• Journal of Practical Engineering Education
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• v.16 no.3_spc
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• pp.391-399
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• 2024

All highway toll gates in Korea use low-speed WIM(Weight-In-Motion) to block overloaded cargo vehicles from entering the main highway, but some cargo vehicle owners are illegally modifying vehicles to operate variable axles and evading crackdowns by manipulating the axles. In previous studies detect all tires of a running vehicle were detected to determine whether there is axle manipulation. However, because the vehicle entry area at the highway toll gate checkpoint is very narrow, there is a problem that it is realistically difficult to film all tires of the entering vehicle in one video frame. In this paper, we proposed a system that can determine whether the axle is being operated through changes in the height of the vehicle's cargo box rather than by detecting tires. To detect changes in the height of a cargo box, we propose a method to extract the representative line of the cargo box using Hough transform and then measure the change in height of the representative line to detect the change in height of the cargo box. In addition, we propose a method to detect changes in the vertical height of a cargo box by accumulating motion vectors of pixels within a certain area of the image using optical flow. And the two methods were compared and their advantages and disadvantages were analyzed and presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.514-521
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• 2021

When calculating an intersection collision speed using a formula, it is very difficult to grasp the degree of deceleration of a vehicle after the collision unless there is road surface trace in the entire section where each vehicle moved from the point of collision to their final positions after the collision. A vehicle's motion trajectory shows an irregular curve after a collision due to the effects of inertia based on the driving characteristics of the vehicle, the eccentric force according to the collision site, and the collision speed. Therefore, it is very important to set the appropriate departure angle after a collision for accurate collision speed analysis. In this study, based on experimental collision data using a computer simulation (PC-Crash), the correlation between an appropriate vehicle departure angle and the post-collision speed was analyzed, and then, a regression analysis model was derived. Through this, we propose a method to calculate collision speed by applying only the vehicle departure angle in some types of collisions for traffic accidents at intersections.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.989-999
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• 2006

In this paper, numerical analysis method to perform linear dynamic analysis of bridge considering the road surface roughness and bridge-vehicle interaction when vehicle is moving on bridge is presented. The vehicle and bridge are modeled as three-dimension where contact length of tire and pitching of tandem spring are considered and single truck with 2-axles and 3- axles, and tractor-trailer with 5-axles are modeled as 7-D.O.F., 8-D.O.F., and 14-D.O.F., respectively. Dynamic equations of vehicle are derived from the Lagrange's equation and solution of the equation is obtained by Newmark-${\beta}$ method. The surface roughness of bridge deck for this analysis is generated from power spectral density (PSD) function. Beam element for the main girder, shell element for concrete deck and rigid link between main girder and concrete deck are used. The equations of the motion of bridges are solved by mode-superposition procedures. The proposed procedure is validated by comparing the results with the experimental data by Whittemore and Fenves.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.5
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• pp.442-449
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• 2004

As underwater robotic vehicles (URVs) become attractive for more sophisticated underwater tasks, the demand of high performance in terms of accuracy and dexterity has been increased. An autonomous underwater robotic vehicle, ODIN (Omni-Directional Intelligent Navigator) was designed and built at the Autonomous Systems Laboratory of the University of Hawaii in 1991. Since 1991, various studies were conducted on ODIN and have contributed to the advancement in underwater robotics. Its refurbished model ODIN II was based on VxWorks in VMEbus. Recently, ODIN was born again as a PC based system, ODIN III with unique features such as new vehicle system software architecture with an objective-oriented concept, a graphical user interface, and an independent and modular structure using a Dynamic Linking Library (DLL) based on the Windows operating system. ODIN III software architecture offers an ideal environment where various studies for advanced URV technology can be conducted. This paper describes software architecture of ODIN III and presents initial experimental results of fine motion control on ODIN III.

• Structural Engineering and Mechanics
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• v.46 no.3
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• pp.353-370
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• 2013

This paper presents a new method to study the impact factor of an old bridge based on the model updating technique. Using the genetic algorithm (GA) by minimizing an objective function of the residuals between the measured and predicted responses, the bridge and vehicle coupled vibration models were updated. Based on the displacement relationship and the interaction force relationship at the contact patches, the vehicle-bridge coupled system can be established by combining the equations of motion of both the bridge and vehicles. The simulated results show that the present method can simulate precisely the response of the tested bridge; compared with the other bridge codes, the impact factor specified by the bridge code of AASHTO (LRFD) is the most conservative one, and the value of Chinese highway bridge design code (CHBDC) is the lowest; for the large majority of old bridges whose road surface conditions have deteriorated, calculating the impact factor with the bridge codes cannot ensure the reliable results.

• Journal of Ocean Engineering and Technology
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• v.23 no.1
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• pp.48-53
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• 2009

Autonomous Underwater Vehicles (AUV's) provide an important means for collecting detailed scientific information from the ocean depths. The hull resistance of an AUV is an important factor in determining the power requirements and range of the vehicle. This paper describes a design method that uses Computational Fluid Dynamics (CFD) to determine the hull resistance of an AUV under development. The CFD results reveal the distribution of the hydrodynamic values (velocity, pressure, etc.) of an AUV with a ducted propeller. This paper also discusses the optimization of the AUV hull profile to reduce the total resistance. This paper demonstrates that shape optimization in a conceptual design is possible by using a commercial CFD package. Optimum design work to minimize the drag force of an AUV was carried out, for a given object function and constraints.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.5
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• pp.547-553
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• 2021

Dynamic object recognition is an important task for autonomous vehicles. Since dynamic objects exhibit a higher collision risk than static objects, our own trajectories should be planned to match the future state of moving elements in the scene. Time information such as optical flow can be used to recognize movement. Existing optical flow calculations are based only on camera sensors and are prone to misunderstanding in low light conditions. In this regard, to improve recognition performance in low-light environments, we applied a normalization filter and a correction function for Gamma Value to the input images. The low light quality improvement algorithm can be applied to confirm the more accurate detection of Object's Bounding Box for the vehicle. It was confirmed that there is an important in object recognition through image prepocessing and deep learning using YOLO.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.5
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• pp.326-334
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• 2019

Development of Small UAV using HILS (Hardware In the Loop Simulation) can be effectively used to improve the reliability of UAV (Unmanned Aerial Vehicle) while reducing cost and time. It is also possible to reduce the damage to people or property by simulating the malfunction of the Flight Control Computer (FCC) that may occur during the actual flight. For applying such HILS, a real-time simulation environment capable of providing an environment similar to an actual flight condition is required. In this paper, we constructed a real - time HILS environment for Small UAV using 6 D.O.F motion table. In order to link the 6 D.O.F motion table developed in the previous research with the HILS environment in real time, the motion algorithm was changed from the position control method to the velocity control method. Also, we implemented modeling of inverse kinematics model for command transmission in Matlab $Simulink^{(R)}$ and verified the action of motion table according to the simulation model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.2
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• pp.125-130
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• 2013

According to the law revision of TPMS mounting obligations in Korea, researches about energy harvester which is the alternative of the battery are actively performed by many groups. Because WSN (Wireless Sensor Network) has the proposition of "Install and forget" and the power supplier also has the same performance as the vehicle's lifetime. In this paper, electromagnetic induction type of energy harvester through the relative motion between the rotating wheel and the fixed brake disc is introduced by using the most efficient source as the rotating motion in the view of vehicle's mechanism. The coil on the wheel and the permanent magnet at the brake disc are arranged in several ways. These various arrangements are the number of coil turns are consisted of design variables. By using the orthogonal array to reduce the experimental cost, the optimal composition is verified through the experiment. Finally the validity of the module is considered by measuring the level of storable electrical energy.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.1
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• pp.1-8
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• 2002

When a body enters waters, its original kinetic energy or momentum is distributed among the body and surrounding water in the form of added mass. Due to the transfer of the energy or momentum, the bode is subjected to the hydrodynamic impact forces and acceleration. This impact behavior can be an important criterion of submersible vehicle launched to the air. In this paper, based on Life-boat model, an approximate method is proposed for the evaluation of the forces and responses of cylindrical rigid bode by water entry impact. The impact forces are calculated by yon Karman's momentum theory and motion responses the body, especially acceleration, are calculated by a numerical integration of the motion equations derived by hydrodynamic force equilibrium. The proposed method is expected to be a simple but efficient tool lot the preliminary design or motion analysis of a body subjected to water entry impact.