• The Research Journal of the Costume Culture
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• v.22 no.4
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• pp.632-639
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• 2014

The purpose of this study was to verify the effect of drive swing on multiple functional wear wearing in golf. The subjects were 6 men ($22.67{\pm}0.82$ yrs, $175.42{\pm}3.42cm$, $78.75{\pm}4.78kg$), who had career each with at least 8 yers golf experience with right-hander. For kinemetical analysis, this study used equipments with 7 motion capture cameras (300Hz) and analysis program (Nexus1.5). The total time of the club head, displacement magnitude of the COM and swing plane were compared of according to functional wear wearing and non-weraing during golf drive swing. The results of the study are as follows. The total time of the club on wearing ($2.18{\pm}0.06sec$) was faster than non-wearing ($2.52{\pm}0.15sec$). Displacement magnitude of the COM on wearing ($4.06{\pm}0.67cm$) was shorter than non-wearing ($5.79{\pm}0.72cm$). Also, swing plane was found to be significantly different of 3 phase excepted BST-DS (back swing top-down swing) phase. AD-BST (address-back swing top) phase on wearing ($13.86{\pm}3.08cm$) decrease more than non-wearing ($20.82{\pm}3.99cm$), DS-IP (down swing-impact) phase on wearing ($6.25{\pm}1.35cm$) decrease more than non-wearing ($7.18{\pm}1.52cm$) and IP-FT (impact-follow though) phase on wearing ($7.93{\pm}2.09cm$) decrease more than non-wearing($9.68{\pm}2.02cm$). The multiple functional wear wearing was contribution to come close for one-plane, a long with consistency and accuracy on golf drive swing.

• New & Renewable Energy
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• v.9 no.3
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• pp.5-13
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• 2013

In the previous research, dynamic results have been analyzed in the time and frequency regions. Time and frequency region can be transformed by the Fourier transform. This transform is very useful about analyzing system behaviors. However, because of coupling, it cannot give clear results in the real system including lots of defects. In this paper, we introduced the analysis based on quefrency region to represent physical means clearly from complicated results. We simulated the drive train system which has defects, and compared between frequency and quefrency region to show its excellence. To do this process, We established mathematical model. The equation of motion was derived by the Lagrange equation and constraint equations. The constraint equation included relationships about gear mesh, flexibility of shaft. About numerical analysis, the Newmark beta method was used to get results. And FFT (Fast Fourier Transform) which converts results from time domain to frequency, qufrequency was used.

• 전자공학회논문지 IE
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• v.43 no.1
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• pp.59-66
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• 2006

In this study, we have proposed a motion equation to control synchro drive mobile robot, a path plan to compute and track the best path to given destination and a technique utilizing uniform distribution and cluster management based Monte Carlo localization to have track current position of moving robot. In the localization test which was repeated 73 times resulted as following. The average process time of original Monte Carlo localization was 12.8ms. The proposed cluster management Monte Carlo localization resulted 9.3ms. Also the proposed method resulted correctly in the cases where original method failed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.475-481
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• 2013

The control system of a direct drive servo valve is a nonlinear system, and the flow force effect on the spool motion is significant and dependent on the load pressure. To satisfy the control system design requirements, the optimal parameters of the lead-lag controller and the derivative feedback controller are searched for using a genetic algorithm and a complex constrained direct search type method. The obtained controller parameters successfully perform their role to satisfy the control system design requirements.

• Journal of Power Electronics
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• v.8 no.4
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• pp.291-300
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• 2008

In this paper power system and drive-train for omni-directional autonomous mobile robots with multiple energy storage units are presented. Because in proposed system, which is implemented in soccer robots, the ability of power flow control from of multiple separated energy storage units and speed control for each motor are combined, these robots can be derived by more than one power source. This capability, allow robot to diversify its energy source by employing hybrid power sources. In this research Lithium ion polymer batteries have been used for main and auxiliary energy storage units because of their high power and energy densities. And to protect them against deep discharge, over current and short circuit, a protection circuit was designed. The other parts of our robot power system are DC-DC converters and kicker circuit. The simulation and experimental results show proposed scheme and extracted equations are valid and energy management and speed control can be achieved properly using this method. The filed experiments show robot mobility functions to perform the requested motion is enough and it has a high maneuverability in the field.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.601-606
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• 2001

Free vibration analysis was performed for a spinning disk/spindle system mounted on a flexible baseplate. A simplified model was presented considering the effects of the baseplate flexibility on a disk/spindle system, and the equations of motion were derived by the assumed mode method and Lagrange's equation. From the results of the tree vibration analysis, the variations of the natural frequencies were investigated by changing rotating speed, baseplate thickness. They were attributed to the coupling between the flexible modes of the spinning disk/spindle system and the baseplate. This simplified model was used to predict the dynamic characteristics of a small size disk drive. The validity of the simplified model was verified by experiments and FE analysis.

• The Journal of Korean Physical Therapy
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• v.34 no.4
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• pp.149-154
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• 2022

Purpose: The purpose of this study was to investigate effects of the modified bent arm tornado exercise on weight shift movement and muscle activity of the impact section in the top of the drive swing. Methods: Twenty subjects were divided professional golfer group and amateur golf group. Subjects were required to complete following modified bent arm tornado exercise. The activity and weight shift of the gluteus group and lower extremity muscles between the two groups were measured and the Wilcoxon rank test was analyzed. Results: The distribution of weight shift in the professional golfer group was higher than that of the amateur golfer group (p<0.05). During the golf downswing of the professional golfer group, muscle activation of the lower extremities was higher than that of the amateur golfer group (p<0.05). The distribution of weight shift after exercise by the amateur golfer group was higher than before (p<0.05). Conclusion: We could confirm was increased significantly of muscle activity and weight shift by applying modified bent arm tornado exercise through this study. This result suggests that exercise is needed to improve weight shift.

• Structural Monitoring and Maintenance
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• v.9 no.4
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• pp.305-321
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• 2022

Bridge structural health monitoring with the aim of continuously assessing structural safety and reliability represents a topic of major importance for worldwide infrastructure managers. In the last two decades, due to their potential economic and operational advantages, drive-by approaches experienced growing consideration from researcher and engineers. This work addresses two technical topics regarding indirect frequency estimation methods: bridge and vehicle dynamics overlapping, and bridge expansion joints impact. The experimental campaign was conducted on a mixed multi-span bridge located in Lombardy using a Ford Galaxy instrumented with a mesh of wireless accelerometers. The onboard time series were acquired for a number of 10 passages over the bridge,performed at a travelling speed of 30 km/h, with no limitations imposed to traffic. Exploiting an ad-hoc sensors positioning, pitch vehicle motion was compensated, allowing to estimate the first two bridge bending frequencies from PSD functions; moreover, the herein adopted approach proved to be insensitive to joints disturbance. Conclusively, a sensitivity study has been conducted to trace the relationship between estimation accuracy and number of trips considered in the analysis. Promising results were found, pointing out a clear positive correlation especially for the first bending frequency.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.359-366
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• 2010

This study proposes the design method for the robot rotation arm which the end effector that is connected in end of the arm keeps parallel motion even though the robot arm rotates. So far, most robot arm rotates together the end effector when the arm rotates. For this, this study proposes the mechanism that the arm is linked to each 4 parallel link so that rotation is possible by 4 pins, and the rotation arm connects 2 joints of diagonal line direction to a link in each 4 joint for rotation, and designs so that can change length of the link. For verification of design, this study targeted that develop the rotation arm for medical examination that use in ophthalmology. It is important that a medical robot offers comport to patient and design compactly so that medical examination and treatment space may can be defined enough. It is designed so that all drive elements may be positioned on interior of the arm and optimization of design for main parts was carried out in this study for this. The robot arm which is developed in this study manufactured to use by medical phoropter arm, and got good result by an experiment. The robot rotation arm which is proposed in this study is judged to contribute very effectively in case use of a medical robot arm for medical examination and treatment, also the robot arm which the end effector that is connected in the end of the arm needs to keep parallel motion. And, the robot arm which is developed in this study made an application as license.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.3
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• pp.129-136
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• 2013

In this paper, a motion control system based on 2-axis gimbal system is designed and implemented to drive a high speed and precision. The proposed system consists of the RS-422 interface, 2-axis gimbal platform, servo control unit integrated with a high speed DSP chip-set, servo amplifier unit, potentiometer sensor unit, and resolver sensor unit. The servo control unit using the high speed DSP firmware is designed to get a fast response without an overshoot with step input and a RMS error of low probability with ramp input. The servo amplifier unit using a voltage control is designed to resolve the zero-crossing distortion for precise motion. To verify the performance and stability of the implemented system, experiments are performed through a measurement of the time and frequency domain response in a laboratory environment by using a PXI(PCI eXtentions for Instrumentation).