• Journal of Mechanical Science and Technology
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• v.18 no.1
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• pp.132-144
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• 2004

This paper presents a new method driving multiple robots to their goal position without collision. To consider the movement of the robots in a work area, we adopt the concept of avoidability measure. The avoidability measure figures the degree of how easily a robot can avoid other robots considering the velocity of the robots. To implement the concept to avoid collision among multiple robots, relative distance between the robots is proposed. The relative distance is a virtual distance between robots indicating the threat of collision between the robots. Based on the relative distance, the method calculates repulsive force against a robot from the other robots. Also, attractive force toward the goal position is calculated in terms of the relative distance. These repulsive force and attractive force are added to form the driving force for robot motion. The proposed method is simulated for several cases. The results show that the proposed method steers robots to open space anticipating the approach of other robots. In contrast, since the usual potential field method initiates avoidance motion later than the proposed method, it sometimes fails preventing collision or causes hasty motion to avoid other robots. The proposed method works as a local collision-free motion coordination method in conjunction with higher level of task planning and path planning method for multiple robots to do a collaborative job.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.4
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• pp.223-232
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• 2003

This paper presents a new method driving multiple robots to their goal position without collision. Each robot adjusts its motion based on the information on the goal location, velocity, and position of the robot and the velocity and position of the .other robots. To consider the movement of the robots in a work area, we adopt the concept of avoidability measure. The avoidability measure figures the degree of how easily a robot can avoid other robots considering the following factors: the distance from the robot to the other robots, velocity of the robot and the other robots. To implement the concept in moving robot avoidance, relative distance between the robots is derived. Our method combines the relative distance with an artificial potential field method. The proposed method is simulated for several cases. The results show that the proposed method steers robots to open space anticipating the approach of other robots. In contrast, the usual potential field method sometimes fails preventing collision or causes hasty motion, because it initiates avoidance motion later than the proposed method. The proposed method can be used to move robots in a robot soccer team to their appropriate position without collision as fast as possible.

• Korean Journal of Applied Biomechanics
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• v.22 no.3
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• pp.305-314
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• 2012

The purpose of this study was to investigate the effects of joint kinetics and coordination on within-individual differences in maximum vertical jump. 10 male subjects aged 20 to 30 performed six trials in maximum vertical jump and with based on jump height the good(GP) and bad(BP) performances for each subject were compared on joint kinetics of lower extremity and coordination parameters such as joint reverse and relative phase. The results showed that maximum moment, power, and work done of hip joint and maximum moment of ankle joint in GP were significantly higher than that in the BP but no significant differences for the knee joint. We could observe a significant difference in joint reverse timing between both conditions. And also the relative phase on ankle-knee and ankle-hip in GP were significantly lower than that in the BP, which means that in GP joint movements were more in-phase synchronized mode. In conclusion, mechanical outputs of hip and ankle joints had an effect on within-individual differences in vertical jump and the inter-joint coordination and coordination including sequence and timing of joint motion also might be high influential factors on the performances within individual.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.33-41
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• 2006

This study was to analysis three dimension angle of the upper extremity segment and trunk to putting the protector in women bowlers. For this study, the subjects selected 4 players of national and university team. All subjects putted in the same wrist support to satisfy the experiment conditions. To get three dimensions position coordination of swing motion used for 6 ProReflex MCU 240 camera produced by Qualisys. After position coordination calculation, Three dimension angle of the trunk and the upper extremity segment calculated for Matlab 6.5. the result is following; In the trunk motion, there were little differences among the subjects in a flexion and extension change. There were a lot of differences in motion change of the abduction-adduction and internal-external rotation, but the motion types translated to the adduction-abduction-adduction and from the internal rotation toward the external rotation. In the upper arm segment the Flexion and extension showed a consistent motion in the down swing and up swing phase. And the motion change of abduction-adduction and pronation-supination showed a abduction-adduction-abduction and pronation-supination change during swing phase. In the forearm segment changes, it showed a lot of differences among the subjects and a similar change with the upper arm segment. Especially, the hand segment showed a supination motion from the backswing apex to release phase, but for increasing a rotation velocity of ball, the hand segment translated toward pronation in follow throw phase.

• Proceedings of the Korea Multimedia Society Conference
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• 1998.04a
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• pp.262-267
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• 1998

A hierarchical motion control system for animation of 3D human character is implemented using the motion database in realtime. The proposed motion control system consists of coordination controller for gait timing and balancing of walking motion, joint servo controller for realistic limb movement, and motion database for goal-directed character animation which makes time-consuming animation relatively easy task. As one example among the various applications of the proposed motion control system. We present a simple virtual reality system in which the motion control system plays a central role in generating realistic motion of virtual human character.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.990-995
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• 1990

A minimum-time trajectory planning for two robot arms with designated paths and coordination is proposed. The problem considered in this paper is a subproblem of hierarchically decomposed trajectory planning approach for multiple robots : i) path planning, ii) coordination planning, iii) velocity planning. In coordination planning stage, coordination space, a specific form of configuration space, is constructed to determine collision region and collision-free region, and a collision-free coordination curve (CFCC) passing collision-free region is selected. In velocity planning stage, normal dynamic equations of the robots, described by joint angles, velocities and accelerations, are converted into simpler forms which are described by traveling distance along collision-free coordination curve. By utilizing maximum allowable torques and joint velocity limits, admissible range of velocity and acceleration along CFCC is derived, and a minimum-time velocity planning is calculated in phase plane. Also the planning algorithm itself is converted to simple numerical iterative calculation form based on the concept of neural optimization network, which gives a feasible approximate solution to this planning problem. To show the usefulness of proposed method, an example of trajectory planning for 2 SCARA type robots in common workspace is illustrated.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.400-403
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• 1995

A robot system is proposed to realize coordinated motion of two arm robot. Due to a 3-D vision sensor, precise coordinated motions could be realized. Using a sophisticated IC chip, real time image processing could be executed using a simple circuit.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.215-219
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• 1992

This paper presents a motion coordination of two robot manipulators coordinating an object. To coordinate the object, a force/position control scheme in a mode of leaer/follower is devised. The dynamics of the object are incorporated into the dynamics of the leader arm, which yields a reduced order model of two arm system. In order to regulate interaction forces between two arm, the dynamics of the follower arm are expressed as force dynamic equations such that a novel direct forces between two arms and two different type of bounded input disturbances, boundedness and asymptotic stability results based on a proposed Lyapunov function are shown. Also, a sufficient condition for a stability robustness is derived based on the Lyapunov approach.

• Journal of the Ergonomics Society of Korea
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• v.20 no.3
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• pp.11-25
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• 2001

AS human movements have the inherent property of anticipating target and can be coordinated to realize a given schedule, finger movements have stereotyped patterns during hand grasping. Finger movements have been studied in the past to find out the coordination pattern of hand joint angular movement. These studies analyzed only a few finger joints for a limited number of hand postures. This study investigated fourteen joint angles during eight hand-grasping motions to analyze the angular correlations between finger joints and to suggest motion factors which represent hand grasping. Hand grasping motions including forward arm motion were examined in ten healthy volunteers. Eight objects were used to represent real hand grasping tasks. $CyberGlove^{TM}$ and $Fasreack^{TM}$ measured hand joint angles and wrist origin. Joint angle correlations between PIJ(proximal interphalangeal joint) and MPJ(metacarpophalangeal joint) at one finger, between neighboring PIJs and MPJs were four factors related to the fast phase of hand grasping motions and eight factors related to the slow phase of hand grasping motions.

• Physical Therapy Korea
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• v.13 no.1
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• pp.54-60
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• 2006

This study aimed to compare movement patterns of shoulder joints between the right and left symmetry in stroke patients and control subjects. This study proposes use of the voluntary response index (VRI) calculated from quantitative analysis of surface electromyographic (sEMG) and motion data recorded during voluntary movement as a feeding task. The VRI is comprised of two numeric values, one derived from the total muscle activity recorded for the voluntary motor task (magnitude), and the other from the sEMG distribution across the recorded muscles with the similarity index (SI). Five stroke patients and five age-matched healthy controls were recruited. Feeding motion was performed using the provided spoon five times with rests taken on a chair in between tasks. EMG data were digitized and analyzed on the basis of the root mean square (RMS) envelope of activity. The average amplitude of responses was calculated. Responsiveness and clinically meaningful levels of discrimination between stroke patients and control for EMG magnitude and SI were determined. The similarity index of the results from two successive examinations of both sides apart for stroke patients and control subjects were .86 and .95 in motion analysis and .84 and .99 in electromyographic analysis. The SI of sEMG data and motion data was significantly correlated in stroke patients. The data suggest that SI is a sensitive program for comparing and analyzing the symmetry of muscle activity and motion in both sides. This analysis method has a clinical value in grading muscular activity and movement impairment after brain injury.