• 한국ITS학회 논문지
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• 제21권2호
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• pp.183-200
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• 2022

자율주행 기술을 활용하여 사고 예방과 정체 감소를 위한 교통운영관리 전략을 개발하는 다양한 연구가 시뮬레이션 기반으로 수행되고 있다. 이를 위해서는 시뮬레이션에서 구현되는 자율차의 거동이 실제상황을 충분히 반영하여야 하며 일반차량의 거동과 차별화되어야 한다. 그러나 실제 자율차의 주행자료와 일반차량과의 상호작용 자료 취득의 어려움으로 인해 시뮬레이션 상의 자율차 거동에 대한 검증이 미흡한 상황이다. 본 연구의 목적은 주행 및 교통 시뮬레이션 실험을 통해 자율차 거동의 적정성을 평가하는 방법론을 개발하는 것이다. 본 연구에서는 개별 자율차 주행 시 요구조건과 교통류 내에서 다른 차량과의 상호작용 결과물인 퍼포먼스에 대한 요구조건을 정립하였다. 두 가지 관점의 요구조건에 대한 만족 여부를 주행 시뮬레이션과 교통 시뮬레이션을 이용하여 평가하는 프레임워크를 제시하였다. 본 연구의 결과는 보다 신뢰성 있는 자율주행 시뮬레이션 분석을 위한 유용한 기초자료로 활용될 것으로 기대된다.

• 한국지반공학회논문집
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• 제18권1호
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• pp.91-99
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• 2002

본 연구에서는 변형률 수준별 실내진동시험 및 지진응답해석의 수행을 기초로 하는 새로운 액상화 평가법을 제안하였다. 제안된 평 가법에서는 비 배수조건 하에서 진동전단하중으로 야기된 과잉간극수압의 누적으로 액상화가 발생하는 점을 고려하여 진동하중을 받는 포화지반의 액상화 거동을 실내진동시험결과의 전단응력-전단변형률 이력곡선을 토대로 산정한 교란도와 소성 전단변형률 상각궤도의 변화로 정의하였으며, 이를 실지진 시간이력의 지반 내 거동변화와 연계시킴으로써 지진이 보유한 연속성 및 불규칙성을 합리적으로 고려하도록 하였다. 또한, 제안된 평가법에서는 진동하중의 변화에 관계없이 액상화 발생시 포화사절토의 동적특성은 일정하다는 일련의 연구사례를 토대로 내친 해석시 이용되는 전변형률 수준의 동적물성 획득시험만으로도 액상화 평가가 가능하도록 하였으며 정현하중의 크기를 달리한 진동삼축시험에서 산정된 액상화 발생시의 소성 전단변형률 상각궤도를 비교함으로써 이에 대한 검증연구를 수행하였다. 연구결과, 진동정현하중의 크기에 관계없이 액상화 발생시 지반의 동적특성 치가 유일한 값을 나타내었다 그러므로, 제안된 평가법은 변형률 수준별 실내진동시험을 통해 지반의 동적물성 획득과 액낭화 평가 수행이 가능할 뿐만 아니라, 지진응답해석을 통해 불규칙한 실지진 시간이력 전부를 고려하는 특징으로 육상화 평가결과의 신뢰성을 향상시킬 수 있을 것으로 판단된다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.593-596
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• 2018

The speed of vehicles has remained a significant factor that influences the severity of accidents and traffic accident rate in many parts of the world including South Korea. This behavior where drivers drive at speeds which exceed a posted safe threshold is known as 'speeding'. Over the past twenty years, the Korean National Police Agency (NPA) has become aware of an increased frequency of drivers who are speeding. Therefore, fixed-type ASE systems [1] have been installed on hazardous road sections of many highways. These system monitor vehicle speeds using a camera. However, the use of ASE systems has changed the behavior of the drivers. Specifically, drivers reduce speed or avoid the route where the cameras are mounted. It is not practical to install cameras at every possible location. Therefore, it is challenging to thoroughly explore the location where speeding occurs. In view of these problems, the author of this paper designed and implemented a prototype visualization system in which point and color are used to show vehicle location and associated over-speed information. All of this information was used to create a comprehensive visualization application to show information about vehicle driving. In this paper, we present an approach detecting vehicles moving at speeds which exceed a threshold and visualizing the points those violations occur on a map. This was done using vehicle trajectory data collected in Daegu city. We propose steps for exploring the data collected from those sensors. The resulting mapping has two layers. The first layer contains the dynamic vehicle trajectory data. The second underlying layer contains the static road networks. This allows comparing the speed of vehicles on roads with the known maximum safe speed of those roads, and presents the results with a visualization tool. We also compared data about people who drive over threshold safe speeds on each road on days and weekends based on vehicle trajectories. Finally, our study suggests improved times and locations where law enforcement should use monitoring with speed cameras, and where they should be stricter with traffic law enforcement. We learned that people will drive over the speed limit at midnight more than 1.9 times as often when compared with rush hour traffic at 8 o'clock in the morning, and 4.5 times as often when compared with traffic at 7 o'clock in the evening. Our study can benefit the government by helping them select better locations for installation of speed cameras. This would ultimately reduce police labor in traffic speed enforcement, and also has the potential to improve traffic safety in Daegu city.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.754-756
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• 2004

The ultrasonic piezo motor is a new type motor that has an excellent performance and many useful features that electromagnetic motors do not have. But, it suffers from severe system non-linearities and parameter variations especially during speed control. Therefore, it is difficult to accomplish satisfactory control performance by using the conventional PID controller. In this paper, to achieve the precise control, we analyzed response time & change with a driving time, and proposed PD controller combined with neural network. The backpropagation algorithm is used to train a given trajectory. The effectiveness of the used method is confirmed by experiments. The effectiveness of the used method is confirmed by experiments using the ultrasonic motor made in Korea.

• 대한기계학회논문집
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• 제15권2호
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• pp.515-522
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• 1991

Determining the motion using optimal technique about traveling time and trajectory planning has been studied often in recent years, but the study of determining the optimal robot dimensions is rare, the authors attempt to find out the least driving torques and energy as the optimization of link length ratio referred to 2R SCARA and 3R robot manipulators. For the given linear path with triangular velocity profile, the inverse kinematic and dynamic problems are examined in order to lead into solution of problem, which is suggested for optimal design of link lengths. Accordingly, optimal link length ratio is obtained with respect to each case.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.442-445
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• 1995

This paper presents the position tracking control of a laser scanning mirror system in which piezoelectic actuator is incorporated. Using the shear mode of the piezoelectric actuator,angular oscillation of a laser scanning mirror is derived. Torsion bar is rhen designed and attached to the piezoelctric actuator in order to magnify the amplitude generated by the actuator. Finite element modeling and analysis are essntial for designing the piezoelectic actuator. The torsional resonance mode of the piezoelectric actuator is found from the model analysis of the actuator and the mechanical shear is matched with the driving frequency. Transfer function between the electrical excitation and the mechanical shear deformation at resonance frequency is found form the response of the actuator calculated by the finite element analysis and the governing equation of the system is derived from d'Alembert's principle. Tracking control performance for desired trajectory which is, in fact, sinusoidal curve is presented in order to demonstrate the validity of the proposed system.

• 로봇학회논문지
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• 제7권2호
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• pp.113-119
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• 2012

In this paper we propose the method that detects moving objects in autonomous navigation vehicle using LRF sensor data. Object detection and tracking methods are widely used in research area like safe-driving, safe-navigation of the autonomous vehicle. The proposed method consists of three steps: data segmentation, mobility classification and object tracking. In order to make the raw LRF sensor data to be useful, Occupancy grid is generated and the raw data is segmented according to its appearance. For classifying whether the object is moving or static, trajectory patterns are analysed. As the last step, Markov chain Monte Carlo (MCMC) method is used for tracking the object. Experimental results indicate that the proposed method can accurately detect moving objects.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 D
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• pp.647-649
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• 2000

Brushless DC motors are widely used in many industrial fields as an actuator of robot and driving power motors of electrical vehicle. In this paper adaptive fuzzy sliding mode scheme is developed for velocity control of brushless DC motor. The proposed scheme does not require an accurate dynamic model. yet it guarantees asymptotic trajectory tracking despite torque variations. Numerical simulation and DSP-based experimental works for velocity control of brushless DC motor are carried out.

• 한국전기전자재료학회논문지
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• 제21권1호
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• pp.49-52
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• 2008

In this study, multilayer structured ultrasonic linear motor was simulated using Atila for investigating its optimum driving conditions. The ultrasonic linear motors mainly consist of an ultrasonic vibrator to generate elliptical displacement. The ultrasonic linear motor simulated in this paper was the use of the 1st longitudinal(Ll) and 4th bending vibrations (B4). Whit the increase of the number of piezoelectric actuator layers, displacement of node was increased. Maximum total displacement of node was about $3,91{\mu}m$ at the 13 layered ultrasonic motor under 5 V.

• 제어로봇시스템학회논문지
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• 제18권11호
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• pp.1051-1058
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• 2012

The unified lateral control algorithm for automatic valet parking for various types of vehicles is presented and its feasibility is shown experimentally via field tests for the given parking scenario. First, a trajectory generation algorithm for forward driving and backward multi-step parking maneuvers is developed. Then, with consideration of different types of vehicles and operating conditions, a kinematic vehicle model is used and validated using field test data. Using the nonlinear vehicle model, the lateral controller is designed based on dynamic surface control. Finally the proposed lateral control law is validated via hardware-in-the-loop simulations for different types of vehicles and experimentally using a test vehicle through field tests.