• 대한임베디드공학회논문지
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• 제12권5호
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• pp.319-330
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• 2017

In remote USV (Unmanned Surface Vehicle) maritime operation, the remote operation and control technic and autonomous control technic is required and the emergency mode algorithm is needed certainly for sailing and accomplishing various surveillance, reconnaissance, and underwater search missions of USV. In this paper, we review the countermeasures in emergency situation of the existing USV system (Barracuda) and propose the emergency mode algorithm considering the operation and control, and autonomous control level for the stable USV operation in case of emergency. We analyzed the autonomous control level in view of the mission complexity and environmental difficulty, and human interface, and verified the performance of the autonomous control level when we apply four emergency mode algorithms. It is expected that more stable and reliable operation and cotrol are possible if the proposed algorithm is applied to the environments requiring the various multi-mission USV sailing and mission achievement.

• 제어로봇시스템학회논문지
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• 제3권3호
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• pp.227-237
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• 1997

Autonomous Underwater Vehicles(AUVs) have become an important tool for various purposes in subsea: inspection, recovery, construction, etc., and the development of autonomous control system is luglay desirable- thete zffe many problems associated with designing the control system for AUV due to unknown underwater envimn-Tnent, the possibility of subsystem failures, and unpredictable changes in the dynamics of the vehicle. In this paper, an autonomous control system based on the intelligent control theory to enhance operation efficiency of the ALTV is presented. The control system has a hierarchical structure which consists of mission planning level, mission control level, navigation level, and execution level. The performance of the control system is investigated by computer simulation. The results show that the proposed control system can be applied successfully to the AUV in spite of the possibility of failures in the vehicle and the collision hazard in the sea environment.

• 자동차안전학회지
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• 제13권4호
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• pp.129-143
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• 2021

This paper proposes actuator fault detection and adaptive fault-tolerant control algorithms using performance index and human-like learning for longitudinal autonomous vehicles. Conventional longitudinal controller for autonomous driving consists of supervisory, upper level and lower level controllers. In this paper, feedback control law and PID control algorithm have been used for upper level and lower level controllers, respectively. For actuator fault-tolerant control, adaptive rule has been designed using the gradient descent method with estimated coefficients. In order to adjust the control parameter used for determination of adaptation gain, human-like learning algorithm has been designed based on perceptron learning method using control errors and control parameter. It is designed that the learning algorithm determines current control parameter by saving it in memory and updating based on the cost function-based gradient descent method. Based on the updated control parameter, the longitudinal acceleration has been computed adaptively using feedback law for actuator fault-tolerant control. The finite window-based performance index has been designed for detection and evaluation of actuator performance degradation using control error.

• 자동차안전학회지
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• 제12권1호
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• pp.15-25
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• 2020

This paper presents a longitudinal control algorithm for ensuring takeover time of autonomous vehicle using V2V communication. In the autonomous driving of more than level 3, autonomous systems should control the vehicles by itself partially. However if the driver's intervention is required for functional safety, the driver should take over the control reasonably. Autonomous driving system has to be designed so that drivers can take over the control from autonomous vehicle reasonably for driving safety. In this study, control algorithm considering takeover time has been developed based on computation method of takeover time. Takeover time is analysed by conditions of longitudinal velocity of preceding vehicle in time-velocity plane. In addition, desired clearance is derived based on takeover time. The performance evaluation of the proposed algorithm in this study was conducted using 3D vehicle model with actual driving data in Matlab/Simulink environment. The results of the performance evaluation show that the longitudinal control algorithm can control while securing takeover time reasonably.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제9권6호
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• pp.674-682
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• 2003

선박 자율운항시스템(autonomous navigation system)이란 선박운항에 있어 항해계획을 수립하고 현재의 선박운항 상태를 파악하여 주변 상황변화를 예측하고 대처하는 항해 전문가의 능력을 전산화한 것이다. 선박 자율운항시스템은 항해, 충돌회피, 선체유지, 자료융합, 운동제어 그리고 이를 통합하는 아키텍처로 구성되어 있다. 운동제어시스템은 선박의 유체학적 특성을 고려하여 해도 상에 원하는 위치로 선박을 이동하기 위해서 추진 및 조타장치를 제어하는 시스템으로 자율운항제어시스템에 필수적인 구성 시스템 중에 하나이다. 본 논문은 운영플랫폼인 가상세계시스템을 기반으로 운영되는 선박자율운항시스템과 운동제어시스템의 연동과 구현에 관한 연구이다. 운동제어시스템은 충돌회피시스템으로부터 상위 레벨의 고수준제어 요구치를 전달받아 조타 및 추진치로 변환하고 조타장치와 추진장치를 제어하는 시스템이다. 본 논문에서 선박 운동 특성을 수학적으로 모방하는 Oldenburger의 제어 이론에 기반하여 선박운동제어기를 개발하고 성능검정을 위해 선박시뮬레이터에서 다양한 시나리오를 바탕으로 시뮬레이션 한다.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권5호
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• pp.182-189
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• 2002

This paper presents a framework of hybrid dynamic control systems for the motion control of wheeled mobile robot systems with nonholonomic constraints. The hybrid control system has the 3-layered hierarchical structure: digital automata for the higher process, mobile robot system for the lower process, and the interface as the interaction process between the continuous dynamics and the discrete dynamics. In the hybrid control architecture of mobile robot, the continuous dynamics of mobile robots are modeled by the switched systems. The abstract model and digital automata for the motion control are developed. In high level, the discrete states are defined by using the sensor-based search windows and the reference motions of a mobile robot in low level are specified in the abstracted motions. The mobile robots can perform both the motion planning and autonomous maneuvering with obstacle avoidance in indoor navigation problem. Simulation and experimental results show that hybrid system approach is an effective method for the autonomous maneuvering in indoor environments

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.152-152
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• 2000

In this paper, we propose a new approach to intelligent motion and autonomous maneuvering of mobile robots using hybrid system. In high Level, the discrete states are defined by using the sensor-based search windows and the reference motions of a mobile robot as a low vevel are specified in the abstracted motions, The mobile robots can perform both the motion planning and autonomous maneuvering with obstacle avoidance in indoor navigation problem. Simulation and experimental results show that hybrid system approach is an effective method for the autonomous maneuvering in indoor environments.

• 자동차안전학회지
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• 제15권2호
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• pp.28-34
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• 2023

The Republic of Korea aims to complete the commercialisation of Level 4+ cooperative autonomous driving in 2027. It also plans to include V2X OBU in the K-NCAP evaluation items. Therefore, communication performance safety evaluation criteria for V2X OBU need to be established, and an OBU with necessary functions is needed to develop V2X communication performance safety evaluation technology for vehicles. In this study, we implemented a V2X OBU control board prototype that can be used to develop a V2X communication performance safety evaluation technology for Level 4+ autonomous vehicles, and confirmed that the control board prototype works normally.

• 한국ITS학회 논문지
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• 제17권2호
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• pp.142-151
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• 2018

제4차 산업혁명 시대가 도래하면서 전 세계적으로 자율주행자동차에 대한 연구개발이 활발히 진행되고 있다. 이러한 국제적인 기조 속에서 국토교통부는 2020년 SAE 기준 레벨 3이상의 자율주행자동차 상용화를 목표로 자율주행자동차 관련 연구개발을 적극적으로 추진하고 있다. 레벨 3 수준의 자율주행자동차에서는 운전자와 자동차 상호 간의 운행주체를 주고받는 제어권 전환이 필수적으로 발생하게 된다. 본격적인 자율주행자동차 시대에 앞서 본 연구에서는 우선적으로 고속도로를 대상으로 가상현실을 이용한 제어권 전환 안전성 평가를 위하여 대표 시나리오를 개발하였다. 이를 위해 자율주행자동차의 고속도로 주행 시나리오를 만들었고, 2014년 발생한 고속도로 교통사고 경위자료와 제어권 전환 특성을 고려하여 6개의 제어권 전환 시나리오를 개발하였다. 개발된 시나리오에서 고려된 변수는 운전자, 차량, 그리고 환경요인으로 크게 나눌 수 있으며, 총 36개의 변수가 포함되었다.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권1호
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• pp.33-40
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• 2000

In this paper, an integrated method for the path planning and motion control of wheeled mobile robots using a hybrid system model and control is presented. The hybrid model including the continuous dynamics and discrete dynamics with the continuous and discrete state vector is derived for a two wheel driven mobile robot. The architecture of the hybrid control system for real time path planning and following is designed which has the 3-layered hierarchical structure : the discrete event system using the digital automata as the higher process, the continuous state system for the wheel velocity controls as the lower process, and the interface system as the interaction process between the continuous system as the low level and the discrete event system as the high level. The reference motion commands for autonomous navigation are generated by the abstracted motion in the discrete event system. The motion control tasks including the feasible path planning and autonomous motion control with various initial conditions are investigated as the applications by the simulation studies.