• 소음진동
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• 제11권1호
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• pp.147-155
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• 2001

This paper is concerned with the real-time automatic tuning of the multi-input multi-output positive position feedback controllers for smart structures by the genetic algorithms. The genetic algorithms have proven its effectiveness in searching optimal design parameters without falling into local minimums thus rendering globally optimal solutions. The previous real-time algorithm that tunes a single control parameter is extended to tune more parameters of the MIMO PPF controller. We employ the MIMO PPF controller since it can enhance the damping value of a target mode without affecting other modes if tuned properly. Hence, the traditional positive position feedback controller can be used in adaptive fashion in real time. The final form of the MIMO PPF controller results in the centralized control, thus it involves many parameters. The bounds of the control Parameters are estimated from the theoretical model to guarantee the stability. As in the previous research, the digital MIMO PPF control law is downloaded to the DSP chip and a main program, which runs genetic algorithms in real time, updates the parameters of the controller in real time. The experimental frequency response results show that the MIMO PPF controller tuned by GA gives better performance than the theoretically designed PPF. The time response also shows that the GA tuned MIMO PPF controller can suppress vibrations very well.

• 한국항행학회논문지
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• 제16권6호
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• pp.1123-1133
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• 2012

논문에서는 극저속 영역 및 저속 영역에서 안정적이고 동특성이 우수한 벡터제어 시스템을 구성하여, 축소차원 상태관측기를 이용한 순시속도 관측기와 극 저속 제어, 회전자 속도를 추정하는 벡터제어 시스템에 관한 방법을 제안하였다. 본 시스템에서 제안된 관측기는 축소차원 상태관측기를 부하토크 추정에 적용하여 속도추정에 이용함으로서 시스템구성을 간단히 구현 하면서도 극 저속 영역에서 정확한 순시속도 추정이 가능하였다. 또한, 시스템 잡음에 의한 영향을 줄이고, 관측기의 극을 변화시키는 일 없이 부하외란 이나 모델화 오차, 측정 잡음 등에 강인한 유도전동기 속도제어 시스템을 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.986-988
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• 2001

This paper presents a digitally speed sensorless control system for induction motor with direct torque control (DTC). Some drawbacks of the classical DTC are the relatively large torque ripple in a low speed range and notable current pulsation during steady state. They are reflected speed response and increased acoustical noise. In this paper, the DTC quick response are preserved at transient state, while better qualify steady state performance is produced by space vector modulation (SVM). The system are closed loop stator flux and torque observer for wide speed range that inputs are currents and voltages sensing of motor terminal, model reference adaptive control (MRAC) with rotor flux linkages for the speed fuming signal at low speed range, two hysteresis controllers and optimal switching look-up table. Simulation results of the suggest system for the 2.2 [kW] general purposed induction motor are presented and discussed.

• 소음진동
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• 제9권1호
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• pp.121-130
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• 1999

Generally, A Dynamic Absorber by using Active viscous Damping is highlighted for effective suspension system, such as improved ride comfort and handling in the market. Lately, this system based on the Sky-Hook damper theory is introduced by the name of "Active Dynamic Absorber" to us. This system has an excellent performance in contrast to Passive. Adaptive Dynamic Absorber, besides having low cost components of system, low energy consumption. light weight of system. In this viewpoint. most of car-maker will adopt this system in the near future. For this reason, we developed Dynamic Absorber by using Active viscous Damping which is equipped with continuously variable Dynamic Absorber and Control logic consisting Filter and Estimator. control apparatus of Dynamic Absorber operated by 16-bit microprocessor of high performance. variable device of viscous Damping. G-sensor so on. In this paper. several important points of development procedure for realizing this system will be described with results in which is obtained from experiment by simulation and Full car test in Proving ground. respectively.pectively.

• 한국통신학회논문지
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• 제29권10A호
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• pp.1223-1229
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• 2004

본 논문에서 ETRI 0.5$\mu\textrm{m}$ MESFET 라이브러리 공정을 이용하여 동작 주파수 5GHz대 저전압구동 가변이득 저잡음 증폭기 MMIC를 설계 및 제작하였다. 이 저잡음 증폭기는 HIPERLAN/2의 Adaptive Antenna Arrays와 함께 사용할 수 있도록 이득조절이 가능하도록 설계하였다. 가변이득 저잡음 증폭기는 2단 캐스케이드 구조이며, 게이트전압에 따라 채널저항이 제어되는 증가형 MESFET과 저항으로 구성된 부귀환 회로를 제안하였다. 제작된 가변이득 저잡음 증폭기의 측정값은 $V_{DD}$ =1.5V, $V_{GG1}$=0.4V, $V_{GG2}$=0.5V일때 5.5GHz의 중심 주파수, 14.7dB의 소신호 이득, 10.6dB의 입력 반사손실, 10.7dB의 출력 반사손실, 14.4dB의 가변이득, 그리고 잡음지수 2.98dB이다. 또한, 가변이득 저잡음 증폭기는 -19.7dBm의 입력 PldB, -10dBm의 IIP3, 52.6dB의 SFBR, 그리고 9.5mW의 전력을 소비한다.다.다.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권3호
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• pp.272-275
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• 2014

An improved fuzzy Kalman filtering speed estimation scheme was proposed by means of measuring stator side voltage and current value based on vector control state equation of induction motor. The designed fuzzy adaptive controller conducted recursive online correction of measurement noise covariance matrix by monitoring the ratio of theory residuals and actual residuals to make it approach real noise level gradually, allowing the filter to perform optimal estimation to improve estimation accuracy of EKF. Meanwhile, co-simulation scheme based on MATLAB and Ansoft was proposed in order to improve simulation accuracy. Field-circuit coupling problems of induction motor under the action of vector control were solved and the parameter optimization accuracy was improved dramatically. The simulation and experimental results show that this algorithm has a strong ability to inhibit the random measurement noise. It is able to estimate motor speed accurately, and has superior static and dynamic characteristics.

• 한국음향학회지
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• 제33권6호
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• pp.375-382
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• 2014

많은 실제 능동 소음 제어 분야에서 주요 소음은 다수의 인접한 배음으로 구성된다. 또한 협대역 능동 소음 제어 시스템은 정현파 세트나 혹은 합으로 구성된 기준 신호에 의해 동작하는 적응 필터들로 구성된다. 본 논문은 직접형, 병렬 형, 간소화한 병렬 형의 능동 소음 제어 시스템이 기본 주파수와 인접한 정현파의 주파수 간격에 영향을 받음을 보여주고 이를 분석한다. 또한 본 논문은 기준 주파수에 독립적인 새로운 간소화한 병렬 형 협대역 능동 소음 제어 시스템을 제안한다. 본 논문에서의 제시한 분석을 증명하고 새로운 협대역 능동 소음 제어 시스템을 기존 협대역 능동 소음 제어 시스템과 비교하기 위해 컴퓨터 시뮬레이션을 수행한다.

• Journal of Power Electronics
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• 제15권3호
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• pp.730-740
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• 2015

This paper presents model reference adaptive system speed estimators based on Type-1 and Type-2 fuzzy logic controllers for the speed sensorless direct torque and flux control of an induction motor drive (IMD) using space vector pulse width modulation. A Type-1 fuzzy logic controller (T1FLC) based adaptation mechanism scheme is initially presented to achieve high performance sensorless drive in both transient as well as in steady-state conditions. However, the Type-1 fuzzy sets are certain and cannot work effectively when a higher degree of uncertainties occurs in the system, which can be caused by sudden changes in speed or different load disturbances and, process noise. Therefore, a new Type-2 FLC (T2FLC) - based adaptation mechanism scheme is proposed to better handle the higher degree of uncertainties, improve the performance, and is also robust to different load torque and sudden changes in speed conditions. The detailed performance of different adaptation mechanism schemes are performed in a MATLAB/Simulink environment with a speed sensor and sensorless modes of operation when an IMD is operates under different operating conditions, such as no-load, load, and sudden changes in speed. To validate the different control approaches, the system is also implemented on a real-time system, and adequate results are reported for its validation.

• Smart Structures and Systems
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• 제15권1호
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• pp.227-244
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• 2015

This study develops a two stage procedure to identify the structural damage based on the optimized artificial neural networks. Initially, the modal strain energy index (MSEI) is established to extract the damaged elements and to reduce the computational time. Then the genetic algorithm (GA) and artificial neural networks (ANNs) are combined to detect the damage severity. The input of the network is modal strain energy index and the output is the flexural stiffness of the beam elements. The principal component analysis (PCA) is utilized to reduce the input variants of the neural network. By using the genetic algorithm to optimize the parameters, the ANNs can significantly improve the accuracy and convergence of the damage identification. The influence of noise on damage identification results is also studied. The simulation and experiment on beam structures shows that the adaptive parameter selection neural network can identify the damage location and severity of beam structures with high accuracy.

• Smart Structures and Systems
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• 제32권6호
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• pp.393-402
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• 2023

Recently, hybrid and electric vehicles have been actively developed to replace internal combustion engine (ICE) vehicles. However, their vibrations and noise with complex spectra cause discomfort to drivers. To reduce the vibrations transmitted through primary excitation sources such as powertrains, structural changes have been introduced. However, the interference among different parts is a limitation. Thus, active mounting systems based on smart materials have been actively investigated to overcome these limitations. This study focuses on diminishing the source movement when a structure with two active mounting systems is excited to a single sinusoidal and a multi-frequency signal, which were investigated for source movement reduction. The overall structure was modeled based on the lumped parameter method. Active vibration control was implemented based on the modeled structure, and a multi-normalization least mean square (NLMS) algorithm was used to obtain the control input for the active mounting system. Furthermore, the performance of the NLMS algorithm was compared with that of the quantification method to demonstrate the performance of active vibration control. The results demonstrate that the vibration attenuation performance of the source component was improved.