• International journal of advanced smart convergence
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• v.8 no.2
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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.

• Journal of The Korea Institute of Healthcare Architecture
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• v.17 no.3
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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)).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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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.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.11
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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.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.3
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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.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.1
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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.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.3
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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.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.2
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• pp.95-111
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• 2021

As the population decreases in an aging society, the average age of drivers increases. Accordingly, the elderly at high risk of being in an accident need autonomous-driving vehicles. In order to secure driving safety on the road, several technologies to respond to various obstacles are required in those vehicles. Among them, technology is required to recognize static obstacles, such as poor road conditions, as well as dynamic obstacles, such as vehicles, bicycles, and people, that may be encountered while driving. In this study, we propose a deep neural network algorithm capable of simultaneously detecting these two types of obstacle. For this algorithm, we used 1,418 road images and produced annotation data that marks seven categories of dynamic obstacles and labels images to indicate road damage. As a result of training, dynamic obstacles were detected with an average accuracy of 46.22%, and road surface damage was detected with a mean intersection over union of 74.71%. In addition, the average elapsed time required to process a single image is 89ms, and this algorithm is suitable for personal mobility vehicles that are slower than ordinary vehicles. In the future, it is expected that driving safety with personal mobility vehicles will be improved by utilizing technology that detects road obstacles.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.1
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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.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.2
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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.