• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.6
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• pp.391-398
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• 2015

The swing noise of an excavator is reduced in this study. When an excavator is under a swing motion, it produces the annoying noise which is required to be reduced. To identify the characteristics of the swing noise, the signals of noise and vibration from an excavator are measured during the swing motion. From the variation of the driving motor speed, the noise and vibration signals are picked up and plotted in the waterfall plots. From the waterfall plots, we identify the frequency components corresponding to the driving motor frequency, the gear mesh frequency of the planetary gear, and their harmonics. In addition, the natural frequencies and modes of the center frame are extracted by using the experimental modal test. It is found that the swing noise is amplified when the gear mesh frequencies coincide with the natural frequencies of the center frame. To reduce the swing noise, the structural modification is performed to the center frame. Finally, it is observed that the noise is considerably reduced by the structural modification.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.153-158
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• 2000

The sway motion of the spreader during and after movement causes an efficiency problem of position control in unmaned gantry crane. The objective of this research is to investigate the phenomenon that the load is taken by the sway motion of crane. For deriving the dynamic equations related to the swing motion of crane, we introduced a conception of spring and damper in the upper part of the crane. During the crane and trolley is driving along the velocity profile, the swing motion of the spreader and crane will be simulated. The simulation result of the equation of motion using the Runge-Kutta method is presented in this paper. And we will show an effect of the swing of the crane in this research.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.708-712
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• 2000

The sway motion of the spreader during and after movement causes an efficiency problem of position control in unmaned gantry crane. The objective of this research is to investigate the phenomenon that the load is taken by the sway motion of crane. For deriving the dynamic equations related to the swing motion of crane, we introduced a conception of spring and damper in the upper part of the crane. During the crane and trolley is driving along the velocity profile, the swing motion of the spreader and crane will be simulated. The simulation result of the equation of motion using the Rung-Kutta method is presented in this paper. And we will show an effect of the swing of the crane in this research.

• Journal of Korea Game Society
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• v.14 no.2
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• pp.67-76
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• 2014

Recently there have been many interests on tangible sport games that can recognize the motions of players. In this paper, we propose essential technologies required for tangible games, which are methods for swing motion recognition and the calculation of shuttle cock's trajectory. When a user carries out a badminton swing while holding a smartphone with his hand, the motion signal generated by smartphone-embedded acceleration sensors is transformed into a feature vector through a Daubechies filter, and then its swing type is recognized using a k-NN based method. The method for swing motion presented herein provides an advantage in a way that a player can enjoy tangible games without purchasing a commercial motion controller. Since a badminton shuttle cock has a particular flight trajectory due to the nature of its shape, it is not easy to calculate the trajectory of the shuttle cock using simple physics rules about force and velocity. In this paper, we propose a method for calculating the flight trajectory of a badminton shuttle cock in which the wind effect is considered.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.395-398
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• 1996

In this study, when the nonlinear overhead crane which allows simultaneously travel and traverse motion moves a desired transport route, the object suspended the end of rope does undesirable swing motion. Nonlinear overhead crane pertubes in the vicinity of an operating point, therefore the nonlinear overhead crane is modified to linear overhead crane for the operating point. The linear overhead crane was controlled to swing angles of the object by the ratio of torque inputs to motors of the girder and the trolley. As a basis for the result of the linear overhead crane, the nonlinear overhead crane was controlled swing angles of the object and positions of the overhead crane without collision with environmental equipment by partial state feedback control.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.522-525
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• 2005

The purpose of this study was to analyze the pattern of muscle usage during swing motion with a soft golf club in comparison with that with a normal golf club. The subjects were normal healthy young adults. The subjects performed swing motion using normal and soft golf clubs in turn. Then, we compared and analyzed the muscular activities for the two cases. The muscular activities of the subject was measured using MP100(BIOPAC Systems, Inc.). For the analysis of muscular activities, we measured EMG(Electromyography) of the subjects during swing motion. The muscles analyzed were deltoid, latissimus dorsi, external oblique, and rectus abdominis of the upper limbs and rectus femoris, biceps femoris, gastrocnemius, and soleus of the lower limbs. The result of the experiment showed that the pattern of muscle usage with soft golf club was similar to that with a normal golf club but the muscular activities with the soft golf was smaller than that with the normal golf club.

• Korean Journal of Applied Biomechanics
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• v.28 no.1
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• pp.1-8
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• 2018

Objective: The purpose of this study is to investigate the differences in biomechanical variables of golf driving motion according to gender. Method: A total of 21 healthy golfers (11 men and 10 women) who have more than 5 years of professional experience and have been registered in the Korea Golf Association was recruited. A 250-Hz 8-camera motion capture system (MX-T20, Vicon, LA, USA) was used to capture the motion trajectories of a total of 42 reflective markers attached to the golfer's body and club. Moreover, two 1,000-Hz AMTI force plates (AMTI OR6-7-400, AMTI, MA, USA) were used to measure the ground reaction force. The mean and standard deviation for each parameter were then calculated for both groups of 21 subjects. SPSS Windows version 23.0 was used for statistical analysis. The independent t-test was used to determine the differences between groups. An alpha level of .05 was utilized in all tests. Results: There were differences in joint angles according to gender during golf driver swing. Men showed a statistically significantly higher peak joint angle and maximum range of angle in sagittal and frontal axis of the pelvis, hip, and knee. Moreover, women's swing of the pelvis and hips was found to have a pattern using the peak joint angle and range of angle in the vertical axis of the pelvis and hip. There were the differences in peak joint moment according to gender during golf driver swing. Men used higher joint moment in the downswing phase than women in the extensor, abductor, and external rotator muscles of the right hip; flexor and adductor muscles of left hip joint; and flexor and extensor muscles of the right knee. Conclusion: This result reveals that male golfers conducted driver swing using stronger force of the lower body and ground reaction force based on strength of hip and thigh than female golfers.

• 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.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.90-96
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• 2008

In general, the swing motions of a crane are controlled and suppressed by controlling the trolley motion. In many of our previous studies, we suggested a new type of anti-sway control system for a crane. In this proposed control system, a small auxiliary mass (moving-mass) is installed on the spreader and moving this auxiliary mass controls tire swing motion. The actuator reaction against the auxiliary mass applies inertial control forces to the container in order to reduce the swing motion in the desired manner. However, measuring systems based on a laser sensor or other means are not veryuseful in real-worldapplications. So, in this paper, animage sensor is used to measure the motions of the spreader and the measured data are fed back to the controller in real time. The applied image processing technique is a kind of robust template matching method called Vector Code Correlation (VCC), which was devised to consider real environmental conditions. The H $\infty$ based control technique is applied to suppress the swing motion of the crane. Experimental results showed that the proposed measurement and control system based on an image sensor is useful and robust to disturbances.

• Journal of the Korea Safety Management & Science
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• v.15 no.2
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• pp.55-61
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• 2013

For years, many studies have mainly been investigated in a complicated human motion analysis. Recently, many motion analysis equipments have been studied and developed. Therefore, the more complex human movement analyses are possible, we have enabled us to perform more and more complicated human movement analyses. A Three-dimensional(3D) motion analysis on of the several methods is a useful tool for analyzing the human motion analysis. The purpose of this study was to develop the 3D human motion analysis using a kalman filter algorithm and a gyro sensor. The algorithm and sensor were used to human motion analysis with high-speed motion capture. In this study, the developed system will be adapted to facilitate golf swing analysis. Using the developed system, golfers and coaches who do not have advanced biomechanical knowledge can easily be used to their golf swing analysis. Future study is necessary for more practical and efficient area such as other sports industries, 3D game industries, rehabilitation training, etc..