• 한국산학기술학회논문지
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• 제12권5호
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• pp.2061-2066
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• 2011

사이클로이드 감속기는 기계의 회전수를 조절하기위한 장치이다. 사이클로이드 감속기는 큰 토크로 변환시킬 수 있는 장점이 있지만 높은 회전수 에는 적합하지 않다. 한편 200톤 하중이 가해지는 수송기기에 있어서 감속기의 사용한계속도를 찾아내기는 불가능하다. 본 연구에서는 LS-DYNA를 이용하여 마찰손실동력을 수치 해석적으로 검토하였다. 최대토크3.5ton-m에 있어서 회전수 60rpm 그리고 162rpm으로 구동하여 해석을 수행한 결과 다음과 같은 결과를 얻었다. 60rpm회전의 경우 최대응력은 RV gear의 경우 463MPa 핀기어의 경우 507MPa이 발생하였다. 마찰손실동력은 50kW이며, 162rpm의 경우 최대응력값은 RV gear와 핀기어 각각 550MPa, 538MPa이 발생하였다. 손실동력은 175kW이 발생하여 사용이 불가능하다는 것을 알 수 있었다.

• 대한토목학회논문집
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• 제34권2호
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• pp.627-635
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• 2014

현재 도로상에서의 최고속도제한은 교통 혼잡이나 기상변화에 대처하기 힘들기 때문에 교통사고를 유발하는 요인이 될 수 있다. 물론 도로교통법에 따르면 악천후 시 20~50% 속도를 감속시켜야 하지만 운전자들의 판단에 맡겨야 하는 어려움이 있고, 감속하는 차량과 하지 않는 차량들간의 상대속도가 달라져서 주행환경과 안전에 큰 영향을 끼친다. 따라서 가변속도제어는 도로상의 운전자들에게 적절한 최고속도제한을 지정해 줌으로서 운전자들이 악천후 시에 감속된 속도로 달리게 하여 사고를 미연에 방지하거나 사고피해 심각도를 낮출 수 있을 거라 예상된다. 본 연구의 목적은 교통사고가 잦은 부산광역시의 연속류(도시고속도로)를 중심으로 적절한 구간에서 가변속도제어가 실시될 수 있도록 교통사고의 특성을 분석하여 사고 심각도를 조사하였다. 그리고 도시고속도로의 기하구조상 많은 곡선부 환경을 가지고 있으므로 평면 곡선부 지점을 건조한 노면과 젖은 노면을 비교 시뮬레이션 해봄으로써 비에 젖은 노면일수록 속도에 따른 사고위험이 크다는 결과를 얻었다. 이러한 결과를 토대로 먼저 도시고속도로에서 기본구간, 터널부근, 램프부근, 요금소 부근, 진 출입부 등 다양한 요인을 고려한 뒤 속도감소가 필요한 구간에서 우선 실시하여 운전자들의 참여의식과 필요성을 인식시키고 향후 도시고속도로 전 구간에 설치 및 운영이 확대되어야 할 것으로 판단된다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.311-315
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• 2007

In this paper, a new approach for the Synchronous Reluctance Motor control which ensures producing Maximum Torque per Ampere(MTPA) over the entire field weakening region is presented. In addition, This paper presents a speed sensorless control scheme of SynRM using artificial neural network. Also, by adjusting the base speed for the field weakening operation according to the flux level, the current and voltage limit, the smooth and precise transition into the field weakening operation can be achieved The proposed scheme is verified validity through simulation.

• 한국정밀공학회지
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• 제19권9호
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• pp.172-178
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• 2002

One of the ever-increasing demands on the performances of heterodyne interferometers is to improve the measurement resolution, of which current state -of-the-art reaches the region of sub-nanometers. So far, the demand has been met by increasing the clock speed that drives the electronics involved fur the phase measurement of the Doppler shift, but its further advance is being hampered by the technological limit of modem electronics. To cope with the problem, in this investigation, we propose a new scheme of phase -measuring electronics that reduces the measurement resolution without further increase in clock speed. Our scheme adopts a super-heterodyne technique that lowers the original beat frequency to a level of 1 MHz by mixing it with a stable reference signal generated from a special phase- locked-loop. The technique enables us to measure the phase of Doppler shift with a resolution of 1.58 nanometer at a sampling rate of 1 MHz. To avoid the undesirable decrease in the maximum measurable speed caused by the lowered beat frequency, a special form of frequency up-down counting technique is combined with the super-heterodyning. This allows performing required phase unwrapping simply by using programmable digital gates without 2n ambiguities up to the maximum velocity guaranteed by the original beat frequency.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.159-163
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• 2004

The KNR(Korean National Railroad) has a speed limit regulation(130km/h) for the train passing the turnout to guarantee a safety. Since that speed is set as below the maximum commercial speed(140km/h), it has been regarded as a major factor to obstacle the total efficiency. The crossing rail part of the turnout system is formed into a antisymmetric, furthermore, there are several discontinuous part. Thus, measuring the strain signals of this part is impossible actually and it must be in the most difficult work related the turnout research. In this research, the program that can anticipate the signals at the various conditions with considering its own shape was developed and the preciousness of its results had been examined by comparing analyzed and measured ones at the other parts. The simulation was performed with varying the factors such as train speed and contact depth. As a results, it was proved that the regulation was not useless and very important guide at least up to now.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 춘계학술대회 논문집
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• pp.399-403
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• 2002

The transmission system of high speed train serve in the severe condition compared with those of other trains, namely, they have to transmit high power to run with high speed and they have to make maximum use of the limited space. To clarify the strength of gear for Korea High-Speed Train, a bending fatigue test of gear specimen is performed and compare with actual gear's. From this result, specimen test is useful to infer S-N curve and endurance limit of actual gear that much time and expense are consumed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.984-988
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• 2010

In Korea, the next generation high-speed train, whose target is maximum speed of 400km/h and operating speed of 370km/h, has been developed since 2007. In this paper, the safety of the next generation high-speed train is compared UIC 518OR under the malfunctioning situation of the suspension system. The bogie of the next generation high-speed train has two suspensions. Two different vehicle models of the next generation high-speed train are created by using VAMPIRE and ADAMS/Rail, which are specialized to design railway vehicle. And Those models are showed same dynamic properties. First of all, the sensitivity analysis of ModelCenter is performed using model of VAMPIRE. One suspension element which has significant effects on the safety are selected by result of the sensitivity analysis. And then, the dynamic analysis when the suspension element is broken is performed using ADAMS/Rail. The 30km track between Pungsegyo and Biryong tunnel in Gyeongbu High-speed Line was used at the dynamic analysis. The estimated value is found by using the normal method of UIC 518OR. The estimated values on the normal/fault state and the limit values of UIC 518OR are compared. Finally, the safety of the next generation high-speed train is verified.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1456-1458
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• 2005

In this paper, a new approach for the synchronous reluctance motor control which ensures producing maximum torque per ampere(MIPA) over the entire field weakening region is presented. In addition, This paper presents a speed sensorless control scheme of SynRM using artificial neural network. Also, by adjusting the base speed for the field weakening operation according to the flux level, the current and voltage limit, the smooth and precise transition into the field weakening operation can be achieved. The proposed scheme is verified validity through simulation.

• Journal of Magnetics
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• 제16권1호
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• pp.71-73
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• 2011

Hybrid electric vehicles have attracted much attention of late, emphasizing the necessity of developing traction motors with a high input current and a wide speed range. Among such traction motors, various researches have been conducted on interior permanent-magnet synchronous motors (IPMSMs) with high power density and mechanical solidity. Due to the complexity of its parameters, however, with nonlinear motor characteristics and current vector control, it is actually difficult to accurately estimate the base speed within an actual operating speed range or a voltage limit. Moreover, it is impossible to construct an efficiency map as the efficiency differs according to the control mode. In this study, a simulation method for operation performance considering the nonlinearity of IPMSM was proposed. For this, datasets of various nonlinear parameters were made via the finite-element method and interpolation. Maximum torque-per-ampere and flux-weakening control were accurately simulated using the datasets, and an IPMSM efficiency map was accurately constructed based on the simulation. Lastly, the validity of the simulation was verified through tests.

• 전기학회논문지P
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• 제50권3호
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• pp.109-116
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• 2001

In this paper, we adapted BLDC motor to PV water pumping systems to maintain high efficiency in the wide speed area. Also, to design confidence we adapted the vector control that drive the maximum torque at each speed limit. We designed optimal gain value of current, speed and pressure PI controller. Inverter gate pulse used Space Vector PWM to reduce torque pulsation of BLDC motor. According to, it was improve general matters of high water storage tank method by direct water supply pumping method.