• Journal of Power System Engineering
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• v.13 no.2
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• pp.71-82
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• 2009

This paper presents a real-time haptic rendering method for a realistic force feedback in a remote environment with varying communication time-delay. The remote environment is assumed as a virtual environment based on a computer graphics, for example, on-line shopping mall, internet game and cyber-education. The properties of a virtual object such as stiffness and viscosity are assumed to be unknown because they are changed according to the contact position and/or a penetrated depth into the object. The DARMAX model based output estimator is proposed to trace the correct impedance of the virtual object in real-time. The output estimator is developed on the input-output relationship. It can trace the varying impedance in real-time by virtue of P-matrix resetting algorithm. And the estimator can trace the correct impedance by using a white noise that prevents the biased input-output information. Realistic output forces are generated in real-time, by using the inputs and the estimated impedance, even though the communication time delay and the impedance of the virtual object are unknown and changed. The generated forces trace the analytical forces computed from the virtual model of the remote environment. Performance is demonstrated by experiments with a 1-dof haptic device and a spring-damper-based virtual model.

• Journal of the Korea Society of Computer and Information
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• v.21 no.12
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• pp.43-49
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• 2016

This paper presents the design and implementation of virtual aquarium by generating 3D models of fishes that are colored by viewers in an aim to create interaction among viewers and aquarium. The virtual aquarium system is composed of multiple texture extraction modules, a single interface module and a single display module. The texture extraction module recognize the QR code on the canvas to get information of the predefined mapping table and then extract the texture data for the corresponding 3D model. The scanned image is segmented and warp transformed onto the texture image by using the mapping information. The extracted texture is transferred to the interface module to save on the server computer and the interface module sends the fish code and texture information to the display module. The display module generates a fish on the virtual aquarium by using predefined 3D model with the transmitted texture. The fishes on the virtual aquarium have three different swimming methods: self-swimming, autonomous swimming, and leader-following swimming. The three different swimming methods are discussed in this paper. The future study will be the implementation of virtual aquarium based on storytelling to further increase interactions with the viewer.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.11
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• pp.80-85
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• 2001

In Part 2, dynamic cutting force model, thermal behavior model, and feed drive model are presented for development of a virtual machine tool. Some relevant results with brief descriptions for each model are presented to verify the proposed models. Experimental results for each model agreed well with the estimated ones. The developed models in this two-part paper are partially integrated as a comprehensive software environment.

• Proceedings of the IEEK Conference
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• 2000.11c
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• pp.193-196
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• 2000

In this paper, we present a model based 3d facial modeling method for virtual reality application using only one front of face photography. We extract facial feature using facial photography and modify mesh of the basic 3D model by the facial feature. After this , We use texture mapping for more similarity. By experiment, we know that the modeling technic is useful method for Movie, Virtual Reality Application, Game , Clothing Industry , 3D Video Conference.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.3
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• pp.42-47
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• 2003

In Part 2 of this paper, the dynamic cutting force model, thermal behavior model, and feed drive model used in the development of a virtual machine tool (VMT) are briefly described. Some results are presented to verify the proposed models. Experimental data agreed well with the predicted results fer each model. A comprehensive software environment to integrate the models into a VMT is also proposed.

• Journal of Digital Contents Society
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• v.12 no.2
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• pp.185-194
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• 2011

This paper introduces a Statecharts-based progressive behavior LOD model for computer games and virtual reality systems. In order to use computing resources efficiently and generate an LOD model having arbitrary complexity, we defined a progressive behavior LOD model which including a Statecharts-based specification process, refinement operations, a switching policy, and an LOD selection policy. Additionally, in order to show the possibility of the proposed approach, we demonstrate an example of progressive LOD models by illustrating a step-by-step design of a virtual vehicle.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.5
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• pp.419-424
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• 2017

The purpose of this study is to develop a virtual testbed capable of predicting the functional performance of a linear electromagnetic actuator for a high voltage relay in order to reduce its development costs and time. The virtual testbed is defined by a multiphysics coupling approach in order to consider the complex interactions of multi-domains such as the solenoid model of electromagnets, the mass-spring-damper model of mechanical systems, the electric circuit model for an external control unit, and the thermal model for predicting temperature variations. The performances of the existing high voltage relay were estimated by the virtual testbed, and then the effectiveness and validation of the proposed testbed were discussed in comparison with the experimental test results. This study showed that the virtual testbed can be applied in design, optimization, and investigation of high voltage relays.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.989-992
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• 2004

In general, it is known that walking stability of a quadruped is determined by its COG(Center of Gravity). In this paper, in order to know whether our virtual quadruped robot is applicable to the real quadruped robot, we simulated our virtual model using the data from the real robot‘s walking. We were able to evaluate the stride of quadruped based on direct and inverse kinematics and compared the stride of the simulation with real robot’s it. During the simulation we calculated the COG of the virtual model and evaluated the walking stability of real model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.60-63
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• 2000

In this study, efficient force reflection algorithm is developed for the Haptic Display by using a proxy concept and friction model. When there are not any contacted obstacles the proxy is following human operator's command trajectory in the 3D virtual space. But when the operator's command trajectory is locating inside of the object, the proxy is constrained by the surface of the object. Here only with the information of the proxy position and operator's command trajectory at every time step, we can calculate the reflection force and its orientation. To display the friction force between two virtual stiff material which are sliding against each other, modified Karnopp's friction model is used. In the friction model, a damping term and a Stribeck effect term are included to display the relative velocity effect and stick-slip effect at the very low relative velocity region respectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.368-375
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• 2012

Durability performance evaluation of automotive components is very important and time consuming task. In this paper, to reduce vehicle component development time and cost virtual testing simulation technology is used to evaluate durability performance of a passenger car front aluminum sub-frame. Multibody dynamics based vehicle model and virtual test simulation model of a half car road simulator are validated by comparisons between rig test results and simulation results. Durability life prediction of the sub-frame is carried out using the model with road load data of proving ground which can evaluate accelerated durability life. We found that the durability performance of the sub-frame is sufficient and it can be predicted within short time compared to rig test time.