• Journal of Astronomy and Space Sciences
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• 제22권4호
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• pp.513-526
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• 2005

본 연구의 목적은 회전안정화 우주비행체 내부에 탑재된 유동질량의 운동을 보다 광범위한 파라미터 영역에 대해 해석하고, 관련 분야에서 활용할 수 있는 적정한 설계 기준을 제공하기 위한 것이다. 문제의 해석을 위해 perturbation 기법을 이용하였고, 그 결과로 파라미터 공간에서의 안정-불안정 영역을 결정할 수 있는 Ince-Strutt 선도를 구하였다. 해석 방법 및 확보된 결과의 적정성을 입증하기 위하여 선도에서 취한 여러 파라미터 값에 대한 수치적 시뮬레이션을 수행하였다. 유동체 운동의 위상평면 분석을 통하여 수행된 해석 과정 및 결과가 적정한 것으로 입증되었으며, 회전 비행체에 탑재된 유동질량의 운동은 파라미터 값의 선택에 따라 여러 가지 형태의 안정-불안정 현상을 유발함을 알 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.395-400
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• 1991

In spinning satellite, a gyrotorquer generates a control torquer along two orthogonal axes normal to the spin axis of the vehicle. Matrix Fraction Description(MFD) are used to obtain minimal realization of the transfer matrix relating the attitude angles and the rate of rotation of the gimbals of gyrotorquer. In this paper, the Linear Quadratic Gaussian with Loop Transfer Recovery and H.meihodologies are used to design controller for spinning satellite.

• Journal of Mechanical Science and Technology
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• 제19권4호
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• pp.985-992
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• 2005

Vehicle Stability Control (VSC) system prevents vehicle from spinning or drifting out mainly by braking intervention. Although a control threshold of conventional VSC is designed by vehicle characteristics and centered on average drivers, it can be a redundancy to expert drivers in critical driving conditions. In this study, a manual adaptation of VSC is investigated by changing the control threshold. A control threshold can be determined by phase plane analysis of side slip angle and angular velocity which is established with various vehicle speeds and steering angles. Since vehicle side slip angle is impossible to be obtained by commercially available sensors, a side slip angle is designed and evaluated with test results. By using the estimated value, phase plane analysis is applied to determine control threshold. To evaluate an effect of control threshold, we applied a 23-DOF vehicle nonlinear model with a vehicle planar motion model based sliding controller. Controller gains are tuned as the control threshold changed. A VSC with various control thresholds makes VSC more flexible with respect to individual driver characteristics.

• Steel and Composite Structures
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• 제24권3호
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• pp.351-358
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• 2017

Due to the increasing competition, automotive manufacturers have to manufacture highly safe and light vehicles. The parts which make up the body of the vehicle and absorb the energy in case of a crash, are usually manufactured with sheet metal forming methods such as deep drawing, bending, trimming and spinning. The part may get thinner, thicker, folded, teared, wrinkled and spring back based on the manufacturing conditions during manufacturing and the type of application methods. Transferring these effects which originate from the forming process to the crash simulations that are performed for vehicle safety simulations, makes accurate and reliable results possible. As a part of this study, firstly, the one-step and incremental sheet metal forming analysis (deep drawing + trimming + spring back) of vehicle front bumper beam and crash boxes were conducted. Then, crash performances for cases with and without the effects of sheet metal forming were assessed in the crash analysis of vehicle front bumper beam and crash box. It was detected that the parts absorbed 12.89% more energy in total in cases where the effect of the forming process was included. It was revealed that forming history has a significant effect on the crash performance of the vehicle parts.

• Journal of Positioning, Navigation, and Timing
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• 제8권3호
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• pp.107-117
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• 2019

When a vehicle moves with a high rotation rate, it is not easy to measure the angular velocity using an off-the-shelf gyroscope. If the angular velocity is estimated using the extended Kalman filter in the gyro-free inertial navigation system, the effect of the accelerometer error and initial angular velocity error can be reduced. In this paper, in order to improve the navigation performance of the gyro-free inertial navigation system, an angular velocity estimation method is proposed based on an extended Kalman filter with an accelerometer random bias error model. In order to show the validity of the proposed estimation method, angular velocities and navigation outputs of a vehicle with 3 rev/s rotation rate are estimated. The results are compared with estimates by other methods such as the integration and an extended Kalman filter without an accelerometer random bias error model. The proposed method gives better estimation results than other methods.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권1호
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• pp.95-95
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• 2004

The objectives of this study are to perform extensive analysis on internal mass motion for a wider parameter space and to provide suitable design criteria for a broader applicability for the class of spinning spacecraft. In order to examine the stability criterion determined by an analytical method, some numerical simulations will be performed and compared at various parameter points. (omitted)

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.44_46
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• 2009

Becoming effective on Kyoto protocol, reduction of greenhouse gas is an urgent concern of our world. Transportation, depending on fossil fuel, is required to transfer higher effiency and green tech. oriented one. Electric Vehicle-EV-is take attention with its ability not only to reduce CO2 emission in transportation, but also to support load levelizing, spinning reserve, increase power quality on microgrid. This paper presents the recent policy for EV diffusion and the effects on power system demand and local system power quality.

• 한국자동차공학회논문집
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• 제23권5호
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• pp.515-523
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• 2015

In this paper, we fabricated and evaluated the gas sensor for the detection of CO gas and $NO_X$ gas among the vehicle exhaust emission gasses. The $SnO_2$ (tin dioxide) layer is used as the detection material, and the thin-film type and the nano-fiber type layers are deposited with various thicknesses using sputtering method and electro spinning method, respectively. The experiments are performed in the chamber where the gas concentration is controlled with mass flow controller. The fabricated devices are applied to the CO and $NO_X$ gas, where the device with the thinner $SnO_2$ layer shows better sensitivity. The nano-fiber has the larger surface area, and the shorter response time and recovery time are obtained. From the experimental results, both types of gas sensors successfully detect CO and $NO_X$ gases, which can be applied to measure those gases from the vehicle emissions.

• 드라이브 ㆍ 컨트롤
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• 제10권3호
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• pp.1-6
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• 2013

Traction control suppresses the spinning of the driven wheel during drive away or acceleration on slippery road condition. In this study, the estimation method of brake pressure hardly measured is proposed. The estimation method of brake pressure and the brake pressure control with pulse width modulation(PWM) are verified a good performance through experiment. Also, the vehicle simulation on slippery road conditions is validated the applicability of brake pressure control for traction control. The simulation results have showed that the brake pressure can be used the control variable for traction control.

• 한국소음진동공학회논문집
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• 제13권2호
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• pp.92-98
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• 2003

A rate gyroscope has been used popularly to measure the angular motion of a given vehicle using a symmetric rotor spinning rapidly about its symmetry axis. Since the rapid rotation is required in this type of gyroscope, the motor has been used to make the rotor spin, so that it results in a heavy configuration. The toning-fork gyroscope has been developed to avoid this problem, which utilizes a Coriolis coupling term and vibration about one axis. Due to the Coriolis effect, the vibration of one axis is transferred to other axis when the angular motion along the vibrating axis is given to the system. The concept of a tuning-fork gyroscope was recently realized using MEMS techniques. However, the dynamic characteristics of the tuning-fork gyroscope has not been discussed in detail. In this study. we derived the equations of motion for the tuning-fork type gyroscope using the energy approach and investigated the dynamic characteristics by means of numerical analysis.