• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.661-669
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• 1995

A mobile robot, named KAEROT, has been developed for inspection and maintenance operations in nuclear facilities. The main feature of locomotion system is the planetary wheel assembly with small wheels. This mechanism has been designed to be able to go over the stairs and obstacles with stability. This paper presents the inverse kinematic solution that is to be operated by remote control. The automatic stair climbing algorithm is also proposed. The. proposed algorithms generates the moving pathes of small wheels and calculates the angular velocity of 3 actuation wheels. The results of simulations and experiments are given for KAEROT peformed on the irregular stairs in laboratory. It is shown that the proposed algorithm provides the lower inclination angle of the robot body and increases its stability during navigation.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.6
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• pp.9-21
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• 2001

This paper defines the mobility and rotatability, and a desired mobility and rotatability that can be achieved by adjusting the distance between two wheels of a mobile robot dynamically. The radii of wheels are assumed to be constant in this paper. If a mobile robot has a fixed axis connecting the two wheels, it may not be able to avoid a sudden obstacle because of the constraint of mobility and rotatability. The focus of this paper is on the instant rotatability with high and stable mobility. That is, by dynamically changing the distance between the two wheels, the mobile robot could get the high rotatability instantly and high mobility with high stability. Supposed that the mobility and rotatability that are defined in this paper are supplied to the design of a mobile robot, it will suggest a theoretical basis on the optimal design of the mobile robot with a given route condition and its states. The experimental data support the validity of the aforementioned mobility and rotatability.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2021-2032
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• 1992

A redundant sensor system, which consists of two incremental encoders and a gyro sensor, has been proposed for the estimation of the posture of mobile robots. A hardware system was built for estimating the heading angle change of the mobile robot from outputs of the gyro sensor. The proposed hardware system of the gyro sensor produced an accurate estimate for the heading angle change of the robot. A sensor data fusion algorithm has been developed to find the optimal estimates of the heading angle change based on the stochastic measurement equations of our readundant sensor system. The maximum likelihood estimation method is applied to combine the noisy measurement data from both encoders and gyro sensor. The proposed fusion algorithm demonstrated a satisfactory performance, showing significantly reduced estimation error compared to the conventional method, in various navigation experiments.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.886-890
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• 1995

최근 몇년사이에 산업 전분야에서 로보트의 이용이 증가하고 있는데, 로보트 시스템의 주요목적은 작업영역내에서 작업물을 빠르고 정확하게 다른 장소로 이동시키는 것이다. 이러한 로보트의 이용에 있어서의 어려움 중 하나는 로보트가 목표점으로 움직이는 동안에 작업장내에 있는 장애물, 즉 각종 공구, 시설등의 물체와의 충돌을 피할 수 있도록 프로그램 되어야 하며, 이를 위해서 많은 시간이 소요된다는 것이다. 본 연구에서는 SOM 네트워크를 이용하여 장애물이 존재하는 작업 공간에서 로보트가 장애물과 충돌없이 움직일 수 있는 경로를 구하기 위한 SOM의 응용방안을 소개한다. 본 연구에서는 SOM의 최적 size, 학습계수 요인을 고려하여 2관절 로보트의 충돌회피 경로 발견을 위한 시뮬레이션을 수행하였다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.5
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• pp.1-12
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• 2000

In this paper we propose a design method of the adaptive fuzzy controller for autonomous navigation of mobile robots based on the fuzzy theory. We present two improvements. First, unnecessary rules in the fuzzy inference process make data processing time increase. We reduce this data processing time by generating suitable fuzzy inference rules and membership functions according to the current state of a mobile robot. It is implemented with the clustering method using input and output data pairs, and then it is possible for a mobile robot to navigate in shorter processing time with less fuzzy inference rules. Second, existing algorithms used fixed membership functions of input and output variables, hence converged slowly. We improve convergence time via scaling membership functions generated by the clustering method. To evaluate and compare the performance of the proposed method with the existing fuzzy navigation controller, computer simulations and navigation experiments of a mobile robot are Presented.

• Nuclear industry
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• v.7 no.4 s.50
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• pp.70-73
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• 1987

고도의 보전작업을 하기 위해서는 고도의 지적판단을 가지며 발전소 내를 자유로이 이동하여 범용공구나 자동공구 등을 사용해서 사람 대신에 다양한 작업을 하는 범용고기능로보트의 개발이 요망되고 있다.

• 전기의세계
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• v.40 no.4
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• pp.50-58
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• 1991

본 연구에서는 로보트에 현재위치와 목적지가 주어지면 로보트가 가지고 있는 세계지도(world map)로부터 경로를 탐색하여 경로의 주위 환경 정보를 가진 경로지도(route map)을 생성하고 이를 해석하여 주행을 하도록 한다. 그리고, 인간은 매우 복잡한 상황을 간단하게 이행하는 능력을 갖고 있으나, 그 상황을 감지하는데 필요한 정보들은 불확실성과 모호성을 내포하고 있으며, 인간의 주관적 판단에 의한 것과 불완전 계측에 의한 것들을 처리하기 위해 퍼지 이론을 이용한 추론 및 주행 알고리즘을 제안한다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.30-41
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• 1989

In this paper, a robust and simple structured light sensory system has been studied to endow mobile robots with the ability of navigating in real world. A mobile robot with this sensor can be applied in two ways: first, real time navigation in 3-dimensional world, second, modeling and recognition of environment. Range data obtained with this sensor are fairy accurate, and the data aquisition speed is satisfactory. Experiments in diverse situation show effectiveness of the structured light sensor for the mobile robot.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.10
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• pp.1173-1182
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• 1988

The stability, energetic efficiency and walking volume are affected by the geometric structure of legs of a walking robot. A quadruped walking robot is considered to have large stability margin among the walking robots and pantograph leg permits large walk stroke and mutually independent vertical and horizontal movements, but the kinematic characteristics are difficult to analyze. Graphical method may be useful to characterize three dimensional legged motion of the pantograph mechanism. We present the modelling method for three different quadruped robots with pantograph legs that have different joints mechanism. The modeled robots are animated by a path that is planned with respect to the center of body. In particular, graphical animation incorporates leg control to rotation and side walking and uses the window of Sun-3 system for displaying joint information.

• 전기의세계
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• v.36 no.5
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• pp.299-304
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• 1987

다각 보행로보트 혹은 이동로보트에 있어서 관리제어, 특히 자율경로계획 문제의 해결은 잘 정돈된 환경이라 할지라도 아직은 명실상부한 기준(de facto standard)이 없는 실정이며 더 나아가, 자연환경같이 험난하고 잘 묘사될 수 없는 경우의 연구는 거의 시작 단계에 있는 실정이다. 이러한 문제의 해결을 위해서는 더욱 더 빠른 계산능력과 강력한 새로운 센서 및 잘 정돈되지 않은 환경을 효율적, 효과적으로 묘사할 수 있는 새로운 방법들의 출현이 필연적이다.