• 제어로봇시스템학회논문지
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• 제6권11호
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• pp.1003-1012
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• 2000

When a robot hand grasp an object, the number of ways to grasp it stably are infinite and thus an optimal grasp planning is needed to find the optimal grasp points for satisfying the objective of the given task. In this paper, we first define some grasp indices to evaluate the quality of each feasible grasp and then a weighted composite grasp index by combining all of the grasp indices is also defined. Next, we propose a method to find the optimal grasp points of the given object by comparing the defined weighted composite grasp index for each feasible grasp points. By simulation results, we show the effectiveness of the proposed optimal grasp planning method and also discuss the trend of each grasp index as the grasp polygon.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.462-465
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• 2002

This paper deals with the problem of synthesis of stable and optimal grasps with unknown objects by 3-finger hand. Previous robot grasp research has analyzed mainly with either unknown objects 2D by vision sensor or unknown objects, cylindrical or hexahedral objects, 3D. Extending the previous work, in this paper we propose an algorithm to analyze grasp of unknown objects 3D by vision sensor. This is archived by two steps. The first step is to make a 3D geometrical model of unknown objects by stereo matching which is a kind of 3D computer vision technique. The second step is to find the optimal grasping points. In this step, we choose the 3-finger hand because it has the characteristic of multi-finger hand and is easy to modeling. To find the optimal grasping points, genetic algorithm is used and objective function minimizing admissible farce of finger tip applied to the object is formulated. The algorithm is verified by computer simulation by which an optimal grasping points of known objects with different angles are checked.

• 한국정밀공학회지
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• 제19권11호
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• pp.54-64
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• 2002

This paper deals with the problem of synthesis of stable and optimal grasps with unknown objects by 3-finger hand. Previous robot grasp research has mainly analyzed with either unknown objects 2-dimensionally by vision sensor or known objects, such as cylindrical objects, 3-dimensionally. As extending the previous work, in this study we propose an algorithm to analyze grasp of unknown objects 3-dimensionally by using vision sensor. This is archived by two steps. The first step is to make a 3-dimensional geometrical model for unknown objects by using stereo matching. The second step is to find the optimal grasping points. In this step, we choose the 3-finger hand which has the characteristic of multi-finger hand and is easy to model. To find the optimal grasping points, genetic algorithm is employed and objective function minimizes the admissible force of finger tip applied to the objects. The algorithm is verified by computer simulation by which optimal grasping points of known objects with different angle are checked.

• 제어로봇시스템학회논문지
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• 제12권11호
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• pp.1102-1110
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• 2006

This paper addresses the problem of computing grasp stability of the object for two-fingered robots in two dimensions. The concepts of force-closure and dual space are introduced and discussed in novel point of view, and we transform friction cones in a robot work space to line segments in a dual space. We newly define a grasp stability index by calculating intersection condition between line segments in dual space. Moreover, we propose a method to find the optimal grasp points of the given object by comparing the defined grasp stability index. Its validity and effectiveness are investigated and verified by simulations for quadrangle object and elliptic objects.

• 대한기계학회논문집A
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• 제27권7호
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• pp.1110-1119
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• 2003

This paper deals with the synthesis of the 3-dimensional grasp planning for unknown objects. Previous studies have many problems, which the estimation time for finding the grasping points is much long and the analysis used the not-perfect 3-dimensional modeling. To overcome these limitations in this paper new algorithm is proposed, which algorithm is achieved by two steps. First step is to find the whole 3-dimensional geometrical modeling for unknown objects by using stereo matching. Second step is to find the optimal grasping points for unknown objects by using the neural network trained by the result of optimization using genetic algorithm. The algorithm is verified by computer simulation, comparing the result between neural network and optimization.

• 한국정밀공학회지
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• 제20권4호
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• pp.112-117
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• 2003

This paper deals with the problem of synthesis of the 3-dimensional Grasp Planning. In previous studies the genetic algorithm has been used to find optimal grasping points, but it had a limitation such as the determination time of grasping points was so long. To overcome this limitation we proposed a new algorithm which employs the Neural Network. In the Neural network we chose input parameters based on the shape of the object and output parameters resulted from optimization with the GA method. In this study the GRNN method is employed, it has been trained by the result value of optimization method and it has been tested by known object. The algorithm is verified by computer simulation.

• 제어로봇시스템학회논문지
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• 제10권4호
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• pp.350-356
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• 2004

This paper presents a farce manipulability analysis of multi-legged walking robots, which calculates force or acceleration workspace attainable from joint torque limits of each leg. Based on the observation that the kinematic structure of the multi-legged walking robots is basically the same as that of multiple cooperating robots, we derive the proposed method of analyzing the force manipulability of walking robot. The force acting on the object in multiple cooperating robot systems is taken as reaction force from ground to each robot foot in multi-legged walking robots, which is converted to the force of the body of walking robot by the nature of the reaction force. Note that each joint torque in multiple cooperating robot systems is transformed to the workspace of force or acceleration of the object manipulated by the robots in task space through the Jacobian matrix and grasp matrix. Assuming the torque limits are given in infinite norm-sense, the resultant dynamic manipulability is derived as a polytope. The validity of proposed method is verified by several examples, and the proposed method is believed to be useful for the optimal posture planning and gait planning of walking robots.

• 한국도로학회논문집
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• 제14권2호
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• pp.63-72
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• 2012

가로 및 교차로에 설치된 단순입체시설의 현행 분석기법은 시설을 이용하는 주교통류를 분석대상에 포함시키지 않고 있어 불합리한 도로 및 신호운영을 유도하여 엇갈림현상, 병목현상과 같은 도로의 혼잡을 야기한다. 이러한 여건에도 불구하고 단순 입체시설을 이용하는 교통류 분석기법의 연구가 거의 수행된 바 없다. 또한 개략적으로 제시되어 있는 설정기준 역시 여러 가지 도로 및 교통조건을 반영하지 못하고 있는 실정으로, 단순입체시설이 포함된 교차로분석 시 지체도가 과소 추정되는 경향이 있다. 그러므로 본 연구는 도시내 입체시설의 효과를 파악하기 위한 선행과정으로서 대상시설의 효과를 파악할 수 있도록 입체시설의 분석기법을 개발하고 분석교차점의 적정간격을 응용하는데 그 목적이 있다. 본 연구는 다음과 같이 수행하였다. (1) 기존 분석기법의 문제점 제기, (2) 새로운 분석기법의 정립, (3) 사례지역의 적용 및 비교검정, (4) 분합류구간의 적정간격에 대한 민감도 분석을 수행한다. 연구결과, 본 연구에서 제시한 분석기법은 기존 분석기법의 모호한 부분을 명확히 하고 합리적인 결과를 추정할 수 있었다. 또한 그 분석기법을 응용하여 분합류구간에 대한 적정간격을 추정한 결과, 본선에서는 65m, 측도에서는 45m로 나타나 최소한 그 이상의 위치에 접속지점을 설치하는 것이 타당하다고 판단된다. 본 연구의 수행으로 얻어지는 가치는 다음과 같다. (1) 당해 시설에 대한 선행연구 또는 분석방법이 없었으므로 대상시설물로 인한 파급효과를 파악할 수 있다. (2) 본 연구의 분석기법은 기존 교차로의 분석방법을 차용함으로써 새로운 분석방법을 숙지하지 않아도 용이한 분석이 가능하다. (3) 본 연구에서 제시한 분석기법에 의하면 기존에 제외된 통과교통량을 포함시켜 분석할 수 있다. 이러한 방법을 통해 교차로 및 가로분석 시에 현황과 동떨어질 수 있는 결과에 대한 오류를 최소화할 수 있다. (4) 새로운 분석기법을 이용하면 신설 또는 기존 시설물에 대한 문제점을 도출하여 도로운영 및 신호운영 등의 개선방안을 제시할 수 있다.