• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.388-391
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• 2003

We've been following research on the obstacle avoidance that is based on fuzzy control. We previously proposed a new method of automatically generating membership functions, which play an important role in improving accuracy of fuzzy control, by using genetic programming (GP). In this paper, we made two improvements to our proposed method, for the purpose of achieving better intelligence in fuzzy robots. First, the mutation rate is made to change dynamically, according to the coupled chaotic system. Secondly, the population partitioning using deme is introduced by parallel processing. The effectiveness of these improvements is demonstrated through several computer simulations.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.707-710
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• 2009

최근 다양한 센서를 이용한 자율 주행 장치의 개발이 이루어지고 있으며 전방에 있는 물체를 감지하여 회피한 후 다시 원래의 차선으로 돌아올 수 있는 시스템은 자율주행자동차를 위한 기본적인 알고리즘이다. 본 논문에서는 이동로봇에 장착된 초음파 센서를 이용하여 전방에 있는 장애물을 능동적으로 피해갈 수 있는 시스템을 구축하였다. 많은 초음파센서를 부착할수록 정밀도는 높아질 수 있지만 시스템의 가격상승이 불가피하기 때문에 본 연구에서는 하나의 초음파센서를 이용하여 알고리즘을 개발하였다. 연구 내용으로는 주행로 확보를 위하여 라인트레이서를 이용한 방식을 채용하였고 장애물을 감지 시 회피 후 복귀를 위한 알고리즘을 개발하였다. 또한 실 주행 시험을 통해 시스템의 장애물 감지 및 회피 성능을 확인할 수 있었다.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2777-2779
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• 2005

최근 로봇 기술의 발전으로 인해 로봇에 관련된 제반 기술에 대한 연구가 활발히 진행되고 있다. 이러한 연구 중의 하나가 이동 로봇이 스스로 장애물을 감시하여 회피하도록 적절한 이동 경로를 생성해주는 연구이다. 따라서 본 논문에서는 이동 경로 상에 존재하는 장애물을 회피하기 위한 방법으로 비전 시스템에 기반하여 주행 거리 및 주행 시간을 최소화하여 목표점에 도달한 수 있도록 장애물을 회피하는 방법에 대하여 연구하였다. 시뮬레이션을 통해 제안한 방법의 성능을 검증하여보았다.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.261-265
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• 2005

In this paper, we constructed the infrastructure with wireless LAN and Access Point in the indoor environment and implemented the teleoperation. Wireless LAN based teleoperation system is irregular communication delay according to environment condition and occurrence possibility of blackout is very high. In this paper, In case these problem happened, we measured communication delay time by real time, and did mobile robot to control harmoniously through vision and force reflection information. Also, we present obstacle-avoidance mode that mobile robot can travel without collision using direction information in case communication delay time is large. We proved usefulness of presented algorithm through teleoperation experiment to apply presented algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.486-491
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• 2005

There come various types of robot with researches for mobile robot. This paper introduces the multi-joint snake robot having 16 degree of freedom and composing of eight-axis. The biological snake robot uses the forward movement friction and the proposed artificial snake robot uses the un-powered wheel instead of the body of snake. To determine the enable joint angle of each joint, the controller inputs are considered such as color and distance using PC Camera and ultra-sonic sensor module, respectively. The movement method of snake robot is sequential moving from head to tail through body. The target for movement direction is decided by a certain article be displayed in the PC Camera. In moving toward that target, if there is any obstacle then the snake robot can avoid by itself. In this paper, we show the method of snake robot for tracing the target with experiment.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1770-1781
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• 1989

Two robots working in a common workspace may collide with each other. In this paper, a collision-free motion planning algorithm using view time concept is proposed to detect and avoid collision before robot motion. Collision may occur not only at the robot end effector but also at robot links. To detect and avoid potential collisions, the trajectory of the first robot is sampled periodically at every view time and the region in Cartesian space swept by the first robot is viewed as an obstacle during a single sampling period. The forbidden region in the joint constraint map (JCM). The JCM's are obtained in this way at every view time. An algorithm is established for collision-free motion planning of the two robot system from the sequence of JCM's and it is verified by simulations.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.288-291
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• 2001

This paper present effective odometry error compensation using multisensor fusion for the accurate positioning of mobile robot in navigation. During obstacle avoidance and wall following of mobile robot, position estimates obtained by odometry become unrealistic and useless because of its accumulated errors. To measure the position and heading direction of mobile robot accurately, odometry sensor a gyroscope and an azimuth sensor are mounted on mobile robot and Complementary-filter is designed and implemented in order to compensate complementary drawback of each sensor and fuse their information. The experimental results show that the multisensor fusion system is more accurate than odometry only in estimation of the position and direction of mobile robot.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.38.3-38
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• 2001

In the planetary surface exploration , micro-rovers or nano-rovers are very attractive choices for a surface exploration system providing mobility functions and other features required in the surface probe missions at small mass and relatively small cost. This paper surveys and summarizes the requirements for Mars exploration rovers in micro or nano scale and outlines the control concepts for navigation including the obstacle/hazard avoidance and the path planning. In this context, autonomous reaction capabilities are the key elements to control design in conjunction with the remote control schemes to deal with the significant signal propagation delays. Other navigation and control aspects such as the instrument fine positioning and the flip-over of the rovers are also briefly introduced. The current technical limitations of the micro- and nano-rovers are summarized.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.790-793
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• 2002

In this paper, dynamic path planning of two mobile robots using a modified Hopfield neural network is studied. An area which excludes obstacles and allows gradually changing of activation level of neurons is derived in each step. Next moving step can be determined by searching the next highest activated neuron. By learning repeatedly, the steps will be generated from starting to goal points. A path will be constructed from these steps. Simulation showed the constructed paths of two mobile robots, which are moving across each other to their goals.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.12
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• pp.1-12
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• 1996

A new local path planning algorithm using DPH (distance profile histogram) is suggested in this paper. The proposed method makes a grid type world map using distance values from multiple ultrasonic sensors and genrates local points through which the mobile robot can avoid obstcles safely. The DPH (distance profile historgram) represents geometrical arrangement of obstacles around the robot in the local polar coordinate system which is assumed to be atached to the robot. To control robot's navigation, a three-layered control structure is adopted. The proposed local path planning algorithm is placed on the top level. And a point-to-point translation controller takes the middle level. The bottom level consists of a velcoity servo and sonar driver modules which take charge of driving physical hardwares. The validity of the propsoed method is demonstated through several experiments.