• Journal of Institute of Control, Robotics and Systems
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• v.5 no.4
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• pp.496-503
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• 1999

In this paper, the improvement of cap tilting system in heavy truck and the development of program for automatic design are discussed. Cab tilting system takes some important roles in heavy truck, absorbing discomfort vibration from load, increasing repair efficiency and making sure of safety. Common manual cab tilting system cannot be easily tilt up in sloped road, giving difficulty to driver as cal tilting up/down. So recently hydraulic cab tilting system is in wide use. But some problem such as tilting up/down speed is not constant and sudden swing of cab has brought discredit from user. Therefore, this paper presents advanced cab tilting system which prevents sudden swing of cab and development of program for selecting design parameters automatically.

• Journal of Ocean Engineering and Technology
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• v.19 no.3
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• pp.66-73
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• 2005

The sway motion control problem of a container hanging on the trolley is considered in this paper. In the container crane control problem, the main issue involves suppressing the residual swing motion of the container at the end of acceleration, during deceleration, or for an unexpected disturbance input. For this problem, in general, many trolley motion control strategies are introduced and applied. In this paper, we introduce and synthesize a swing motion control system, in which a small auxiliary mass is installed on the spreader. In this control system, the actuator reacting against the auxiliary mass applies inertial control forces to the container to reduce the swing motion in the desired manner. In many studies, the controllers used to suppress the vibration have been synthesized for the given mathematical model of plants. In many cases, the designers have not been able to utilize the degree of freedom to adjust the structural parameters for the control object. To overcome this problem, so called "Structure/Control Simultaneous Method" is used. From this, in this paper the simultaneous design method is used to achieve optimal system performance. And the experimental result shows that the proposed control strategy is useful, to the case of that the controlled system is exposed to the uncertainties and, robust to disturbances like wind.

• Earthquakes and Structures
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• v.15 no.4
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• pp.411-417
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• 2018

To solve the seismic response problem of a vertical floating roof tank with base isolation, the floating roof is assumed to experience homogeneous rigid circular plate vibration, where the wave height of the vibration is linearly distributed along the radius, starting from the theory of fluid velocity potential; the potential function of the liquid movement and the corresponding theoretical expression of the base shear, overturning the moment, are then established. According to the equivalent principle of the shear and moment, a simplified mechanical model of a base isolation tank with a swinging effect is established, along with a motion equation of a vertical storage tank isolation system that considers the swinging effect based on the energy principle. At the same time, taking a 150,000 m 3 large-scale storage tank as an example, a numerical analysis of the dampening effect was conducted using a vibration mode decomposition response spectrum method, and a comparative analysis with a simplified mechanical model with no swinging effect was applied.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.9
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• pp.88-95
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• 2009

Input shaping has been a very effective control method for reducing payload swing in industrial bridge and gantry cranes. However, conventional input shapers often degrade performance when applied to tower cranes because of the nonlinear coupled dynamics between rotational and radial motions in tower cranes. To alleviate this problem, a new input shaper for tower cranes is developed by means of dynamic modeling, analysis and optimization. This work investigates the tower crane dynamics along with parameters of the tower crane varied. A performance index for input shaper design is proposed so as to reduce the coupled residual vibration of a tower crane using only rotational motion of tower crane. The proposed new input shaper is verified to be effective through simulations and experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.742-747
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• 2000

The optical storage device has recently experienced significant improvements, especially for the aspects of high capacity and fast transfer rate. However, it is the fact that the optical storage device has the lower access time for the randomly scattered data compared to the hard disk drives. It is, therefore, necessary to develop a new type of optical storage system. In this study, we investigate the air bearing characteristics for the optical disk drives which have the swing arm actuator similarly to the hard disk drives. Considering the requirements of the optical disk drives, we parametrize the shape of the air bearing surface and investigate its sensitivity to the flying characteristics for further optimized design outputs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.780-785
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• 2003

Recently the trends in information storage devices need small size, mobility, high capacity, and low power consumption etc. To satisfy those, the development of high performance actuator is an important issue. Compared with general linear actuator for optical disk drive, swingarm type rotary actuator is suitable to design in small form factor and has fast access time for random access. Swingarm actuator is designed considering the structural problem and the actuating force of VCM(Voice Coil Motor). The increase of mass caused by optical components makes vibration problems of swing-arm, therefore resonance frequency should be increased and inertia has to be reduced. ANSYS FEM tool is employed in optimizing swingarm. The VCM is designed using 3-D electro-magnetic analysis, and parameters of magnetic circuit are determined to matte large flux density. The large flux density enables to achieve low power consumption. VCM holder is designed to get the mass balance of total actuator and this balance reduces the magnitude of critical mode relative to pivot bearing, It is expected that swingarm type rotary actuator designed by this method is available to variable type of micro optical disk drives.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.5
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• pp.385-393
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• 2004

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 an SFF ODD(small form factor optical disk drive), in order to achieve fast access speed and precise track-following control. Over the past few decades there have been a lot of researches related to the VCM and dual-stage actuator. In this paper, we focus our attention on the design and control of the PZT actuator. Due to the dual cantilever structure. the PZT actuator can generate precise translational tracking motion at its tip to which an optical pickup is attached. 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 it 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.406-411
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• 2003

One of the trends on information storage device is focused on the development of micro-optical devices with OFH (Optical Flying Head). Many different types of sliders for OFH and optical component systems have been introduced in the literature. However, the important issue on the mechanical system, which consists of suspension, swing arm and VCM (Voice Coil Motor) part has not been discussed up to date. In this research, we analyses the suspension, which is used for the small form factor MO drive. The analysis is in process two ways. One is probabilistic analysis, another is dynamic shock analysis. Probabilistic analysis is a technique you can use to assess the effect of uncertain input parameters and assumptions on your analysis model. Using a probabilistic analysis you can and out how much the results of a finite elements analysis are affected by uncertainties in the model. Dynamic shock analysis is used for the mobile applications. The mechanical robustness of the suspension simulating the shock responses of a disk-suspension is proposed in this paper.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.642-651
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• 2009

The history of excavator design is not long enough which still causes most of the design considerations to be focused on static analysis or simple functional improvement based on static analysis. However, the real forces experiencing on each component of excavator are highly transient and impulsive. Therefore, the prediction and the evaluation of the movement of the excavator by dynamic load in the early design stage through the dynamic transient analysis of the excavator and ensuring of design technique plays an importance role to reduce development-cost, shorten product-deliver, decrease vehicle-weight and optimize the system design. In this paper, Commercial software DADS and ANSYS help to develop the track model of the crawler type excavator, and to evaluate the performance and the dynamic characteristics of excavator with various simulations. For that reason, the track of crawler type excavator is modelled with DADS Track Vehicle Superelement, and the reaction forces on the track rollers were predicted through the driving simulation. Also, the upper frame and cabin vibration characteristics, at the low RPM idle state, were evaluated with engine rigid body modelling. And flexibility body effects were considered to determine the more accurate joint reaction forces and accelerations under the upper frame swing motion.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.227-231
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• 2004

Technological advance in information technology has sparked the necessity of small form factor (SFF) optical disk for mobile devices. Small form factor optical disk is highly anticipated to be a next generation storage device because it can be used for a cost-effective way compared with solid state memory. For the application to the 5 mm height small-form-factor optical disk drive, we have presented an optical flying head and swing arm actuator. In this study, we propose a small 1-axis actuator for compensating ficus error and SA due to the variation of cover-layer thickness in the cover-layered small optical disk. The main design issues of the 1-axis actuator are the realization of compact structure and the new support structure of the actuator: Finally, the compensating principle and performance of the 1-axis actuator will be explained.