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HDD용 구동 및 현가 장치의 축소 진동 모델의 생성 및 해석
한정삼(Jeong Sam Han) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월
In the case of mechanical control systems, it is highly useful to be able to provide a compact model of the mechanical system to control engineers using the smallest number of variables, while still providing an accurate model. The reduced mechanical model can then be inserted into the complete mechanical control system models and used for system-level dynamic simulation. In this paper, a moment-matching based model order reduction (MOR) which reduces the number of degrees of freedom of an original finite element model via the Arnoldi process is considered to study the dynamic responses of a HDD actuator and suspension system.
Krylov 부공간을 이용한 압전구조체의 모델차수축소법
한정삼(Jeong Sam Han) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
A piezoelectric device is widely used for actuation and sensing in many applications and its design often requires calculation of a frequency response which is computationally very expensive when an interesting frequency is up to a high range or when a wide range of actuating frequency should be considered. To alleviate the problem of high computation cost, this paper presents the Krylov subspace-based model order reduction (MOR) for frequency responses of a piezoelectric structure. The frequency response analysis can be performed efficiently from reduced low dimensional numerical models generated by the model order reduction which reduces the number of degrees of freedom of an original ANSYS finite element models via the Arnoldi process. A piezoelectric bimorph actuator and micro gyroscope were studied to demonstrate the feasibility of the suggested simulation method for the piezoelectric harmonic analysis.
한정삼(Jeong Sam Han) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5
In this paper a frequency response analysis using Krylov subspace-based model reduction and its design sensitivity analysis with respect to design variables are presented. Since the frequency response and its design sensitivity information are necessary for a gradient-based optimization, the problem of high computational cost may occur in the case that frequency response of a large sized finite element model is involved in the optimization iteration. In the suggested method reduced order models are used to calculate both frequency response and frequency response sensitivity, therefore one can maximize the speed of numerical computation for the frequency response and its design sensitivity. As an example, an array-type 2×2 MEMS resonator is adopted to show the accuracy and efficiency of the suggested approach. The frequency response sensitivity through the model reduction shows a good agreement with that from the initial full finite element model.
한정삼(Jeong Sam Han),에브게니 루디니(Evgenii B. Rudnyi),얀 코빙크(Jan G. Korvink) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.4
Currently most practical vibrational and structural problems in automotive suspensions require the use of the finite element method to obtain their structural responses. When the finite element model has a very large number of degrees of freedom, the harmonic and dynamic analyses are computationally too expensive to repeat within a feasible design process time. To alleviate the computational difficulty, this paper presents a moment-matching based model order reduction (MOR) which reduces the number of degrees of freedom of the original finite element model and speeds up the necessary simulations with the reduced-size models. The moment-matching model reduction via the Arnoldi process is performed directly to ANSYS finite element models by software mor4ansys. Among automotive suspension components, a knuckle is taken as an example to demonstrate the advantages of this approach for vibrational simulation.
전자기 로렌츠력을 이용한 다중안정성 마이크로 액추에이터의 비선형 구조 및 전기-열 해석
한정삼(Jeong Sam Han) 대한기계학회 2010 大韓機械學會論文集A Vol.34 No.8
본 논문에서는 작동 평면상의 네 위치에서 사중안정점을 가지는 신개념 전자기형 마이크로 액추에이터의 구조체와 전자기 로렌츠력을 이용하는 구동 방식을 제시하고, 이의 타당성을 비선형 구조해석 및 전기-열해석을 통하여 검증하였다. 사중안정성 액추에이터의 구현을 위해서 관련 분야에서 널리 연구되고 있는 쌍안정성 액추에이터의 개념을 확장 응용하였다. 비선형 유한요소해석을 이용하여 사중안정성 미소 구조체의 정적 해석과 과도동적 해석을 수행함으로써 액추에이터 구조체의 다중안정성 유무를 파악하고 이 결과를 분석하여 구조체 설계에 반영하였다. 사중안정성 미소 구조체를 도체화하여 자기장 내에서 구조체에 전류를 통할 때에 발생하는 로렌츠력으로 평면상의 네 안정점으로 구조체를 구동할 수 있도록 고안하고, 그 때 필요한 구동전류의 크기 및 전자기 구동에 의한 주울열에 의한 온도분포를 계산하여 전반적인 타당성을 검토하였다. 본 논문은 지금까지의 관심 대상인 쌍안정성의 이용이 아니라 더욱 확장된 다중안정성을 가진 미소 액추에이터의 구조체와 전자기 구동방법을 제안하여 향후에 다중안정성을 필요로 하는 마이크로 시스템에 활용될 수 있도록 하는데 그 의미가 있다. In this paper, the design and nonlinear simulation of a multistable electromagnetic microactuator, which provides four stable equilibrium positions within its operating range, have been discussed. Quadstable actuator motion has been made possible by using both X- and Y-directional bistable structures with snapping curved beams. Two pairs of the curved beams are attached to an inner frame in both X- and Y-directions to realize independent bistable behavior in each direction. For the actuation of the actuator at the micrometer scale, an electromagnetic actuation method in which Lorentz force is taken into consideration was used. By using this method, micrometer-stroke quadstability in a plane parallel to a substrate was possible. The feasibility of designing an actuator that can realize quadstable motion by using the electromagnetic actuation method has been thoroughly clarified by performing nonlinear static and dynamic analyses and electrothermal coupled-field analysis of the multistable microactuator.