• Journal of Magnetics
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• v.14 no.4
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• pp.175-180
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• 2009

This paper describes the design and analysis of a tubular linear actuator for intelligent AAP (Active Accelerate Pedal) system. In a driving emergency, the electromagnetic actuator produces an additional pedal force such as the active pedal force and vibration force to release the driver's foot on accelerator pedal. A prior study found that the linear actuator with a ferromagnetic core had a problem in transferring the additional force naturally to a driver due to the cogging force. To reduce the cogging force and obtain higher performance of the AAP system, a coreless tubular linear actuator is suggested. Electromagnetic finite element analysis is executed to analyze and design the coreless tubular actuator, and dynamic analysis is performed to characterize the dynamic performance of the AAP system with the suggested tubular actuator for two types of thrust force.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1462-1464
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• 2005

The demand for linear electrical machines, for both controlled motion and electrical power generation, has increased steadily in recent years. For example, for applications in the high-speed packaging and manufacturing sectors, linear electromagnetic machines, which provide thrust force directly to a payload without the need to convert rotary to linear motion, offer significant advantages in terms of simplicity, efficiency, positioning accuracy, and dynamic performance in both acceleration capability and bandwidth. So, this paper describes analysis the dynamic characteristics of Tubular Type Linear BLDC Motor by simulation and experiments.

• Journal of the Korean Society for Railway
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• v.5 no.1
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• pp.40-47
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• 2002

In this study, and analytical method for ride sensitivity analysis of a train with non-linear suspension elements are proposed. Non-linear characteristics of springs and dampers for primary and secondary suspensions of a train are parameterized using polynomial interpolation. Vertical dynamic model of a three-body train running on straight rail with the predetermined roughness expressed in terms of spectral density function is set up and its equations of motion for ride analysis are derived. Using the direct differentiation method, sensitivity equations of the vertical dynamic model with respect to design parameters associated with non-linearity of suspensions are obtained. Based on the sensitivity analysis, improvement of ride is achieved by varying appropriate suspension parameters.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.1
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• pp.61-70
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• 2020

In this study, system modeling and dynamic analysis of crane are conducted. Especially, among many different kinds of a crane system, the issues on crane operating problems installed on the vessel are considered. As well known, marine systems including cranes are exposed to various disturbances such as vessel motions, hydrodynamic forces, wave and wind attack, etc. In order to analysis the system dynamic with environmental conditions, the authors derived the nonlinear dynamic model of offshore crane and derived a linear model which is used for designing the control system. Using the obtained nonlinear and linear models, simulations were conducted to evaluate the usefulness of the obtained models. By simulation and result evaluation, the usefulness of the linear model, which presents the dynamics, is effectively verified.

• Coupled systems mechanics
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• v.1 no.1
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• pp.39-57
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• 2012

This study intends to explore dynamic interaction behaviors between actively controlled maglev vehicle and guideway girders by considering the nonlinear forms of electromagnetic force and current exactly. For this, governing equations for the maglev vehicle with ten degrees of freedom are derived by considering the nonlinear equation of electromagnetic force, surface irregularity, and the deflection of the guideway girder. Next, equations of motion of the guideway girder, based on the mode superposition method, are obtained by applying the UTM-01 control algorithm for electromagnetic suspension to make the maglev vehicle system stable. Finally, the numerical studies under various conditions are carried out to investigate the dynamic characteristics of the maglev system based on consideration of the linear and nonlinear electromagnetic forces. From numerical simulation, it is observed that the dynamic responses between nonlinear and linear analysis make little difference in the stable region. But unstable responses in nonlinear analysis under poor conditions can sometimes be obtained because the nominal air-gap is too small to control the maglev vehicle stably. However, it is demonstrated that this unstable phenomenon can be removed by making the nominal air-gap related to electromagnetic force larger. Consequently it is judged that the nonlinear analysis method considering the nonlinear equations of electromagnetic force and current can provide more realistic solutions than the linear analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5323-5329
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• 2013

Many companies have tried to develop the horizontally vibrating linear motor, for sliming the smart phone. Mathematical modeling and analysis is one of method to simulate the dynamic performance of the horizonatally vibrating linear motor. However, the horizontally vibrating linear motor vibrates in twisting mode because there are two kinds of force acting on the vibrating part. One is are the horizontal force by Lorentz force. The other is the vertical force by attraction force between magnet of vibrating part and bracket and the gravity force of vibrating part. However, those are very difficult to be included in mathematical modeling which generate the simulation errors. In this paper, we perform MFBD (multi flexible body dynamics) simulation using commercial dynamic analysis program "DAFUL". In our new model, the force effects those are neglected in mathematical model, are included. For the verification, the simulation results are compared with the experiment results with manufactured prototype.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.5
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• pp.1-11
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• 2001

The purpose of this study is to develop the main program and pre/post processor for the geometric and plastic non-linear analysis of steel jacket structures subjected to wave and earthquake loadings. In this paper, steel jackets are modelled using geometric non-linear space frames and wave loadings re evaluated based on Morrison equation using the linear Airy theory and the fifth Stokes theory. Random wave is generated using JONSWAP spectrum. For earthquake analysis, dynamic analysis is performed using artificial earthquake time history. Also the plastic hinge method is presented for limit analysis of steel jacket. In the companion paper, the pre/post processor is developed and the numerical examples are presented for linear and non-linear dynamic analysis of steel jackets.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.9 s.90
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• pp.868-876
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• 2004

The linear motion(LM) guide using ball bearing has many advantages compared with conventional sliding guides. Therefore, LM guide using ball bearing has been widely used to increase the accuracy of the position of a system. This research investigates dynamic characteristics of LM guide through mainly linear analyses. Linear analysis is accomplished by Lagrange equation and the finite element method. And another trial that performs nonlinear analysis about one mode(bouncing mode) of LM guide from Hertzian contact theory is accomplished in the latter half of this research. Through nonlinear analysis we could observe the softening characteristic due to the Hertzian contact nonlinearity.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.11
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• pp.1069-1076
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• 2007

The purpose of this study is to improve the performance of a linear feeder that can transport grains uniformly. In order to analyze the dynamic behaviors of a linear feeder, the displacements of the feeder are measured by several accelerometers when it is in an operating condition. After the signal data from the accelerometers are captured in the time domain, the feeder motion in the space is visualized by using graphic computer software. In addition, a dynamic model of the feeder is established for a multi-body dynamics simulation. For the dynamic simulation, RecurDyn, which is a commercial multi-body dynamic package, is used. From the experimental and the computational approaches, an optimal dynamic motion is obtained for uniform transportation of grains. Furthermore, we also consider the determination of design parameters for optimal dynamic motion such as centroid, stiffness, and damping coefficient of the feeder system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.498-503
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• 2003

Dynamic analysis of a plate with non-linearity due to large deformation is performed in the study. There have been many researches about the non-linear dynamic behavior of plates examining by means of theoretical or numerical analyses. But it is important how exactly model the actual system. In this respect, the Continuous-Time system identification technique is used to generate non-linear models, for stiffness and damping terms, to explain the observed behaviors with single mode assumptions for the simplicity after comparing the experimental results with the numerical results of a linear plate model.