• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권1호
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• pp.1-7
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• 2004

This paper presents a sensorless control strategy of a PMSM(Permanent Magnet Sycchoronous Motor). This method is very simple to compute the position angle of a rotor. A principle and a practical solution are described. A sensorless control algorithm is proposed to remove a mechanical position sensor. The theory is based on the superposition principle. The state equation of a motor is divided into two conditions: one is the state equation of exciting voltage and phase current in a constraint, the other is the state equation of back EMF(Electromotive Force) and phase current in a short circuit. Based on the analysis, short circuit current by back EMF is computed and then the information of position angle is calculated. The proposed method is verified by experimental results.

• 전기학회논문지
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• 제64권5호
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• pp.792-798
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• 2015

Joint angle generally can be measured to check the recovery process in rehabilitation field. This paper suggests to measure joint angle with Infrared sensor based on triangulation principle. We performed various experiments to find the optimal condition of the sensor’s attached distance, height, and angle. The results were compared with commercial goniometer for accuracy. The proposed infrared joint angle sensor can be effectively used in rehabilitation and sport science fields.

• Journal of the Optical Society of Korea
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• 제19권6호
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• pp.586-591
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• 2015

In recent years, along with the rapid development of LED technology, indoor positioning systems based on visible light communication (VLC) have been researched. In this paper, we propose an accurate indoor positioning method using white-light LEDs and a dual image sensor. Indoor LED lights are located at the ceiling in a room and broadcast information on their positions using VLC technology. A mobile device with a dual image sensor receives LED position information by VLC and estimates its position and azimuth angle. Simulation and experimental results are given to show the performance of the proposed indoor positioning system.

• 비파괴검사학회지
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• 제10권1호
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• pp.10-17
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• 1990

Recently, object recognition ultrasonic sensor is being used with automatization of industrial machine. Points which characterize the object can be deleted by measuring the propagation time of ultrasonic impulse and azimuth which gives its maximum amplitude, and from these points shape, position and orientation of the object are deduced. A new measuring method is adopted, where the distance to the object is calculated by sound reflection time which is measured from O-cross point of sound wave, and azimuth is measured by angle indicating maximum amplitude. The measuring accuracy of 1.0mm for distance and $0.5-2^{\circ}$ for azimuth have been accomplished. By rotational scanning of sensor the characteristic point of an object can be known and it gives the information of its shape, position and orientation. Experimental results showed that the object of some complicated shape can be recognized, which suggest its applicability to robot.

• 한국정보통신학회논문지
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• 제21권12호
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• pp.2365-2370
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• 2017

본 논문에서는 체험형 VR 환경을 고려한 동작 및 위치 인식 기법을 제안한다. 동작 인식은 신체부위에 복수개의 AHRS 디바이스를 부착하고 이를 기준으로 좌표계를 정의한다. 각각의 AHRS 디바이스로부터 측정되는 9축 움직임 정보를 기반으로 사용자의 동작을 인식하고 신체 분절 간의 관절각을 추출하여 동작을 보정한다. 위치인식은 AHRS 디바이스의 관성센서를 통해 보행 정보를 추출하여 상대위치를 인식하고 BLE Fingerprint를 이용하여 누적오차를 보정한다. 제안하는 동작 및 위치인식 기법의 구현을 위해 AHRS기반의 위치인식과 관절각 추출 실험을 진행하였다. 위치 인식 실험의 평균 오차는 0.25m, 관절 각 추출 실험에서 관절 각 평균 오차는 $3.2^{\circ}$로 나타났다.

• 한국정밀공학회지
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• 제16권7호
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• pp.40-50
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• 1999

Recently, a laser displacement sensor is widely used for the manufacturing automation. The sensor is generally composed of a diode laser and a light receiving device. The diode laser emits a laser beam and the receiving device detects the light reflected from the measured object. The object position is obtained based upon triangulation method. As a light receiving device, a PSD is usually utilized since its structure is very simple and rugged and has a high accuracy. Although the theoretical relationship for this sensor had been developed, the characteristics of the sensor have not been much experimentally studied. In this paper, several experimental results will presented. The measurement accuracy is affected by the surface conditions such as the reflectance characteristics, the angle of the object's surface and the laser intensity. In addition, it is found that the PSD and the signal processing circuit have nonlinearities and showed that those nonlinearities can be reduced by controlling the emitting laser intensity.

• 한국멀티미디어학회논문지
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• 제14권4호
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• pp.517-528
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• 2011

본 논문에서는 시각장애인이 실내에서 특정 목적지까지 안전하게 보행할 수 있도록 하는 시스템을 제안한다. 이 시스템은 카메라로 찍은 영상을 분석하여 마커의 ID를 구한 후 이로부터 보행자의 절대위치를 파악하고, IMU(Inertial Measurement Unit)의 가속도 센서와 자이로 센서를 통해 들어온 이동거리와 각도를 이용하여 보행자의 이전위치에 대한 상대위치를 파악하여 다음 진행 방향을 결정한다. 동시에 다수의 초음파 센서들을 이용하여 보행자 전방의 장애물 위치를 파악하여 사용자에게 최적의 진행방향을 알려준다. 이때 경로상의 계단이 있을 경우 IR(Infrared Rays)센서로 감지하여 보행자에게 알려준다. 본 시스템은 다중 복합 센서들을 융합하여 시각장애인에게 위치정보를 제공하고 원하는 목적지까지 안전하게 보행할 수 있도록 한다.

• Journal of Biosystems Engineering
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• 제25권6호
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• pp.457-462
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• 2000

Boom sprayers have been known by their excellency in field efficiency worker’s safety and pest control efficacy. The boom sprayer in Korea that was developed for paddy field is not suitable for upland field of which shape is irregular and inclination is steep, due to heavy chemical tank long boom width and manual on-off control of spraying. The goal of the study was to develope a boom control system that could control boom angles of left and right boom automatically and independently corresponding to local field slope. The prime mover was selected as a cultivating tractor. Main results of this study were as follows. 1. Ultrasonic sensor whose response time was 0.1s and response angle was within $\pm$20$^{\circ}$was selected to measure distance. Voltage output of the sensor(X, Volt) had a highly significant linear relationship with the vertical distance between the sensor and ground surface(Y, mm) as follows; Y=0.0036X-0.437 2. Left and right section of the boom could be folded up by a position control device(on-off control) which could control the left and right boom independently corresponding to local slope by equalizing distances between the sensor and boom at the center and left/right boom. Most reliable DB(dead band) was experimentally selected to be 75$\Omega$(6cm). 3. At traveling velocity of 0.3~0.5m/s RMS of error between desired and achieved height was less than 4.5cm The developed boom angle controller and boom linkage system were evaluated to be successful in achieving the height control accuracy target of $\pm$10cm.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
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• pp.222-224
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• 2000

This Paper investigates the speed control of Switched reluctance motor(SRM) using one chip microcomputer The SRM has the advantages of simple structure low rotor inertia. and high efficiency. The Position sensor is essential in SRM in order to synchronize the Phase excitation to the rotor position. The proposed system consists of phase locked loop controller, switching angle controller and inverter. The Performances in the Proposed system are verified through the experiment.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2005년도 동계학술연구발표회 및 2차 아시안포럼
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• pp.44-45
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• 2005