• Journal of the HCI Society of Korea
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• v.14 no.2
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• pp.13-20
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• 2019

For encountered haptic display systems among the virtual training systems for industrial safety, visual-haptic co-location is required for natural interaction between virtual and real objects. In this paper, we performed the user evaluation of the immersive VR haptic system which implement some level of visual-haptic co-location through a careful and accurate calibration method. The goal of the evaluation is to show that user performance (reaction time and distance accuracy) for both environments is not significantly different for certain tasks performed. The user evaluation results show statistically significant differences in reaction time but the absolute difference is less than 1 second. In the meantime, the distance accuracy shows no difference between the virtual and the actual environments. Therefore, it can be concluded that the developed haptic virtual training system can provide inexpensive industrial safety training in place of costly actual environment.

• International Journal of Control, Automation, and Systems
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• v.2 no.2
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• pp.238-246
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• 2004

In displaying a virtual wall using a passive haptic device equipped with passive actuators such as electric brakes, unsmooth motion frequently occurs. This undesirable behavior is attributed to time delay due to slowness in the virtual environment update and force approximation due to the inability of a brake to generate torque in arbitrary directions. In this paper a new control scheme called direct control is proposed to achieve smooth display on the wall-following task with a passive haptic device. In direct control, brakes are controlled so that the normal component of a resultant force at the end-effector vanishes, based on the force analysis at the end-effector of the passive haptic device using the passive FME (Force Manipulability Ellipsoid). Various experiments have been conducted to verify the validity of the direct control scheme with a 2-link passive haptic system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.11 s.254
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• pp.1401-1407
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• 2006

In a haptic interface system with a nanoscale virtual environment (NVE) using an atomic force microscope (AFM), impedance scaling is important. In order to explicitly derive the relationship between performance and impedance scaling factors, a nanoscale virtual coupling (NSVC) concept and a selection method of scaling factors of velocity (or position) and force are introduced. An available scaling factor region is represented based on Llewellyn's absolute stability criteria and the physical limitation of the haptic device. Experiments have been performed for tele-nanomanipulation tasks such as positioning, indenting and nanolithography with available force scaling factor in the NVE.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.283-295
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• 2009

Haptics technology allows one to interact with virtual environments, augmented environments, and real environments providing tactual sensory information. Science and technology of haptics can in general be classified into three groups: machine haptics, computer haptics, and human haptics. This paper surveys the state-of-the-art of haptic control technology for virtual environments and teleoperation (real environments) and then proposes possible future research directions in the following areas: haptic stability control, bilateral teleoperation control, and stability enhancement control.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5338-5343
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• 2013

In a haptic system, a virtual wall is modeled as a virtual spring. The larger the stiffness of the virtual spring is, the more improved the reality of the virtual wall is, but the more unstable the haptic system becomes. This paper shows how to increase the stiffness of the virtual spring while the stability of the haptic system is guaranteed and shows the effects of a mass (Md) and a damper (Bd) of a haptic device on the stability when first-order hold method is applied and a virtual wall is modeled as a virtual spring (Kw). The simulation results show the boundary of the virtual spring is proportional to the square root of the mass (Md) and the damper (Bd) while maintaining the stability. The relation among the virtual spring (Kw), the mass (Md) and the damper (Bd) of the haptic device, and sampling time (T) is inferred as $K_w{\leq}{1.611M_d}^{0.50}{B_d}^{0.50}T^{-1.51}$, by using the simulation results. The maximum available stiffness of the virtual spring in first-order hold method is larger than in zero-order hold method. So the reality of the virtual wall can be improved.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.64-69
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• 2007

이 논문은 촉각 가상 환경(Haptic Virtual Environment)에서 촉각(haptic) 데이터를 촉각 데이터 특성에 맞추어 네트워크에 적응적이고 효율적으로 전송할 수 있는 전송 알고리즘을 제안한다. 촉감 상호작용 측정을 위해 네트워크 햅틱 협업 응용을 작성하였고 지연, 지터, 손실에 따른 변화를 분석하였다. 이를 바탕으로 네트워크 트래픽에 적응할 수 있는 알고리즘을 구성하였다. 손실되거나 지터의 영향을 받은 패킷에는 간단한 선형예측 방법을 사용하여 보상하여 손실과 지터로 인한 오차를 줄였다. 이는 심각한 손실이나 지터에 의해 떨림 현상이 나타나는 햅틱 장치의 문제점을 개선하게 되었다. 또한 네트워크 협업에서 지연이 발생할 때 나타나는 클라이언트들 사이의 비동시성을 해결하기 위하여 완충시간을 두었다. 지연이 큰 클라이언트는 버퍼를 사용하지 않고 실시간으로 처리하고, 지연이 적은 클라이언트는 버퍼를 사용하여 전송받은 좌표를 완충시킨 후에 처리하는 방법을 사용하여 클라이언트들 사이의 햅틱 렌더링을 동기화 하였다. 제안된 알고리즘은 다양한 네트워크 상황에서의 협업에서 개선된 결과를 보였다. 이를 바탕으로 향후 선형예측 방법을 다양하게 적용시키고 서버와 클라이언트 사이의 동기화를 구현하는 알고리즘을 작성할 것이다. 본 논문은 다양한 네트워크 상황 에서 햅틱 데이터를 전송하고 처리하는 연구의 기초자료가 될 수 있을 것이다.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.8
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• pp.807-814
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• 2014

In this paper, we proposed a haptic navigation system which used the tactile data for the user guides of the mobile robot to the reference point via tele-operation in unknown blind environment. This navigation system can enable a mobile robot to avoid obstacles and move to the reference point, according to the direction provided by the device guides through a haptic device consisting of a vibration motor in a blind environment. There are a great deal of obstacles in real environments, and so mobile robots can avoid obstacles by recognizing the exact position of each obstacle through the superposition of an ultrasonic sensor. The navigation system determines the direction of obstacle avoidance through an avoidance algorithm that uses virtual impedance, and lets users know the position of obstacles and the direction of the avoidance through the haptic device consisting of 5 vibration motors. By letting users know intuitionally, it lets the mobile robot precisely reach the reference point in unknown blind environment. This haptic device can implement a haptic navigation system through the tactile sensor data.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.49-54
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• 2008

In order to do a maintenance task, a maintenance operator should learn the basic skills of the maintenance task such as assembly and disassembly (A/D). However, the key of the learning process is to learn the A/D task intuitively and naturally. Haptic guidance promises to give effectiveness and benefit qualitatively since a person can be trained to do the optimal task based on information that comes from an expert, database, or intelligent algorithms. By applying haptic guidance, a maintenance training process can be made more intuitive and natural in a virtual environment. This paper describes the development of a maintenance training system by using haptic guidance.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.3 no.2
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• pp.161-165
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• 2003

In this paper, we investigate the issues on the design and implementation of tele-operation system based on the haptic interface. Here, the 3-DOF haptic device and the X-Y-Z stage are employed as master controller and slave system respectively. For this master-slave system, the force feedback algorithm, the modeling of virtual environments and the control method of X-Y-Z stage are presented. In this paper, internet network is used for data communication between master and slave. We construct virtual environment of the real convex surface from the force-feedback in controlling the X-Y-Z stage and measuring the force applied by the 3-DOF haptic device.

• Journal of Digital Contents Society
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• v.18 no.8
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• pp.1489-1494
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• 2017

The purpose of this study is to investigate the limitations of virtual space game contents staying in the first-person viewpoint in the field of digital games with various genres through precedent researches and case studies, and to investigate the differences of immersion, presence, and fun based on the user interfaces, such as the viewpoints (first-person, third-person) and haptic feedback. The experimental results show that when the game is the first-person with the haptic feedback, the immersion, presence, and fun increase. However, the interaction effect between the virtual space environment and the game viewpoint was not found. As a result, it is appropriate to use the haptic feedback and the first-person viewpoint in the virtual reality games, but the fact that the game viewpoints and the virtual space environment are not huge relevant, and the third-person viewpoint is more popular than first-person viewpoint game, therefore the possibility of a third-person viewpoint game would be suggested.