• 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.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.2
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• pp.115-121
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• 2022

As city environments have recently become crowded, there are many obstacles that interfere with the walking of the visually impaired on pedestrian roads. Typical examples include ballads, parking breakers and standing signs, which usually do not get in the way, but blind people may be injured by collisions. To solve such a problem, many solutions have been proposed, but they are limited in applied in practical environments due to the several restrictions such as outside use only, inaccurate obstacle sensing and requirement of special devices. In this paper, we propose a new method to automatically detect obstacles while walking on the pedestrian roads and warn the collision risk in advance by using only sensors embedded in typical mobile phones. The proposed method supports the walking of the visually impaired by notifying the type of obstacles appearing in front of them as well as the distance remaining from the obstacles. To accomplish this goal, we utilized an object recognition technology applying the latest deep learning algorithms in order to identify the obstacles appeared in real-time videos. In addition, we also calculate the distance to the obstacles using the number of steps and the pedestrian's stride. Compared to the existing walking support technologies for the visually impaired, our proposed method ensures efficient and safe walking with only simple devices regardless of the places.

• Korean Journal of Applied Biomechanics
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• v.20 no.3
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• pp.261-266
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• 2010

Human body is hard to be in perfect balance during walking. Most of time the trunk is supported by one leg and the center of mass(COM) falls to the contralateral side. Thus, dynamic variables such as the velocity of the COM should be considered when gait stability is evaluated. The purpose of this study was to investigate whether the extrapolated center of mass(XCom) which utilized the COM position and its velocity, is appropriate to evaluate gait stability. Ten healthy adults participated in this study and performed 3 different types of gaits(normal(NG), hands on waists(HWG), and hands on shoulders(HSG)) onto 4 different types of obstacle(obstacle height: 0%, 30%, 40% and 50% of leg length). Medio-lateral Com-CoP and XCom-CoP inclination angle were calculated during support phase. For all condition, greater M-L XCoM-CoP inclination angles were found(p<.05) compared with those of matched obstacle height CoM-CoP. Especially, M-L XCoM-CoP inclination angle at 50% height revealed the best condition for monitoring dynamic stability. Significantly increased in M-L XCoM-CoP inclination angle was found(p<.05) as obstacle height increased on NG and HWG.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1926-1930
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• 2004

We suggest a turning gait planning of a quadruped walking robot with an articulated spine. Robot developer has tried to implement a gait more similar to that of natural animals with high stability margin. Therefore, so many types of walking robot with reasonable gait have been developed. But there is a big difference with a natural animal walking motion. A key point is the fact that natural animals use their waist-oint(articulated spine) to walk. For example, a crocodile which has short legs relative to a long body uses their waist to walk more quickly and to turn more effectively. The other animals such as tiger, dog and so forth, also use their waist. Therefore, this paper proposes discontinuous turning gait planning for a newly modeled quadruped walking robot with an articulated spine which connects the front and rear parts of the body. Turning gait is very important as same as straight gait. All animals need a turning gait to avoid obstacle or to change walking direction. Turning gait has mainly two types of gaits; circular gait and spinning gait. We apply articulated spine to above two gaits, which shows the majority of an articulated spine more effectively. Firstly, we describe a kinematic relation of a waist-joint, the hip, and the center of gravity of body, and then apply a spinning gait. Next, we apply a waist-joint to a circular gait. We compare a gait stability margin with that of a conventional single rigid body walking robot. Finally, we show the validity of a proposed gait with simulation.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.3
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• pp.169-175
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• 2016

There are many researches to develop robots that improve its mobility and task planning to adapt in various uneven environments. In this paper, we propose the design method and task planning of quadruped robot which can have top-bottom docking structure. The proposed quadruped robot is designed to adjust leg length using linear actuators and perform top-bottom docking and undocking using octagonal cone shaped docking module. Also, to stable walking and information gathering in the various environments, a geomagnetic sensor, PSD sensor, LRF sensor and camera. We propose an obstacle avoidance method and the topbottom docking algorithm of the two quadruped robots using linear actuator. The robot can overcome obstacles using adjusting leg length and activate the top-bottom docking function. The top-bottom docking robots of two quadruped robot can walk 4 legged walking and 6 legged walking, and use 4 arms or 2 arms the upper. We verified that the docking robots can carry objects using 4 leg of the upper robot.

• Korean Journal of Applied Biomechanics
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• v.29 no.2
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• pp.97-104
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• 2019

Objective: The aim of this study was to investigate the strategies for avoiding moving and stationary walker using body segments during walking. Method: Ten healthy young adults (10 males, age: $24.40{\pm}0.49yrs$, height: $175.80{\pm}5.22cm$, body mass: $70.30{\pm}5.22kg$) participated in this study. Each participant was asked to perform a task to avoid collisions with another walker who was moving or stationary during walking on the 10 m walkway. Both walkers were performed at natural self-selected walking speed. Results: Medio-lateral avoidance displacement of the trunk and the pelvis were significantly increased when avoiding a stationary walker (p<.05). There were no significant differences in medio-lateral center of mass trajectory. Rotation angle of trunk, pelvis and foot on the vertical axis were significantly increased when avoiding a stationary walker (p<.05). Conclusion: Based on our results, when another walker moves continuously, the walker recognizes another walker as the object of social interaction and performs the avoidance strategies while expecting the cooperative distance. On the other hand, when another walker is stopped, it is determined that the walker has an obligation to avoid, and the walker performs a relatively safer avoidance strategy.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.190-198
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• 2020

The development in smartphone technology has brought convenience to the life of the mankind, but an excessive use of smartphones sometimes causes various accidents. This research tried to propose an application service 'Smombie Safe Go' UI(User Interface) that allows the prevention of such accident while using smartphones when walking. For this, after research and user observations, produced walker journey maps and derived necessary main functions needed for safety, and the result showed that transparent interface, obstacle location alert, warning of dangers functions were necessary. To make the contents of the service more detailed, hazardous situations faced during smartphone use when walking were classified into 3 situations : 1. Obstacle appearing in front, 2. traffic lights on crosswalks 3. No traffic lights on crosswalks. Scenarios by hazardous situation were written, and the flow and UI of the app service that warns its users in each situation of hazards were designed. it is predicted that 'Smombie Safe Go' may be possible to be utilized as an app service that provides a safe walking experience for not only regular pedestrians but also the blind population.

• Journal of the Korea Society of Computer and Information
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• v.23 no.8
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• pp.101-106
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• 2018

Most people with visual impairments can not use both hands freely because they carry a cane. And unnecessary contact with people around you during walking can occur. Other guides include guide dogs, but the price and maintenance cost are expensive and difficult to manage. In this paper, we propose a smart glove, which prevents unnecessary contact when blind people use the cane, detects the obstacle ahead by using the ultrasonic sensor, and informs the presence of the obstacle by using the servo motor. In addition, the electrostatic proximity touch module on the fingers executes a specific application of the smart phone connected by Bluetooth when the finger touches each other. It is designed to allow you to use text or phone calls when you are lost or in an emergency. The results of this study will be used as a tool to provide a more convenient life for the visually impaired.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.12
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• pp.984-990
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• 2005

The aim of this paper is to investigate a control framework for mobile robots, operating in shared environment with humans. The Intelligent Space (iSpace) can sense the whole space and evaluate the situations in the space by distributing sensors. The mobile agents serve the inhabitants in the space utilizes the evaluated information by iSpace. The iSpace evaluates the situations in the space and learns the walking behavior of the inhabitants. The human intelligence manifests in the space as a behavior, as a response to the situation in the space. The iSpace learns the behavior and applies to mobile agent motion planning and control. This paper introduces the application of fuzzy-neural network to describe the obstacle avoidance behavior teamed from humans. Simulation results are introduced to demonstrate the efficiency of this method.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.565-568
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• 1998

In this paper, we implemented the electornic moving aid system for safe walking of the blind. An obstacle detecting of each sector used ultrasound and a distance measurement used time of flight. The alarm is designed to have a sound and a tactile function that can be selected on an user's convenience. This system can detect and obstacle of upward, forward, downward and optimally warn to the blind with vibration, beep sound by appling warning algorithm on object detection. Experimental testing and performance evaluation have been successfully carried out with a prototype cane, and the experiment shows the capability of the function to detect unknown objects within an assigned distance, under knees, over head height, and crushed puddles.