• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.27-30
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• 2000

In this paper, we determine the design criteria of haptic device considering the human haptic system and determine the design specifications. We developed a new 2DOF haptic device based on the specifications. It has the wide workspace, statically-balanced, constant inertia matrix, well-conditioned Jacobian matrix and so on. There also is not singularity point within workspace of the device. We show that it has better performance than other 2DOF haptic device in the many aspects.

• ETRI Journal
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• 제25권1호
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• pp.25-33
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• 2003

This paper describes interactive dynamic simulation schemes for articulated bodies in virtual environments, where user interaction is allowed through a haptic interface. We incorporated these schemes into our dynamic simulator I-GMS, which was developed in an object-oriented framework for simulating motions of free bodies and complex linkages, such as those needed for robotic systems or human body simulation. User interaction is achieved by performing push and pull operations with the PHANToM haptic device, which runs as an integrated part of I-GMS. We use both forward and inverse dynamics of articulated bodies for the haptic interaction by the push and pull operations, respectively. We demonstrate the user-interaction capability of I-GMS through on-line editing of trajectories for 6-dof (degrees of freedom) articulated bodies.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권7호
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• pp.646-656
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• 2008

본 논문에서는 촉감지원 NVE (networked virtual environment) QoE (quality of experience) 프레임워크의 프로토타입을 제안한다. 제안하는 NVE QoE 프레임워크는 가변적인 네트워크 상황과 이질적인 시스템 상에서도 제한된 자원을 효율적으로 사용하여 사용자에게 높은 현실감을 제공하는 것을 목표로 한다. 이를 위해서 촉감지원 NVE에서 요구되는 현실감 수준을 효율적으로 수치화 할 수 있는 방법을 제안하고 이를 기반으로 QoE 요구조건을 충족시키기 위해 필요한 컴포넌트들을 정의한다. 또한 다양한 미디어들이 결합되어있는 촉감 지원 NVE의 서비스에 따른 네트워크 요구조건을 분석하고 다양한 요구 조건을 효율적으로 수용하기 위해 필요한 촉감 지원 NVE 전송 컴포넌트들을 제안한다. 실험결과에 따르면 제안된 3D NVE QoE 프레임워크는 효율적인 cpu 및 네트워크 사용을 보장하며 이를 기반으로 제한된 자원 하에서도 사용자의 현실감을 개선시킨다.

• 한국CDE학회논문집
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• 제15권2호
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• pp.136-143
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• 2010

Realistic Modeling is to maximize the reality of the environment in which perception is made by virtual environment or remote control using two or more senses of human. Especially, the field of haptic rendering, which provides reality through interaction of visual and tactual sense in realistic model, has brought attention. Haptic rendering calculates the force caused by model deformation during interaction with a virtual model and returns it to the user. Deformable model in the haptic rendering has more complexity than a rigid body because the deformation is calculated inside as well as the outside the model. For this model, Gibson suggested the 3D ChainMail algorithm using volumetric data. However, in case of the deformable model with non-homogeneous materials, there were some discordances between visual and tactual sense information when calculating the force-feedback in real time. Therefore, we propose an algorithm for the Volume Haptic Rendering of non-homogeneous deformable object that reflects the force-feedback consistently in real time, depending on visual information (the amount of deformation), without any post-processing.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.780-785
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• 2007

Accurate and fast haptic simulations of deformable objects are desired in many applications such as medical virtual reality. In haptic interactions with a coarse model, the number of nodes near the haptic interaction region is too few to generate detailed deformation. Thus, local refinement techniques need to be developed. Many approaches have employed purely geometric subdivision schemes, but they are not proper in describing the deformation behavior of deformable objects. This paper presents a continuum mechanics-based finite element adaptive method to perform haptic interaction with a deformable object. This method superimposes a local fine mesh upon a global coarse model, which consists of the entire deformable object. The local mesh and the global mesh are coupled by the s-version finite element method (s-FEM), which is generally used to enhance accurate solutions near the target points even more. The s-FEM can demonstrate a reliable deformation to users in real-time.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.373-380
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• 2006

Accurate and fast haptic simulations of deformable objects are desired in many applications such as medical virtual reality. In haptic interactions with a coarse model, the number of nodes near the haptic interaction region is too few to generate detailed deformation. Thus, local refinement techniques need to be developed. Many approaches have employed purely geometric subdivision schemes, but they are not proper in describing the deformation behavior of deformable objects. This paper presents a continuum mechanics-based finite element adaptive method to perform haptic interaction 'with a deformable object. This method superimposes a local fine mesh upon a global coarse model, which consists of the entire deformable object. The local mesh and the global mesh are coupled by the s-version finite element method (s-FEM), which is generally used to enhance accurate solutions near the target points even more. The s-FEM can demonstrate a reliable deformation to users in real-time.

• 한국HCI학회논문지
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• 제1권2호
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• pp.1-8
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• 2006

본 논문은 새로운 햅틱 API인 "K-$Touch^{TM}$"의 개발에 관한 것으로 역/촉감 상호작용이 가능하도록 설계된 소프트웨어 아키텍처이다. K-$Touch^{TM}$는 햅틱 세부 기술을 잘 알지 못해도 응용분야를 쉽게 제작할 수 있도록 구성되어 있으며, 햅틱 기술을 개발하는 개발자가 쉽게 개발 내용을 추가할 수 있도록 구성되어 있다. 그래픽 하드웨어 기반의 핵심 역감 알고리즘을 기반으로 개발된 K-$Touch^{TM}$ API는 가상 환경을 구성하는 다양한 데이터 형식(2D, 2.5D depth(height field), 3D polygon 및 볼륨 데이터)에 대한 햅틱 상호작용을 가능하게 하고, 새로운 햅틱 알고리즘 및 장치 개발에 필요한 소프트웨어 확장성을 제공함과 동시에 사용자가 쉽고 빠르게 햅틱 응용분야를 개발할 수 있도록 설계되었다. 아울러 햅틱 감각의 중요 요소인 역감 및 촉감 상호작용을 위해 기존의 햅틱 SDK 및 API와 달리 역/촉감을 동시에 렌더링할 수 있는 알고리즘이 개발되었다. 본 논문에서 제안하는 새로운 햅틱 API의 효용성을 검증하기 위해 다양한 응용분야의 예를 구현하였다. 새로운 햅틱 API인 K-Touch는 사용자 및 연구자에게 보다 효율적으로 햅틱 연구를 진행 할 수 있도록 도움을 주는 툴킷(Toolkit)으로써 중요한 역할을 할 것으로 기대된다.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.45-51
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• 2009

본 논문은 에너지 바운딩 알고리즘 (EBA: Energy Bounding Algorithm) 기반의 힘 반향 원격 제어 시스템의 투명성을 분석하고 이를 기반한 네트워크 적응형 전송기법을 제안한다. EBA 는 양방향 원격 조작의 안정성을 확보하는 알고리즘으로 시간지연의 크기와 변동 및 손실에 상관없이 양방향 원격 조작의 안정성을 보장한다. 하지만 네트워크 지연 및 손실에 의한 투명성 저하는 EBA 로 극복하기에는 한계가 있다. 따라서 효과적인 전송기법을 이용하여 투명성을 향상시킬 필요가 있다. 제안하는 투명성 분석은 네트워크 지연 및 손실에 따른 힘 피드백의 왜곡 현상을 수식화한다. 이를 기반으로 촉감 데이터 동기화 기법 및 전송률 제어 기법의 투명성을 향상시킨다. 조작자가 요구하는 투명성 요구 조건과 현재 네트워크 상황에 맞추어 투명한 촉감 상호작용을 위한 동기화 지연 시간과 전송되어야 하는 촉감데이터량을 결정한다. Matlab 시뮬레이션을 통해서 제안한 투명성 분석의 타당성을 검증하고 촉감데이터 동기화 기법 및 전송률 제어 기법의 투명성을 확인한다.

• 제어로봇시스템학회논문지
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• 제14권7호
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• pp.663-671
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• 2008

This paper presents a real-time haptic rendering method for multi-contact interaction with virtual environments. Haptic systems often employ physics-based deformation models such as finite-element models and mass-spring models which demand heavy computational overhead. The haptic system can be designed to have two sampling times, T and JT, for the haptic loop and the graphic loop, respectively. A multi-rate output-estimation with an exponential forgetting factor is proposed to implement real-time haptic rendering for the haptic systems with two sampling rates. The computational burden of the output-estimation increases rapidly as the number of contact points increases. To reduce the computation of the estimation, the multi-rate output-estimation with reduced parameters is developed in this paper. Performance of the new output-estimation with reduced parameters is compared with the original output-estimation with full parameters and an exponential forgetting factor. Estimated outputs are computed from the estimated input-output model at a high rate, and trace the analytical outputs computed from the deformation model. The performance is demonstrated by simulation with a linear tensor-mass model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.992-995
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• 2003

A haptic device operated by the user's hand can receive information on position and orientation of the hand and display force and moment generated in the virtual environment to the hand. For realistic haptic display, the detailed information on collision between objects is necessary. In the past, the point-based graphic environment has been used in which the end effector of a haptic device was represented as a point and the interaction of this point with the virtual environment was investigated. In this paper, the shape-based graphic environment is proposed in which the interaction of the shape with the environment is considered to analyze collision or contact more accurately. To this end. the so-called Gilbert-Johnson-Keerthi (GJK) algorithm is adopted to compute collision points and collision instants between two shapes in the 3-D space. The 5- DOF haptic hand controller is used with the GJK algorithm to demonstrate a peg-in-hole operation in the virtual environment in conjunction with a haptic device. It is shown from various experiments that the shape-based representation with the GJK algorithm can provide more realistic haptic display for peg-in-hole operations.