• 조명전기설비학회논문지
• /
• 제28권3호
• /
• pp.63-71
• /
• 2014

A single-inverted-pendulum model is presented to simulate and predict the passive response of human balance control. This simplified biomechanical model was comprised of a torsional spring and damper, and a lump mass. An estimation of frequency response function was conducted to parameterize the complexity. The frequency domain identification method is used to identify the parameters of the model. The equivalent viscoelastic parameters of standing body were obtained and there was good conformity between the simulation and experimental result.

• Nuclear Engineering and Technology
• /
• 제38권6호
• /
• pp.551-560
• /
• 2006

In this study, a controller for a nuclear reactor power is designed. The reactor is modeled using the three dimensional reactor design code MASTER. From the relationship of the input and output of the reactor code, a reactor dynamic model is derived by the system identification method. This model is more realistic than the one based on mathematical theories. With this model, a robust controller is designed by the extended frequency response method. As this method has the same theoretical background as the classical method, all of the existing design techniques of the classical method can be used directly. Furthermore, by introducing the real part of a Laplacian operator into the frequency response, the control design specification can be considered at the initial stage of design. The designed controller is simple, and gives a sufficient robustness with good performance.

• 한국추진공학회지
• /
• 제24권2호
• /
• pp.83-93
• /
• 2020

압력전달시스템의 주파수응답특성의 효과 때문에 동압센서를 하드웨어에 flush 마운트 형태로 설치해야 한다. 그러나 측정을 위한 포트 주변의 협소한 조건 혹은 고온의 연소가스로부터 센서가 손상되는 것을 막기 위해 벽면 안쪽에 recess 마운트 방식을 설계하기도 한다. 압력전달시스템에서 동압 신호의 왜곡이 발생하기 때문에 동적 응답 특성을 반드시 고려해야 한다. 본 연구에서는 섭동 모델과 2차 축소 모델을 실험치와 비교하였고 주파수응답모델을 선택하기 위한 가이드라인을 제시하였다.

• 대한기계학회논문집A
• /
• 제31권5호
• /
• pp.541-549
• /
• 2007

In the case of control for mechanical 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 state variables, while still providing an accurate model. The reduced mechanical model can then be inserted into the complete system models and used for extended system-level dynamic simulation. In this paper, moment-matching based model order reductions (MOR) using Krylov subspaces, which reduce the number of degrees of freedom of an original finite element model via the Arnoldi process, are presented to study the eigenvalue and frequency response problems of a HDD actuator and suspension system.

• 한국자동차공학회논문집
• /
• 제15권6호
• /
• pp.177-182
• /
• 2007

In this paper, automotive hydraulic pipeline systems are modeled in which a straight blocked pipe, two pipes with sudden expansion or contraction are connected in series and terminated with a chamber. The frequency response characteristics of these composite pipeline systems are investigated experimentally. The theoretical analysis for various pipe configurations is base on transfer matrix method with frequency dependent viscous friction distributed parameter pipeline model. The gain and phase of transfer functions are included for comparison with experimental results. There is close agreement between the results of experimental and theoretical determination of pressure response in automotive hydraulic pipeline systems.

• 대한기계학회논문집
• /
• 제19권1호
• /
• pp.45-60
• /
• 1995

It is attempted to estimate excitation force of a linear vibratory system using measured vibration responses. The excitation force is estimated from the relationship between the vibration response and system characteristic matrices which are extracted from both the mathematical model of the system and actual response in contrast to the usual approach of inverting the frequency response matrices. This extraction scheme is based on the fact that the vibration response can be expressed in term of linear combination of frequency domain modal vectors defined as mutually orthonormal basis vectors in frequency domain. The extracted frequency domain basis vectors are very stable in computational manipulation. It is found that the estimated excitation force is in good agreement with actually measured force except at the natural frequencies the structure, which is the common feature still to be overcome by the research efforts in this area. From the results of this paper, this disagreement is considered to come from the discrepancy between the model and actual value of the mass, damping and stiffness of the structure.

• 대한기계학회논문집A
• /
• 제26권5호
• /
• pp.872-880
• /
• 2002

The finite element analysis is frequently used to predict dynamic responses of complex structures. Since the predicted responses often differ from experimentally measured ones, updating of the finite element models is performed to make the finite element results agree with the measured ones. Among several model updating methods, one is to use FRF(frequency response function) data without a modal analysis. This paper investigates characteristics of the model updating method in order to improve the method. The investigation is focused on how to obtain FRFs for unmeasured rotational displacements and how to consider damping. For the investigation simulated data and experimental data for a cantilever beam are used.

• 소음진동
• /
• 제7권6호
• /
• pp.1049-1058
• /
• 1997

To verify the Finite Element Method(FEM) model of an Exhaust System, Frequency Response Function(FRF) is utilized. Up to now, generally, comparisons of natural frequencies and mode shapes of the Exhaust System between numerical analysis and experimental results are adopted to prove completion of the FEM model. However, the comparisons of natural frequencies and mode shapes are not sufficient to have the perfect FEM model of the Exhaust system. Instead of these comparisons. FRF method is introduced for the more accurate FEM model.

• 제어로봇시스템학회논문지
• /
• 제4권4호
• /
• pp.413-419
• /
• 1998

A novel order-reduction technique for model predictive control(MPC) is proposed based on the singular value decomposition(SVD) of a pulse response circulant matrix(PRCM) of a concerned system. It is first investigated that the PRCM (in the limit) contains a complete information of the frequency response of a system and its SVD decomposes the information into the respective principal directions at each frequency. This enables us to isolate the significant modes of the system and to devise the proposed order-reduction technique. Though the primary purpose of the proposed technique is to diminish the required computation in MPC, the clear frequency decomposition of the SVD of the PRCM also enables us to improve the robustness through selective excitation of frequency modes. Performance of the proposed technique is illustrated through two numerical examples.

• 센서학회지
• /
• 제21권3호
• /
• pp.235-239
• /
• 2012

This paper presents frequency response compensation technique, and a self-oscillation circuit for capacitive microresonator with the compensation technique using programmable capacitor array, to compensate for the frequency response distorted by parasitic capacitances, and to obtain stable oscillation condition. The parasitic capacitances between the actuation input port and capacitive output port distort the frequency response of the microresonator. The distorted non-ideal frequency response can be compensated using two programmable capacitor arrays, which are connected between anti-phased actuation input port and capacitive output port. The simulation model includes the whole microresonator system, which consists of mechanical structure, transimpedance amplifier with automatic gain control, actuation driver and compensation circuit. The compensation operation and oscillation output of the system is verified with the simulation results.