• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2265-2267
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• 2003

In this paper, the virtual reality system is tried to developed, which controls not only the sense of sight and hearing but also the sense of touch, In order to develope the sense of touch in this study, the stable tactual transaction system, based on summing up the basic algorithm and theory is embodied. Especially, the graphic deformation algorithm is developed in realtime with using the deformed FEM. To apply the FEM, a deformed material model is produced and then the graphic deformation with this model is able to force. Finally, the graphic transaction algorithm is deduced by the realtime calculation and simplification because the purpose of this system is to transact in real time. The result of this study is that the proposed system is possible to deform the graphics and transact the haptic in real time in PC. The simulation program has been made to prove this result.

• 제어로봇시스템학회논문지
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• 제11권7호
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• pp.602-608
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• 2005

In the virtual environment, force feedback to the human operator makes virtual experiences more realistic. To ensure the safe operation and enhance the haptic feeling, stability should be guaranteed. Both motors and brakes are commonly used for haptic devices. Motors can generate a torque in any direction, but they can make the system active during operation, thus leading to instability. Brakes can generate a torque only against their rotation, but they dissipate energy during operation, which makes the system intrinsically stable. Consequently, motors and brakes are complementing each other. In this research, a two degree-of-freedom (DOF) haptic device equipped with motors and brakes has been developed to provide better haptic effects. Each DOF is actuated by a pair of motor and brake. Modeling of the environment and the control method are needed to utilize both actuators. Among various haptic effects, contact with the virtual wall, representation of friction and representation of plastic deformation have been investigated extensively in this paper. It is shown that the hybrid haptic device is more suited to some applications than the motor-based haptic device.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.557-562
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• 2004

For constructing virtual environment it is more natural to model object as deformable body than as rigid body. High accuracy of simulation of model and low-latency computational cost for real-time simulation should be guaranteed. We pre-compute Green function through finite element analysis of deformable body and it is possible to simulate deformation of body in real-time environment using Capacitance Matrix Algorithm. Also, the capacitance matrix algorithm enables to construct the haptic rendering which serves the reaction force through a haptic device. The Newmark scheme is used for the more realistic haptic rendering and dynamic simulation in real-time.

• 한국정보과학회논문지:시스템및이론
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• 제31권12호
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• pp.682-691
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• 2004

본 논문에서는 햅틱 인터페이스를 통해 실제 찰흙을 만지는 것처럼 자연스럽게 가상 모델의 일부를 덧붙이거나 제거하여 원하는 모양을 만드는 햅틱 가상 조각 시스템을 소개하고자 한다. 햅틱 렌더링과 햅틱 툴에 의한 가상 모델의 변형은 볼륨 간접 표면 법을 기반으로 이루어진다. 본 시스템에서는 기존의 불륨 데이타 기반의 햅틱 조각 시스템이 갖는 문제점들을 개선하고 빠르고 안정된 알고리즘을 제안하였다. 먼저 가상의 물체를 조각하는 동안 빠른 햅틱 응답 속도(1 KHz)에 비해 훨씬 느린 비쥬얼 프로세싱(~30 Hz)의 속도 차이로 인해 발생되는 문제를 극복하기 위해 조각과정의 연속적인 두 모델의 중간 표면들을 생성하여 부드러운 햅틱 렌더링을 구현하였다. 조각 툴에 의해 변형되는 불륨 간접 표면은 비쥬얼 디스플레이를 위해 메쉬 모델로 컨버전 되는데 이때 메쉬 모델은 표면의 복잡도를 반영하여 적은 폴리곤으로 복잡한 모양을 보여줄 수 있는 비 군일 메쉬 생성 기법을 사용하였다. 실시간 조각과정에서 가상 물체의 다양한 비쥬얼 효과를 위해 메쉬 기반의 솔리드 덱스쳐링, 페인팅, 그리고 모델의 양각/음각기법도 구현하였다.

• 한국가시화정보학회지
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• 제15권1호
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• pp.32-40
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• 2017

Interaction between fluid and a rigid object is frequently observed in everyday life. However, it is difficult to simulate their interaction as the medium and the object have different representations. One of the challenging issues arises especially in handling deformation of the object visually as well as rendering haptic feedback. In this paper, we propose a real-time simulation technique for multimodal interaction between particle-based fluids and soluble solids. We have developed the dissolution behavior model of solids, which is discretized based on the idea of smoothed particle hydrodynamics, and the changes in physical properties accompanying dissolution is immediately reflected to the object. The user is allowed to intervene in the simulation environment anytime by manipulating the solid object, where both visual and haptic feedback are delivered to the user on the fly. For immersive visualization, we also adopt the screen space fluid rendering technique which can balance realism and performance.

• 한국정보과학회논문지:소프트웨어및응용
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• 제37권8호
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• pp.611-619
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• 2010

본 논문에서는 사용자가 실제와 같은 촉감을 느끼면서 가상 도자기의 물레 성형을 체험할 수 있는 E-Learning 시스템을 제안한다. 원통형으로 대칭을 이루는 도자기 모양의 특징에 착안하여 부채꼴 모양을 가진 요소의 집합으로 3차원 도자기를 모델링하였다. 부채꼴 요소법에 최적화된 충돌 처리와 인접요소간 상호작용 알고리즘을 고안하였으며, GPU 기반의 빠른 햅틱 모델과 시각 모델의 동기화를 구현하였다. 성능 평가 결과 부채꼴 요소법은 기존의 변형체 렌더링 기법에 비해 훨씬 더 조밀한 도자기 모델의 현실적인 실시간 햅틱 렌더링이 가능한 것을 확인하였다. 우리가 구현한 시스템을 도자기와 관련된 교육적인 컨텐츠와 잘 결합한다면 초등학생들을 대상으로 한 E-Learning 시스템으로 성공적인 활용이 가능할 것으로 예상된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
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• pp.183-186
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• 2007

Realistic deformation of computer simulated anatomical structures is computationally intensive. As a result, simple methodologies not based in continuum mechanics have been employed for achieving real time deformation of virtual reality. Since the graphical interpolations and simple spring models commonly used in these simulations are not based on the biomechanical properties of tissue structures, these "quick and dirty"methods typically do not accurately represent the complex deformations and force-feedback interactions that can take place during surgery. Finite Element(FE) analysis is widely regarded as the most appropriate alternative to these methods. However, because of the highly computational nature of the FE method, its direct application to real time force feedback and visualization of tissue deformation has not been practical for most simulations. If the mathematics are optimized through pre-processing to yield only the information essential to the simulation task run-time computation requirements can be drastically reduced. To apply the FEM, We examined a various in verse matrix method and a deformed material model is produced and then the graphic deformation with this model is able to force. As our simulation program is reduced by the real-time calculation and simplification because the purpose of this system is to transact in the real time.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권5호
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• pp.309-314
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• 2004

In the established virtual-reality system, although it is possible to transact a faculty of sensation and graphic in a single PC, virtual object forcibly treated with rigid body for the reason of the huge amount of calculation, and the number of polygon is restricted. Furthermore, there is some difficulty in the financial aspect and a program field, because the existing virtual-reality system needs at least two workstations or super computers. In this study, the new force-reflecting algorithm called as "Proxy" and a finite element method of Hyperion are applied to this system in order to transact in real-time. Consequently, though the number of polygon, which brings about an obstacle is increased in the real-time graphic transaction, this system makes it possible to transact in the real-time, not being influenced by the size of the virtual object.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 1부
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• pp.210-218
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• 2006

본 논문은 광주과학기술원(GIST)에서 개발하고 있는 전남지역 '운주사'의 천불천탑 설화를 근간으로 한 반응형 가상 문화 체험 시스템(Responsive Multimedia System for virtual storytelling)의 햅틱 변형 상호작용에 관한 것이다. 기존의 디지털 문화재 체험 시스템은 사실적인 체험을 제공하기 위해 시각 및 청각 기술 개발에 많은 연구 및 노력이 이루어져왔다. 그러나 최근 인간의 인지 체계의 중요 요소인 촉감 상호작용의 중요성이 증대 됨에 따라, 본 논문에서는 가상 문화재 체험을 위한 햅틱 변형 알고리즘 및 상호작용 시스템을 개발하여 가상 불상을 만져보고 그 표면을 변형시키게 함으로써 몰입감을 증대하고 재미를 주는 시스템을 제공하였다. 아울러 체험의 몰입감 증대를 위해 본 시스템은 시/청각과 더불어 청각 효과를 가미하여 체험 시 발생되는 주변 환경의 소리(새, 물, 바람소리)를 제공하고, 기존의 문화체험 시스템과의 차별성을 위해 3 차원 입력장치를 이용하여 체험자가 직접 가상 불상을 변형시키면서 체험자 고유의 작품을 만들어낼 수 있는 상호작용을 제공한다. 따라서 제안된 햅틱 변형 상호작용 시스템은 체험자의 능동적 참여 및 흥미 유발을 통하여 문화 유산에 대한 교육적 효과 및 관심 증대에 기여할 수 있을 것이라 여겨진다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.410-414
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• 2003

In this paper, the virtual-reality system is tried to developed, which controls not only the sense of sight and hearing but also the sense of touch, In order to develope the sense of touch in this study, the stable tactual transaction-system, based on summing up the basic algorithm and theory, is embodied. The hardware of this system consists of the 6DOF haptic interface, a controller and a driver In the case of the software, the proxy algorithm is applied for the force-transaction and the mopping algorithm is used for graphic transaction. In addition to this, the imaginary-device driver is utilized for controlling the system and manager-class is also included in this system to manage the position-change and the like. Consequently, the proxy algorithm Is applied, which makes the system possible to be more stable and prompt with and imaginary object. Moreover, the impulse-algorithm is applied to work out a problem which the tactual transaction-period is different from the graphic transaction-period.