• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.1157-1164
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• 2003

Dynamic Load/unload (L/UL) mechanism is an alternative to the contact start stop (CSS) technology which eliminates stiction and wear failure modes associated with CSS. Other benefits of L/UL include increased areal density due to smooth disk surfaces, thinner overcoats, and lower head flying height Improved shock resistance due to elimination of head slap, and reduced power consumption. Inertia latch mechanism becomes important for mobile disk drives because of non operating shock performance. Various types of latch designs have been introduced in hard disk drives to limit a rotary actuator from sudden uncontrolled motion. In this paper, a single spring inertia latch is introduced for a small form optical disk drive, which uses a rotary actuator for moving an optical pick-up. A new small inertia latch with single spring is designed to ensure both feasible and small size. The shock performance of the new inertia latch is experimentally verified.

• 한국소음진동공학회논문집
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• 제19권8호
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• pp.788-794
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• 2009

Various types of latch designs for hard disk drives using load/unload mechanism have been introduced to protect undesired release motions of a voice coil motor(VCM) actuator from sudden disturbances. Recently, various inertia-type latches have been widely used because locking performance is better than that of other types of latch. However there has been a limit in the inertia type in order to guarantee perfect latch and unlatch operations because of changes in latch/unlatch conditions due to mechanical tolerance and temperature-dependent friction. In this paper, a reliable and robust magnetic latch mechanism is proposed through only simple modifications of coil and yoke shapes in order to overcome the mechanical limit of current inertia-type latches. This new magnetic latch does not have only a simple structure but it also ensures reliable operations and anti-shock performance. The operating mechanism of the proposed latch is theoretically analyzed and optimally designed using an electromagnetic simulation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.743-748
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• 2008

This paper presents an inertia type of piezostack based active mount for unmanned aero vehicle (UAV) camera system. After identifying the stiffness and damping properties of the rubber element and piezostack a mechanical model of the active mount system is established. The governing equation of mount is them derived and expressed in a state space farm. Subsequently, a sliding mode controller which is robust to uncertain parameters is designed in order to reduce the vibration imposed according to the military specification associated with UAV camera mount system operation. Control performances such as acceleration and transmitted force are evaluated through both computer simulation and experimental implementation.

• 한국소음진동공학회논문집
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• 제18권12호
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• pp.1278-1285
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• 2008

This paper presents an inertia type of piezostack based active mount fur unmanned aero vehicle (UAV) camera system. After identifying the stiffness and damping properties of the rubber element and piezostack a mechanical model of the active mount system is established. The governing equation of mount is then derived and expressed in a state space form. Subsequently, a sliding mode controller which is robust to uncertain parameters is designed in order to reduce the vibration imposed according to the military specification associated with UAV camera mount system operation. Control performances such as acceleration and transmitted force are evaluated through both computer simulation and experimental implementation.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권1호
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• pp.62-80
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• 2013

This paper has been focused on developing a new hybrid mount for shipboard equipment used in naval surface ships and submarines. While the hybrid mount studied in our previous research was 100 kg-class series-type mount, the new hybrid mount has been designed as an inertia-type mount capable of supporting a static of 500 kg. The proposed mount consists of a commercial rubber resilient mount, a piezostack actuator and an inertial mass. The piezostack actuator connected with the inertial mass generates actively the control force. The performances of the proposed mount with a newly designed specific controller have been evaluated in accordance with US military specifications and compared with the passive mount. An isolation system consisting of four proposed mounts and auxiliary devices has been also tested. Through a series of experimental tests, it has been confirmed that the proposed mount provides better performance than the US Navy's standard passive mounts.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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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.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.564-568
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• 2006

Smooth picture module is operated by vibration to tilt the light from the DMD (digital micro mirror device) of DLP projection TV, which makes the screen of the TV smoother and DMD chip cost lower. To satisfy the vibration characteristics of smooth picture module, it is designed by optimizing moment of inertia, spring constant and damping coefficient, using structural and fluid dynamic simulation that showed a good agreement with experimental data. To reduce the material cost and moment of inertia, engineering plastic is used and the reliability is estimated. A VCM (voice coil motor) type actuator for smooth picture has to satisfy performance requirements such as higher driving force, lower power consumption, and lower cost. The initial design and optimization for VCM was performed using FE analysis. It allowed us to optimize the design of magnetic circuit of the proposed actuator to obtain higher force while maintaining a lower cost.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.283-286
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• 2004

This work presents a 3-axis active mount featuring the piezoelectric stack actuators. The inertia configuration for the piezoelectric actuators is adopted to achieve appropriate force and moment in each axis. In addition, the rubber mount is integrated to provide stiffness for system loading. In order to analyze the active mount, the governing equation for the force and moment is derived and its validity is demonstrated by comparing generated force and moment of each actuator between analysis and experiment. In addition, the natural frequency of each actuator is identified though both simulation and experiment.

• 드라이브 ㆍ 컨트롤
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• 제13권3호
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• pp.32-38
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• 2016

For this paper, the position-control performances of dual EHA(electro-hydrostatic actuator) systems were investigated according to two cases wherein the double-rod- and single-rod-type hydraulic cylinders were combined. Since the control performance is significantly dependent on the load conditions including external forces such as the inertia load, it is proposed here that the two sub-EHAs are driven by separate position and force controllers, instead of two identical position controllers. According to the simulation results, the best performance was achieved by the position-controlled single-rod-type EHA that was combined with a force-controlled double-rod-type EHA. As the force-controlled double-rod-type EHA compensated for the external loads on the position-controlled single-rod-type EHA, the position-control performance was not influenced by external forces including the inertia load. In addition, the position-controlled single-rod-type EHA contributed to the enhancement of the damping ratio by absorbing the pressure peaks through its internal accumulator. Due to the symmetrical piston areas, the double-rod-type EHA is more suitable for force control than the single-rod- type EHA.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.587-592
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• 2009

This paper is concerned with the development of linear magnetic actuator for active vibration control. The newly developed linear magnetic actuator consists of permanent magnets and copper coils. On the contrary to the voice-coil type actuator, the linear magnetic actuator utilizes magnetic flux to generate the shaft movement. In this study, experiments on the prototype linear magnetic actuator were carried out to investigate its dynamic characteristics. Block and inertia forces generated by the actuator were measured. The experimental results show that the actuator can be used as both actuator and active tuned-mass damper. The linear magnetic actuator was attached to a cantilever as the active-tuned mass damper and active vibration control experiment was carried out. The experimental results show that the newly developed linear magnetic actuator can be effectively used for the active vibration control of structures.