• 제어로봇시스템학회논문지
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• 제22권10호
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• pp.817-825
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• 2016

In this paper, we introduce a flexible gripper that we have engineered to precisely pinch in parallel and compliantly grasp objects. As found in most conventional industrial grippers, the parallel pinching property is essential for precise manipulation. On the other hand, the grippers with a flexible structure are more adept at grasping objects with arbitrary shapes and softness. To achieve these disparate properties, we introduce a flexible gripper mechanism composed of multiple flexible beam structures. Utilizing these beam structures, the proposed gripper is able to grasp arbitrarily shaped objects. Additionally, a unique combination of flexible beams enables the gripper to pinch objects using the parallel fingertips for enhanced precision. A detailed description of the proposed mechanism is provided, and an analysis of the strength and stiffness of the fingertip and finger body is presented. The Results section compares the theoretical and experimental analyses and verifies the properties and performance of the proposed gripper.

• 한국기계가공학회지
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• 제19권10호
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• pp.111-116
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• 2020

Flexible tactile sensors, which are primarily used as grippers in robots, are mainly used to handle highly elastic or highly flexible objects. That is, flexible grippers are used when an object cannot be sufficiently controlled by applying a specific output force or taking a specific grabbing action. This is because a flexible tactile sensor needs to measure the pressure applied directly to held objects while deforming according to the shape of the object to be handled. CNT-based sensors used to be made from a highly flexible polymer to give flexibility and it is known that the sensors are greatly affected by the contact resistance of the terminal that connects the sensor to an electrical circuit; therefore, this paper clarifies the contact resistance of MWCNTs-based flexible tactile sensors and terminals. The effects of main and plating materials for terminals are investigated and the combinations of main and plating materials that exhibit contact resistance are measured in a typical industrial environment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.383-386
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• 1997

Electrostatic suspension is a method to levitate an object by using electrostatic forces. Its main advantage is to levitate objects without any mechanical contact which fulfills the requirement of an object handling in ultra clean environment. In this paper, the electrostatic suspension system for film-like thin plate such as aluminum sheet, is designed and controlled. In contrast with the conventional electrostatic suspension system which requires the costly and bulky high-voltage amplifiers, it is suggested to use the switching voltage control method in consideration of real industrial application for the handling of such flexible bodies. Some experimental results show that the developed electrostatic suspension system shows good performances to levitate flexible film-like thin plate.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.583-586
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• 2002

In this research, we propose a flexible conveying system (FCS) which consists of multiple arrays of cells. Each cell is a wheel driven by a two degree-of-freedom mechanism. The direction and velocity of cell are controlled based on the concept of hybrid control under a distributed network. Each cell has its own controller under a subsumption architecture for low-level control. A cell communicates with its four neighboring cells to manipulate n targeted object towards its desired position. The high-level control assigns a desired position and direction of the object to each cell. The path of each object is generated by many supporting cells. Moreover, the FCS can handle multiple objects simultaneously. To study the flexible conveying system, a GUI-based simulator of flexible conveying system is constructed. The simulated results show that the system can handle multiple objects independently and simultaneously under the proposed hybrid control architecture.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.460-463
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• 1995

The present paper studies a robot manipulator's contact tasks on the uncertain flexible objects. The flexible object's distributed parameter model is approximated into a lumped "position state-varying" model. By using the well-known nonlinear feedback compensation, the robot's control space is decomposed into the position control subspace and the object's torque control subspace. The optimal state feedback is designed for the position loop, and the robot's contact force is controlled through controlling the resultant torque on the object using model-reference simple adaptive control. Experiments of a PUMA robot interacting with an aluminum plate show the effectiveness of this control approach. approach.

• 예술인문사회 융합 멀티미디어 논문지
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• 제7권6호
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• pp.897-906
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• 2017

프로젝션 맵핑(공간증강현실)은 현실세계에서 다양한 가상의 환영(幻影)을 만들어내는 것으로 최근에 많은 분야에 사용되고 있다. 기존의 프로젝션 맵핑에서는 사용자와의 자연스러운 상호작용으로서 접히거나 구부러지는 것 과 같은 유연한 물체의 기하학적인 변형 속성(예: 용지)의 움직임을 고려하지 않았다. 또한, 정적 물체에 대한 프로젝션 맵핑에 대한 많은 연구가 있었지만, 유연한 타깃의 움직임을 추적하고 사용자와의 상호작용 측면에서 모양이 변형된 물체에 맵핑을 정확히 하는 다이내믹 프로젝션 맵핑은 여전히 도전해야할 연구 분야이다. 따라서 본 논문에서는 Unity3D와 ARToolkit을 이용한 실험을 통해 단단하지 않은 물체에 대한 견실한 추적과 정확한 맵핑 방법을 제안한다. 제안하는 방법은 큐빅 베지어 곡면 형성, 움직임 변형 값 렌더링 과정, 멀티플 마커 인식과 트래킹 과정, 실시간 웹캠 지속 촬영의 4가지 실험 단계로 구성된다. 사용자는 물체에 변형을 주기 위해 직접 접고, 휘고, 구부리고 비틀 수 있다. 제안 방법은 세 가지 긍정적인 결과를 도출할 수 있다. 첫째, 물체의 형태가 강하게 변형되어 있어도 감지 가능하다. 둘째, 사용자가 직접 물체에 변형을 주는 과정에서 물체의 일부분을 차단하고 있을 때의 Occlusion오류를 줄일 수 있어 정확한 트래킹을 할 수 있다. 셋째, 제안 방법의 견실하고 정확함은 빠른 속도로 물체의 움직임을 감지하게 하므로 실시간으로 결과 값을 물체에 투영할 수 있다.

• 한국컴퓨터그래픽스학회논문지
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• 제5권1호
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• pp.27-33
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• 1999

본 논문은 유연한 비정형 물체의 애니메이션을 위한 효율적인 기법을 제안한다. 비정형 물체를 표현하기 위해 질량-스프링 모텔이 사용되었다. 지금까지 많은 기법들이 부드러운 객체의 사실적인 애니메이션을 생성하기 위해 질량-스프링 모델을 사용하였다. 질량-스프링 모텔의 애니메이션을 수행하기 위한 가장 손쉬운 접근법은 명시적 오일러 방법 (explicit Euler method)인데, 이 방법은 '불안정성 문제'라는 잘 알려진 문제가 발생한다는 단점을 가지고 있다. 이 불안정성 문제를 해결하기 위한 해법으로 암시적 적분법이 사용될 수 있다. 그러나, 이 암시적 방법의 가장 결정적인 약점은 대규모의 선행 시스템을 풀어야 한다는 것이다. 본 논문은 암시적 방법의 근사(approximation)를 이용하여 질량-스프링 모델을 빠른 시간에 애니메이션 할 수 있는 기법을 제시한다. 제안된 기법은 n 개의 질점이 O(n) 개의 스프링으로 연결되어 있을 때, 각 질점의 상태를 O(n) 시간에 안정적으로 갱신할 수 있다. 본 논문은 사실적인 결과를 위해 비정형 물체와 공기와의 상호 작용도 고려하였다.

• 한국정밀공학회지
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• 제23권6호
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• pp.104-110
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• 2006

A design and control of electrostatic suspension system for flexible objects is presented. A number of electrode pairs of which the number depends on the object flexibility are positioned above the object and the voltages applied to each electrode pair are controlled, independently on the others, on the basis of the gap length. To implement the system with low cost and compactness, switched-voltage control scheme that is based on the relay feedback control is utilized. Relay feedback control method deploys only a single high-voltage power supply that can deliver a DC voltage of positive and/or negative polarity and thus high voltage amplifiers that are costly and bulky are not needed any more. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping originating from the electrodes and levitated object. Employing fourteen electrode pairs, a thin aluminum plate with a thickness of 0.1 mm has been suspended at a gap length of 0.75mm.

• 한국공간정보시스템학회 논문지
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• 제11권2호
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• pp.19-26
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• 2009

Ubiquitous service based on Spatio-temporal dataspaces requires not only the moving objects data but also the spatial objects. However, existing methods can not handle the moving objects and spatial objects together. To overcome the limitation of existing methods, we propose a new index structure called UIL (Union Indexing Lists) which contains two parts: MOL (Moving Object List) and SOL (Spatial Object List) to index the moving objects and spatial objects together. In addition, it can suppose the flexible queries on these data. We present the results of a series of tests which indicate that the structure perform well.

• 대한산업공학회지
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• 제24권2호
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• pp.223-240
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• 1998

The purpose of this paper is to develop the pattern recognition system with a 'Robust' concept to be applicable to flexible manufacture automation in practice. The 'Robust' concept has four meanings as follows. First, pattern recognition is performed invariantly in case the object to be recognized is translated, scaled, and rotated. Second, it must have strong resistance against noise. Third, the completely learned system is adjusted flexibly regardless of new objects being added. Finally, it has to recognize objects fast. To develop the proposed system, contouring, spectral analysis and Fuzzy ART neural network are used in this study. Contouring and spectral analysis are used in preprocessing stage, and Fuzzy ART is used in object classification stage. Fuzzy ART is an unsupervised neural network for solving the stability-plasticity dilemma.