• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.375-380
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• 2004

Seismic Isolation and Shock/vibration Control Laboratory has performed the National Research Laboratory(NRL) project, 'Design and Application of Control Devices against Earthquake/Shock/Vibration'. In this project, the prototypes of the vibration control devices for structural control against earthquake and wind were developed and verified their performances. And also, the computer programs were developed for the seismic response analysis and the optimum design of the base-isolated structures with vibration control devices. This paper introduces the developed vibration control devices and computer programs.

• ICROS
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• v.20 no.3
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• pp.22-26
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• 2014

본 기술 동향에서는 햅틱 기술과 관련된 최근의 동향에 대해서 살펴보기로 한다. 특히 진동 촉각을 기반으로 한 모바일 기기용 햅틱스는 관련 연구들이 활발하게 진행 중이며 이 중에 몇 가지 연구들과 활용되는 액추에이터 등에 대한 연구들을 바탕으로 앞으로의 촉각 기반 생태계를 예측해 보고, 아울러 의료 휴대폰, 컴퓨터, 재활 분야등에서 필요로 하고 또 활용 가치가 있는 햅틱 기술들에 대해서 고찰해 보기로 한다. 최근에 각광받는 웨어러블 기기등도 내부에 다양한 센서와 액추에이터를 내장하려는 움직임이 있고, 휴대폰 등에서 진동 액추에이터를 활용하여 소리를 대체하듯 촉각 기술이 터치 스크린 기반 시장을 한 단계 발전시켜 차세대 입력 장치로 발전할 수 있는 가능성을 가늠해 볼 수 있을 것이다. 지속적인 연구를 통해 관련 분야에서 필요한 촉각 기술을 개발한다면 햅틱 연구자들이 그토록 염원하는 촉각 기반 시장의 확대 성장도 그리 오랜 시일이 걸리지 않을 것으로 기대한다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.11 s.116
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• pp.1165-1171
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• 2006

This paper presents a new type of jetting dispenser for the integrated circuit (IC) fabrication and surface mount technology The proposed system is featured by the piezoelectric actuator and hydraulic magnification device. After describing structural component of the dispensing mechanism and its operation principle, both the fluid modeling and the hydraulic magnification modeling are undertaken with a lumped-parameter method based on the analogy of the fluid system and mechanical system. A mathematical governing equation is then derived by integrating the fluid model with the mechanical model of the driving piston and piezoelectric actuator. Subsequently, in order to achieve a desired dispensing amount, control algorithm adjusting duty cycle of the driving voltage is synthesized and control responses are presented in time domain.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.387-392
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• 2007

The paper presents control performance of a magnetorheological (MR) fluid-based haptic knob which is applicable to invehicle comfort functions. As a first step, MR fluid-based haptic knob is devised to be capable of both rotary and push motions with a single device. Under consideration of spatial limitation, design parameters are optimally determined to minimize a reciprocal of control torque using finite element analysis. The proposed haptic knob is then manufactured and its fielddependent torque is experimentally evaluated. Subsequently, in-vehicle comfort functions are constructed in virtual environment and make them communicate with the haptic knob. Control performances such as reflection force are experimentally evaluated via simple feed-forward control strategy.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.3
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• pp.307-314
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• 2008

The paper presents control performance of a magnetorheological(MR) fluid-based haptic knob which is applicable to in-vehicle comfort functions. As a first step, MR fluid-based haptic knob is devised to be capable of both rotary and push motions with a single device. Under consideration of spatial limitation, design parameters are optimally determined to minimize a reciprocal of control torque using finite element analysis. The proposed haptic knob is then manufactured and its field-dependent torque is experimentally evaluated. Subsequently, in-vehicle comfort functions are constructed in virtual environment and make them communicate with the haptic knob. Control performances such as reflection force are experimentally evaluated via simple feed-forward control strategy.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.428-433
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• 2006

This paper presents a new type of jetting dispenser for the integrated circuit(IC) fabrication and surface mount technology. The proposed system is featured by the piezoelectric actuator and hydraulic magnification device. After describing structural component of the dispensing mechanism and its operation principle, both the fluid modeling and the hydraulic magnification modeling are undertaken with a lumped-parameter method based on the analogy of the fluid system and mechanical system. A mathematical governing equation is then derived by integrating the fluid model with the mechanical model of the driving piston and piezoelectric actuator. Subsequently, in order to achieve a desired dispensing amount, control algorithm adjusting duty cycle of the driving voltage is synthesized and control responses are presented in time domain.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1125-1130
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• 2007

This paper presents a maneuver analysis of a full-vehicle featuring electrorheological (ER) suspension and ER brake. In order to achieve this goal, an ER damper and an ER valve pressure modulator are devised to construct ER suspension and ER brake systems, respectively. After formulating the governing equations of the ER damper and ER valve pressure modulator, they are designed and manufactured for a middle-sized passenger vehicle, and their field-dependent characteristics are experimentally evaluated. The governing equation of motion for the full-vehicle is then established and integrated with the governing equations of the ER suspension and ER brake. Subsequently, a sky-hook controller for the ER suspension and a sliding mode controller for the ER brake are formulated and implemented. Control performances such as vertical displacement and braking distance of vehicle are evaluated under various driving conditions through computer simulations.

• Journal of KSNVE
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• v.8 no.3
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• pp.533-541
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• 1998

Recently, optical disk drives are increasingly demanded to have higher speed as well as high information density, especially for applications like CD ROM drives. To this end, improvement of their optical pickup structure and control is recognized the very challenging issue. In this paper, the pickup is first analytically modelled in a plane to describe its coupled auto-focusing and auto-tracking motions. Subsequently, the model is linearized and combined with actuator dynamics for the auto-focusing system. With its unmeasurable parameters being estimated based on experimental data, an approximate I-DOF linear model is obtained neglecting the coupling term. To design the high speed and robust positional servo controller realistic design specifications are addressed, and H control method is employed based on the approximate model. Finally, taking the pickup in a commerical high speed CD ROM drive as an example performance of the designed controller is verified through realtime experiments.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.4 s.44
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• pp.43-54
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• 2005

This paper presents cost-effectiveness evaluation of semi-active control system for cable-stayed bridge under earthquake excitations with various magnitudes and frequency contents. Semi-active control system, which is operated by using Bi-stale control method on the basis of linear quadratic Gaussian (LQG) optimal controller, is designed for the benchmark control problem proposed by Dyke et at. The cost-effectiveness of the proposed control system is defined by the ratio of life-cycle costs between a bridge structure with shock transmission units and a bridge structure with the semi-active control devices. The simulated results show that the damper cost has little influence on the cost-effectiveness of the semi-active control system while the cost-effectiveness is quite sensitive to the damage cost induced by the bridge failure. It is also found that the semi-active control system guarantees relatively high cost-effectiveness for the cable-stayed bridge subject to the ground motions in the regions of moderate seismicity with soft soil condition and strong seismicity with stiff soil condition.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.3
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• pp.1-18
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• 1995

This paper deals with the vibration absorbers of gravitational and centrifugal pendulum types for vibration controls of ship's substructures such as radarmasts, bridgewings and funnels. The mathematical model of such a vibrating system with an absorber is described as a 2 degree of freedom system and an efficient formulation for optimum design of the absorber is presented. For investigation applicability of the two types of the absorbers to a structure system, numerical calculations and experiments hove been performed with variation of mass ratios for each type. According to the results of investigations, the vibration absorber of gravitational type proved to be more useful and efficient than one of centrifugal pendulum type in a view point of mass ratio.