• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1212-1220
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• 2004

The structural unbalance mass and laundry are the important sources of the severe vibrations of automatic washing machines. In this paper, a mathematical model is developed for the dynamic analysis of the vertical axis automatic washing machines of pulsator-type. In the model, the rigid body motion of tub assembly is represented by six degrees of freedom and the dynamics of automatic hydraulic balancer is represented by one degree of freedom. The fundamental elastic modes of the tub shell and four suspension bars are also taken into account in the mathematical model, based on analytical and experimental modal analysis results. The 12 degrees of freedom equations of motion are derived by using the Lagrange's equations and the present dynamic model is evaluated by comparing the numerical simulation results with experimentally measured data.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.2 s.95
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• pp.169-175
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• 2005

In this paper, a novel vibration control scheme for a single-link flexible manipulator system without using a vibration feedback sensor is proposed. In order to achieve the vibration information of the flexible link, a reaction moment estimator based on the dynamic characteristics of the flexible manipulator is proposed. While the manipulator is maneuvering the reaction moment is reciprocally acting on the flexible link and the hub inertia due to the vibration of the link. A sliding mode controller based on the equivalent rigid body dynamics corresponding to the proposed flexible manipulator is then augmented with the reaction moment estimator to realize a decentralized control system. The reaction moment estimator is implemented via the first order low pass filter. The performance of the proposed control scheme is verified by computer simulation and experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.772-777
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• 2013

This article presents the reduction of vibration generated by an automobile fuel pump. In order to analysis the vibration of the fuel pump, a simplified dynamic model is established, which is composed of a rigid rotor and a equivalent springs. The equivalent stiffnesses of the upper and lower assemblies are evaluated by the comparison of modal testing results and the finite element analysis. the stiffness for the oil film of the journal bearing is extracted by using Reynold's equation. In addition, the time responses for the vibration of the fuel pump are computed by using a commercial multi-body dynamics software, RecurDyn. Based on these results, some design suggestions are proposed to reduce the vibration of an automobile fuel pump.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.643-647
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• 1996

The dynamic behavior of hydrostatic table is represented as the theoretical model, 1-dof, 2-dof rigid body spring-damper system, and finite element model. By the experimental and theoretical methods, the validity of these models and some other dynamic behaviors, such as the effects of unbalanced load and three dimensional motion, are investigated. To make easier to consider the dynamic behavior of hydrostatic table in design process, the stiffness and damping coefficients are calculated using the simple approximation method delived from the mass flow continuity condition, and compared with experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.341-345
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• 1996

This paper presents the dynamics and the teal-time control of a horizontally rotating inverted pendulum. The dynamic equations representing three degrees of freedom rigid body motion of the pendulum are derived, and the state feedback controller is applied to the motion control of the pendulum. A 32 bit counter board with 16 bit hardware communication ability is developed to improve the real-time control performance and is applied to a horizontally rotating inverted pendulum. The simulation and experimental studies are conducted to evaluate the performance of the developed pendulum system and the timing in the real-time control is analyzed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.9 s.102
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• pp.1030-1036
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• 2005

This paper is concerned with the application of perturbation method to the dynamic analysis of space structure floating in space. In dealing with the dynamics of space structure, the use of Lagrange's equations of motion in terms of quasi-coordinates were suggested to derive hybrid equations of motion for rigid-body translations and elastic vibrations. The perturbation method is then applied to the hybrid equations of motion along with discretization by means of admissible functions. This process is very tiresome. Recently, a new approach that applies the perturbation method to the Lagrange's equations directly was proposed and applied to the two-dimensional floating structure. In this paper. we propose the application of the perturbation method to the Lagrange's equations of motion in terms of quasi-coordinates. Theoretical derivations show the efficacy of the proposed method.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.428-435
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• 2001

In this paper, the design factors of stacker crane for the automatic warehouse are verified by dynamic simulation process. Simulation model is designed as the form of rigid elements and discrete flexible beam connections. The various result for structural design of stacker crane is produced by dynamic simulation and experiment. For the simulation of structural dynamics, ADAMS which is a software for kinematic & dynamic simulation, is used. In order to verify the analysis method, simulation and experiment result are compared.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.881-886
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• 2004

This paper presents the inverse dynamic analysis of the wheel loader manipulator based on the experimental data. A three dimensional rigid multi-body model of the wheel loader manipulator was built up. The inverse dynamic analysis for the typical operation mode was carried out by the ADAMS program. In order to verify the analysis result with the measured one, the hydraulic pressure and displacements of the cylinders were measured and the inverse dynamic analysis was carried out using experimental data. From the results of the analysis and measurement, it was concluded that the computational driving force showed good agreement with the measured one.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.445-450
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• 1998

In this paper, a robust nonlinear prediction-type controller (RNPC) is developed for the continuous time nonlinear system whose control objective is composed of system output and its desired value. The basic control law of RNPC is derived such that the future response of the system is first predicted by appropriate functional expansions and the control law minimizing the difference between the predicted and desired responses is then calculated. RNPC which involves two controls, i.e., the auxiliary and robust controls into the basic control, shows the stable closed loop dynamics of nonlinear system of any relative degree and provides the robustness to the nonlinear system with parameter/modeling uncertainty. Simulation tests for the position control of a two-link rigid body manipulator confirm the performance improvement and the robustness of RNPC.

• Journal of KSNVE
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• v.10 no.1
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• pp.153-159
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• 2000

This paper presents a new method for including the dynamic stiffness of the stationary parts in rotordynamic analysis. As a consequence of the support dynamics, critical speeds are varied and/or additional critical speeds are introduced. Therefore, dynamic effects of the support are often significant in high speed turbomachinery, but most of analysis has considered the support as a rigid body or a simple structure. The proposed method is based on the coupled characteristics of the driving point and transfer frequency response functions of the support system to model the equivalent spring-mass series in finite element analysis. To demonstrate the applicability of the simulation procedures provided, it is applied to the rotor model of the double suction centrifugal pump. Results of the suggested equivalent-support rotor model including coupled effects agree well with the entire pump model.