• 한국산업융합학회 논문집
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• 제17권3호
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• pp.93-102
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• 2014

Recently the interest in permanent magnet alternating motor using for electric compressor become great. Especially the research on Interior Permanent Magnet Motor has been doing actively for its advantages in the energy density and the efficiency. In order to control the output of motor to the desired value, the current control or speed control of motor are required. The accurate detection of rotor position and speed information are necessary for the control of motor. In general, the encoder, hall sensor, and resolver are used to obtain the information of motor position and speed and the speed detection algorithm, M/T method, is applied. However, the M/T method causes the error depending on rotor speed. Therefore, this M/T speed detection method is not perfect. In this paper, it is proposed that the PI control with a 1st transfer function and the integration element between velocity and position are composed in series and this feeds back to the reference value of position angle. The proposed algorithm is a function of the integral elements 2nd term, speed element, is used as an output. Thus, it is possible to detect the correct speed by configuring like the mechanical structure similarly. The proposed algorithm is verified by using PSIM DLL and is applied to the BLAC motor drive. And also it is confirmed that this system estimates the accurate speed regardless of rotor speed changes. As a example, the experimental results and simulations shows that the proposed method is very effective.

• Wind and Structures
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• 제20권5호
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• pp.701-718
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• 2015

The joint distribution of wind speed and wind direction at a bridge site is vital to the estimation of the basic wind speed, and hence to the wind-induced vibration analysis of long-span bridges. Instead of the conventional way relying on the weather stations, this study proposed an alternate approach to obtain the original records of wind speed and the corresponding directions based on field measurement supported by the Structural Health Monitoring System (SHMS). Specifically, SHMS of Sutong Cable-stayed Bridge (SCB) is utilized to study the basic wind speed with directional information. Four anemometers are installed in the SHMS of SCB: upstream and downstream of the main deck center, top of the north and south tower respectively. Using the recorded wind data from SHMS, the joint distribution of wind speed and direction is investigated based on statistical methods, and then the basic wind speeds in 10-year and 100-year recurrence intervals at these four key positions are calculated. Analytical results verify the reliability of the recorded wind data from SHMS, and indicate that the joint probability model for the extreme wind speed at SCB site fits well with the Weibull model. It is shown that the calculated basic wind speed is reduced by considering the influence of wind direction. Compared to the design basic wind speed in the Specification of China, basic wind speed considering the influence of direction or not is much smaller, indicating a high safety coefficient in the design of SCB. The results obtained in this study can provide not only references for further wind-resistance research of SCB, but also improve the understanding of the safety coefficient for wind-resistance design of other engineering structures in the similar area.

• 한국철도학회논문집
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• 제18권3호
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• pp.203-211
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• 2015

차량의 승차감은 차체의 성능 뿐만 아니라 궤도의 특성에 의해서도 영향을 받게 되므로, 궤도선형 및 궤도틀림의 관리를 위하여 차량의 승차감 평가결과를 이용한다. 본 논문에서는 차체의 진동가속도 계측데이터를 이용하여 궤도유지보수와 상관성이 있는 Continuous comfort 승차감 평가방법을 통해 국내 경부고속철도노선 및 유럽 고속철도노선에 대한 승차감 평가를 수행하였다. 승차감 평가결과를 속도대역 별로 구분하여 국내외 고속철도노선의 승차감 분포현황을 정량적으로 분석하고 승차감 수준을 비교하였다. 국내의 경부고속철도의 승차감이 유럽 고속철도노선에 비하여 다소 우수한 것으로 평가되었으며, 이를 통해 국내 고속선의 궤도선형 및 궤도틀림의 관리가 적절하게 수행되고 있음을 유추할 수 있었다.

• 한국운동역학회지
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• 제16권1호
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• pp.11-17
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• 2006

The purpose of this study was to evaluate the smoothness of movement during various walking speeds. Based on the maximum smoothness theory (or the minimum jerk theory), we hypothesized that the walking speed at the maximum smoothness (or minimum normalized jerk) is the same as that at the minimum energy consumption. Eleven university students participated in treadmill walking experiment with 11 different walking speeds (1.11, 1.19, 1.25, 1.33, 1.56, 1.78, 1.9, 2, 211, 233, and 2.47m/sec). Normalized jerk at 15 markers and the center of mass was calculated. Results showed that there existed a quadratic relationship between the normalized jerk of the vertical direction at the center of mass and the walking speed As the walking speed increased, the normalized jerk of all directions at the heel decreased Our hypothesis that the previously published energetically optimal walking speed ($1.25\;{\sim}\;1.4m/s$) is the same as the minimum jerk speed (1.78m/s) did not agree with this result. The minimum normalized jerk at the center of mass occurred at the walking speed of 1.78m/s which was the preferred walking speed by subjects' questionaries. Further studies concerning the energetically optimal walking speed, preferred walking speed, and walk-run transition speed or run-walk transition speed are necessary based on actual energy consumption experiment and various multi-dimensional analysis.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.377-383
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• 2011

The paper is to perceive accurately speed of the train through redundant processor operation. When Slip/slide is occurred at the axle, the train is applied brake force using the Tachometer and the Doppler sensor which assistance equipment. One of the main features of railway signaling system is that rolling stock is made stop to avoid collision with the rolling stock ahead when the rolling stock exceeds its maximum operating speed in line. In addition, in the case of the rolling stock with automatic train operation, it carries out activities such as braking and propulsion using the difference between its actual speed and target speed at the point. To perform these functions, it is essential to calculate the exact speed of the rolling stock in signaling equipment on vehicles. Train speed detection unit are composed of the Tachometer and the Doppler sensor, and speed information is sent to the SDU unit. The processor of SDU unit calculates the speed of the train using compare logic the received speed information. Even if there are Slip/Slide, signaling system is available to apply exact braking, to improve stop on position and to guarantee the safety of trains.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2064-2071
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• 2011

We are developing an innovative super-speed land transportation system running in a partial vacuum in tunnels with small inside diameter to reduce the aerodynamic drag forces. This paper presents the experimental results obtained on a small scale model when a super-speed train model passing through a tunnel with small inside diameter and a partial vacuum to reduce the aerodynamic drag forces. The experiments were performed on a 1/52-scale moving model rig in which a train model with a diameter of 58 mm and a length of 603 mm was accelerated in a launching tube with 12.27 m length by means of the compressed air launcher and then passed through a tunnel model with 17.149 m length. The partial vacuum was maintained in the tunnel in order to reduce the energy consumption of the propulsion system of the super-speed tube train at super-speed of 700 km/h. In this study, the blockage ratio of train to tunnel model is 0.336. Experimental results show the nonlinear effects of the vacuum on the speed-up of the train model in the tunnel model under the partial vacuum up to 0.21 atm and at the velocity up to 684 km/h. This paper is first study for experiments on the speed-up of a super-speed train model in the partial vacuum tunnels.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.726-728
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• 2004

In this paper, the gain of the observer is properly set up using the fuzzy control and Fuzzy-Sliding observer(FSQ) that have a superior transient characteristic and is easy to implement compared to the existing method is designed. It estimate the differentiation of the armature current directly using the armature current measured in the AC motor. It estimate the speed of the rotor using the differentiation. It is proposed speed sensorless control method using the estimated speed. Optimal gain of speed observer(Luenberger observer) was set up using the fuzzy control and adapted speed control of AC servo motor. To verify the performance of designed Fuzzy-Sliding observer, simulation compared with fixed speed observer gain of G.B Wang and S.S Peng's sliding observer is performed. Also, it was proved the excellence and feasibility of the proposed observer from the comparison test with a speed sensor and without a speed sensor which used a highly efficient drive and 400W AC servo motor starting system.

• 한국해양공학회지
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• 제25권2호
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• pp.113-119
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• 2011

The Korea navy has a vital national interest in maritime security. The national strategy for maritime security focuses on preventing terrorism, crime, and hostile acts in the maritime domain. This requires the development of high speed crafts for maritime security in the South Korea domain. This paper reviews the state of the art on the development of high speed craft internationally, including efforts by the U.S. navy, and analyses the riverine environment to operate high speed crafts in South Korea. This paper makes specific proposals for high speed craft such as their main dimensions, speed, endurance, hull structure material, propulsion system, and general arrangement and 3D shape. This paper was used in the generation of basic resources for future ROC (requirement of capability) of high speed crafts using an engineering methodology.

• 한국지능시스템학회논문지
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• 제24권4호
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• pp.366-371
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• 2014

본 논문에서는 정격풍속 이상에서 발전량을 일정하게 유지하기 위하여 회전속도의 변화율을 이용한 신경망 피치제어기가 제안되었다. 제안된 신경망 피치제어기는 발전기의 정격 회전속도와 현재 회전속도의 차이를 기본정보로 사용하고 추가적으로 발전기 회전속도의 변화율을 사용하였다. 시뮬레이션은 Matlab/simulink에서 수행되었으며, 시뮬레이션을 통해 제안된 피치제어기를 사용한 풍력발전기는 발전기의 정격 회전속도인 122.9[rad/s]로 잘 유지 되는 것을 확인하였다.

• 한국산학기술학회논문지
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• 제7권3호
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• pp.338-343
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• 2006

본 논문에서는 직류전동기 구동 시스템의 전류 및 속도 제어를 위하여 dSPACE 1104 시스템을 이용하여 전류 궤환을 갖는 속도 제어시스템을 구현하였다. 전류 및 속도 제어기의 설계는 MATLAB/SIMULINK 프로그램을 사용하여 간편하고 손쉽게 구현하였으며, 직류전동기 속도제어의 안정성과 응답성을 향상시킬 수 있었다. 직류전동기의 전류제어 및 속도제어는 DSP 보드와 dSPACE 시스템을 사용하여 수행하였으며, 속도의 궤환은 속도센서인 엔코더 펄스를 이용해서 QEP로 처리하였고, 전류의 궤환은 전류센서인 홀센서를 통해서 A/D 변환기로 처리하였다. 제어기들은 각각 PI 전류제어기 및 PI 속도제어기를 설계하였고 시뮬레이션과 실험을 통해서 전류 및 속도 응답을 확인하였다.