• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.359-362
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• 2003

Damping systems have been widely used to various industrial structures and are mainly hydraulic and pneumatic devices nowadays. In this work, a novel damping system based on the colloidal suspension in the field of nanotechnology is investigated. The colloidal suspension consists of Iyophobic working fluid and hydrophobic-coated porous particle. The mechanism of mechanical energy dissipation in damping system based on the colloidal suspension with nano-porous particles is different from that of the existing hydraulic damping system. The absorbed energy of the damping system using colloidal suspension can be calculated through the mechanical equilibrium condition by the superficial tensions of liquid-gas Interface in the hydrophobic surface in nano-porous particles. The results from an analytic approach have a reasonable agreement with experimental results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.486-494
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• 2001

This paper presents a real-time multibody vehicle dynamic analysis method using recursive Kanes formulation and suspension composite joints. To shorten the computation time of simulation, relative coordinate system is used and the equations of motion are derived using recursive Kanes formulation. Typical suspension systems of vehicles such as MacPherson strut suspension system is modeled by suspension composite joints. The joints are derived and utilized to reduce the computation time of simulation without any degradation of kinematical accuracy of the suspension systems. Using the develop program, a multibody vehicle dynamic model is formed and simulations are performed. Accuracy of the simulation results is compared to the real vehicle field test results. It is found that the simulation results using the proposed method are very accurate and real-time simulation is achieved on a computer with single PowerPC 604 processor.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.47-52
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• 2005

A lot of information storage devices have been introduced and developed for recently years. The trends of those devices are high capacity, compact size, low power consumption, reliability, and removability for data interchange with other device. As a satisfaction of these trends, near-field technique is in the spotlight as the next generation device. In order for a near-field recording to be successfully implemented in the storage device, a slider and suspension is introduced as actuating mechanism. The optical slider is designed considering near-filed optics. Suspension is not only supports slider performance, and tracking servo capacity but also meets the optical characteristics such as tilt aberration, and guarantee to satisfy shock performances for the mobility fir the actuator. In this study, the optical slider and the suspension for near-field probe array are designed and analyzed considering dynamic performance of head-gimbal assembly and shock simulation..

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.943-946
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• 2010

In this study, a front suspension system, which is mounted on the handle itself, was suggested because of its light weight and cost efficiency. The shock absorption was evaluated for the three types of suspension models; non-suspension, suspension on front forks (existing model), and suspension on handle (suggested model). The human body model was used for performing impact simulation for comparing the shock absorption for the suspension models. The result of the simulation shows that shock absorption for the proposed suspension model was not as good as that for the front fork suspension model. Nevertheless, the shock absorption observed for the proposed suspension model was significant when compared to the non-suspension model. Consequently, the proposed suspension model could be applied to lightweight bicycles.

• Transactions of the Society of Information Storage Systems
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• v.5 no.1
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• pp.47-52
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• 2009

Most hard disk drives that apply the ramp load/unload technology unload the heads at the outer edge of the disk while the disk is rotating. The load/unload includes the benefits as like an increased areal density, a reduced power consumption and an improved shock resistance. A lot of papers investigating the effects of the various load/unload parameters such as a suspension tab, a limiter, a ramp and air-bearing surface designs have been published. However, in previous researches, an effect of the suspension is not considered at each load/unload step. In this paper, we focus that a variation of the state matrix affects the load/unload performance on based on a state matrix that is a stiffness matrix of the suspension. Because the state matrix is related to the suspension at each load/unload step, to change the state matrix means the structural change of the suspension. Therefore, we investigated a range of a pitch static attitude(PSA) and a roll static attitude(RSA) for load/unload performance. We also analyzed an effect of the variation of the state matrix a range of load/unload velocity occurred a slider-disk contact. We determined the variation of the state matrix to improve the load/unload performance through comparison of each factor of state matrix.

• Structural Engineering and Mechanics
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• v.87 no.3
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• pp.255-272
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• 2023

Spatial cable systems can provide more transverse stiffness and torsional stiffness without sacrificing the vertical bearing capacity compared with conventional vertical cable systems, which is quite lucrative for long-span earth-anchored suspension bridges' development. Higher economy highlights the importance of refined form-finding analysis. Meanwhile, the internal connection between the lateral and vertical sags has not yet been specified. Given this, an analytic algorithm of form-finding for the earth-anchored suspension bridge with spatial cables is proposed in this paper. Through the geometric compatibility condition and mechanical equilibrium condition, the expressions for cable segment, the recurrence relationship between catenary parameters and control equations of spatial cable are established. Additionally, the nonlinear general reduced gradient method is introduced into fast and high-precision numerical analysis. Furthermore, the analytic expression of the lateral and vertical sags is deduced and discussed. This is very significant for the space design above the bridge deck and the optimization of the sag-to-span ratio in the preliminary design stage of the bridge. Finally, the proposed method is verified with the aid of two examples, one being an operational self-anchored suspension bridge (with spatial cables and a 260 m main span), and the other being an earth-anchored suspension bridge under design (with spatial cables and a 500 m main span). The necessity of an iterative calculation for hanger tensions on earth-anchored suspension bridges is confirmed. It is further concluded that the main cable and their connected hangers are in very close inclined planes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.513-517
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• 1995

In this paper, a relation of matrix Q in cost function to distances between the closed-loop and open-loop poles of a multi input controllable systems is studied. Futhmore, the state feedback gain with exact desired eigenvalues in the LQR is computed. The proposed scheme is applied to designing automotive active suspension control system for a half-car model and its performance is compared with the existing LQR control system design methodology.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1155-1160
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• 1993

The control-ability of vehicle active suspension is strongly affected by the performance of pressure control valve especially in the view of dynamic response and energy consumption. Important design parameters in the valve are selected and the effect of variation of those is analized experimentally to enhance the performance of pressure control valve used in Active Suspension.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.888-891
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• 1996

The objective of a mixed H$_{2}$/H$_{\infty}$ controller of active suspension system is to achieve not only the general performance improvement(H$_{2}$) but also the worst case disturbance rejection(H$_{\infty}$). In this paper, a mixed H$_{2}$/H$_{\infty}$ controller for an active suspension system, comparing the performance with that of an H$_{2}$ controller and of an H$_{\infty}$ controller.ler.EX> controller.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.115.3-115
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• 2002

To improve the performance of the tracked vehicle system, we examined the feasibility of using the preview control for the tracked vehicles suspension system. We proposed a method to apply a linear optimal preview control to the tracked vehicle system. To avoid the complexity of modeling the track subsystem and kinematical nonlinearity in the trailing arm suspension, we classified these as unknown dynamics and disturbances. We used the Time Delay Control(TDC) method to make sprung mass dynamics follow that of linear preview controlled tracked vehicle model by compensating the uncertainties and disturbances. We have verified by the computer simulation that the proposed method shows good robus...