• International journal of advanced smart convergence
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• 제8권2호
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• pp.30-38
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• 2019

Recently, the spread of personal mobility has been rapidly increasing due to the development of environmentally friendly alternative transportation means. In addition, the level of battery technology is also rapidly developing, accelerating the popularization of personal mobility. Such personal mobility has convenience of location transfer, amusement, and high portability compared to other transportation devices. Most personal mobility, however, is made up of small wheels, which cannot overcome obstacles such as rugged roads or obstacles on the road. In this paper, to solve these problems, we tried to devise a device that can easily overcome obstacles by combining wheels with small moving means. The wheel size can be mounted on the front wheel of the small moving means in a protruding manner so that obstacles can be encountered before the front wheels and the safety and ride comfort of the running can be improved.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제17권3호
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• pp.43-51
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• 2011

The mobility and accessibility enhancement is gradually becoming a global interest due to the growth in the aging population and concerns about people with disabilities. The main purpose of this study is to know the current situation in barrier-free level in railroad facilities in order to allow the mobility handicapped to travel in a safe and convenient manner. The research has started with investigating current situation for the mobility handicapped people and explores the needs of barrier-free facilities. 84 domestic railroad facilities were evaluated based on assessment tool developed from the mobility handicapped act. As a result, the fact that the mobility handicapped experienced limited accessibility due to various types of obstacles in the facilities was discovered. Based on the evaluation, obstacles in the facilities were analyzed and categorized by specific dimensions, users' accessibility, mobility, usability, and clarity (way-finding). This study suggests barrier-free design for passenger facilities focused on train station. Because mobility and accessibility are emphasized in current society, improvement of the mobility handicapped' movement should be considered. Barrier-free design for passenger facilities should be realized throughout comprehending the reasons why these obstacles occur in the facilities not using installation convenience facilities. This study has meaning in finding out the obstacles in each cause of occurrence(accessibility, mobility, usability, and clarity (way-finding)).

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.490-496
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• 1995

A four-legged mobile robot can move on the plain terrain with mobility and stability, but if there exist any obstacles on the terrain of the motion direction, it takes extra times for a mobile robot to cross those obstacles and the stability should be considered during motion. The main objevtive is the study of a quadruped which can cross obstacles with better mobility, stability and fuel economy than any other wheeled or tracked vehicles. Vertical step, isolated wall and ditch are the basic obstacles and by understanding those three cases perfectly, a quadruped can move on any mixed rough terrain as 4-legged animal moves. Each leg of a determine the crossing capability in a static analysis. A quadruped can be simplified with links and joints. By applying the research method, a quadruped can determine the control procedures as soon as it receives the terrain informations from scanner and finally can be moved as animals move with mobility and stability.

• 한국정밀공학회지
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• 제13권11호
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• pp.152-162
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• 1996

A four-legged Walking Machine can move on the plain terrain with mobility and stability and stability, but if there exist any obstacles on the terrain of the motion direction, it takes extra time to cross those obstacles and the stability should be considered during motion. The main objective is the study a Quadruped which can cross obstacles with better mobility, stability and fuel economy than any other wheeled or tracked vehicles. Vertical step, isolated wall and ditch are the basic obstacles and by understanding those three cases perfectly, a Quadruped can move on any mixed rough terrain as 4-legged terrestrial vertebrates move. Each leg of a Quadruped has a limited walk space called a walking volume and this is very important to deter- mine the crossing capability in a static analysis. A Quadruped can be simplified with links and joints. By applying the research method, a quadruped can determine the control procedures as soon as it receives the terrain information from scanner and finally can move with mobility and stability.

• 한국항공운항학회지
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• 제30권3호
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• pp.19-27
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• 2022

Urban Air Mobility is expected to resolve some problems in urban transportation such as traffic congestion and air pollution. Various studies for a large-scale commercialization of UAM are being actively conducted. To that end, the UAM Traffic Management system aims at securing a safety and an efficiency of UAM operations. In this study, a risk assessment model is proposed to evaluate the risk of collision between a vehicle and surrounding obstacles. The proposed model is conceived from the past studies for determining a proper separation distance between parallel runways for their independent operations. The model calculates the risk that the surveillance system fails to meet a target level of safety for a given buffer zone size between a designed route and surrounding obstacles. The model is applied to one of the routes proposed in K-UAM roadmap to evaluate its performances.

• 한국전자통신학회논문지
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• 제4권1호
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• pp.37-45
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• 2009

The power wheelchair is an important and convenient mobility device. The demand of power wheelchair is increasing for assistance in mobility. In this paper we proposed a robotic wheelchair for mobility aid to reduce the burden from the disabled. The main issue in an autonomous wheelchair is the automatic detection and avoidance of obstacles and going to the pre-designated place. The proposed algorithm detects the obstacles and avoids them to drive the wheelchair to the desired place safely with panning scan from sensors of distance measurement and fuzzy control. By this way, the disabled will not always have to worry about paying deep attention to the surroundings and his path.

• 한국정보전자통신기술학회논문지
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• 제6권3호
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• pp.174-182
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• 2013

The power wheelchair is an important and convenient mobility device. The demand of power wheelchair is increasing for assistance in mobility. In this paper we proposed a robotic wheelchair for mobility aid to reduce the burden from the disabled. The main issue in an autonomous wheelchair is the automatic detection and avoidance of obstacles and going to the pre-designated place. The proposed algorithm detects the obstacles and avoids them to drive the wheelchair to the desired place safely with panning scan from sensors of distance measurement and fuzzy control. By this way, the disabled will not always have to worry about paying deep attention to the surroundings and his path.

• 한국ITS학회 논문지
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• 제20권2호
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• pp.95-111
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• 2021

인구의 감소 및 고령화 사회가 진행되면서 운전자의 평균 연령은 높아지게 된다. 그에 따라 잠재적인 사고의 위험성이 높은 고령 운전자들은 자율 주행형 개인 이동체가 필요하게 된다. 이러한 이동체가 도로 주행 중에 안전성을 확보하기 위하여 여러 장애물에 대응할 기술이 요구된다. 그 중에서도 주행 중에 마주할 수 있는 차량, 자전거, 사람과 같은 동적 장애물뿐만 아니라 도로 노면의 불량 상태와 같은 정적 장애물을 인식하는 기술이 가장 우선적으로 필요하다. 이를 위해서 본 논문에서는 두 종류의 장애물을 동시에 탐지할 수 있는 심층 신경망 알고리즘을 제안했다. 이 알고리즘을 개발하기 위해서 1,418장의 영상을 이용하여 7종의 동적 장애물에 표기한 annotation data와 도로 노면 파손을 표시한 label 영상을 확보했다. 이를 이용하여 학습한 결과, 46.22%의 평균 정확도로 동적 장애물을 탐지하고 74.71%의 mean intersection over union으로 도로 노면 파손을 탐지했다. 또한 한 장의 영상을 처리하는데 평균 소요시간은 89ms로 일반 차량보다 느린 개인 이동 차량에 사용하기 적합한 알고리즘을 개발했다. 향후 주행 중 마주할 있는 도로 장애물을 탐지하는 기술을 활용하여 개인 이동 차량의 주행 안전성이 향상되길 기대한다.

• 한국생산제조학회지
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• 제7권1호
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• pp.9-21
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• 1998

This paper a new solution approach to moving obstacle avoidance problem of a mobile robot. A new concept avoidability measure (AVM) is defined to describe the state of a pair of a robot and an obstacle regarding the collision between them. As an AVM, virtual distance function (VDF), is derived as a function of the distance from the obstacle to the robot and outward speed of the obstacle relative to the robot. By keeping the virtual distance above some positive limit value, the robot avoids the obstacle. In terms of the VDF ,an artificial potential field is constructed to repel the robot away from the obstacle and to attract the robot toward a goal location. At every sampling time, the artificial potential field is updated and the force driving the robot is derived from the gradient of the artificial potential field. The suggested algorithm drives the robot to avoid moving obstacles in real time. Since the algorithm considers the mobility of the obstacle as well as the distance, it is effective for moving obstacle avoidance. Some simulation studies show the effectiveness of the proposed approach.

• 제어로봇시스템학회논문지
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• 제13권2호
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• pp.93-100
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• 2007

The mobile robots to rescue a life in a disaster area and to explore planets demand high mobility as well as recognition of the environment. To avoid unknown obstacles exactly in unknown environment, accurate sensing is required. This paper proposes a sensor fusion to recognize unknown obstacles accurately by using low-cost sensors. Ultrasonic sensors and infrared sensors are used in this paper to avoid obstacles. If only one of these sensors is used alone, it is not useful fer the mobile robots to complete their tasks in the real world since the surrounding environment in the real world is complex and composed of many kinds of materials. So infrared sensor may not recognize transparent or reflective obstacles and ultrasonic sensor may not recognize narrow obstacles, far example, columns of small diameter. Therefore, I selected six ultrasonic sensors and five infrared sensors to detect obstacles. Then, I fused ultrasonic sensors with infrared sensors in order that both advantages and disadvantages of each sensor are utilized together. In fusing sensors, fuzzy algorithm is used to cope with the uncertainties of each sensor. TAMRY which is terrain-adaptive mobile robot is used as the mobile robot for experiments.