• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 동계연구발표회 논문개요집
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• pp.230-231
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• 2002

고주파전류가 통전되고 있는 연자성체에 외부자계가 인가되면 자성체의 표피효과(Skin effect)에 의해서 임피던스가 변화하게 된다. 따라서 고주파의 정전류를 통전시키면 자성체의 양단에서 전압의 크기는 외부에서 인가되는 자계에 따라 변화하게 되는데, 이 때의 전압을 자계로 환산함으로써 자계의 검출이 가능하다. 이러한 현상을 이용하여 자계를 검출하는 소자를 자기임피던스 센서(Magneto-Impedance sensor)라고 한다$^{1.2}$ . 자기임피던스 센서는 주로 연자성이 우수한 아몰퍼스 자성체를 이용하여 구성되고, 구조가 간단하며, 극히 우수한 자계 검출능력을 나타내므로, 차세대의 고감도 자계센서로서 주목을 받고 있다. (중략)

• 대한전기학회논문지
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• 제41권5호
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• pp.474-482
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• 1992

This paper describes the speed control system of an induction type ac servomotor drive on the vector control basis of slip frequency and constant secondary flux control for a quick torque response. The system is composed of a digital controller using a SCB-V50 microprocessor and a PWM inverter with power MOSFETs for high speed switching. And, for the measurement of actual instantaneous currents, MDCS A070-051 hall sensors are employed. The rising time of step responce by this system through the test of a 600[W] ac servomotor is 30[ms]. Overall experimental result shows that the drive performance of the system is similar to that of a separately excited armature current control of a dc motior.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1997년도 추계학술발표회논문집
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• pp.70-73
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• 1997

This paper describes the technique for detecting failure symptom of mold transformer. This study uses the vibration signal analysis method and FEM as the technique. A loading back method is constructed for experiment, accelation sensors are adhered for measurement of vibration signal. Vibration signal measured by this method is analyzed into variation trend of measurement variables by control of control variables. Magnetic field distribution of molded winding is also acquired by FEM considering the design specfication and the characteristics of insulation material, in conclusion, he relation of results between vibration signal and FEM is studied by these methods.

• 한국군사과학기술학회지
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• 제8권3호
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• pp.101-110
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• 2005

In this paper, the experiments have been conducted to measure the residual velocity for 3.5g steel ball perforating light weight metal plates of aluminum alloy and magnesium alloy. Non-contact electro-magnetic sensors were used to measure the velocity of steel ball before/after perforating plates. The thicknesses of specimens used were about 2.8mm and 4.8mm. The impact velocities of steel ball were from 662m/s to 3594m/s. With same conditions, numerical analysis using Autodyn 2D has been conducted. The results of numerical analysis corresponded with those of experiments. Also, It is suggested that the difference between the residual velocity of experiment or numerical analysis and that of THOR experimental equation of BRL grew smaller as the impact velocity were increased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.955-957
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• 2003

In this paper deal with Initial Pole Position Estimation for Interior Permanent Magnet Motor. Generally, Brushless motor is considered Initial Pole Position with absolute encoder or resolver, etc. In the motor, the flux from the magnets is large enough to saturate the stator iron, results in different inductance values along the pole position. Based upon the relationship between magnitude of inductance and the resultant magnetic filed, initial pole position is estimated at standstill without position sensors, especially, this paper provide the direction of the magnetization. Finally, analysis results are presented to confirm ability of initial pole position estimation.

• 센서학회지
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• 제20권4호
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• pp.260-265
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• 2011

The silicon vertical hall devices are fabricated using a modified bipolar process. It consists of the thin p-layer at Si-$SiO_2$, interface and n-epi layer without $n^+$buried layer to improve the sensitivity and influence of interface effects. Experimental samples are a sensor type I with and type H without p+isolation dam adjacent to the center current electrode. The experimental results for both type show a more high current-related sensitivity than the former's vertical hall devices. The sensitivity of type H and type I are about 150 V/AT and 340 V/AT, respectively. This sensor's behavior can be explained by the similar J-FET model.

• Journal of Power Electronics
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• 제13권6호
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• pp.1051-1057
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• 2013

This paper proposes an implementable sun tracking algorithm for portable systems powered by alternative energy sources. The proposed system uses a 2-axis tilt sensor and a 3-axis magnetic sensor to measure the orientation and posture of the system, according to a horizon coordinates system, and compensate for tilt effects. Then, through an astronomical calculation, using the present time and position information obtained from GPS sensors, the azimuth and altitude of the sun in that location is calculated and converted to portable sun tracking system coordinates and used to control the A- and C-axes of the system.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.26.2-26.2
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• 2008

• 반도체디스플레이기술학회지
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• 제17권1호
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• pp.88-92
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• 2018

Currently drone industry has become one of the fast growing markets and the technology for unmanned aerial vehicles are expected to continue to develop at a rapid rate. Especially small unmanned aerial vehicle systems have been designed and utilized for the various field with their own specific purposes. In these fields the path planning problem to find the shortest path between two oriented points is important. In this paper we introduce a path planning strategy for an autonomous flight of unmanned aerial vehicles through reinforcement learning with self-positioning technique. We perform Q-learning algorithm, a kind of reinforcement learning algorithm. At the same time, multi sensors of acceleraion sensor, gyro sensor, and magnetic are used to estimate the position. For the functional evaluation, the proposed method was simulated with virtual UAV environment and visualized the results. The flight history was based on a PX4 based drones system equipped with a smartphone.

• 한국정밀공학회지
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• 제12권2호
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• pp.37-47
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• 1995

In recent years, it has been variously developed for testing the accuracy of circular motion of NC machine tools, for example Telescoping Ball Bar Method by Bryan, Circular test Method by Knapp and $r^{-{\theta} }$ Method by Tsutsumi etc., but these methods are all 2-dimentional measuring methods on plane. These simple methods of circular motion accuracy test of NC machine tools have been studied by many reserchers as above, but it is not yet settled in the code of measuring methods of motion errors of NC machine tools, because of errors of measuring units and sensors, and also especially the difficulties of centering of measuring units and the spindle of machining center. In this paper, in use of 2 rotary encoders and 1 magnetic type linear scale with resolution of 0.5 .mu. m, it has become possible for measuring of 3 dimentional space motion accuracy.