 59.3% (58/98) of patient ASES scores were ≥80, and 73.5% of patients (72/98) were satisfied with the outcome. Group B (n=14) demonstrated a significantly higher rate of dominant-arm involvement compared to group A (78.6% vs. 48.8%, p=0.046). However, initial calcification size, shape, number, density, subscapularis involvement, lavage, and procedure time did not differ significantly between the groups. Group B showed poorer final FVAS (7 [interquartile range, 6-8] vs. 8 [interquartile range, 7-9], p=0.036) and subjective satisfaction compared to group A (satisfied: 5 [35.7%] vs. 67 [79.8%], p<0.001]. Conclusions: US-GND with subacromial steroid injection is a viable treatment option for calcific tendinitis of the shoulder. Dominant-arm involvement was the only independent factor for repeated US-GND. Final outcome of repeated US-GND for unimproved patients was promising; however, these outcomes were poor compared to those of the patients who improved after the first procedure.

자동차 조립공정에서 공기압력식 진동공구의 국소진동평가 (Assessment of Vibration Produced by Pneumatic Hand Tools Used in Automobile Assembly)

  • 김선술;백남원
    • 한국산업보건학회지
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    • 제6권1호
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    • pp.1-16
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    • 1996
  • This study was conducted at an automobile assembly line located in Kyonggi-do, Korea from January 16 to February 28, 1995. The purposes of this study were to assess worker exposures to hand-arm vibration and the performance of gloves for reduction of vibration. The exposure to vibration was measured using to the ISO 5349(1986) method. Vibration acceleration and frequency spectra for each tool were determined on-line replicating actual working conditions and analyzed together with exposure time for evaluating individual worker exposure. Eight pneumatic hand tools, 60 workers exposured to hand-arm vibration, and three pairs of gloves were involved in this study. Results are summarized as follows. 1. Dominant frequencies of vibration for all tools(n=8) measured in this study ranged from 250 Hz to 800 Hz. 2. There was no significant correleration between dominant frequencies and free running speed (p>0.05). 3. Total predicted exposure times of using impact, hammer type did not exceed 40 minutes, but metal finish task, using grinder and sander exceeded 40 minutes. Total exposure time affected significantly the frequency-weighted, 4 hr equivalent acceleration. 4. Predicted prevalence and observed exposure period data were compared in workers(n=60), according to ISO 5349. In this results, 23(50.0 %) and 24(48.07 %) persons exceeded the mean latency periods for vibration-induced white finger(VWF) at 10 % (n=46) and 50 % (n=52) standards, respectively. On the basis of ISO equation, mean latent periods for VWF were 3.23, 4.72 years at 10 %, 50 % standards, respectively. 5. Reduction of vibration by gloves was evaluated. Since impact pneumatic tools produced low frequency vibrations, conventional gloves did not provide any protection. Gloves A and C amplify somewhat the signal at frequency below 400 Hz; the attenuation increases progressively by frequency to reach 18 dB ($7.94{\times}10^{-6}m/s^2$) at 1,000 Hz, slightly worsening Glove B did not provide any protection and made the situation slightly worse. However, since they make the hands warm, the occurrence of vibration-induced white fingers may be reduced.

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