• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.309.1-309
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• 2002

This paper is concerned with the dynamic modeling of a rectangular plate with piezoelectric actuators and sensors. The experimental frequency response plots can be used to verify the theoretical modeling. The active vibration control was achived by using positive position feedback controller. Theoretical analysis will follow.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.10a
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• pp.117-124
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• 1993

본 연구에서는 공기스프링을 능동요소로 사용한 방진대를 1자유도 및 2자유도로 모델링하여 이론해석을 수행하였고, 이에 따른 컴퓨터시뮬레이션과 실험을 통하여 이론의 타당성을 검증하였다. 다음으로 공기스프링 방진대의 방진성능 향상을 위하여 비례제어밸브, 컴퓨터, 측정센서 등을 이용하여 공기 스프링내의 공기압력을 능동적으로 조절할 수 있는 제어계를 구성한 후, 최적제어 및 퍼지제어 알고리즘을 적용하여 상태귀환 제어를 실시하였다.

• Smart Structures and Systems
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• v.17 no.5
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• pp.773-793
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• 2016

This work presents a methodology to distribute piezoelectric material for structural vibration active control. The objective is to design controlled structures with actuators which maximizes the system controllability. A topology optimization was formulated in order to distribute two material phases in the domain: a passive linear elastic material and an active linear piezoelectric material. The objective is the maximization of the smallest eigenvalue of the system controllability Gramian. Analytical sensitivities for the finite element model are derived for the objective functions and constraints. Results and comparisons with previous works are presented for the vibration control of a two-dimensional short beam.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.171-177
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• 1995

환경 보호와 연비 향상을 목표로 한 고출력 엔진과 초경량 차체의 차량을 설계하려는 최근의 차량 개발 추세는 진동과 소음의 문제를 더욱 악화시키느 요인이 되었다. 이에 반해 차량을 구입하는 고객은 보다 정숙한 주행 성능을 요구하고 있다. 이런 상황에서 커다란 설계의 변경이나 차체의 중량 증가없이도 ㅈ거용가능한 능동 제어 기술(Active Control Technique)은 차량의 진동, 소음문제에서 훌륭한 해결책의 하나로 등장하였다. 최근까지 능동 소음제어와 관련한 연구는 여러 분야에서 수행되었으며, 실제로 시작차량뿐만 아니라 양산차에 적용된 사례가 있다. P.A.Nelson등은 음향 공동내의 음향 에너지를 최소화시키는 소음 제어에 관한 이론, 컴퓨터 시뮬레이션 및 실험에 대하여 발표하였다. 또한 최근의 디지탈 신호 처리기(DSP, Digital Signal Processor)의 개발에 힘입어 해석의 검즈외에도 실제 차량에 적용한 사례도 있다. 로터스(LOTUS,영)는 다양한 시작차를 제작하여 그 효과를 검증하였으며, 닛산(Nissan, 일)은 양산차에 적용하여 판매하고 있는 실정이다. 본 논문에서는 능동 소음 제어 장치를 개발하여 승용차에 적용한 결과를 보이도록 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.672-672
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• 2011

This study describes the comparison of noise suppression performances at different locations of two error microphones in active noise control (ANC) for outdoor applications. For this study, 12 different locations were predefined to decide best locations for error sensors in terms of suppressing noise. As shown in Fig. 1, the ANC system with one primary loudspeaker, two secondary loudspeakers and two error microphones is operated by a filtered-x LMS (FXLMS) algorithm which is implemented in a TI 6713 DSP board and Realsys 4713 AD/DA Extension board. The noise for the primary source is a typical road noise measured at a highway roadside. The lengths of adaptive filters of W1 and W2 are varied from 32 to 128 respectively. An intensive computer simulation was accomplished before outdoor ANC experiments. It is expected from the simulation results that the ANC performances are very much dependent upon the locations of the two error microphones.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.397-401
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• 1994

This paper proposes an identification method for a thin plate where multiple actuators and sensors are bonded. Since a thin plate has small damping ratios of all modes, each mode can be identified seperately with a bandpass filter for each modal signal. With the bandpass filter and the characteristics of the plate, the Multi-Input Multi-Output (MIMO) model of the plate can be converted to several Multi-Input Single-Output(MISO) models of second order linear difference equations of the modes. Parameters for each mode are obtained by using the Least Square method. Form there MISO models, the MIMO model is obtained in the form of the state space. Experiments were performed for an all-clamped plate with two pairs of piezoelectric actuators and sensors. The outputs of the identified model and the experimental data match well.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.8
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• pp.525-531
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• 2015

Driving sound is an effective element to promote the product identity of a vehicle by providing customers with attractive sound which reflects the concept of a vehicle. Recently, major automakers are focusing on the target sound setting so that the sound can represent the brand image as well as the unique concept of a vehicle. In this study, a new method of target setting for the driving sound will be introduced based on using formant filter and musical harmonics characteristics. In addition, a target sound suggested from this method will be realized and verified by using active noise control in vehicle.

• Smart Structures and Systems
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• v.12 no.6
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• pp.595-617
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• 2013

Semi-active control equipments are used to effectually enhance the seismic behavior of structures. Magneto-rheological (MR) dampers are semi-active devices that can be utilized to control the response of structures during seismic loads and have received voracious attention for response suppression. They supply the adaptability of active devices and stability and reliability of passive devices. This paper presents an optimal fuzzy logic control scheme for vibration mitigation of buildings using magneto-rheological dampers subjected to near-fault ground motions. Near-fault features including a directivity pulse in the fault-normal direction and a fling step in the fault-parallel direction are considered in the requisite ground motion records. The membership functions and fuzzy rules of fuzzy controller were optimized by genetic algorithm (GA). Numerical study is performed to analyze the influences of near-fault ground motions on a building that is equipped with MR dampers. Considering the uncontrolled system response as the base line, the proposed method is scrutinized by analogy with that of a conventional maximum dissipation energy (MED) controller to accentuate the effectiveness of the fuzzy logic algorithm. Results reveal that the fuzzy logic controllers can efficiently improve the structural responses and MR dampers are quite promising for reducing seismic responses during near-fault earthquakes.

• Journal of KSNVE
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• v.6 no.6
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• pp.851-856
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• 1996

The active noise cancellation system showing the effective convergence and stability has been studied by simplifying the controller structures using the weighting factors of control error path to the multi-channel filtered-x LMS algorithm which needs a lot of calculations and the performance has been verified experimentally. Besides, to implement the system performance in a vehicle cabin, experimental work for selecting the suitable numbers and positions of the microphones and speakers was accomplished. Effectively combining a TMS 320C 31 main processor conducting real number calculations and having various functions with other components, the purpose-built system board for active noise cancellation has been designed and with this board, car active noise cancellation system showing maximum stable 10dB noise reduction has been obtained at the car idling conditions above 3000rpm range.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.1
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• pp.17-22
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• 2002

Endoscopes for industrial and medical fields are expected to have multi degree-of-freedom (DOF) motions. A multi-DOF ultrasonic motor we developed consists of a spherical rotor and a bar-shaped stator, and the rotor rotates around three perpendicular axes using three natural vibration modes of the stator. In this study, a multi-DOF unilateral master-slave system for active endoscope using the multi-DOF ultrasonic motor is developed. The configurations of master and slave arms for active endoscope are similar, so that an operator can easily handle the master-slave system. First, driving characteristics of the multi-DOF ultrasonic motor are measured in order to design the slave arm and its controller. Next, the master arm and the slave arm are designed. Then, the unilateral feedback controller for the master-slave system is developed. Finally, the motion control tests of rotor are conducted. As a result, the possibility of the endoscope is confirmed.