Inwook Hwang

Electronics and Telecommunications Research Institute | ETRI · Broadcasting and Telecommunications Media Research Laboratory

In this paper, we propose a novel and facile methodology to chemically construct a thin and highly compliant metallic electrode onto a twisted and coiled nylon–6 fiber (TCN) with a three–dimensional structure via surface modification of the TCN eliciting gold–sulfur (Au–S) interaction for enabling durable electro–thermally–induced actuation perform...

This paper presents a model for estimating the perceived intensity of a superimposed dual-frequency vibration from the perceived intensities of its two component vibrations. Based on the previous findings in the literature, we hypothesize that the three variables follow the Pythagorean relationship. Two psychophysical experiments were performed for...

In this paper, we proposed a novel light-driven polymer actuator that could produce remotely controllable tensile stroke in response to near infrared (NIR) light. The light-driven polymer actuator was composed of a twisted and coiled nylon-6 fiber (TCN) and a thin poly(3,4-ethylenedioxythiophene) doped with p-toluenesulfonate (PEDOT-Tos) layer. By...

A vibrotactile actuator driven by light energy is developed to produce dynamic stimulations for haptic rendering on a thin-film structure. The actuator is constructed by adopting a thermal bimorph membrane structure of poly(3,4-ethylenedioxythiophene) doped with p-toluenesulfonate (PEDOT-Tos) coated onto a polyethylene terephthalate (PET) film. Upo...

We empirically explore fundamental requirements for achieving VR in-air typing by observing the unconstrained eyes-free in-air typing of touch typists. We show that unconstrained typing movements differ substantively from previously observed constrained in-air typing movements and introduce a novel binary categorization of typing strategies: typist...

We developed an improved version of midair visuohaptic virtual piano utilizing multiple ultrasonic array modules. We implemented scheduling algorithm for simultaneous generation of haptic points to increase the output efficiency. Our algorithm is based on temporal switching of modulated ultrasonic signals and player draft system on multiple ultraso...

The current research provides a perceptually transparent rendering algorithm for an ultrasound-based mid-air haptic device. In a series of experiments, we derive a systematic mapping function relating from the device command value to final user's perceived magnitude of a mid-air vibration feedback. The algorithm is designed for the ultrasonic mid-a...

The use of distinguishable complex vibrations that have multiple spectral components can improve the transfer of information by vibrotactile interfaces. We investigated the qualitative characteristics of dual-frequency vibrations as the simplest complex vibrations compared to single-frequency vibrations. Two psychophysical experiments were conducte...

We introduce our initial design of gesture interface for the TV control of visually impaired users, with its implementation and user study. Two bare-hand gesture sets were designed using simple linear and circular motions of arms. For the two gesture sets, a rule-based recognition system was developed using a Kinect sensor. In a user study, the lin...

This paper presents improvements made on our previous haptic music player designed to enhance music listening experience with mobile devices. Our previous haptic music player featured with dual-band rendering; it delivers bass beat sensations in music with rough superimposed vibrations and high-frequency salient features in music with high-frequenc...

This paper is concerned with the perception of complex vibrotactile stimuli in which a few sinusoidal vibrations with different frequencies are superimposed. We begin with an observation that such vibrotactile signals are analogous to musical chords in which multiple notes are played simultaneously. A set of so-called "vibrotactile chords" are desi...

We report the difference thresholds of the slope of a virtual surface rendered via a force–feedback haptic interface with the body frontal plane as a reference. The factors varied in experiments were the stiffness of a virtual plane, the lateral velocity with which the haptic probe scanned the plane, the length of a scanning interval, the movement...

We introduce a novel dual-band haptic music player for real-time simultaneous vibrotactile playback with music in mobile devices. Our haptic music player features a new miniature dual-mode actuator that can produce vibrations consisting of two principal frequencies and a real-time vibration generation algorithm that can extract vibration commands f...

Vibrotactile rendering is an emerging interaction method for information transmission in mobile devices, replacing or supplementing visual and auditory displays. To design effective vibrotactile actuators or display algorithms, an understanding of the perceived intensity (strength) of their vibrations is essential. This paper aims to build a robust...

In this study, we measured the perceived intensity of vibrations in the hand for mechanically grounded objects. We conducted an absolute magnitude estimation experiment for two within-subject factors: the amplitude and the frequency of vibration. We revised the vibration generation method and the experimental design adopted in our previous study. A...

This study investigates the effect of mechanical ground on the perceived intensity of vibration transmitted through a handheld object. To this end, we carried out an intensity matching experiment in which the points of subjective equality were measured between grounded and ungrounded conditions. Results showed that the grounded vibrations were perc...

This paper is concerned with the perception of complex vibrotactile stimuli in which a few sinusoidal vibrations with different frequencies are superimposed. We begin with an observation that such vibrotactile signals are analogous to musical chords where multiple notes are played simultaneously. A set of “vibrotactile chords” are designed based on...

This paper proposes a new interactive interface TAXEL, which aims at developing a reconfigurable self-morphing visio-haptic interface. We first present the overall architecture and concept of a self-morphing visuo-haptic interface. Key hardware components are developed and tested, including three tactile actuators using a piezoelectric active linea...

In the past five years, how to utilize the haptics technology in the mobile device to improve its limited user interface has emerged as an attractive research topic. In this paper, we report two kinds of perceptual data related to vibrotactile signals perceived through a mobile device held in the hand. In Experiment I, we estimated perceptual dissi...

A mobile haptic interface (MHI), a force-feedback haptic interface with a mobile base, allows to render very large virtual objects in a safe and portable manner. In this paper, we present a novel MHI system, featured with: 1) extended horizontal workspace using a omni-directional mobile base, 2) extended vertical workspace using a linear lift, 3) h...

Purpose The purpose of this paper is to present a surgical robot for spinal fusion and its control framework that provides higher operation accuracy, greater flexibility of robot position control, and improved ergonomics. Design/methodology/approach A human‐guided robot for the spinal fusion surgery has been developed with a dexterous end‐effector...

A mobile haptic interface (MHI) refers to a system where a grounded force-feedback haptic interface is mounted onto a mobile robot to provide the user with unlimited workspace, especially for large virtual environments. In MHI, the mobile base needs to quickly change the movement direction, thus a omni-directional robot is preferred. In this paper,...

This article introduces a novel haptization method for rendering surface topography with varying stiffness via a force-feedback haptic interface. Previously, we showed that when surface topography with varying stiffness is rendered with the conventional penalty- based method, topography information perceived by the user can be distorted from its mo...

In this paper, we present practical issues in a Mobile Haptic Interface (MHI) and their improvements. The improvements can be categorized in three parts: 1) high-accuracy estimation of the world position of the haptic interface point, 2) motion planning algorithm to move the mobile base while avoiding collisions with the user and other objects, and...