• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.971-980
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• 2010

In this paper, we present a navigation control algorithm for mobile robots that move in environments having static and moving obstacles. The algorithm includes a global and a local path-planning algorithm that uses $D^*$ search algorithm, a fuzzy logic for determining the immediate level of danger due to collision, and a fuzzy logic for evaluating the required wheel velocities of the mobile robot. To apply the $D^*$ search algorithm, the two-dimensional space that the robot moves in is decomposed into small rectangular cells. The algorithm is verified by performing simulations using the Python programming language as well as by using the dynamic equations for a two-wheeled mobile robot. The simulation results show that the algorithm can be used to move the robot successfully to reach the goal position, while avoiding moving and unknown static obstacles.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.1
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• pp.47-54
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• 2011

The remote control mobile robot is the robot accomplishing a task according to the orders giving by a user through departed communication system using a joystick. Basically, to supply a lot of information, as this type of robot uses visual information, the user can check the transmitted information by eyes and give orders to the robot. But the weak point of this type of robot is that it has a possibility to come into a collision with an obstacle not be seen to the user because of the communication delay occurring in a communication system and dead zone happening in visual information. To solve the problem, in this paper, we try to suggest a system applying a fuzzy control system to the robot to avoid collision with an obstacle by an immediate order of the user. The fuzzy control system has better performance than any other existing control methods in the change of noise and parameter. And it is more efficient than any other since it solves easy the complexity of the system analysis occurring because of the nonlinear feature of the mobile robot system. In this paper, we made experiments how the mobile robot controlled by the fuzzy control system avoids an obstacle, tracks the path and avoids the obstacle in the path, to prove the performance and to check the evaluation and the application possibility of the fuzzy control system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1034-1041
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• 2014

This paper propose a fuzzy inference model for obstacle avoidance for a mobile robot with an active camera, which is intelligently searching the goal location in unknown environments using command fusion, based on situational command using an vision sensor. Instead of using "physical sensor fusion" method which generates the trajectory of a robot based upon the environment model and sensory data. In this paper, "command fusion" method is used to govern the robot motions. The navigation strategy is based on the combination of fuzzy rules tuned for both goal-approach and obstacle-avoidance. We describe experimental results obtained with the proposed method that demonstrate successful navigation using real vision data.

• Journal of the Korean Institute of Navigation
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• v.24 no.4
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• pp.235-246
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• 2000

인공 지능 분야에서 특히 퍼지와 같은 기술은 전반적인 산업 자동화에 많이 사용되어 왔다. 퍼지 제어는 인간의 추론 과정을 모델링한 기술로서 인간에 유사한 결정 능력과 복잡하고 다양한 환경에 매우 효과적이다. 본 논문은 이러한 퍼지 제어의 장점을 연근해의 선박 자동 항해에 적용시켜 보았다. 심해에서는 공간상의 제약이 없기 때문에 선박의 자동항해는 원하는 목표지점까지 안전하게 운항할 수 있지만, 연근해안에는 심해와 달리 각종 장애물들(작고 큰 섬들과 해안, 연근해에 작업중인 선박들)이 있으며 이것들로 인한 충돌사고가 종종 발생하고 있는 실정이다. 그러므로 연근해안에서 보다 안전하고 자율적인 항해를 위해 인공 지능 기술인 퍼지 기술을 선박에 적용시켰다. 본 논문에서 제안된 다변수 퍼지 시스템을 2개의 서로 다른 동적 환경을 가지는 지형에 적용시켜 보았고, 그에 따른 실험들을 수행했을 때, 만족할만한 결과를 얻을 수 있었다. 따라서, 본 논문에서 제안된 다변수 퍼지 제어시스템을 이용한 선박이 동적인 환경에서도 스스로 장애물을 인식하고 회피함으로 안전하게 연근해를 운항할 수 있음을 보였다.

• Journal of Navigation and Port Research
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• v.32 no.6
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• pp.447-452
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• 2008

In this paper, the automatic depth control system and the collision avoidance system of the Manta UUV have been established in vertical and horizontal plane. The PID control theory and the Fuzzy theory are adopted in this system. The 6-DOF MMG model had been established by theoretical calculations and captive model test results. The depth control simulation results have been fully presented. The collision risks of the UUV had calculated by the fuzzy theory with the virtual sonar system. Finally, the automatic depth control system and the collision avoidance simulation system of Manta UUV have been fully developed and simulated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.319-322
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• 1995

This paper addresses that through the use of Fuzzy Logic Control, a reactiv behavior (e.g. avoiding obstacles on the way) are smoothly blended into one sequence of control action. In this classical problem, the aim is to guide a mobile robot along its path to avoid any static obstacles in front of it. This controller presented here uses three sub-controllers. This fuzzy controller was apply to a miniature mobile robot. This robot follows a left wall, maintining a minimum distance.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.570-575
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• 2000

This paper presents a delayed time path planning method of the Autonomous Mobile Robot using fuzzy logic controller for avoidance of obstacles in unknown environment. It is the objective of this paper to develop fuzzy control algorithms using delayed time techniques to deal with moving obstacles randomly. This control method gives the benefit of the collision free movement in real time and optimal path to the pre-settled goal. The computer simulations are demonstrated the effective of the suggested control method in obstacle avoidance.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.05a
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• pp.292-295
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• 2003

로봇의 기능이 다양해지며 복잡해지고 있다 주위의 환경을 감지하는 센서로는 거리정보 뿐만이 아니라 영상 정보, 음성 정보까지 이용하고 있다 본 논문에서는 다양한 입력정보를 가지고 로봇을 제어하기 위한 알고리즘으로 2-Layer Fuzzy Control을 제안한다 장애물 회피의 경우에 다수의 초음파 센서를 이용하였는데 이것을 앞쪽, 왼쪽, 오른쪽으로 분류하여 3개의 sub-controller를 가지고 퍼지 추론을 한 다음 2단계에서는 이 3개의 sub-controller의 출력으로 조합된 퍼지 추론을 하여 통합적인 추론을 한다 본 논문에서는 2-Layer Fuzzy Controller와 비슷한 구조를 갖는 Hierarchical Fuzzy Controller와 성능비교를 하였으며 Robot following에도 적용하여 각각에 대한 시뮬레이션과 실험을 통해 확인한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.329-336
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• 2008

Nowadays with advancement in technology and aging society, the number of disabled citizens is increasing. The disabled citizens always need a caretaker for daily life routines especially for mobility. In future, the need is considered to increase more. To reduce the burden from the disabled, various devices for healthcare are introduced using computer technology. 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. By this way, the disabled will not always have to worry about paying deep attention to the surroundings and his path.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.4
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• pp.498-504
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• 2005

A fuzzy logic for collision avoidance of underwater robots is proposed in this paper. The VFF(Virtual Force Field) method, which is widely used in the field of mobile robots, is modified for application to the autonomous navigation of underwater robots. This Modified Virtual Force Field(MVFF) method using the fuzzy logic can be used in either track keeping or obstacle avoidance. Fuzzy logics are devised to handle various situations which can be faced during autonomous navigation of underwater robots. The obstacle avoidance algorithm has the ability to handle multiple static obstacles. Results of simulation show that the proposed method can be efficiently applied to obstacle avoidance of the underwater robots.