• Journal of Power System Engineering
• /
• v.7 no.1
• /
• pp.51-59
• /
• 2003

The recent amount of container freight continuously has been increased, but the low efficiency of container crane causes jamming frequently in transportation and cargo handling at port. It is required that the working velocity and safety are improved by control of moving the trolley as quick as possible without large overshoot and any residual swing motion of container at the destination. In this paper, a LQ Fuzzy controller for a container crane is proposed to accomplish an optimal design of improved control system for minimizing the swing motion at destination. In this scheme a mathematical model for the system is obtained in state space form. Finally, the effectiveness of the proposed controller is verified through computer simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.424-429
• /
• 2003

This paper proposes a swing-arm type dual-stage actuator, which consists of a PZT actuator for fine motion and a VCM(Voice Coil Motor) for coarse motion, for SFF ODD(Small Form Factor Optical Disk Drive), in order to achieve fast access speed and precise track following control. We focus our attention on the design and control of the PZT actuator, because there have been a lot of previous researches related to the VCM and dual-stage actuators. Due to the dual cantilever structure, the PZT actuator can generate precise translational tracking motion at its tip where optical pickup is attached at, and the effect of hysteric behavior of the PZT element is reduced. The dynamic model of the PZT actuator is derived by using the Hamilton's principle, and verified by comparing with the experimental frequency response. The sliding mode control is designed in order to be robust against modeling uncertainties. Simulations and experimental results confirm the effectiveness of the suggested control scheme.

• Wind and Structures
• /
• v.30 no.3
• /
• pp.317-323
• /
• 2020

A novel approach is presented to improve dynamic responses of a pedestrian bridge by utilizing decorative wind chimes. Through wind tunnel tests, it was verified that wind chimes can provide stabilization effects against flutter instability, especially at positive or negative wind angles of attack. At zero degrees of angle of attack, the wind chimes can change the flutter pattern from rapid divergence to gradual divergence. The decorative wind chimes can also provide damping effects to suppress the lateral sway motion of the bridge caused by pedestrian footfalls and wind forces. For this purpose, the swing frequency of the wind chimes should be about the same as the structural frequency, which can be achieved by adjusting the swing length of the wind chimes. The mass and the swing damping level are other two important and mutually interactive parameters in addition to the swing length. In general, 3% to 5% swing damping is necessary to achieve favorite results. In the study case, the equivalent damping level of the entire system can be increased from originally assumed 1% up to 5% by using optimized wind chimes.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.21 no.5
• /
• pp.40-46
• /
• 2013

Automatic swing door for an automotive application is considered. The equation of motion for a driver side swing door is introduced and gravity cancellation control scheme is adapted. The control scheme supposed to cancel the moment due to the tilt of the car. A speed control is suggested for door operation automation but the output of the speed control is not suppose to be precise as for the manufacturing system control. In the frame of the velocity control of the door, feedback linearization was applied for collision detection. The collision detection performance is satisfactory. The estimate of the magnitude of disturbance due to the collision is close to the actual magnitude of disturbance. Simulation study has been performed to gain insight into the system behavior. Also real test on the prototype hardware has been performed for verification purpose.

• Journal of the Korean Society of Physical Medicine
• /
• v.7 no.3
• /
• pp.293-302
• /
• 2012

Background & Purpose : The purpose of this study is to evaluate the impairment of SVMC(selective voluntary motor control) of the lower extremity by assessing each joints of lower limb and to analyze the motional relationship between each joints of lower limb using SCALE(Selective Control Assessment of the Lower Extremity) during the swing phase of gait cycle in children with spastic diplegia. Method : 11 children with spastic diplegia CP who could walk independently and 10 normal developing children were participated. SCALE(Selective Control Assessment of the Lower Extremity) assessments were conducted for 11 children with CP. Gait analysis were accomplished in all participants. Qualisys motion analysis was used as a statistical tool to assess the motional relationship between hip joint, knee joint and ankle joint in each limb. We used descriptive statistics, cross-tabulation, independent t-test, linear regression to analysis motional relationship between each joints of lower limb using by SPSS ver.17.0. Result : Firstly, there were significant differences in SCALE scores between the cerebal palsy group and the control group in knee joint(p<0.05), but no significant difference in hip and ankle joints during the swing phase of gait cycle. Secondly, the difference of SCALE scores showed no statistical motional difference in knee and ankle joints during the swing phase, and showed significant motional difference in hip joints during the swing phase(p<0.05). Thirdly, there was a liner relationship between the motion of hip and ankle joints during the swing phase. Conclusion : The nature of SVMC(selective voluntary motor control) in each joints of the lower limb may reflect the ability of gait, thus SCALE may be used for assessing and for treating the cerebal palsy patients who are able to walk independently. Also we knew that the impairment of SVMC(selective voluntary motor control) increases from the proximal to the distal joints.

• Journal of Institute of Control, Robotics and Systems
• /
• v.2 no.2
• /
• pp.96-101
• /
• 1996

In this paper, a simulator is designed along with S/W package for crane controllers. Due to trolley's acceleration or deceleration, cranes inherently cause swing motion of the objects in transporting heavy objects. This swing not only deteriorates the crane handling safety but also increases the processing time. To overcome these drawbacks, the fuzzy rule-based simulator is developed with inhibitory swing at final action. The computer simulation shows that the swing at initial and final positions is removed fast with small position error. The proposed simulator can be used for handling object stabley and the study of effectiveness in unmanned operation of cranes.

• Journal of the Society of Naval Architects of Korea
• /
• v.58 no.6
• /
• pp.339-347
• /
• 2021

Piston type wave makers or flap type wave makers are usually adopted as a wave maker which disturbing the fluid domain with sinusoidal motion. Recently hybrid wave maker which could be operated as not only piston type and/or flap type but also swing type wave maker have been devised by utilizing the link mechanism. The wave board of hybrid wave maker has been devised to be independently controlled by the horizontal actuators on upper and lower end of the wave board. The wave board could operate as a flap type wave board when the lower hinge is in a stationary condition and the upper hinge is operated with sinusoidal motion. On the contrary, the swing type wave board could be obtained by the lower hinge is activated and the upper hinge is in a stationary condition. When both end of the wave board is activated in a synchronized condition, the wave board motion become piston motion. In addition the hybrid wave maker could enhance the piston motion with flap motion or swing motion by selecting control parameters. Various wave board motion of hybrid wave maker and relevant wave form have measured on the wave board and departed location. It is appeared that the novel hybrid wave maker could be utilized for the improvement of wave qualities in experiments.

• Journal of Biomedical Engineering Research
• /
• v.28 no.6
• /
• pp.744-749
• /
• 2007

Kinematic and kinetic analysis has been performed for Soft Golf swings utilizing realistic three dimensional computer simulations based on three dimensional motion tracking data. Soft Golf is a newly developed recreational sport in South Korea aimed to become a safe and easy-to-learn sport for all ages. The advantage of Soft Golf stems from lighter weight of the club and much larger area of the sweet spot. This paper tries to look into kinematic and kinetic aspects of soft golf swings compared to regular golf swing and find the advantages of lighter Soft Golf clubs. For this purpose, swing motions of older aged participants were captured and kinematic analysis was performed for various kinematic parameters such as club head velocity, joint angular velocity, and joint range of motions as a pilot study. Kinetic analysis was performed by applying kinematic data to computer simulation models constructed from anthropometric database and the measurements from the participants. The simulations were solved using multi-body dynamics solver. Firstly, the kinematic parameters such as joint angles were obtained by solving inverse dynamics problem based on motion tracking data. Secondly, the kinetic parameters such as joint torques were obtained by solving control dynamics problem of making joint torque to follow pre-defined joint angle data. The results showed that mechanical loadings to major joints were reduced with lighter Soft Golf club.

• Korean Journal of Applied Biomechanics
• /
• v.30 no.4
• /
• pp.293-299
• /
• 2020

Objective: The aim of this study was to investigate the swing and aerial motion of Kovacs, and evaluate the skill level of Kovacs by Korean adult players on horizontal bar. Method: The subjects for this study were 6 male top athletes participated in the 46th National Gymnastics against Cities and Provinces. After the motions of Kovacs were filmed by digital highspeed camcorder setting in 90 frames/s, kinematical data were calculated through DLT method. The variables were computed in the lapse time, the joint angle, the position·velocity of body COG, the inferred tension force of bar, and body COG path were simulated according to skill level of Kovacs. Results: Firstly, it was revealed that the lapse time was 1.19±0.03 s in the swing phase, and 0.83±0.03 s in the aerial phase. Secondly, it was revealed that the shoulder·hip joint motions of S1 and S2 were better than the other subjects in the swing phase, and the knee joint motions of S1 and S2 were better than the other subjects in the aerial phase. Thirdly, it was revealed that the horizontal·vertical velocity of body COG were -1.40±0.03 m/s, 3.80±0.07 m/s respectively, and the vertical positions of S1 and S2 were higher a little than the other subjects. Lastly, the skill level of Kovacs of this subjects was evaluated into 3 steps; excellent, advanced, normal. They need to train the swing motion including a giant circle, and body motions in the air. Conclusion: It would be suggested that Korean domestic players should improve to increase the vertical velocity at release instant and train to control the limbs elaborately in the air.

• Korean Journal of Applied Biomechanics
• /
• v.19 no.1
• /
• pp.167-177
• /
• 2009

The purpose of this study was to investigate effect of golf shoe design on kinematic variables during golf swing. Five professional male golfers with shoe size 270mm were recruited for the study. Swing motion was collected using 8 high speed camera motion analysis at a sampling of 180Hz. Kinematic variables were calculated by EVaRT 4.2 software. Driver swing was divided into four events; El(adress), E2(top), E3(impact) and E4(finish). Time, peak velocity, velocity of center of mass, velocity of the foot and ankle angle during Phase 1(El-E2), Phase 2(E2-E3), and Phase 3(E3-E4) were analyzed in order to investigate the relationship between golf shoe design and swing performance. The findings indicated that type C golf shoes would be beneficial for stability and control of movement during address and swing performance. Furthermore, faster speed of golf shoes, center of mass, and both feet were observed with Type C golf shoes. It is expected that golfers with Type C golf Shoes provide greater force as they control the center of mass faster and increase rotational force during impact compared to other golf shoes.