• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.7
• /
• pp.705-710
• /
• 2012

Research involving discomfort or pain related to haptic vibratory stimulation the for prosthesis users of myoelectrical hand is very lacking. Our objective of this study was to evaluate the displeasure and sensitivity of areas in forearm using vibration stimulation system between upper limb amputees and non-amputees. Twenty transradial amputees and forty non-amputees (20 youth, 20 elderly) were involved. We set up custom-made vibration stimulation system including eight actuators (4 medial parts and 4 lateral parts) and GUI-based acquisition system, to investigate changes of residual somatosensory sensibility and displeasure at proximal 25% of forearm. Eight vibration actuators were attached to the circumference of proximal 25% point of forearm at regular intervals. Sensitivity tests were used to stimulate the 120Hz and discomfort experiment was used to 37 ~ 223Hz. The subjective responses were evaluated by 10 point scale. The results showed that both groups were similar in sensitive areas. Response at around of radius was most sensitive than other areas in all subjects. Elderly group do not appear discomfort of vibrotactile; however, youth group and amputee presented discomfort of vibrotactile. Prosthesis with a vibrotactile feedback system should be developed considering the sensitivity. Furthermore, Future studies should investigate the scope of application of that principle.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.1683-1687
• /
• 2009

This paper addresses a haptic actuator which can be applied to mobile devices. For haptic feedback in mobile devices, we have to consider not only stimulating force and frequency but also the size and the power consumption of a haptic module. Thus far, vibration motors have been widely used in mobile devices to provide tactile sensation. The reason is that a vibration motor is small enough to be inserted into a mobile device. This paper addresses vibrotactile actuators and other haptic actuators which can generate a wide variety of tactile sensations.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.8
• /
• pp.815-821
• /
• 2014

In this paper, we propose a novel CALL (Computer-Assisted Language Learning) system, which is called POMY (POSTECH Immersive English Study). In our system, students can study English while talking to characters in a computer-generated virtual environment. POMY also supports haptic feedback, so students can study English in a more interesting manner. Haptic feedback is provided by two platforms, a haptic chair and a force-feedback device. The haptic chair, which is equipped with an array of vibrotactile actuators, delivers directional information to the student. The force-feedback device enables the student to feel the physical properties of an object. These haptic systems help the student better understand English conversations and focus on studying. We conducted a user experiment and its results showed that our haptic-enabled English study contributes to better learning of English.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.396-401
• /
• 2009

This paper describes the improvements made on hardware and software of the remote controller for realistic contents. The controller can provide vibrotactile feedback which uses both of a voice-coil actuator and a vibration motor. A vision tracking system for the 3D position of the controller is optimized with respect to the marker size and the camera parameters. We also present the improvements of motion recognition due to the effective motion segmentation and the fusion of vision and acceleration data. We apply the developed controller to realistic contents and validate its usability.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.44 no.2 s.314
• /
• pp.37-46
• /
• 2007

In this paper, we propose technologies for enhancing the immersive realization of virtual objects in AR-based product design. Generally, multimodal senses such as visual/auditory/tactile feedback are well known as a method for enhancing the immersion in case of interaction with virtual objects. By adapting tangible objects we can provide touch sensation to users. A 3D model of the same scale overlays the whole area of the tangible object so the marker area is invisible. This contributes to enhancing immersion. Also, the hand occlusion problem when the virtual objects overlay the user's hands is partially solved, providing more immersive and natural images to users. Finally, multimodal feedback also creates better immersion. In our work, both vibrotactile feedback through page motors, pneumatic tactile feedback, and sound feedback are considered. In our scenario, a game-phone model is selected, by way of proposed augmented vibrotactile feedback, hands occlusion-reduced visual effects and sound feedback are provided to users. These proposed methodologies will contribute to a better immersive realization of the conventional AR system.

• 한국HCI학회:학술대회논문집
• /
• 2008.02c
• /
• pp.30-35
• /
• 2008

This paper summarizes research results on the perceptual characteristics of mobile device vibrations carried out in the Haptics and Virtual Reality Laboratory at POSTECH, as a companion paper for the presentation to be offered in the haptics workshop of Korea HCI 2008. The physical characteristics, the absolute detection thresholds, and the perceived magnitudes of mobile device vibrations are briefly summarized, followed introduction to perceptually transparent vibration rendering.

• Journal of Internet Computing and Services
• /
• v.25 no.1
• /
• pp.9-15
• /
• 2024

As virtual reality technology became popular, a high demand emerged for natural and efficient interaction with the virtual environment. Mid-air manipulation is one of the solutions to such needs, letting a user manipulate a virtual object in a 3D virtual space. In this paper, we focus on manipulating a remote virtual object while visually displaying the object and providing tactile information on the object's weight. We developed two types of wearable interfaces that can provide cutaneous or vibrotactile feedback on the virtual object weight to the user's fingertips. Human perception of the remote virtual object weight during manipulation was evaluated by conducting a psychophysics experiment. The results indicate a significant effect of haptic feedback on the perceived weight of the virtual object during manipulation.