• 전자공학회논문지B
• /
• 제30B권6호
• /
• pp.9-19
• /
• 1993

This paper presents a new concept of a reconfigurable manipulator system which adjusts its mechanical structure to suit the kinematic characteristics of a given task. A highly redundant manipulator designed as a general purpose manipulator needs to be reconfigured for a specific task. A general task can be decomposed of motion and force components with different control requirements: either gross motion control or fine motion control. Each of these task components are distributed to each part of the manipulator based on the control requirements and the structure of the manipulator. Through the reconfiguration, a redundant manipulator is decomposed into two local arms, and the kinematic characteristics of each local arm is adjusted to suit the assigned task. The reconfigured redundant manipulator has two local arms well-configured for the local tasks and cooperating in serial for a given task. This globally enhances the performance of a redundant manipulator to execute a specific task. The simulation results are shown.

• Structural Engineering and Mechanics
• /
• 제8권1호
• /
• pp.53-72
• /
• 1999

The most important features of linear soil-foundation-structure interaction are reviewed, using stochastic modeling and considering kinematic interaction, inertial interaction, and structural distortion as three separate stages of the dynamic response to the free-field motion. The way in which each of the three dynamic stages modifies the spectral density of the motion is studied, with the emphasis being on interpretation of these results, rather than on the development of new analysis techniques. Structural distortion and inertial interaction analysis are shown to be precisely modeled as linear filtering operations. Kinematic interaction, though, is more complicated, even though it has a filter-like effect on the frequency content of the motion.

• 제어로봇시스템학회논문지
• /
• 제18권12호
• /
• pp.1106-1114
• /
• 2012

To achieve synchronized motion between a wearable robot and a human user, the redundancy must be resolved in the same manner by both systems. According to the seven DOF (Degrees of Freedom) human arm model composed of the shoulder, elbow, and wrist joints, positioning and orientating the wrist in space is a task requiring only six DOFs. Due to this redundancy, a given task can be completed by multiple arm configurations, and thus there exists no unique mathematical solution to the inverse kinematics. This paper presents analysis on the kinematic and dynamic aspect of the human arm movement and their effect on the redundancy resolution of the human arm based on a seven DOF manipulator model. The redundancy of the arm is expressed mathematically by defining the swivel angle. The final form of swivel angle can be represented as a linear combination of two different swivel angles achieved by optimizing different cost functions based on kinematic and dynamic criteria. The kinematic criterion is to maximize the projection of the longest principal axis of the manipulability ellipsoid for the human arm on the vector connecting the wrist and the virtual target on the head region. The dynamic criterion is to minimize the mechanical work done in the joint space for each two consecutive points along the task space trajectory. As a first step, the redundancy based on the kinematic criterion will be thoroughly studied based on the motion capture data analysis. Experimental results indicate that by using the proposed redundancy resolution criterion in the kinematic level, error between the predicted and the actual swivel angle acquired from the motor control system is less than five degrees.

• 한국운동역학회지
• /
• 제16권3호
• /
• pp.43-51
• /
• 2006

The purpose of this study was to analyze kinematic variables during turing back kick motion of Taekwondo. The subjects of this study were the 4 skilled and 4 unskilled of male university player in respectively. The experiment of this study was used two 16mm high speed cameras and its speed 125 frames/s. Analysis of this data was three dimensional cinematography using KWON3D program package. The results were as following; 1. In the elapsed time, there was no significance difference statically between a skilled and unskilled group. But skilled group was more fast during the motion of I phase. And unskilled group was more fast during the motion of II phase so called force production section, which had an influence on Diechagi's velocity. 2. In the center of gravity of human body, the changing of it was $1.10{\pm}0.04m$, $1.12{\pm}0.03m$ of LFM(left foot movement) and $1.36{\pm}0.08m$, $1.39{\pm}0.09m$ of RKF(right knee flection), and $1.44{\pm}0.08m$, $1.42{\pm}0.09m$ of RFI(right foot impact). There was no significance difference statically between the two groups. 3. The velocity of heel on impact was 1.13m/s in the skilled group and 1.23m/s in the unskilled group, when each angle of knee was $110.4{\pm}10.9deg/s$, $114.8{\pm}28.4deg/s$. The maximum velocity of each performance was reached before the RKF, and the velocity and angle at impact along by two groups did not show any significant difference statically. 4. In the angular velocity of just RKF of lower leg, there was significance difference statically between the two groups(p<.05).

• 대한의용생체공학회:의공학회지
• /
• 제26권3호
• /
• pp.151-155
• /
• 2005

Interspinous spacers have been developed as an alternative surgical treatment for laminectomy or fusion with pedicle screws and rods for the treatment of lumbar spinal stenosis. However, its biomedical efficacies are well not known. In this study, we evaluated kinematic behaviors of the surgical and the adjacent levels before and after inserting interspinous spacers. Three porcine lumbar spines were prepared. On each specimen, an interspinous spacer was inserted at the L4-L5. Flexion-extension moments (0, 2.5, 5.0, 7.5, 10Nm) were applied. A stereophotogrammetric set-up with DLT algorithm was used to assess the three-dimensional motions of the specimen where three markers $({\square}0.8mm)$ were attached to each vertebra. Results showed that extension motion decreased by $15-24\%$ at the surgical level (L4-L5) after insertion of interspinous spacer. At the adjacent levels, the range of motion remained unchanged. In flexion, no significant changes in motion were observed regardless of levels. Therefore, our experimental results demonstrated the interspinous spacer is very effective in limiting the extension motion that may cause narrowing of the spinal canal and vertebral foramen while maintaining kinematic behaviors at the adjacent levels. Further, these results suggested that the use of interspinous spacer may be able to prevent lower back pain at the surgical level and to lower the incidence of degenerative changes at the adjacent levels.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.117.1-117
• /
• 2001

A motion handling technique that transforms existing animation motion data to a mathematically well-defined form. The transformed data can be utilized in any kind of autonomous motion creation process that handles such cases as changed environment, structure (kinematic / dynamic) modification, or changed constraints. To overcome the computational burden of traditional spacetime optimization, we divide full motion data frame into several parts, and we applied the transformation technique to each part using an optimizing tool(CFSQP). To show Ire feasibility of the proposed method, a comparison study results with traditional technique is included.

• 한국운동역학회지
• /
• 제17권2호
• /
• pp.23-29
• /
• 2007

The purpose of this study was to examine if there are kinematic variables differences between national representative players (NRP) and non national representative players (NNRP) during 500 m inline skate starting motion. Four NRP and six NNRP were recruited for the study. Each subject executed starting motion five times on a $2{\times}12m$ start way in a gymnasium. Kinematic variables were analyzed by the three-dimensional motion analysis system (60Hz). It was hypothesized that there are difference in elapsed time and center of mass acceleration in starting phase between groups since starting phase has been considered important in sprinting. The results showed that the NRP had significantly shorter starting phase time than that of NNRP. 1) An elapsed time in phase P1 of NRP was shorter than that of NNRP, and excellent players have early started their first stroke. 2) Both NRP and NNRP have started at the same spot, and displacement of the center of gravity in starting posture of NRP group was at the front compared to NNRP group. 3) Average step lengths of NRP were longer than those of NNRP, and a step change of NRP was stabler compared to that of NNRP. 4) In a speed change of the center of gravity NRP showed comparatively high speed from P1 to P4.

• 한국HCI학회:학술대회논문집
• /
• 한국HCI학회 2009년도 학술대회
• /
• pp.324-329
• /
• 2009

Proactive computing의 핵심 기술인 손동작 인식 (Hand Motion Recognition, HMR) 기술은 인간과 컴퓨터 사이의 상호작용(Human Computer Interaction, HCI) 분야에서 많은 연구가 진행되고 있다. 본 연구에서는 3축 가속도 센서를 부착한 data glove를 제작하고, 3차원 손 모델을 구현한 후, 이를 이용한 손동작 인식 기술을 개발하였다. Data glove는 가상현실에 대한 입력 장치로써 본 논문에서는 3축 가속도 센서를 사용하여 획득된 신호를 wireless communication으로 PC에 전송할 수 있도록 구현하였다. 손 모델링은 ellipsoid를 이용한 kinematic chain 이론 바탕의 3차원 손 모델을 구현하였으며, data glove에서 얻어진 가속도 정보에 rule 기반의 알고리즘을 적용하여 구현된 3차원 손 모델을 통하여 간단한 손동작(가위, 바위, 보)을 인식하였다.

• 한국운동역학회지
• /
• 제17권1호
• /
• pp.175-184
• /
• 2007

The first purpose of this study was to compare kinematic variables during spinning motion with or without upper extremity and identify the most effective spinning method. The second purpose of this study was to compare functional difference between novice and elite dancers with the term of training. Ten experienced female dancers and ten novices were recruited as subjects for this study. Elite group was asked to perform turn motion with three types of upper extremity. Novice group has taken training of spotting technique for five weeks. Four Falcon HiRES cameras were used to analyze kinematic variables including head angular velocity and CG displacement during spinning. These data were sampled before training, after 3-week, and 5-week of training. Eight different events in two consecutive turns were defined for statistical comparison. One-way ANOVA was performed to compare among the kinematics of turning motion with three types of upper extremity. Independent t-test also used to compare kinematics between elite and novice at three different length of training. As results, spinning with both arm increased angular velocity and stability compared to the turning motion with one arm or with arm strapped and found out that the turn with both arm was the most effective way of spin. Also, for novice dancers, three weeks of training were needed to complete spinning motion.

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