• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.3
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• pp.233-245
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• 2011

A new BWIM(bridge weigh-in-motion) algorithm using both measured strain and acceleration data is proposed. To consider the effects of bridge vibration on the estimation of moving loads, the dynamic governing equation is applied with the known stiffness and mass properties but damping is ignored. Dynamic displacements are computed indirectly from the measured strains using the beam theory and accelerations are measured directly by accelerometers. To convert a unit moving load to its equivalent nodal force, a transformation matrix is determined. The incompleteness in the measured responses is considered in developing the algorithm. To examine the proposed BWIM algorithm, simulation studies, laboratory experiments and field tests were carried. In the simulation study, effects of measurement noise and estimation error in the vehicle speed on the results were investigated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1098-1104
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• 2011

This paper presents the development of the surface profile sensing system (SPSS) and its application to analysis of road surface. The SPSS which can robustly reconstruct the road input profiles from the intermixed data with the vehicle's dynamic motion, is implemented using the multi-sensor system with the optimally shaped transfer function. The performance of this system is evaluated by a series of experimental works in the devised simulator. And a real car test equipped with the proposed system is performed in the proving ground over both deterministic and random road surfaces. Finally, a feasibility of the system is investigated considering the road model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.11
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• pp.1943-1949
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• 1997

In this paper, the analysis of the shift transient characteristics for the Ravigneaux type automatic transmission has been carried out using dynamic models of the automatic trnasmission. It is necessary to understand the overall system including multi-plate clutch, band brake, one way clutch, and planetary gears. The equations of motion are derived from the dynamic models of the automatic transmission. The GUI computer simulation program has been developed to analyze the shift transient characteristics of the vehicle equipped with the Ravigneaux type automatic transmission.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.377-387
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• 2005

The equations of motion of two-wheeled vehicles, e.g. bicycles or motorcycles, are developed by using Lagrange's equations for quasi-coordinates. The pure rolling constraints between the ground and the two wheels are considered in the dynamical equations of the system. For each wheel, two nonholonomic and two holonomic constraints are introduced in a set of differential-algebraic equations (DAE). The constraint Jacobian matrix is obtained by collecting all the constraint equations and converting them into the velocity form. Equilibrium, an algorithm for searching for equilibrium points of two-wheeled vehicles and the associated problems are discussed. Formulae for calculating the radii of curvatures of ground-wheel contact paths and the reference point are also given.

• Structural Engineering and Mechanics
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• v.61 no.4
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• pp.453-461
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• 2017

This paper presents the series multiple tuned mass dampers (STMDs) to suppress the resonant vibrations of railway bridges under the passage of high-speed trains (HSTs). A STMD device consisting of two spring-mass-damper units connected each other in series is installed on the bridge. In solution, bridge is modeled as a simply-supported Euler-Bernoulli beam with constant cross-section, and vehicle is simulated as a series of moving forces with constant speed. By the assumed mode method, the governing equations of motion of the beam-TMD device coupled system traversed by a moving train are obtained. The optimum values for the parameters of the STMD device are obtained for the criterion based on the minimization of the maximum dynamic displacement of the beam at its midspan. Single TMD and multiple TMDs in parallel are also considered for demonstration of the STMD device's performance. The results show that STMDs are effective in bridge vibration suppression and robust to parameters' change in the main system and the absorber itself.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.3
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• pp.252-261
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• 1992

The accuracy of the position fixing with telemetry techniques depends in general on the accuracy of the location of the receiving point(hydrophone). To increase the accuracy of the coordinates of four hydrophones suspended down at both sides of the vessel anchored, each hydrophone motion is compensated using a depth pinger mounted on the seabed of 30m depth. The pinger location is calculated with a hyperbolic method. Using this technique so called hydrophone coordinates calibration, the movement of the Remotely Operated Vehicle(ROV), which has the same type of pinger mentioned above could be tracked down more accurately. Under the maximum variation ranges of a hydrophone of 5.2m in athwartships, 3.2m in alongship, and about 0.2m/s of the moving velocity in both directions, the ROV track with calibration is more close to the reality than that without calibration Tow depth pingers of same frequency can be distinguished by the use of three factors; The pulse period, the phase and the pulse period variation allowed in acquisition of the pinger as far as its pulse period is varied in smooth.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.209-219
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• 1997

A fuzzy driver model based on a preview-predictor and yaw rate is developed. The model is used to investigate the handling performance of two wheel steering system(2WS) and four wheel steering system(4WS) vehicles. The two degree-of- freedom model which has yaw and lateral motion predicts the path of the vehicles. Based upon the yaw rate and lateral deviations, the fuzzy engine describes the human driver's complicated control behavior which is adjusted for the driving environment. Both typical single lane change maneuver and double lane change maneuver are adopted to demonstrate the feasibility of fuzzy driver model.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.11a
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• pp.262-266
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• 2002

본 연구에서는 가상환경 및 시뮬레이션에서 활용이 가능한 인체 모델을 개발하였다. 한국인 인체 측정 자료를 바탕으로 각 지체에 대한 기구학적 특성치와 상관관계를 얻고 인체 모델을 구성하였다. 인체 모델은 17개의 독립된 지체들로 구분되며 조인트로 연결된다. 구성된 모델은 가상환경의 신 그래프(scene graph)상에 자료화되고 DCS를 이용하여 애니메이션이 가능하도록 하였다. Madymo를 이용하여 차량 운전자의 전방 충돌 및 범퍼 통과시 지체의 거동을 해석하고 그 결과 값을 변환하여 OpenGL Performer 라이브러리를 통해 가상 공간에 가시화하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.5
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• pp.848-872
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• 2015

Hydrodynamic derivatives or coefficients are required to predict the maneuvering characteristics of a marine vehicle. These derivatives are obtained numerically for a DTMB 5512 model ship by virtual simulating of captive model tests in a CFD environment. The computed coefficients are applied to predict the turning circle and zig-zag maneuvers of the model ship. The comparison of the simulated results with the available experimental data shows a very good agreement among them. The simulations show that the CFD is precise and affordable tool at the preliminary design stage to obtain maneuverability performance of a marine vehicles.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.601-607
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• 2005

This paper describes a hydrodynamic modelling study based on the Feldman's equation to predict the nonlinear and coupled maneuvering characteristics of high speed submarine. The hydrodynamic coefficients set is obtained from the modeling of the cross flow drag force and sail induced vorticity, and the captive model experiments(VPMM and RA test) results used to improved the accuracy. The results contained in this paper will be helpful to predict the behavior of tight turn maneuver and to improve the SOE(Safety Operational Envelope) analysis in case of emergency maneuver.