• 로봇학회논문지
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• 제18권1호
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• pp.93-98
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• 2023

In this paper, the development of an autonomous electric vehicle for logistics with a robotic arm is introduced. The manual driving electric vehicle was converted into an electric vehicle platform capable of autonomous driving. For autonomous driving, an encoder is installed on the driving wheels, and an electronic power steering system is applied for automatic steering. The electric vehicle is equipped with a lidar sensor, a depth camera, and an ultrasonic sensor to recognize the surrounding environment, create a map, and recognize the vehicle location. The odometry was calculated using the bicycle motion model, and the map was created using the SLAM algorithm. To estimate the location of the platform based on the generated map, AMCL algorithm using Lidar was applied. A user interface was developed to create and modify a waypoint in order to move a predetermined place according to the logistics process. An A-star-based global path was generated to move to the destination, and a DWA-based local path was generated to trace the global path. The autonomous electric vehicle developed in this paper was tested and its utility was verified in a warehouse.

• 대한기계학회논문집A
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• 제40권1호
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• pp.103-111
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• 2016

본 논문에서는 차량의 횡방향 안정성을 향상시키기 위해 자세 제어 장치(ESC)와 능동 전륜 조향(AFS)을 이용하는 통합 새시 제어의 적응 가변 가중치 조절 방법을 제안한다. 제어기 설계 방법론을 적용하여 차량을 안정화시키는데 필요한 제어 요 모멘트를 구한 후 이를 가중 역행렬 기반 제어 할당 방법(WPCA)을 이용하여 ESC 의 제동력과 AFS 의 추가 조향각으로 분배한다. 저마찰 노면에서는 차량의 속도가 높다면 횡슬립각이 증가하여 횡방향 안정성이 저하되므로 이를 방지하기 위해 WPCA 의 가변가중치를 상황에 따라 조절하는 방법을 제안한다. 차량 시뮬레이션 패키지인 CarSim 에서 시뮬레이션을 수행하여 제안된 방법이 통합 섀시 제어기의 횡방향 안정성을 향상시킨다는 사실을 검증한다.

• 한국컴퓨터정보학회논문지
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• 제20권3호
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• pp.9-17
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• 2015

본 논문에서는 자동차 기능안전 표준인 ISO 26262에서 요구하는 위험원 분석 및 위험 평가에서 온톨로지와 추론 규칙을 적용하는 방법을 제안한다. 위험원 분석 및 위험 평가는 일반적으로 수작업으로 수행되어 많은 노력이 소요되고 오류가 발생하기 쉬우며 일관성과 정확성이 부족한 문제점이 있다. 이러한 문제를 해결하기 위해서 본 논문에서는 위험원을 온톨로지로 표현하고, 평가를 위한 온톨로지 규칙을 정의하여 자동화하고 일관성 및 정확성 문제를 개선한다. 본 제안 방법을 검증하기 위해서 ESCL(electronic steering column lock) 시스템에 적용하였다. 온톨로지 규칙 적용 결과를 DL(Description Logics) Query를 실행하여 제대로 동작하는지 확인하였으며, 이를 통해 위험 평가 시에 발생할 수 있는 오류를 파악할 수 있었다.

• 한국전자통신학회논문지
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• 제17권2호
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• pp.245-254
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• 2022

본 논문에서는 항 재밍 GPS 안테나의 설계 최적화에 관하여 연구하였다. 이를 위해 항 재밍 성능 분석 기준 및 방법을 제시하였다. 제시된 방법을 적용하기 위한 안테나 시스템의 구조는 7개의 방사소자가 배열된 구조이다. 여기서 6개 방사소자는 원형 등각 배열되었으며, 나머지 1개 방사소자는 원형 중앙에 배치하였다. 제시된 기준 및 방법을 기반으로 상기 안테나를 최적화 하였으며, 최적화된 안테나의 설계 요소(원형 배열의 반지름)의 전기적 길이는 0.48 λ이다. 모의실험 결과, 주 빔의 조향각도(θ, ϕ)가 (0°, 0°)인 경우, 항 재밍을 위한 패턴 널 형성 범위(θ 기준)가 57°부터 90°가 됨을 확인하였다.

• Journal of Information Display
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• 제9권3호
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• pp.1-7
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• 2008

With the aim of creating a high-quality display system with value-added functions, we designed a current mode multiplexer for LTPS TFT devices. The multiplexers had less than 1 volt logic swing, and speed improvement was evident compared with that of conventional CMOS architecture. We refined the multiplexer to achieve a more stable current steering operation. By using the versatility of the multiplexer, a new NAND/AND and NOR/OR logic gates were designed through the simple modification of signal connections. Two micron LTPS TFT parameters were used during the HSPICE simulation of the circuits.

• International Journal of Advanced Culture Technology
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• 제4권1호
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• pp.37-50
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• 2016

In recent years, the development and application of green energy resources have attracted more and more /$^*$ 'tention of people. The training room presented here is focused on the terminal applications of a photovoltaic power generation system (PPGS). Through introducing the composition and the general design principles, we aimed at leading the students to master the fundamental skills required for its design, installation and construction. The training room consists of numerous platforms, such as: PPGS, Wind and Photovoltaic Hybrid Power Generation Systems, Wind Power Generation Equipments, Simulative Grid-Connected Power Generation System, Electronic Technology Application of New Energy, etc. This enables the students to obtain their project and professional skills training via assembling, adjusting, maintaining and inspecting, etc., various component parts of the photovoltaic and new energy power generation systems, to further grasp the fundamental and related theoretical knowledge, and to further reinforce their practical and operational skills, so as to improve their problem-analyzing and problem-solving abilities.

• International Journal of Automotive Technology
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• 제6권6호
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• pp.599-604
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• 2005

A functional suspension model is proposed as a kinematic describing function of the suspension, that represents the relative wheel displacement in polynomial form in terms of the vertical displacement of the wheel center and steering rack displacement. The relative velocity and acceleration of the wheel is represented in terms of first and second derivatives of the kinematic describing function. The system equations of motion for the full vehicle dynamic model are systematically derived by using velocity transformation method of multi-body dynamics. The comparison of test and simulation results demonstrates the validity of the proposed functional suspension modeling method. The model is computationally very efficient to achieve real-time simulation on TMS 320C6711 150 MHz DSP board of HILS (hardware-in-the-loop simulation) system for ECU (electronic control unit) evaluation of semi-active suspension.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1309-1313
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• 2008

This paper suggests an example of modification of the durability test specifications of electronic control unit for an automotive system in phase of design validation. The basic concept to redefine the specifications of durability test is based on the Arrhenius relationship for accelerated temperature test and the modified Coffin-Manson model for temperature cycle test. The ambient temperature of the powered-event durability test is increased to reduce the required test time of the current specification. Furthermore, the holding time between the events to cool down the temperature of the components is shortened and the resultant temperature rise affects the durability of the components. Thus, the acceleration factor due to the increased temperature range of temperature cycle is also estimated by the modified Coffin-Manson model.

• International Journal of Automotive Technology
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• 제7권2호
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• pp.201-208
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• 2006

This paper describes the control philosophy of ESP(Electronic Stability Program) which consists of the stability control the fault diagnosis and the fault tolerant control. Besides the functional performance of the stability control, robustness of control and fault diagnosis is focused to avoid the unnecessary activation of the controller. The look-up tables are mentioned to have the accurate target yaw rate of the vehicle and obtained from vehicle tests for the whole operation range of the steering wheel angle and the vehicle speed. The wheel slip control with a design goal of wheel slip invariance is implemented for the yaw compensation and the target wheel slip is determined by difference between the target yaw rate and actual yaw rate. Since the ESP has a high severity level and the robust control is required, the robustness margin for the stability control is determined according to several uncertainties and the robust fault diagnosis is performed. Both computer simulation and test results are shown in this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2351-2353
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• 1998

This paper suggests the wheel controller for PWS(Power Wheeled Steering) mobile robot. The proposed controller consists of two parts. To control each motor, the sliding mode controller implemented. This method has robustness about modeling error and disturbance, so the velocity tracking is well guaranteed in the presence of varying load. The design of a fuzzy cross-coupling controller for a PWS mobile robot is described here. Fuzzy cross-coupling control directly minimizes the tracking error by coordinating the motion of the two drive wheels. The fuzzy cross-coupling controller has excellent disturbance rejection and therefore is advantageous when the robot is not loaded symmetrically. The capability of the proposed controller was verified through the computer simulation.