• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.107-114
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• 2004

This paper presents a two-time scale approach for vibration reduction of a high speed Cartesian manipulator. High speed manipulators would be subject to mechanical vibration due to high inertia forces acting on linkages. To achieve high throughput capability, such motion induced vibration would have to be damped quickly, to reduce settling time of the manipulator end-effector. This paper develops a two-time scale model fer a structurally-flexible Cartesian manipulator. Based on the two-time scale model, a composite controller consisting of a computed torque method for the slow time-scale rigid body subsystem, and a linear quadratic state-feedback regulator for the fast time-scale flexible subsystem, is designed. Simulation results show that the proposed two time-scale controller yields good performance in attenuating structural vibration arising due to excitation from inertial forces.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.7
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• pp.557-564
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• 2002

To reduce unwanted vibrations in war ship which may be transmitted through underwater path, it is required to use high damping mounts to isolate the vibration. In this work, the beam structure with squeeze mode ER mount is proposed and response characteristics such as acceleration and force transmissibility of beam with constant voltage and optimal controller are experimentally analyzed. The controller is empirically realized and control responses are evaluates in frequency domains. Experiments show vibration reduction capability of squeeze mode ER mount.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.659-662
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• 2009

Railway has been pointed to the efficiency of transportation, rapid transit, and comfortable train ride. the construction of railway near the downtown area and station building are increasing for maximization of utilization and convenience. but the heavy of transportation and rapid transit lead to increase noise and vibration. the noise and vibration of railway may cause the civil appeal, decline in the serviceability and insufficiency of environmental standard. In this study, floating slab system which is one of the solution to avoid noise and vibration in railway has been introduced, and analyzed floating Slab Track into arrangement of reduction material of vibration. As a result of analysis, It was estimated the bearing installation though slab have not a negative factor and terminal arrangement of reduction material of vibration have advantage for static behavior.

• Journal of KSNVE
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• v.3 no.4
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• pp.325-330
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• 1993

The longitudinal vibration of the tape in the tape transport system influences the performance of the nagnetic tape-recording system. Generally it is controlled by a passive method with impedance roller which is easy to implement and cost-effective. Therefore the effect of the impedance roller in reducing the tape vibration was analyzed in this paper. The practical tape transport system was modelled mathematically as a mass-spring system. Both simulation and experimental study were carried out in order to show the vibration reduction effect of the impedance roller.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.767-770
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• 2002

Reduction of the propagation noise generated during pass-by of KTX by noise barrier was measured and analysed for the two kinds of top-shaped noise reduction devices; one as a plywood board and the other as a PVC pipe were placed periodically. The height and length of reference noise barrier are 2.4 m and 50 m, respectively. The noise reduction with and without noise reduction devices was investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.692-692
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.889-890
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1051-1052
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• 2011

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1439-1443
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• 2007

In this paper, vibration reduction techniques of a voice coil motor (VCM) actuator are presented for AFM imaging system. The damping coefficient of the actuator driven by VCM with a flexure hinge is quite low and it cause the about 30dB peak amplitude response at the resonance frequency. To decrease this peak response, we design and apply elliptical band-stop filters to xy and z axis VCM actuator. Frequency response of each actuator with filter is measured to verify the effect of the filters. As a sensor, capacitive sensor is used. Vibration reduction rate of the xy actuator with the filter is also measured while real AFM scanning condition. As another method, closed loop control with the capacitive sensor is applied to the xy axis actuator to add an electrical damping effect and vibration reduction rate measured. These vibration reduction rates with each method are compared. In the case of z axis actuator, the frequency response of force (gap) control loop is measured. For comparison, the frequency response using a conventional PID controller is also obtained. Finally, the AFM image of a standard grid sample is measured with the designed controller to analyze the effect in the AFM imaging.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.463-470
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• 1999

In this paper, a numerical method for evaluating the efficiency of vibration reduction of substructure under slab track is developed for optimal design of floating slab track. The equation of motion for train and track interaction system is derived by applying compatibility condition at the contact points between wheels and rails. The train is modelled by 3-masses system and the track by continuous support beam system. Numerical analyses are carried out to investigate the effect of train speed, stiffness and damping of slab-pad, and track irregularity upon vibration reduction in substructure under the track.