• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.774-776
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• 2001

This paper describes the finite element analysis(FEA) for the design of common core-type and separated core-type rotational speed sensor(RSS) for SMART MCP and compared with the low/ high speed characteristics of prototype RSS. As a result, it is shown that the characteristics of prototype RSS have a good agreement with the results of FEA.

• Journal of Sensor Science and Technology
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• v.23 no.6
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• pp.362-367
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• 2014

In this study, a postural change detection sensor module (PCDSM) was developed to detect postural changes in activities of daily living (ADL) and falls. The PCDSM consists of eight mercury sensors that measure angle variations in $360^{\circ}$ rotation and $90^{\circ}$ tilting. From the preliminary study, the output characteristics of the PCDSM were confirmed with the angle variations of rotational motion and a tilting table. Three experiments were conducted to test rotational motion, postural changes, and falling and lying. The results confirmed that the PCDSM could effectively detect postural changes, movement patterns, and falls or non-falls.

• The Journal of the Acoustical Society of Korea
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• v.31 no.5
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• pp.280-287
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• 2012

This paper presents a study on the experimental analysis of the impedance characteristics according to the rotational direction of the transmission beam of a cylindrical sensor array. Besides, this suggests a real time control technique of the transmitter output for the effective maximum power transmission, in order to drive efficiently the rotational transmission beam of the active sonar transmitter. The output characteristics of the transmitter and the real-time impedance variations of the sensor array are analyzed under the overload conditions. They are caused by electric and acoustic boundary conditions when the rotational transmission beam is operated. From these results, a new output control method of the transmitter is proposed to protect the transmitter and its loads. It can maximize the output power without the transmission pause even if the transient phenomena occur. The proposed technique is verified from the experiment.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.5
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• pp.21-26
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• 2005

It is important to measure the rotational accuracy of NC lathe spindle as it affects to the qualities of all machines machined by the NC lathe using in industries. The bad rotational accuracy of NC lathe spindle are caused mainly by wearness of the spindle in using and quality of spindle when machining and using low level bearings. It occurs especially in case of NC lathes because the cutting force acting to work-piece act on one side to the spindle not to both sides symmetrically. Therefore in this study, constructing experimental appratus for measuring of rotational accuracy by using eddy current type gap sensors, converters, screw terminal, data acquisition board inserted in computer and software f3r data acquisition, DT VEE ver. 5.0 and then error data acquired in the rotational accuracy test of NC lathe spindle are analysed in plots and statistical treatments.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.43-48
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• 2007

It is important to measure the rotational accuracy of lathe spindle as it affects to the qualities of all machines machined by the lathe using in industries. The bad rotational accuracy of lathe spindle are caused mainly by wearness of the spindle in using and quality of spindle when machining and using low level bearings. It occurs especially in case of lathes because the cutting force acting to work-piece act on one side to the spindle not to both sides symmetrically. Therefore in this study, constructing experimental apparatus for measuring of rotational accuracy by using eddy current type gap sensors AEC5706PS and sensors, s-06LN, data acquisition board DT9834(USB type) and software for data acquisition, DT Measure Foundry ver. 4.0.7 etc., error data acquired in the rotational accuracy test of lathe spindle are analysed in plots and statistical treatments.

• Journal of KSNVE
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• v.5 no.4
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• pp.483-492
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• 1995

For evaluation of rotational accuracy performance of high speed machine tool spindle system, the characteristics of main spindle and tool motion behavior are presented by means of three point accuracy testing method. The results of experiments and analyses are as follows: (1) The high speed spindle rotational accuracy can be evaluated by the combination of the spindle and tool motion behavior. (2) The spindle motion behavior increases up to more that 4 times the tool motion behavior. (3) For the influence of oil viscosity on spindle and tool taper application, 32 cSt of oil viscosity showed the most satisfactory result for rotational accuracy. (4) In order to improve the rotational accuracy of high speed machine tool spindle system, it is needed to reduce the combination error. This can be achieved by improving the working accuracy and supplying the proper lubrication with contact area at the spindle and tool.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.227-230
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• 1999

In this paper, the machining characteristics of high speed ball end milling affected by the rotational error of high speed spindle using air bearing are investigated. The error motions of a spindle have generally influenced on the surface roughness, the form accuracy, the tool life, etc. in end milling. Experiments are carried out over a wide range of rotational speeds(10,000-50,000rpm). The rotational errors of the spindle are measured by the gap sensor mounted on the spindle shaft at various cutting speeds. The relations between the surface roughness and the spindle error motion are presented. Results show that the rotational accuracy of the spindle directly affects the surface roughness of the machined surface.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.183.1-183.1
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• 2010

본 논문에서는 풍력발전기의 회전속도센서의 고장 발생 시 고장을 검출하고 회전속도센서의 사용 없이 Sensorless 제어로의 전환에 관한 연구를 기술하였다. 최근 풍력발전은 급속한 성장함에 따라 풍력발전기의 대형화 및 해상풍력화 추세에 있다. 특히 해상풍력발전은 바람 및 설치장소의 제약에서 벗어나는 이점에 반해 염해, 습도 및 파도에 의한 진동 발생으로 센서의 고장 발생률이 높을 것으로 예상된다. 이에 따라 풍력발전기의 회전속도센서 고장 발생 시 이를 검출하는 방법을 제시하였다. 또한 회전속도센서의 고장이 검출되면 회전속도센서를 이용한 풍력발전기 제어방식에서 Sensorless 제어로의 전환을 통해 안전하게 풍력발전기를 운전할 수 있도록 하였다. 연구된 제어기법은 PSIM을 이용한 시물레이션을 통해 결과를 검증하였다.

• 제어로봇시스템학회:학술대회논문집
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• 1998.10a
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• pp.413-418
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• 1998

We often use induction motor in the hard environment including vibration and high ambient temperature, or in maintenance free operation, because induction motor has durable and simple structure. However, when we use it as servo actuator or accurate speed control motor, we have to equip sensor such as encoder and tachogenerator with the motor control system. And generally those sensor's abilities against bad environment are less than the induction motor itself, So if we can remove these sensors from the system, it'll have more environmental resistance, and the cost will also be reduced. Actually this removal has been achieved in limited field. However, that needs complex calculations and a certain elapse time for data processing. In our study, we intended to estimate the rotational speed from the motor current instead of speed sensor, easily and rapidly in comparison to former methods.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.349-358
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• 2019

This paper aimed at collecting sensor signals to extract characteristic parameter of the rotor. A vibration test rig has been developed to perform model tests. Signal characteristics were analyzed when driving normally. Envelope FFT Analysis is used to extract vibration components caused by periodic impacts from other vibration factors. Signal analysis was performed when load changes were given to speed sensors and vibration test rigs that show low frequency characteristics of the rotor and signal analysis according to rotational speed. The acceleration signal measured in the bearing housing has a small amplitude and produces only the rotational frequency component and harmonic component of the motor. As the number of rotations increases, the amplitude of acceleration can be seen. As the rotational speed increases, it can be seen that there is a difference in the shape of the original data and compared with the acceleration FFT graph, it can be seen that the noise is strong at low frequencies and the corresponding rotational frequency components are clearly represented. It can be seen that changing the load does not increase the main rotational frequency component.