• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.171.5-171
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• 2001

Information that is acquired by adhered sensors on a body has been commonly used for the three-dimensional real-time motion capture algorithm. This paper describes realtime motion capture algorithm using computer vision. In a real-time image sequence, human body silhouette is extracted use a background subtraction between background image and the reference image. Then a human standing posture whether forward or backward is estimated by extraction of skin region in the silhoutte. After then, the principal axis is calculated in the torso and the face region is estimated on the principal axis. Feature points, which are essential condition to track the human gesture, are obtained ...

• 대한인간공학회지
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• 제33권2호
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• pp.155-165
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• 2014

Objective: The aim of this study is to develop an office chair enabling to keep working at reclined sitting posture. Background: Sedentary workers are supposed to change the posture frequently during long hours of sitting. A reclined sitting position has been recommended to reduce disc pressure. But slumped sitting posture caused by the buttock sliding forward without any adjustment of back reclining is commonly observed. The worker seems to have tendency to change the sitting posture maintaining working condition. We assumed the reason to be their hands movement away from the working space when tilting backward. Method: Slide mechanism allowing seat to move forward was designed to maintain the hand position in working space during reclining. A prototype was manufactured and tilting motion was analyzed using motion capture system. Four experiment chairs were tested including the manufactured prototype chair and three other commercial chairs. Results: A backward movements of the hand position were 13.0mm, 101.7mm, 156.1mm and 139.3mm at the prototype chair, compared to chair B, chair C and chair D, respectively. And the movement was remarkably small at the prototype chair. Conclusion: The developed seat sliding chair allows back tilting maintaining hand position at working space. We expect the user tilting back more often than normal tilting chair during seated work. But further investigation is required to figure out the effectiveness of the developed chair using prolonged working hours. Application: The developed office chair directly affects commercialization.

• 제어로봇시스템학회논문지
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• 제15권11호
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• pp.1130-1136
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• 2009

A new control algorithm for the yaw motion control of a unicycle robot has been proposed in this paper. With the increase of life quality, there are various transportation systems such as segway and unicycle robot which provide not only transportation but also amusement. In most of the unicycle robots share the same technology in that the directions of roll and pitch are controlled by the balance controllers, allowing the robots to maintain balance for a long period by continuously moving forward and backward. However, one disadvantage of this technology is that it cannot provide the capability to the robots to avoid obstacles in their path way. This research focuses to provide the yawing function to the unicycle robot and to control the yaw motion to avoid the obstacles as desired. For the control of yawing motion, the yaw angle is adjusted to the inertia generated by the velocity and torque of a yawing motor which is installed in the center axes of the unicycle robot to keep the lateral control simple. Through the real experiments, the effective and robustness of the yawing control algorithm has been demonstrated.

• 한국운동역학회지
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• 제15권3호
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• pp.175-183
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• 2005

This study investigates the kinetic characteristics of the Driggs motion in horse vaulting by stages through the three-dimensional video analysis of YTY and TABARA who won a high score and a low score respectively from the Driggs motion in horse vaulting during the Daegu Universiade 2003, which involves putting one's hands on the horse vaulting rotating sideways, stretching and rotating backward in the air, and twisting 900 degrees, so as to help develop the techniques of Korean gymnastic athletes. From the analyses of the duration of body center, horizontality, vertical position and horizontality, vertical speed and angle factors for each of four phases from the contact of the board to the takeoff from the horse vaulting. I arrived at the following conclusions: 1. It was found that the motion of bending oneself forward while rapidly stretching the knee joint when taking off from the board increases the horizontal speed of body center and shortens the time of the first jump. 2. It was found that S1 who won a high score shortened the time of the contact and takeoff from the horse vaulting and enlarged the shoulder joint angle for full blocking motion. It was also found that horizontal speed decreased while vertical speed increased when you rapidly stretch the right elbow joint while taking off from the horse vaulting. 3. It was found that horizontal distance was shortened to increase the height and time of staying in the air during the second jump.

• 한국운동역학회지
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• 제19권3호
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• pp.425-433
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• 2009

본 연구의 목적은 속구와 멀리던지기 동작 사이의 상호관계를 밟히며, 속구와 멀리던지기 동작의 투구시 운동학적으로 어떠한 차이가 있는 밝히는 것이다. 8명의 대학교 야구선수들이 실험에 참여하였다. APAS(Ariel Performance Analysis System) 동작분석시스템을 이용하여 속구와 멀리던지기 동작에 대한 운동학적 변인을 구하여 분석하였다. 본 연구의 결과로 신체중심의 전후변위에서 투구후반부에서 속구가 멀리던지기보다 신체중심이 앞으로 이동하였고, 상하변위에서는 속구가 더 낮은 자세를 보였다. 오른손의 속도에서는 릴리즈 시 속구가 더 빠르게 나타났고, 팔꿈치관절에서는 투구중반부에서는 속구가 더 신전되었고, 릴리즈에서는 동일하였고, 어깨관절에서는 팔 가속지점에서 속구가 더 신전된 것으로 나타났다. 몸통경사에서는 릴리즈 시 속구는 전방으로 멀리던지기는 후방경사를 취하고 있었다. 보폭은 속구가 더 긴 것으로 나타났다. 2가지 투구동작에서 동일한 자세에서 시작하지만, 각 변인에 따라 공통점과 차이점을 발견할 수 있었다. 이러한 이유로, 속구를 던지기 위해 멀리던지기 훈련이 어느 정도 도움이 될 것으로 생각된다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2010년도 춘계학술대회
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• pp.383-384
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• 2010

선박의 제어판은 전진 또는 후진시 조종성능을 결정하는 중요한 요소이다. 본 연구에서는 단동타의 성능평가를 위하여 $Re=2.0\times10^4$ 에서 2-프레임 그레이레벨 상호상관 PIV기법을 이용하여 모텔 주위의 속도장을 계측하였다. 특히 전진시 영각 10도와 20도 사이에서 발생하는 박리영역을 후진시에 나타나는 영향을 평가하였다. 단동타의 형상은 NACA0018을 사용하여 자유유동이 역 방향으로 위치하여 후진시의 효과를 알아본 결과 박리 영역은 전방과 비슷한 영각에서 발생함을 알 수 있었다.

• PNF and Movement
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• 제15권3호
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• pp.237-246
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• 2017

Purpose: The purpose of this study was to investigate the effects of forward-and-backward shift trunk exercise using a proprioceptive neuromuscular facilitation (PNF) diagonal pattern in a closed kinematic chain exercise on the upper limb function and activity of daily living (ADL) in a stroke patient. Methods: One subject participated in this study. The study used a reversal A-B-A' design, where A and A' were the baseline period (no intervention), and B was the intervention period. The intervention was a forward-and-backward trunk shift exercise, using a PNF diagonal pattern on both a stand-on-hand position and a quadruped position of closed kinematic chain exercises, for 20 min per day for 2 weeks. The range of motion (ROM) of the shoulder joint was measured and a Fugl-Meyer assessment of upper extremity (FMA-UE) and a functional independence measure (FIM) were performed to measure upper limb function and activity of daily living (ADL). Results: ROMs of shoulder joint (flexion, extension, abduction, and external rotation) increased in the intervention phase. The FMA-UE score increased (from 28 to 36) in the intervention phase. The FIM score increased (from 20 to 25) in the intervention phase. These increases were maintained after intervention (Baseline II). Conclusion: These results suggest that forward-and-backward shift trunk exercises using a PNF diagonal pattern in a closed kinematic chain exercise have a positive effect on stroke patients' upper limb function and ADL ability.

• The Journal of Korean Physical Therapy
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• 제24권2호
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• pp.90-97
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• 2012

Purpose: The purpose of this study was to assess the effects of virtual reality-based continuous slow exercise on muscle strength and dynamic balance capacity, in older adults over 65 years of age. Methods: Twenty-six volunteers were randomly divided into two groups; a Virtual Reality (VR) exercise-group ($67.8{\pm}4.1$ yrs) and a Control group ($65.5{\pm}5.2$ yrs). The VR group participated in eight weeks of virtual reality exercise, utilizing modified Tai-Chi provided by a motion capture system, and the Control group had no intervention. The hip muscle strength and dynamic balance of the members of both the VR group and the Control group were measured at pre- and post-intervention, using a multimodal dynamometer, and backward stepping test, respectively. Results: 1. After the 8-week VR-based exercise, the VR group showed significant improvement of hip strength, compared to the control group: hip extension (p=0.00), flexion (p=0.00), abduction (p=0.00), and adduction (p=0.00). 2. After the 8-week VR-based exercise, the VR group showed significant improvement of dynamic balance capacity as ground reaction force, compared to the control group. Eyes opened backward stepping test: Fx (+) (p=0.00), Fy (-) (p=0.02), Ver (+) (p=0.02) direction. Eyes closed backward stepping test: Fx (+) (p=0.04), Fy (-) (p=0.04), Ver (+) (p=0.03) direction. Conclusion: The VR group showed improvement of their hip muscle strength, and dynamic balance capacity. Therefore VR-based continuous slow exercise would contribute to reducing the risk of falls in the elderly.

• 한국의류산업학회지
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• 제17권4호
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• pp.635-645
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• 2015

This study analyzed the range of motion of upper body in different configurations of firefighters' protective clothing and equipment. The purpose of this study was to understand the influence of firefighters' protective clothing and equipment over upper body motion in order to improve design of firefighters' protective clothing and equipment. 12 firefighters' upper body range of motion was analyzed while performing standing and walking trials in five different garment configurations including turnout ensemble, fire boots and the self-contained breathing apparatus. Analysis of upper body range of motion included spinal joints of L5S1, L4L3, T1C7, and C1Head. During standing trials, garment configurations caused a significant difference in range of motions at joints of L5S1, L4L3, T1C7, and C1Head. Analysis on the mean of range of motions at L5S1 and L4L3, showed that firefighters' waist bent forward significantly to a greater extent while they wore a self-contained breathing apparatus. A significantly increased range of motion was found for T1C7 and C1Head while carrying a self-contained breathing apparatus, which indicated an increase in the extension of the trunk and neck backward to stand upright and look squarely. A significant difference in range of motion was also found for L5S1 and L4L3 during walking trials.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.464-469
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• 2001

This work provides the biomechanical evaluations of a manual wheelchair with a bi-directional driving system. The new propulsion strategy can be accomplished by employing a special gear system that converts the oscillatory motion of a handrim into the unidirectional output motion of a wheel. A main feature of the forward. backward propulsion is to supply continuous driving torque without break. Motion. analysis has been performed through 2-dimensional image processing for measuring the kinematic properties of the upper arm and fore arm. Then, the inverse dynamics analysis has been done for obtaining the joint torques, the handrim forces and input/output powers. Results show that the output power by the forward. reverse propulsion is almost twice as much as that by conventional propulsion. Also, the new propulsion is expected to reduce the fatigues and injuries at arm joints by employing more muscle groups for movement. In conclusion, the forward. reverse propulsion can greatly improve the performances of manual wheelchairs by providing better mobility as well as by guaranteeing several advantages from a biomechanical viewpoint. Future development of a manual wheelchair optimized for the bi-directional propulsion will further improve the propulsion performances.