• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.638-647
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• 1996

Robot manipulators for harvesting fruits must be controlled to track the desired path of end-effector to avoid obstacles under the consideration of collision free area and safety path. This paper presents a robot path control algorithm to secure a collision free area with the recognition of work environments. The flexible space, which does not damage fruits or branches of tree due to their flexibility and physical properties , extends the workspace. Now the task is to control robot path in the extended workspace with the consideration of collision avoidance and velocity limitation at the time of collision concurrently. The feasibility and effectiveness of the new algorithm for redundant manipulators were tested through simulations of a redundant manipulator for different joint velocities.

• 제어로봇시스템학회논문지
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• 제16권3호
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• pp.233-238
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• 2010

This paper describes a multi-mobile robot system with fuzzy rule based structure in collision avoidance. Collision avoidance is an important function to perform a given task collaboratively and cooperatively in multi-mobile robot environments. So the important but challenging problem is handled in this paper. Considered obstacles for collision avoidance between multi mobile robots are static, dynamic, or both of them at the same time. Using the fuzzy rule based structure, distance and angle from a robot to obstacles are described as fuzzy linguistic values and steering angle for the robot are updated from the collision environments. As a result, the multi-mobile robot can modify a global path from a robot itself to its own target. In addition, avoiding collision with static or dynamic obstacles for the robot system can be achieved. Simulation based experimental results are given to show usefulness of this method.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.176-181
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• 2000

Collision free task planning for dual-arm robot which perform many subtasks in a common work space can be achieved in two steps : path planning and trajectory planning. path planning finds the order of tasks for each robot to minimize path lengths as well as to avoid collision with static obstacles. A trajectory planning strategy is to let each robot move along its path as fast as possible and delay one robot at its initial position or reduce speed at the middle of its path to avoid collision with the other robot.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1140-1143
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• 1996

A new approach based on artificial potential function is proposed for the obstacle avoidance of redundant manipulators. Unlike the so-called "global" path planning method, which requires expensive computation for the path search before the manipulator starts to move, this new approach, "local" path planning, researches the path in real-time using the local distance information. Previous use of artificial potential function has exhibited local minima in some complex environments. This thesis proposes a potential function that has no local minima even for a cluttered environment. This potential function has been implemented for the collision avoidance of a redundant robot in Simulation. The simulation also employ an algorithm that eliminates collisions with obstacles by calculating the repulsive potential exerted on links, based on the shortest distance to object.

• 조명전기설비학회논문지
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• 제13권2호
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• pp.32-38
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• 1999

운송설비용 자율 주행 운반체는 인간의 지도없이 주어진 환경 내에서 장애물과 충돌을 회피하며 효율적으로 목표지점까지 주행할 수 있는 최적의 이동 경로를 생성해야 한다. 본 논문에서는 장애물과 충돌을 회피하는 전역 및 지역경로를 유전알고리즘을 이용하여 계획하였다. 본 논문에서는 제안한 운송설비용 자율 주행 운반체의 충돌회피 알고리즘은 전통적인 충돌회피 알고리즘에 비해 능률적임을 모의 실험을 통해 확인하였다.

• 한국조명전기설비학회지:조명전기설비
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• 제13권2호
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• pp.164-164
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• 1999

An autonomous mobile vehicle for transport system must plan optimal path in work environment without human supervision and obstacle collision. This is to reach a destination without getting lost. In this paper, a genetic algorithm for global and local path planning and collision avoidance is proposed. The genetic algorithm searches for a path in the entire and continuous free space and unifies global path planning and local path planning. The simulation shows the proposed method is an efficient and effective method when compared with the traditional collision avoidance algorithms.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.345-348
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• 1997

In this paper, a motion control algorithm is developed using a fuzzy control and the optimization of performance function, which makes a robot arm avoid an unexpected obstacle when the end-effector of the robot arm is moving to the goal position. During the motion, if there exists no obstacle, the end-effecter of the robot arm moves along the pre-defined path. But if there exists an obstacle and close to the robot arm, the fuzzy motion controller is activated to adjust the path of the end-effector of the robot arm. Then, the robot arm takes the optimal posture for collision avoidance with the obstacle. To show the feasibility of the developed algorithm, numerical simulations are carried out with changing both the positions and sizes of obstacles. It was concluded that the proposed algorithm gives a good performance for obstacle avoidance.

• 한국정밀공학회지
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• 제15권8호
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• pp.165-173
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• 1998

In this paper, a motion control algorithm is developed by using fuzzy control technique, which makes a robot arm avoid unexpected obstacles when the robot is moving from the start to a goal posture. During the motion, if there exist no obstacles the robot arm moves along the pre-defined path. But if some obstacles are recognized and close to the robot arm, a fuzzy controller is activated to adjust the path of the robot arm. To show the feasibility of the developed algorithm, numerical simulations and experiments are carried out. In the experiments, redundant planar robot arms are considered for the collision avoidance test, and it was proved that the developed algorithm gives good collision avoiding performance.

• 한국지능시스템학회논문지
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• 제18권5호
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• pp.592-598
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• 2008

본 논문에서는 AGVS(Automated Guide Vehicle System)의 충돌 및 교착 상태를 예측 및 회피하는 방법을 제안하고 회피에 따른 AGV의 지연 시간을 분산시킬 수 있도록 경로 점유권(PO: right of Path Occupying)을 제안한다. 이를 위해 먼저, AGV의 복잡한 작업 환경을 AGVS의 필요한 요소로 분류하는 모델을 제시한다. 이후, AGV의 최단 경로 탐색 알고리즘을 그래프 탐색 기법인 A* 알고리즘을 이용하여 구현하고 경로의 소요 시간, 방향 및 방향 전환 벡터를 얻은 뒤 이를 시뮬레이션 프로그램의 입력 데이터 사용하였다. 시뮬레이션 수행은 충돌 예측과 회피를 평가하기 위해 사용되었으며 그 결과 본 논문에서 제안한 방법이 지연시간을 최소화하는데 효과적임을 입증하였다.

• 한국전자통신학회논문지
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• 제7권1호
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• pp.187-194
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• 2012

본 논문에서는 이동 로봇이 자율주행을 하기 위해 사용되는 충돌회피 알고리즘을 실제 로봇과 똑같은 환경에 적용된 시뮬레이터를 통해 성능을 알아본다. 이동 로봇의 충돌회피를 위해 기존에 인공전위계 알고리즘과 Elastic force 알고리즘 등이 제안되어져있다. 본 연구에서는 시뮬레이션을 통해 이 두 가지 방법에 의한 동작시간과 경로의 이동 길이를 비교하였다. 시뮬레이터는 IPC(Inter Process Communication)를 기반으로 개발되어졌으며, 알고리즘의 비교에는 차륜형 이동 로봇을 사용하였다.