Earticle

본 연구는 침상의 인체 위치와 생체신호를 검출할 수 있는 스마트 침상제어시스템의 개발에 관한 것이다. 침상제어 시스템의 메인 제어보드는 인체 감지부, 모터 구동부, MCU로 구성된다. 여기서, 침상의 인체존재 확인의 신뢰성을 높이기 위해 맴브레인 센서에 의한 인체위치 검출부와 EMFI 센서의 생체신호 검출부를 인체감지부로 결합하였다. 또한 검출된 두 신호를 원격으로 앱 모드의 응용 프로그램에 연결하여, 침상위 인체정보를 모니터링할 수 있는 앱모드의 활용이 가능하도록 하였다. 본 연구에서 블루투스 통신에 의해 침상 인체 정보를 모니터링하는 원격 기능은 병원 및 요양기관의 낙상 및 침상부재사고 예방기법으로 활용될 수 있을 것이다.

This study is about the development of a smart bed control system to be able to detect the human position and body signal on bed. The main control board in the bed control system consists of the human sensing part, motor driving part and MCU. Here, to increase the credibility to check the human presence on bed, the human sensing part is combined with the human position part by membrane sensor and the body-signal detecting part of EMFI sensor. Also, remotely connecting the two detected signal to the application program of the app mode makes it possible to monitor human information on bed. In this paper, the remote function monitoring of the on-bed human information by bluetooth communication will be abe to make it applicable to the technical prevention method of the bed fall and absence accident in hospital and care facilities.

후두출 환자나 발음장애가 있는 사람은 음성인식 기술을 사용하지 못하는 불편함이 있다. 이러한 문제를 극복하기 해 발성이 필요 없는 무성인식(Silent Speech Recognition)이 발하고 있다. 본 논문에서는 물리센서 (Physical Sensor)를 이용하여 의 움직임을 감지하고 한국어 무성 자음 ‘ㄱ’, ‘ㄷ’, ‘ㅂ’, ‘ㅅ’, ‘ㅈ’, ‘ㅊ’, ‘ㅋ’, ‘ㅌ’, ‘ㅍ’, ‘ㅎ’ 의 조음 치를 분류하는 방법을 제안한다. 세 개의 특징 추출 알고리즘 VAR(Variance), CC(Cepstral Coefficient), LPC(Linear Predict coding Coefficient)와 ANN(Artificial Neural Network) 분류기를 통해 수집된 데이터를 5개의 조음 치로 분류하다. 조음 치를 분류하는 실험을 통해 평균 79.5%의 정확도를 얻었다.

A patient with laryngectomy or a person with pronunciation problem has inconvenience of not using voice recognition technology. To solve it, the silent speech recognition technology has been emerged. In this paper, the proposed method detects movement of tongue using physical sensor and classifies the articulation position of Korean silent consonants such as‘ㄱ’, ‘ㄷ’, ‘ㅂ’, ‘ㅅ’, ‘ㅈ’, ‘ㅊ’, ‘ㅋ’, ‘ㅌ’, ‘ㅍ’, ‘ㅎ’. Three feature extraction algorithms such as VAR(Varian), CC(Cepstral Coefficient), LPC(Linear Predict coding Coefficient) and ANN(Artificial Neural Network) classifier can recognize collected data into five articulation positions. Experimental results show that the classification accuracy of the proposed method is about 79.5%.

This study introduces the accurate correction method of bearing position error of mobile robots using Stargazer sensor. The mobile robots require some vital functions including map building, localization, path planning, obstacle avoidance for autonomous navigation. In most cases, the localization of angular pose of a robot is essential because its result has a great effect on the performance of the other functions. We demonstrated the validity of the proposed method with the results of real experiments and applied it to the photographer robot for correct bearing position error at the moment of taking a picture.

A mobile robot generates position error when it changes directions. To reduce the position error a gyro sensor can be used. However, the effect of gyro sensor is not fully measured precisely for various conditions. This paper focuses on the effect of gyro sensor by measuring position error which is comprised of angular error and distance error. In the experimentation, the position errors of mobile robots for five different courses are measured for the robot with a gyro sensor and those without it. The closed courses include three, five, seven, nine and eleven direction changes which cause to generate considerable position errors. The experimental result shows that the angular error is reduced to about 14.3%~41.4% after a gyro sensor is used. Further, the position errors in distance are reduced to 22.4~31.8% when a gyro sensor is used. The remarkable difference between the two kind of errors is that the angular error increases steadily whereas the distance error increases rapidly but does not increase anymore over a certain level as the number of direction change increases.

Due to recent increase in energy consumption of lighting, the energy consumption in the building sector is shown high, reaching 34% of total energy consumption. Although a variety of technologies have been on the rise and increased to which IT technology is applied as an alternative to reduce the lighting energy the lighting control technology for energy saving has been limited. And in investigation on existing previous studies, some nonconformities have been found out at the position of illumination sensor. So, in this study, there was derived each position of illumination sensor at the summer solstice and the winter solstice Although a variety of studies for lighting energy saving has been on the rise and increased due to increase in energy consumption of lighting in building sector they are carried out in a limited environment of technology development in the lighting energy. In an investigation on existing previous studies, it has been found out that the position of illumination sensor for control was derived on the basis of work surfaces and eye-level illumination, so in this study, it is intended to construct the foundation materials for lighting control after deriving the position of illumination sensor for dimming lighting control in real life. In this study, there was conducted a performance evaluation through the construction of test bed on a real life basis and the illumination range for lighting control was set to 400 lx on the basis of the KS A 3011. The conclusion is as follows. 1) At the summer solstice, S11 position 1,000mm away from a skylight is shown as a proper position of illumination-environmental collection for dimming lighting control. 2) At the winter solstice, the dimming lighting control is unnecessary, but S1~S3 positions within the range of 5,000mm~6,000mm are shown as proper positions of illumination-environment collection for dimming lighting control. 3) When generalizing the results shown at the summer solstice and the winter solstice, S11 position 1,000mm away from a skylight is shown as a proper position of illumination-environment collection for dimming lighting control. 4) As a result of effectiveness at S11position, energy saving can be attained by 16~44% compared to other positions, and the analysis is carried out effectively. Therefore, it is determined that in the future study it will be necessary to supplement by conducting a performance verification in accordance with illumination standards for lighting control and diverse time zones as well as lighting control positions.

Mobile Wireless Sensor Networks (MWSNs) is one of the rising technologies for numerous areas of application, such as environmental monitoring, industrial sensing and diagnostics and battlefield awareness. Such wireless sensor nodes are often deployed in remote locations. Thus, energy efficient and reliable data forwarding is important because each node has limited resources. In this paper we propose a position-based energy-efficient greedy forwarding scheme to reduce the energy consumption while increasing the packet delivery ratio for Mobile Wireless Sensor Networks (MWSNs).In our paper, each node decides whether or not to be a relay node by itself considering the remaining energy and mobility. Simulation results show that the energy consumption and the average end-to-end delay can be reduced by selecting relay node considering the energy and mobility.

BLDC 전동기는, 영구자석의 고성능화를 비롯한 소재 기술 향상, 고집적∙고기능화를 갖는 구동 IC 기술의 진보, 고점적율화 등의 조립 기술 개선 등으로 인하여 성능이 점점 좋아지고 있다. 이러한 구형파 구동 BLDC 전동기의 장점이 있으면서 보다 사용자의 요구에 대응하기 위해 구형파 구동 BLDC 영구자석 전동기 설계 및 개발, 위치검출방식 회로와 드라이버 개발에 관심이 증가하고 있다. 그러나 스위칭 손실에 의한 효율 저하 및 진동, 소음 등으로 인하여 가격적∙기능 적인 장점에도 불구하고 그 응용에 있어서는 다소 제한적인 실정이다. 따라서 본 논문에서는 정현파가 발생하는 Hall Effect Sensor를 사용하여 BLDC 전동기 회전자의 자속에 비례하여 정현파 신호를 만드는 위치검출 회로를 연구하여 전동기의 효율 증대, 리플 저감, 속도 및 토크 특성이 우수한 정현파 전류 구동을 구현하고자 한다.

BLDC motors are getting better performance due to the improvement of material technology including high performance of permanent magnets, advancement of driving IC technology with high integration and high functionality, and improvement of assembly technology such as high point ratio. While having the advantage of such a square wave driven BLDC motor, interest in the design and development of a square wave driven BLDC permanent magnet motor and development of a position detection circuit and driver is increasing in order to more meet the needs of users. However, in spite of the cost and functional advantages due to reduced efficiency, switching loss and vibration, noise, etc., the application is somewhat limited. Therefore, in this paper, we study a position detection circuit that generates a sinusoidal signal in proportion to the magnetic flux of a BLDC motor rotor using a Hall Effect Sensor that generates a sinusoidal wave to increase the efficiency of the motor, reduce ripple, and drive a sinusoidal current with excellent speed and torque characteristics.

본 연구는 10MHz SC-CUT 크리스탈을 이용한 오븐제어수정발진기(이하 OCXO)의 온도센서 위치에 의한 특성 변화와 주파수 보정방법에 관한 것이다. 기존의 고정밀 10MHz OCXO의 제작 방법은 여러 가지가 있지만, 본 연구에서 는 온도센서의 위치를 조정하는 것만으로도 외부 온도 변화에 대한 주파수 안정도 특성이 향상될 수 있다는 것을 보여준 다. OCXO의 주파수 특성에 영향을 주는 인자로는 크리스탈에 전달되는 온도, 크리스탈에 인가되는 전압, 발진회로를 구성하는 캐패시턴트 등이 있다. 이러한 인자들에 의한 주파수 변화량을 측정하고 온도 변곡점 측정과 캐패시터 값의 변화를 통하여 OCXO 출력주파수의 보정값 변화를 알아보았다.

This study relates to a characteristic change and frequency correction method according to the temperature sensor position of an oven-controlled crystal oscillator (OCXO) using a 10 MHz SC-CUT crystal. Although there are several methods of manufacturing the previous high-precision 10MHz OCXO, the present study shows that the frequency stability characteristics against external temperature changes can be improved simply by adjusting the position of the temperature sensor. Factors that affect the frequency characteristics of the OCXO include the temperature transmitted to the crystal, the voltage applied to the crystal, and the capacitance constituting the oscillation circuit. The amount of change in frequency due to these factors was measured, and the change in the correction value of the OCXO output frequency was investigated by measuring the temperature inflection point and changing the capacitor value.

최근에는 회전자에 희토류 영구자석을 삽입하여 높은 효율과 출력밀도를 얻을 수 있는 매입형 영구자석 (IPM : Interior Permanent Magnet) 전동기 또는 표면부착형 영구자석 (SPM : Surface Permanent Magnet) 전동기처럼 영구자석이 사용된 전동기의 연구가 활발히 이루어지고 있다. 영구자석을 사용하기 때문에 릴럭턴스 전동기나 유도전동 기와 비교해 효율이 높고 출력밀도가 높은 장점이 있으나 회전자에 영구자석을 삽입함으로써 고속운전 및 영구자석의 감자로 인한 신뢰성 감소, 희토류 금속의 원가 상승 등이 문제시되고 있다. 본 논문에서는 희토류 영구자석 전동기를 대체할 수 있는 미래기술 개발과, 희토류 저감형 전동기와 탈 희토류 전동기의 기술 선점을 요구하는 시대적 이슈 (Issue)에 맞춰 영구자석이 필요 없는 스위치드 릴럭턴스 전동기 (Switched Reluvtance Motor, SRM)를 구동시키기 위한 구동 제어에 연구하고자 한다. PSIM 시뮬레이션 프로그램에서 제공하는 3상 SRM library를 이용하여 회전자 위치 정보 센서를 이용한 SRM의 구동 및 제어 시스템 모델링 (Modeling)을 연구하고자 한다.

In recent years, permanent magnets such as IPM (Interior Permanent Magnet) motors or SPM (Surface Permanent Magnet) motors that can obtain high efficiency and power density by inserting rare earth permanent magnets into the rotor are used. Research on the used electric motor is being actively conducted. Since it uses a permanent magnet, it has the advantage of high efficiency and high power density compared to reluctance motors and induction motors, but by inserting a permanent magnet into the rotor, it operates at high speeds and decreases reliability due to demagnetization of the permanent magnets, and increases the cost of rare earth metals. In this paper, in accordance with the development of future technology that can replace rare-earth permanent magnet motors and technological preoccupation of rare-earth reduction type motors and de-rare-earth motors, switched reluctance motors that do not require permanent magnets (Switched Reluvtance Motors) Motor, SRM) to drive driving control. Using the 3-phase SRM library provided by the PSIM simulation program, we will study the driving and control system modeling of SRM using the rotor position information sensor.

스마트폰을 이용한 실내 위치 추적 기술에 관한 연구가 활발하게 진행되고 있다. 특히 스마트폰의 이동 경로를 지도 에 표시하기 위해서는 대부분의 스마트폰에 내장되어 있는 지자기 센서를 이용하여 방위각을 추정해야 하는데, 주변의 쇠구 조물에 의한 자기장의 왜곡과 스마트폰의 기울어짐 때문에 방위각 추정 오차가 발생한다. 본 논문에서는 정지 상태에서의 지자기 센서의 보정 방법과 스마트폰의 기울어짐에 대한 보정 방법을 제시한다. 또한 스마트폰에서 자북과 도북의 차이에 의한 방위각 오차를 보정하는 방법을 제안한다.

Research on indoor location tracking technology using smart phone is actively being carried out. Especially, in order to display the movement path of the smartphone on the map, the azimuth angle should be estimated by using the geomagnetic sensor built in most smart phones. Due to the distortion of the magnetic field due to the surrounding steel structure and the inclination of the smartphone, the estimation error of azimuthal angle may be occurred. In this paper, we propose a correction method of the geomagnetic sensor at the stationary state and a correction method for the inclination of the smartphone. We also propose a method to correct the azimuth error due to the difference between the magnetic north and the grid north.

This paper describes the characteristics of Electronic Throttle Controller (ETC) module in BLDC motor without the hall sensor for detecting a rotor position. The proposed ETC control system, which is mainly consisted of a BLDC motor, a throttle plate, a return spring and reduction gear, has a position sensor with an analogue voltage output on the throttle valve instead of BLDC motor for detecting the rotor position. So the additional commutation information is necessarily needed to control the ETC module. For this, the estimation method is applied. In order to improve and obtain the high resolution for the position control, it is generally needed to change the gear ratio of the module or the electrical switching method etc. In this paper, the 3-phase switching between successive commutations is adapted instead of the 2-phase switching that is conventionally used. In addition, the position control with a variable PI gain is applied to improve a dynamic response during a transient period and reduce vibration at a stop in case of matching position reference. The mentioned method can be used to estimate the commutation state and operate the high-precision position control for the ETC module and the high response characteristics. The validity of the proposed method is examined through the experimental results.

All-surface, all-tooth machining and roll forming of cast iron have been used to manufacture the crankshaft position sensor wheel (CPSW). However, these methods pose many problems such as difficult processing, high material cost, and low tooth precision. Thus, we developed a sintered CPSW with an improved detection ability in order to resolve the problems related with the previous methods of manufacturing CPSW by simplifying the process flow and improving tooth precision. The sintering process is introduced in this study. We conducted an experiment to compare the sintered and roll formed products and analyzed the results to evaluate the reliability of the sintering process. Furthermore, we compared and analyzed stress and displacement in the sintered and roll formed products through the "Finite Element Method(FEM)". According to the experimental and FEM results, the sintered product showed satisfactory mechanical properties. It was less expensive to process and lighter and showed better quality than the roll formed product. The results of this study could be applied to design an optimum CPSW using the sintering process.

In general three position sensors are needed to drive three phases SRM. Single position sensor driving method for three phases Switched Reluctance Motor(SRM) is proposed in this paper. By using single position sensor the cost of SRM is reduced. But position sensor the cost of SRM is reduced. But position detection at the staring is needed for single position sensor driving method. In this paper we propose the active align method to detect the relative position of rotor to three phases and align to the nearest phase. We proved the validity of the method by experiment and compare with other method.

Fast and accurate fault diagnosis of the position sensor is of great significance to ensure the reliability as well as sensor fault tolerant operation of the Switched Reluctance Wind Generator (SRWG). This paper presents a fault diagnostic scheme for a SRWG based on the residual between the estimated rotor position and the actual output of the position sensor. Extreme Learning Machine (ELM), which could build a nonlinear mapping among flux linkage, current and rotor position, is utilized to design an assembled estimator for the rotor position detection. The data for building the ELM based assembled position estimator is derived from the magnetization curves which are obtained from Finite Element Analysis (FEA) of an SRWG with the structure of 8 stator poles and 6 rotor poles. The effectiveness and accuracy of the proposed fault diagnosis method are verified by simulation at various operating conditions. The results provide a feasible theoretical and technical basis for the effective condition monitoring and predictive maintenance of SRWG.

The widely used motors in HEV(Hybrid Electric Vehicles) are IPMSM(Interior Permanent Magnet Synchronous Motor) which has no rotor heat, higher efficiency and advantageous in volume and weight comparing with other motors. For vector control of IPMSM, position information of rotor is required but Resolver is mainly used as the detecting sensor. However, the use of position sensors will reduce the system reliability of hybrid electric vehicles. In this paper, a way to control the motor by sensorless was proposed at the event of sensor failure. We also implemented IPMSM sensorless operation by the expanded EMF(Electro Motive Force) voltage way and harmonic voltage which is applying in the low speed area. And we proposed how to change with sensorless control by detecting the position sensors failure and verified it through experiments.

In micro-manipulations, force sensing devices play an important role in the control and the assembly of micro-objects. To protect these micro-objects from damage, we must have the ability to detect the value of the minute amount of interactive force (about a few ${\mu}N$) upon contact between the tip and the object. To detect this micro-force, we need an optimized design of force sensor to increase the strain values at the positions we place sensing components. Stress concentration can effectively amplify the strain values measured by the force sensors. This paper investigates the effect that the notches have on increasing the strain values at the positions we attach the sensing elements. In addition, the optimal design with a flexible structure improves the sensitivity of the sensor. An algorithm that can calculate both contact force and contact position on the sensor tip is also mentioned. Besides, an optimal location of strain gauges will ensure the accuracy and stability of the measurement. Finally, analysis and experiment are done to verify the proposed idea.