• Journal of electromagnetic engineering and science
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• 제18권1호
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• pp.13-19
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• 2018

Wireless power transfer (WPT) based on magnetic resonant coupling is a promising technology in many industrial applications. Efficiency of the WPT system usually depends on the tilt angle of the transmitter or the receiver coil. This work analyzes the effect of the tilt angle on the efficiency of the WPT system with horizontal misalignment. The mutual inductance between two coils located at arbitrary positions with tilt angles is calculated using a numerical analysis based on the Neumann formula. The efficiency of the WPT system with a tilted coil is extracted using an equivalent circuit model with extracted mutual inductance. By analyzing the results, we propose an optimal tilt angle to maximize the efficiency of the WPT system. The best angle to maximize the efficiency depends on the radii of the two coils and their relative position. The calculated efficiencies versus the tilt angle for various WPT cases, which change the radius of RX ($r_2=0.075m$, 0.1 m, 0.15 m) and the horizontal distance (y=0 m, 0.05 m, 0.1 m), are compared with the experimental results. The analytically extracted efficiencies and the extracted optimal tilt angles agree well with those of the experimental results.

• International Journal of Automotive Technology
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• 제5권2호
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• pp.77-88
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• 2004

Narrow commuter vehicles can address many congestion, parking and pollution issues associated with urban transportation. In making narrow vehicles safe, comfortable and acceptable to the public, active tilt control systems are likely to playa crucial role. This paper focuses on the development of an active direct tilt control system for a narrow vehicle that utilizes an actuator in the vehicle suspension. A simple PD controller can stabilize the tilt dynamics of the vehicle to any desired tilt angle. However, the challenges in the tilt control system design arise in determining the desired lean angle in real-time and in minimizing tilt actuator torque requirements. Minimizing torque requirements requires the tilting and turning of the vehicle to be synchronized as closely as possible. This paper explores two different control design approaches to meet these challenges. A Receding Horizon Controller (RHC) is first developed so as to systematically incorporate preview on road curvature and synchronize tilting with driver initiated turning. Second, a nonlinear control system that utilizes feedback linearization is developed and found to be effective in reducing torque. A close analysis of the complex feedback linearization controller provides insight into which terms are important for reducing actuator effort. This is used to reduce controller complexity and obtain a simple nonlinear controller that provides good performance.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.116-119
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• 2004

In this paper, we have improved a novel (ECB) mode using tilt angle in the unique condition by hot-plate equipment. The new control of tilt angle for nematic liquid crystal (NLC) with negative and positive dielectric anisotropy on the rubbed homeotropic polyimide (PI) using baking method by Hot-plate equipment was investigated. LC tilt angle decreased with increasing baking temperature and time. Especially, the low LC tilt angle of positive type NLC $({\Delta}n>0)$ on the rubbed homeotropic PI surface by increasing temperature and time was measured. The EO characteristics of the novel ECB mode using control of tilt angle on the homeotropic surface than that of conventional OCB cell can be improved. We suggest that the developed the Novel ECB cell using control of tilt angle on the homeotropic surface is a promising technique for the achievement of a fast response time and a high contrast ratio.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.856-860
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• 2008

Wire-suspensions in the conventional actuators mechanically support the moving part and guarantee the accuracy of the actuator without tangential tilt actuation. However, such a suspension configuration has considerable stiffness in the tangential tilt direction with two additional wire beams for the tangential tilt. Thus, we performed a design sensitivity analysis for the wire-suspension stiffness of 4-axis actuator and controlled the main parameters such as distance among wire-suspensions and wire-suspension length to allow tangential tilt flexibility. The elasticity of frame PCB that supports the moving part by wire-suspensions was also exploited to improve the flexibility of wire-suspension in the tangential tilt direction. A novel suspension structure was devised by establishing eight wire-suspensions at both sides of the moving part for electrical connection to coils. The magnetic circuit according to the proposed 4-axis actuator using multi-polar magnet and coils was also suggested for the generation of electromagnetic forces in the focusing, tracking, radial and tangential tilt directions.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.181-184
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• 2005

In this paper, we have improved a novel fast response time liquid crystal operating mode using tilt angle in the unique condition by hot-plate equipment. The new control of tilt angle for nematic liquid crystal (NLC) with negative and positive dielectric anisotropy on the rubbed homeotropic polyimide (PI) using baking method by Hot-plate equipment was investigated. LC tilt angle decreased with increasing baking temperature and time. Especially, the low LC tilt angle of positive type NLC (${\Delta}n$>0) on the rubbed homeotropic PI surface by increasing temperature and time was measured. The EO characteristics of the high tilted OCB(HTOCB) mode using control of tilt angle on the homeotropic surface than that of conventional OCB cell can be improved. We suggest that the developed the HTOCB cell using control of tilt angle on the homeotropic surface is a promising technique for the achievement of a fast response time and a high contrast ratio.

• 한국항행학회논문지
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• 제22권6호
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• pp.500-506
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• 2018

본 논문에서는 유도탄의 정확한 자세를 알기 위해 주 관성항법장치와 유도탄 내부 관성항법장치를 이용하는 one-shot 정렬에 대해 고려하였다. One-shot정렬을 수행하기 위해서는 주 관성항법장치와 부 관성항법장치 사이의 비정렬각을 구해야 되는데, 장입유도탄과 부 관성항법장치 사이의 비정렬각을 구하여 보상하면 된다. 비정렬각은 장입유도탄의 롤 회전을 이용하여 산출되며, 장입유도탄을 회전하기 위한 정렬용 치구, 장입유도탄의 수평 상태를 측정하기 위한 수평각도계와 인터페이스 구조물이 제작되었다. TAS(tilt angle save) 점검 결과, 비정렬각 ${\alpha}$, ${\beta}$, ${\gamma}$ 값이 정상 범위이며 이 값을 보상하여 one-shot 정렬을 수행할 수 있다.

• Smart Structures and Systems
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• 제31권3호
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• pp.301-309
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• 2023

Tilt is a key indicator of structural safety. Real-time monitoring of tilt responses helps to evaluate structural condition, enable cost-effective maintenance, and enhance lifetime resilience. This paper presents a prototype wireless sensing system for structural tilt measurement. Long range (LoRa) technology is adopted by the sensing system to offer long-range wireless communication with low power consumption. The sensor integrates a gyroscope and an accelerometer as the sensing module. Although tilt can be estimated from the gyroscope or the accelerometer measurements, these estimates suffer from either drift issue or high noise. To address this challenging issue and obtain more reliable tilt results, two sensor fusion algorithms, the complementary filter and the Kalman filter, are investigated to fully exploit the advantages of both gyroscope and accelerometer measurements. Numerical simulation is carried out to validate and compare the sensor fusion algorithms. Laboratory experiment is conducted on a simply supported beam under moving vehicle load to further investigate the performance of the proposed wireless tilt sensing system.

• Earthquakes and Structures
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• 제17권6호
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• pp.635-647
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• 2019

Tests and theoretical studies for seismic responses of a transmission tower-line system under coupled horizontal and tilt (CHT) ground motion were conducted. The method of obtaining the tilt component from seismic motion was based on comparisons from the Fourier spectrum of uncorrected seismic waves. The collected data were then applied in testing and theoretical analysis. Taking an actual transmission tower-line system as the prototype, shaking table tests of the scale model of a single transmission tower and towers-line systems under horizontal, tilt, and CHT ground motions were carried out. Dynamic equations under CHT ground motion were also derived. The additional P-∆ effect caused by tilt motion was considered as an equivalent horizontal lateral force, and it was added into the equations as the excitation. Test results were compared with the theoretical analysis and indicated some useful conclusions. First, the shaking table test results are consistent with the theoretical analysis from improved dynamic equations and proved its correctness. Second, the tilt component of ground motion has great influence on the seismic response of the transmission tower-line system, and the additional P-∆effect caused by the foundation tilt, not only increases the seismic response of the transmission tower-line system, but also leads to a remarkable asymmetric displacement effect. Third, for the tower-line system, transmission lines under ground motion weaken the horizontal displacement and acceleration responses of transmission towers. This weakening effect of transmission lines to the main structure, however, will be decreased with consideration of tilt component.

• 대한방사선치료학회지
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• 제22권2호
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• pp.85-95
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• 2010

목 적: 두경부 환자의 CT simulation시 metal artifact가 발생하여 영상의 질 저하와 선량계산의 오차를 유발 할 수 있어 metal artifact를 줄이기 위한 gantry tilt scan의 유용성을 평가하고자 한다. 대상 및 방법: Metal artifact를 줄이기 위하여 $20^{\circ}$ gantry tilt scan하여 $0^{\circ}$로 재구성한 이미지를 획득하였다. AAPM CT performance Phantom을 이용하여 CT number를 비교 분석하고, 아크릴 팬텀을 이용하여 체적의 일치여부를 확인하였다. Metal artifact에 의한 영향을 평가하기 위해 Intensity volume Histogram (IVH)을 통한 CT number의 균질성 및 Dose Volume histogram (DVH)을 통한 선량평가를 시행하였다. 결 과: CT number와 체적의 비교에서는 차이가 0.5% 이하로 나타났다. IVH를 비교 분석결과 gantry tilt scan에서 artifact에 의한 영향이 감소되어 CT number의 균질도가 향상되고, DVH 비교결과는 양쪽 이하선의 0.2~6%의 평균선량 오차를 감소시켰다. 결 론: Head & Neck 방사선치료 시 metal artifact 때문에 체표윤곽의 구별이 어렵고 선량의 오차가 발생한다. Gantry tilt scan을 이용하면 정확한 조직의 묘사가 가능하고, CT number 균질도가 향상되어 선량의 오차를 줄일 수 있었다. Gantry tilt scan 은 Head & Neck 방사선치료 시 정확한 방사선치료에 매우 유용함을 확인하였다.

• Journal of Magnetics
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• 제2권1호
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• pp.22-24
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• 1997

FeN thin films were deposited by RF-reactive diode sputtering to investigate magnetic characteristics variation due to substrate tilt during the film deposition, and their magnetic properties were measured by VSM, SEM and AFM. When the substrate tilt pivot edges were parallel to the applied field, the magnetic anisotropy was increased When the substrate tilt pivot edges were perpendicular to the applied field, the easy magnetization axis became the hard magnetization axis, and the hard axis became the easy axis as the tilt angles were increased. The reason is believed to be due to the fact that the tilt induced shape magnetic anisotropy became larger than the field induced magnetic anisotropy by DC magnetic field as the crystal grains are enlongated along the substrate tilt pivot edges due to "oblique incidence anisotropy" commonly found in eveporated thin films.