• 한국안전학회지
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• 제27권3호
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• pp.161-166
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• 2012

This study deals with the accident of roundabout. The objective is to analyze the traffic accidents occurred in 3-legged and 4-legged roundabouts through the developed models. In developing the multiple linear regression models, this study uses the number of traffic accidents as a dependent variable and such the variables as geometric structures, traffic characters and others as the independent variables. The correlation and multicollinearity of variables were analyzed using SPSS17.0. The main results are as follows. First, R-square value of developed models were analyzed to be 0.851(3-leg) and 0.689(4-leg), respectively. Second, the independent variables in the 3-legged roundabout accident model were analyzed to be the traffic volume and number of crosswalk, and the variables in the 4-legged roundabouts were evaluated to be the traffic volume and signal. Finally, the paired t-test shows that the predicted values and observed values are not statistically different.

• 제어로봇시스템학회논문지
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• 제8권6호
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• pp.477-483
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• 2002

This paper deals with a workspace analysis of multi-legged walking robots in velocity domain(velocity workspace analysis). Noting that when robots are holding the same object in multiple cooperating robotic arm system the kinematic structure of the system is basically the same with that of a multi-legged walking robot standing on the ground, we invented a way ot applying the technique for multiple arm system to multi-legged walking robot. An important definition of reaction velocity is made and the bounds of velocities achievable by the moving body with multi-legs is derived from the given bounds on the capabilities of actuators of each legs through Jacobian matrix for given robot configuration. After some assumption of hard-foot-condition is adopted as a contact model between feet of robot and the ground, visualization process for the velocity workspace is proposed. Also, a series of application examples will be presented including continuous walking gaits as well as several different stationary posture of legged walking robots, which validate the usefulness of the proposed technique.

• 로봇학회논문지
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• 제6권3호
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• pp.284-291
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• 2011

This paper presents the estimation of the frictional coefficient of the wheel-legged robot with hip joint actuation producing maximum tractive force. Slip behavior for wheel-legged robot is analytically explored and physically understood by identification of the non-slip condition and derivation of the torque limits satisfying it. Utilizing results of the analysis of slip behavior, the frictional coefficients of the wheel-legged robot during stance phase are numerically estimated and finally this paper suggests the pseudo-algorithm which can not only estimate the frictional coefficients of the wheel-legged robot, but also produce the candidate of the touch down angle for the next stance.

• 로봇학회논문지
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• 제14권4호
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• pp.264-269
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• 2019

This paper presents mechanical design and control of a bio-inspired legged robot. To achieve a fast legged running mechanism, a novel linkage leg structure is designed based on hind legs of domestic cats. The skeletomuscular system and parallel leg movement of a cat are analyzed and applied to determine the link parameters. The hierarchical control architecture is designed according to the biological data to generate and modulate desired gaits. The effectiveness of the leg mechanism design and control is verified experimentally. The legged robot runs at a speed of 46 km/h, which is comparatively higher speed than other existing legged robots.

• 한국ITS학회 논문지
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• 제9권6호
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• pp.83-93
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• 2010

회전교차로는 신호교차로보다 대형 교통사고, 혼잡비용 및 온실가스 효과를 줄이는 녹색교통체계이다. 본 연구의 목적은 다지 회전교차로의 운영효율을 분석하는데 있다. 이를 위해 본 연구에서는 다지 회전교차로와 신호교차로의 최적의 기하구조를 구축하고, 주도로와 부도로의 진입교통량의 비율을 반영한 분석시나리오를 작성하며, VISSIM을 이용하여 차량당 평균제어지체를 비교 분석하는데 중점을 두고 있다. 연구의 주요 결과는 다음과 같다. 첫째, 총 진입 교통량이 3,500pcph 이하일 때, 5지 1차로와 2차로 모두 회전교차로가 신호교차로보다 효과적으로 분석된다. 둘째, 6지 1차로 교차로일 경우 총 진입교통량이 3,600pcph이하에서 회전교차로가 신호교차로에 비해 효과적이다. 6지 2차로 교차로의 경우엔 회전교차로가 모든 진입교통량 조건에서 신호교차로보다 효과적으로 분석된다.

• 한국콘텐츠학회논문지
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• 제13권9호
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• pp.400-409
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• 2013

본 연구에서는 한국 운전자의 특성을 고려한 회전교차로 진입 임계간격을 조사하여 이를 기반으로 다양한 교통조건 및 다지 회전교차로에 대하여 그 효과를 분석하였다. 회전교차로의 임계간격은 4지, 5지, 6지, 그리고 7지에 대하여 현장조사를 수행하였으며, Raff의 추정기법을 이용하여 임계간격을 도출하였다. 도출된 임계간격은 모의실험을 위한 정산 및 통계적 검증과정을 거쳤으며, 이를 기반으로 다양한 조건에서 회전교차로 운영분석을 수행하였다. 그 결과 운영 교통량 및 회전비율 등에 따른 다지 회전교차로의 설계요소인 내접원 직경을 서비스수준별로 제시하였다. 이는 향후 회전교차로 설계지침에 반영할 수 있을 것으로 사료된다.

• 제어로봇시스템학회논문지
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• 제9권11호
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• pp.943-951
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• 2003

A strategy for fault-tolerant gaits of autonomous legged robots is proposed. A legged robot is considered to be fault tolerant with respect to a given failure if it is guaranteed to be capable of walking maintaining its static stability after the occurrence of the failure. The failure concerned in this paper is a locked joint failure for which a joint in a leg cannot move and is locked in place. If a failed joint is locked, the workspace of the resulting leg is constrained, but legged robots have fault tolerance capability to continue static walking. An algorithm for generating fault-tolerant gaits is described and, especially, periodic gaits are presented for forward walking of a hexapod robot with a locked joint failure. The leg sequence and the formula of the stride length are analytically driven based on gait study and robot kinematics. The transition procedure from a normal gait to the proposed fault-tolerant gait is shown to demonstrate the applicability of the proposed scheme.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1928-1933
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• 2005

This Paper is about landing control of legged robot. Body stiffness and damping is used as landing strategy of a legged robot. First, we only used stiffness control method to control legged robot landing. Second control method,sliding mode controller and feedback linearization controller is applied to enhance position control performance. Through these control algorithm, body center of gravity behaves like mass with spring & damping in vertical direction on contact regime.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.469-472
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• 2016

Jansen Mechanism has been a constant popularity by researchers studying legged robots because of many benefits. This paper proposed the design process of optimized legged robots using Jansen Mechanism and m.Sketch(Jansen Mechanism simulation software). First, driving part of legged robots is designed in compliance with the design regulations of a competitive exhibition. Second, setting the length of link and position of joint is conducted in keeping with the constraints. Third, Ground Length (GL) and Ground Angle Coefficient(GAC) values are extracted by m.Sketch simulation. Finally, by repeating the previous procedures, comparing the GL and GAC values, find the optimum input values. This.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1440-1443
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• 2004

Most previous robots had used the wheels as means for movement. These structures were relatively simple and easy to control and this is why the method had been used until currently. However, there are many realistic problems to move from one place to another in human life, for instance, steps and edges. So we need to develop the two-legged walking humanoid robot. The 2-legged walking Robot system has been vigorously developed in so many corporations and academic circles of several countries. However, 2-legged walking Robot has been mostly studied in view of the static walk. We design a stable humanoid Robot which can walk in high-speed through the research of the dynamic walk in this paper. Especially, worldwide companies have been interested in developing humanoid robots for a long time to solve the before mentioned problems so that they can become more familiar with the human form. The most important thing, for the novel two-legged walk, is to create a stable and fast walking in two-legged robots. For realization of this movement, an optimal mechanical design of 12 DOFS, a distributed control and a parallel processing control are implemented in this paper. This paper proves that high speed and stable walking can be achieved, through experiments.