• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권5호
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• pp.338-344
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• 2000

This paper proposes a field-oriented control strategy without speed sensor in overall speed range. At low speed region including zero speed, the electrical saliency which is due to the main flux saturation is used in order to estimate an instantaneous flux position. This electrical saliency can be obtained from the difference of high frequency impedance by the high frequency signal injection. This method enables the stable operation at zero speed or stator frequency even under heavily loaded condition. However, because of the high frequency signal injection the loss and noise in motor increase and the voltage margin is reduced as the motor speed increases. Therefore, this algorithm must be supplemented with the algorithm based on the electrical model of motor, which is conventionally used in the region except the low speed. This paper proposes the combination algorithm between the high frequency signal infection method and the adaptive observer, in which the rotor flux and motor speed can be simultaneously estimated by the adaptive control theory. This combination algorithm enables the stable operation of field-oriented speed control without speed sensor in overall speed range. This is verified by experimental results.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.385-389
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• 2003

To make high speed spindle system work properly, sensors with outstanding resolution and dynamic characteristics are essential. An optical fiber displacement sensor is based on simple principles. Electrical signal responds to the optical flux change due to the displacement change between a target and a sensor probe. In this paper, the performance of optical fiber displacement sensor has been investigated according to properties of optical fiber Firstly, optical loss has been measured before and after polishing optical fiber endface. Secondly, allowance of optical fiber bending has been tested. thirdly sensitivity and linear range of the sensor has been found out according to the shape of cross section of optical fiber.

• International Journal of Korean Welding Society
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• 제2권2호
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• pp.57-60
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• 2002

Generally, the laser vision sensor makes it possible design a highly reliable and precise range sensor at a low cost. When the laser vision sensor is applied to lap joint welding, however. there are many limitations. Therefore, a specially-designed hardware system has to be used. However, if the multi-lines are used instead of a single line, multi-range data .:an be generated from one image. Even under a set condition of 30fps, the generated 2D range data increases depending on the number of lines used. In this study, a laser vision sensor with a multi-line pattern is developed with conventional CCD camera to carry out high speed seam tracking in lap joint welding.

• 센서학회지
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• 제30권1호
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• pp.30-35
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• 2021

To operate an underwater robot in an environment with fluid flow, it is necessary to recognize the speed and direction of the fluid and implement motion control based on these characteristics. Fish have a lateral line that performs this function. In this study, to develop an artificial lateral line sensor that mimics a fish, we developed a method to measure the flow speed and the incident angle of the fluid using a pressure sensor. Several experiments were conducted, and based on the results, the tendency according to the change in the flow speed and the incident angle of the fluid was confirmed. It is believed that additional research can aid in the development of an artificial lateral line sensor.

• 대한토목학회논문집
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• 제36권6호
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• pp.1059-1068
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• 2016

현재 AVC 장비의 운영방법은 하나의 센서가 고장 나면 해당 차로의 교통량 속도 차량 종류에 대한 모든 정보의 생성을 중단하고 있다. 현재의 운영방법은 정상 센서에서 수집한 자료들을 활용하지 않는다는 비효율이 존재한다. 본 연구는 이런 비효율을 개선하기 위하여 일부 센서가 고장 난 AVC (Automatic Vehicle Classification)장비에서 교통량과 속도의 산출 방법에 대하여 연구를 진행하였다. 센서의 고장유형을 총 4가지로 분류하였으며, 각 고장유형별로 교통량과 속도를 산출하고 이에 대한 정확도분석을 수행하였다. 그 결과 교통량은 정확도가 매우 높은 값(정확도: 100%, 98%, 97%)으로 산출이 가능하였으며, 속도의 경우 충분히 받아들일 만한 수준의 속도 값(RMSE 값 16.9 이하)이 산출되는 것을 확인하였다. 따라서 본 연구에서 제시한 방법론들을 사용하면 AVC 장비의 운영 효율을 증가 시킬 수 있을 것으로 기대된다.

• 한국정보통신학회논문지
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• 제11권8호
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• pp.1478-1485
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• 2007

본 논문에서는 풍향 풍속 계측모듈 및 DSP 센서인터페이스 회로 보드를 포함하는 기상계측 시스템을 제안한다. 이 DSP 시스템은 풍향풍속모듈, 대기압센서, 대기 온도 센서의 정보를 받아들이고, 빠르게 처리하여 PC 모니터링 시스템에 전달한다. 특히 풍향 풍속 모듈과 DSP 하드웨어는 직접 설계하여 적용한다. 풍향 풍속 모듈은 바람에 관한 벡터적 정보를 얻기 위해 4개의 박막형 RTD(Resistive Temperature Detectors) 저항센서를 히팅 코일에 의해 일정하게 가열된 원기둥 모양의 지지 표면에 벡터적으로 배치하는 구조를 채택한다. 이 구조를 채택한 계측 모듈은 진동, 습기, 부식 등에 강인하면서 정확한 계측을 가능케 한다. 센서 신호처리 회로는 TI사의 고속 DSP인 TMS320F2812 사용한다. 적용된 풍향 풍속 모듈을 통해 얻어진 데이터와 DSP 인터페이스 회로보드의 빠른 데이터 처리를 통해 저렴한 기상계측시스템을 구성 할 수 있었다.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권8호
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• pp.451-458
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• 2000

The precise speed and position control technique for Brushless DC Motor demands accurate position and speed feedback information. Generally, resolver or absolute encoders are used as speed and positiion sensor. But they increase cost and more problem happens at low speed than high speed specially. Therefore, in this paper, optimal speed observer is proposed for decreasing size and cost of whole system. And also, we consider the error problem about the system modeling and measurement at low speed range as well as high speed. The overall system consists of two parts, a drive and a speed observer. We make use of Least square curve fitting algorithm as speed observer and can overcome low resolution by proposed observer. Also, because of using the signal of hall sensor, robust control is possible in low speed as well as high speed for the change of the parameters of the system and disturbance. To construct observer using the signal of hall sensor, we design the pulse multiplier circuit and the software of microprocessor, AT89CC2051. Finally, the performance of the proposed observer is exemplified by some simulations and experiments.

• Journal of Advanced Marine Engineering and Technology
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• 제27권1호
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• pp.100-107
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• 2003

This study was to control magnetic field orientation-typed sensorless vector control by applying the theory of a rotor flux observer to drive an induction motor. This research suggested a new speed estimation method that estimates speed with the rotor flux obtained by using a flux observer and the variable of state current detected by a current sensor without a speed sensor. Because the speed estimation method is independent from the motor constants, it is not necessary to control the gain of the parameters and the algorithm is simple. In the findings of the study, the researcher was convinced of the control function and the possibility of realization in the simulation experiment of sensorless vector control system by using DSP(Digital Signal Prosessor).

• 한국산업융합학회 논문집
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• 제2권2호
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• pp.91-102
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• 1999

The paper describes a robust adaptive control algorithm for induction motor drive without speed sensor at low speed range. The control algorithm use only current sensors in a space vector pulse width modulation within loop control with rotor speed estimation and voltage source inverter. On-line rotor speed estimation is based on utilizing parallel model reference adaptive control system. MRAC of the modified flux model for flux and rotor speed estimator uses dual-adaptation mechanism, ${\omega}_r$ and ${\omega}_e$ scheme. The estimated flux components in the model can be compensated from the effects of offset errors on pure integrals. It can be compensated to the parameter variations and torque fluctuation with speed estimation in less then 10 rad/sec. In a simulation, the proposed induction motor control algorithm without speed sensor at very low speed range are shown to operate very well in spite of variable rotor time constant and fluctuating load without change the controller parameters. The suggested control strategy and estimation method have been validated by simulation study, and it proposed the designed system for the implementation using TI320C31 DSP/ASIC controller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.315-318
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• 1997

In terms of productivity, the speed of machining process has been increasing in most of engineering part. But the tapping process does not reach at enough level compared with other machining processes because of its complicate cutting mechanism. In the high speed tapping process, the one of important elements is tool monitoring system to prevent tool breakage. This paper describes tool monitoring system by acoustic emission(AE) in the tapping process. We used 2 types of AE sensors in this test. The one is commercial sensor which is used in other machining monitoring system like polishing and the other is a self-fabricated sensor for this test. In this test we purpose to find out the frequency of AE signal in tapping process and verify the possibility of applying AE sensor in in-process tapping monitoring system. Also grasp of characteristic of tapping process by AE signal is handled.