• Geomechanics and Engineering
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• 제17권3호
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• pp.237-245
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• 2019

In deep mixed rock strata, a double shield TBM (DS-TBM) is easy to be entrapped by a large force during tunneling. In order to reduce the probability of the entrapment, we need to investigate a favorable driving direction, either driving with or against dip, which mainly associates with the angle between the tunneling axis and strike, ${\theta}$, as well as the dip angle of rock strata, ${\alpha}$. We, therefore, establish a 3DEC model to show the changes of displacements and contact forces in mixed rock strata through LDP (longitudinal displacement profile) and LFP (longitudinal contact force profile) curves at four characteristic points on the surrounding rock. This is followed by a series of numerical models to investigate the favorable driving direction. The computational results indicate driving with dip is the favorable tunneling direction to reduce the probability of DS-TBM entrapment, irrespective of ${\theta}$ and ${\alpha}$, which is not in full agreement with the guidelines proposed in RMR. From the favorable driving direction (i.e., driving with dip), the smallest contact force is found when ${\theta}$ is equal to $90^{\circ}$. The present study is therefore beneficial for route selection and construction design in TBM tunneling.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.341-343
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• 1995

In this paper, an algorithm is presented to recogniz the driving direction of a vehicle and obstacles in front of it based on highway road image. The algorithm employs a neural network with 27 sub sets obtained from the road image as its input. The outputs include the direction of the vehicle movement and presence or absence of obstacles. The road image, obtained by a video camera, was digitized and processed by a personal computer equipped with an image processing board.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.472-475
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• 2014

Abnormal cab vibrations in the Y direction in commercial vehicles during driving(70~90kph) are not common vibrations that happen to vehicles during driving and can be an obstacle to normal driving. This study conducted Operation Deflection Shape(ODS) testing to identify the causes of those abnormal cab vibrations and find solutions for them and also a sine sweep test to find resonance and frequency in the cab suspension system and set directions for improvement. The study also altered the shape of the bush inner part for changes to the rigidity features of the cab bush in the Y direction and revised the design with optimal rigidity in the Y direction, thus improving abnormal cab vibrations in the Y direction during driving.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.717-722
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• 2003

A driving simulator is a computer-controlled tool to study an interface between a driver and vehicle response by enabling the driver to participate in judging vehicle characteristics. Using the driving simulator, human factor study, vehicle system development and other research can be effectively done under controllable, reproducible and non-dangerous conditions. An Adaptive Cruise Control (ACC) system is generally regarded as a system that can be achieved in the near future without the demanding infrastructure components and technologies. ACC system is an automatic vehicle following system with no human engagement in the longitudinal vehicle direction. And the influence of the driver is substantial in developing the system. Driving characteristic is very different according to the accident riskiness, gender, age and so on. In this research, experiments have been carried out to investigate driving characteristics with the ACC system, using a driving simulator. Participants are 21 male and 19 female. Driving characteristics such as preferred headway-time, lane keeping ability, eye direction, and head movement have been observed and compared between the driving with ACC and the driving without ACC.

• 한국정밀공학회지
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• 제30권1호
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• pp.18-23
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• 2013

Omni-directional robot is a typical holonomic constraint robot that has three degrees of freedom movement in 2D plane. In this study, a new omni-directional robot whose wheels are arranged in radial directions was proposed to improve driving performance of the robot. Unlike a general omni-directional robot whose wheels were arranged in a circumferential direction, moments do not arises in the proposed robot when the robot travels in a straight line. To analyze driving performance, dynamic modeling of the omni-directional robot, which considers friction and slip, was carried out. By friction measurement experiments, the relationship between dynamic friction coefficient and relative velocity was derived. Dynamic friction coefficient according to the angle difference between robot travel direction and wheel rotation direction was also obtained. By applying these results to the dynamic model, driving performance of the robot was calculated. As a result, the proposed robot was 1.5 times faster than the general robot.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1660-1663
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• 2005

Unwanted vibrations are inevitably induced in other directions when pure unidirectional vibration motion is desired for the vertical scratching mechanism. Pure vertical vibration motion of the scratching machine can be obtained by driving identical two motors with symmetrically positioned eccentric unbalance masses. The desired optimal condition for driving pure vertical vibration for the scratching machine is assumed to be the resonance condition in that direction. Imposing the flexibility of the scratching machine in the horizontal direction, we can find out the amount of horizontal vibration component while maintaining the resonance in vertical direction. The desired stiffness in horizontal direction which produces the minimum vibration in horizontal direction are defined which can be used as a guide line to design the supporting structure of the scratching machine.

• 전기전자학회논문지
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• 제25권1호
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• pp.148-155
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• 2021

로봇 기술이 발전함에 따라 모바일 로봇의 주행 시스템에 대한 연구가 활발히 진행되고 있다. 2륜 및 4륜의 휠을 기반으로 구성되는 모바일 로봇의 주행 시스템은 직선과 같은 단반향 주행에 장점이 있으나 방향 전환 및 제자리 회전에 단점을 가지고 있다. 볼을 휠로 사용하는 볼 로봇은 전방향 이동에 장점이 있으나, 구조적인 불안정한 특성에 의해 균형을 유지하기 위한 자세 제어 및 이동을 위한 주행 제어가 요구된다. 기존의 볼 로봇은 모터에 부착된 엔코더를 이용하여 주행제어를 위한 위치를 추정함으로써 오차가 누적되는 한계를 가지고 있다. 본 연구에서는 영상처리를 통해 볼 로봇의 위치 좌표를 추정하고, 이를 주행 제어에 사용하는 주행 제어 시스템을 제안하였다. 볼 로봇의 위치를 추정하기 위한 영상처리부, 통신부, 표시부 및 제어부를 포함하는 볼 로봇의 주행 제어 시스템을 설계 및 제작하고, 주행 제어 시스템을 적용한 볼 로봇의 주행 실험을 통해 x축 방향 ±50.3mm 및 y축 방향 ±53.9mm의 오차범위 이내에서 오차의 누적 없이 제어됨을 확인하였다.

• 한국군사과학기술학회지
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• 제10권3호
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• pp.139-147
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• 2007

In military transportation, the use of wide trailer for transporting the large and heavy weight equipments such as tank, armoured vehicle, and mobile gunnery is quite common. So, the vulnerability of causing traffic accidents for these wide military trailer to bump or collide with another car in adjacent lane is very high due to its broad width in excess of its own lane's width. Also, the possibility of these strayed accidents can be increased especially by the careless driver. In this paper, the recognition system of lane and vehicle headway direction is developed to detect the possible collision and warn the driver to prevent the fatal accident. In the system development, Kalman filtering is used first to extract the border of driving lane from the video images supplied by the CCD camera attached to the vehicle and the driving lane detection is completed with regression analysis. Next, the vehicle headway direction is recognized by using neural network scheme with the extracted parameters of the detected driving lane feature. The practical experiments for the developed system are also carried out in the real traffic road of Seoul city area and the results show us the more than 90% accuracy in recognizing the driving lane and vehicle headway direction.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.981-984
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• 1995

The feed system using ball screw is constructed by ball screw, support bering and LM guide, and servo system for driving ball screw. AC servo motr drives ball screw which was connected by coupling. In this study, a new axial direction dynamic modeling of ball screw driving system was developed, and forced vibraition test using the impact hammer was experimented. The simulation result is compared with experimental result, which defines the reliability of mathematical modeling.

• 한국군사과학기술학회지
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• 제15권6호
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• pp.721-728
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• 2012

The tracked SUGVs(Small Unmanned Ground Vehicles) are frequently operated in the narrow slope such as stairs and trails. But due to the nature of the tracked vehicle which is steered using friction between the track and the ground and the limited field of view of driving cameras mounted on the lower position, it is not easy for SUGVs to trace narrow slopes. To properly trace inclined narrows, it is very important for SUGVs to keep it's heading direction to the slope. As a matter of factor, no roll value control of a SUGV can makes it's heading being located in the direction of the slope in general terrains. But, the problem is that we cannot directly control roll motion for SUGV. Instead we can control yaw motion. In this paper, a new slope driving method that enables the vehicle trace the narrow slopes with IMU sensor usually mounted in the SUGV is suggested which including an estimation technique of the desired yaw angle corresponding to zero roll angle. In addition, a fuzzy steering controller robust to changes in driving speed and the stair geometry is designed to simulate narrow slope driving with the suggested method. It is shown that the suggested method is quite effective through the simulation.