• International Journal of CAD/CAM
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• v.8 no.1
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• pp.41-44
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• 2009

This paper describes an implementation of virtual teeth modeling for a haptic dental simulation. The system allows dental students to practice dental procedures with realistic tactual feelings. The system requires fast and stable haptic rendering and volume modeling techniques working on the virtual tooth. In our implementation, a volumetric implicit surface is used for intuitive shape modification without topological constraints and haptic rendering. The volumetric implicit surface is generated from input geometric model by using a closest point transformation algorithm. And for visual rendering, we apply an adaptive polygonization method to convert volumetric teeth model to geometric model. We improve our previous system using new octree design to save memory requirement while increase the performance and visual quality.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.313-318
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• 2001

A haptic hand controller 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. This paper presents a design method for KU-HHC, 6 DOF Korea University-haptic hand controller, which allows separation of workspace from linkage mechanism in consideration of the efficient user operation. First, the 3 DOF mechanism in which all the actuators are mounted on the fixed base is developed by combining a 5-bar linkage and gimbal mechanism. Then, the 6 DOF HHC is designed by connecting the two 3 DOF devices through a handle. This paper presents the forward and inverse kinematics for this device and Jacobian analysis. Improvement of the kinematic characteristics using performance index is also discussed. The hand controller KU-HHC based on this design concept and kinematic analysis was manufactured and shows excellent performance.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.67-71
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• 2002

In this paper, we propose a new deformable model based on non-linear elasticity, anisotropic behavior and the finite element method and developed the high-speed controller for haptic control. The proposed controller is based on the PCI/FPGA technology, which can calculate the real position and transmit the force data to device rapidly, The haptic system is composed of 6DOF force display device, high-speed controller and HIR library for 3D graphic deformation algorithm & haptic rendering algorithm. The developed system will be used on constructing the dynamical virtual environment. we demonstrate the relevance of this approach for the real-time simulating deformations of elastic objects. To show the efficiency of our system, we designed simulation program of force-reflecting, As the result of the experiment, we found that the controller has much higher resolution than some other controllers.

• Transactions on Electrical and Electronic Materials
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• v.18 no.3
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• pp.144-147
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• 2017

In this study, two- and three-layer ceramic piezoelectric actuators were designed and simulated according to SUS316 thickness, actuator width, and mass using ATILA software in order to develop a piezoelectric actuator for haptic application. Numerical modelling based on the finite element method was performed to find the resonance frequencies and modal shapes of the actuator. The resonance frequency was affected by the thickness of the SUS316 plate and mass. On the other hand, the width of the actuator did not have a significant impact. Maximum displacements were generated at the center of a haptic three-layer ceramic piezoelectric actuator. The two-layer ceramic piezoelectric actuator with a mass of 2.6 g was suitable as $16.28{\mu}m$ at 265 Hz for haptic sensation application.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.213-216
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• 2005

This paper presents force feedback control performance of a 3DOF haptic device that can be used for minimally invasive surgery (MIS). As a first step, a 3DOF electrorheological (ER) joint is designed using a spherical mechanism. And it is optimized based on the mathematical torque modeling. Subsequently, the master haptic device is manufactured by the spherical joint. In order to achieve desired force trajectories, model based compensation strategy is adopted for the ER master. Therefore, Preisach model fur the PMA-based ER fluid is identified using experimental first order descending (FOD) curves. A compensation strategy is then formulated through the model inversion to achieve desired force at the ER master. Tracking control performances for sinusoidal force trajectory are presented, and their tracking errors are evaluated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.551-552
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.343-344
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• 2011

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.331-332
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• 2011

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.4968-4974
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• 2012

A haptic device is regarded as the human machine interface technology for easier, more accurate, and intuitive operation. The purpose of this paper is to study how to improve the cognitive ability of the existing vehicle haptic device used only tactile feedback. In this study, usability evaluation used the multi-sensory feedback which is adding auditory feedback to the existing tactile feedback. The emotional factor that drivers have on the haptic device is extracted by the sensibility analysis. The result of study provides some consideration and direction to need in implementation of a haptic device and it also confirms their possibility meaningfully. And it is possible to suggest the design direction that satisfies the driver.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.6
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• pp.553-559
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• 2015

The purpose of this research is to develop a gait assistive device to enhance the gait stability and training efficiency of stroke patients. The configuration of this device is mainly composed of a motored wheel and a single cane whose lower end is attached to a motored wheel frame. A patient can feel haptic information from continuous ground contact from the wheel while walking through the grip handle. In addition, the wheeled cane can avoid using excessive use of the patient's upper limb for weight support and motivate the patient to use a paralyzed lower limb more actively. Moreover, the proposed device can provide intuitive and safe user interaction by integrating a force sensor and a tilt sensor equipped to the cane frame, and a switch sensor at the cane's handle. The admittance control has been implemented for the patient to change the walking speed intuitively by using the interaction forces at the handle. A hemi-paretic stroke patient participated in the walking assistive experiments as a pilot study to verify the effectiveness of the proposed haptic cane system. The results showed that the patient could improve walking speed and muscle activations during walking with a constant speed mode of the haptic cane. Moreover, the patient could maintain the preferred walking speeds and gait stability regardless of the magnitude of resistance forces with the admittance control mode of the haptic cane. The proposed robotic gait assistive device with a simple and intuitive mechanism can provide efficient gait training modes to stroke patients with high possibilities of widespread utilizations.