• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.450-453
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• 2004

A tactile stimulator array using stacked PZT is fabricated and evaluated in this paper. The purpose of this research is the development of a tactile stimulator to represent the obstacle information for the visually disabled. As a first step of this research, we investigate the physiological characteristics of tactile stimuli and design a tactile stimulator based on the investigated results. Also we evaluated a fabricated tactile stimulator. The prototype of tactile stimulator which has 2$\times$2 tactor elements with 3mm spacing is fabricated using stacked PZT actuator. In order to evaluate the characteristics of this tactile stimulator, physiological experiments are carried out. In the experiment, the threshold of tactile stimulus intensity within a frequency range of 5-500Hz at various stimulus amplitudes are investigated. According to the obtained experimental result, the input signal of tactile stimulator for the effective transfer of obstacle information is determined. Also physiological experiments of multi-stimuli recognition such as shift and rotation are carried out

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.8
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• pp.783-789
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• 2007

In this paper, firstly, we propose a generating method of the 3-D obstacle map using ultrasonic sensors. Secondly, we try to find the necessary stimulation conditions of compact tactile display device for effective transfer of obstacle information. The final goal of this research is the development of a walking guide system for the blind to walk safely. The walking guide system consists of a guide vehicle for the obstacle detection and a tactile display device for the transfer of the obstacle information. The guide vehicle, located in front of the walking blind, detects the obstacle using ultrasonic sensors. The processed information makes an obstacle map and transmits safe path and emergency situation to the blind by the tactile display. The tactile display device, located in the handle which is connected with the guide vehicle by cane, offers the processed obstacle information such as position, size, moving, shape of obstacle and safe path, etc. The concept of a walking guide system with tactile display is introduced, and experiments of 3-D obstacle detection and tactile perception are carried out and analyzed.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.171-175
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• 2004

A tactile stimulator array using stacked PZT is fabricated and evaluated in this paper. The purpose of this research is the development of a tactile stimulator to represent the obstacle information for the visually disabled. As a first step of this research, we investigate the physiological characteristics of tactile stimuli and design a tactile stimulator based on the investigated results. Also we evaluated a fabricated tactile stimulator. The prototype of tactile stimulator which has 2x2 tactor elements with 3mm spacing is fabricated using stacked PZT actuator. In order to evaluate the characteristics of this tactile stimulator, physiological experiments are carried out. In the experiment, the threshold of tactile stimulus intensity within a frequency range of 5-500Hz and at various stimulus amplitudes are investigated. According to the obtained experimental result, the input signal of tactile stimulator for the transfer of obstacle information is determined. Also physiological experiments of multi-stimuli recognition such as shift and rotation are carried out.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.888-891
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• 2005

In this paper, the prototype of a walking guide robot with tactile display is introduced, and the psychophysical experiment of the tactile recognition for a tactile display is carried out and analyzed. The objective of this research is the development of a walking guide robot for the blind to walk safely. A walking guide robot consists of a guide vehicle and a tactile display device. A guide vehicle, located in the front of the walking blind, detects the obstacle using ultrasonic sensors and offers the information of position and walking direction acquired from GPS module to the walking blind by voice. The tactile display device, located in the handle which is connected with the guide vehicle by cane, offers the processed obstacle information such as position, size, moving, shape of obstacle and safe path, etc. The psychophysical experiments for the threshold of perception and recognition ability of tactile stimulation are carried out by the estimation of the subject group. As a result the appropriate tactile stimulus intensity and frequency to recognize tactile stimulation effectively are discussed and derived.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.2
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• pp.1-8
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• 2011

In this paper, we propose a haptic display system that can convert Braille and tactual map(braille map) to tactile information recognizable through sense of touch almost in real-time. The proposed system consists of a haptic display hardware device, which actually delivers tactile signal to visually impaired people, and a device control software program, which converts Braille and tactile information to tactile signal and transfers it to the hardware device. Experimental evaluations of the proposed system were performed with 10 visually impaired persons. Experimental results show that the proposed system can provide similar Braille recognition rate and speed to those of existing Braille information devices. In addition, the proposed system converts tactile information to tactile signal under maximum 1.1 seconds, so that it can provide graphic information in almost real-time which is not possible with existing tactile devices, such as Braille printer.

• Design & Manufacturing
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• v.6 no.2
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• pp.59-63
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• 2012

In various industries, tactile recognition has been one of the important ways in displaying information because peoples like to touch and feel. Especially, how much the tactile information is efficiently recognizable is crucial for visually impaired persons in their daily lifes. However, existing design guidelines are insufficient to lead good tactile recognition. In this study, an experiment was performed to investigate proper tactile shapes (relievo / intaglio vs. filled / unfilled), sizes and depths for efficient tactile recognition. Moreover, this study scrutinized whether the recognition speed or error was varied depending on the type of displayed symbols (open vs. closed types) in tactile. The experimental results revealed that the 'relieve-filled' shape type was more rapidly recognizable than the other shapes, and the 'closed' type symbols (e.g., ${\square }$. ${\bigcirc}$) were more robustly recognizable than the 'open' type symbols (e.g, +, ^). Several design guidelines were presented based on the results. These guidelines can be applied to the design of tactile buttons in the devices that users should control them without visual attention, such as car steering wheels or MP3 players.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.4
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• pp.9-15
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• 2012

This paper presents application of a new tactile slippage sensation algorithm in robot hand control system. The optical three-axis tactile sensor is a type of tactile sensor capable of defining normal and shear forces simultaneously. The tactile sensor is mounted on fingertip of robotic hand. Shear force distribution is used to define slippage sensation in the robot hand system. Based on tactile slippage analysis, a new control algorithm was proposed. To improve performance during object handling motions, analysis of slippage direction is conducted. The control algorithm is classified into two phases: grasp-move-release and grasp-twist motions. Detailed explanations of the control algorithm based on the existing robot arm control system are presented. The experiment is conducted using a bottle cap, and the results reveal good performance of the proposed control algorithm to accomplish the proposed object handling motions.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.4
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• pp.464-478
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• 1998

In teleoperation, it is important for an operator to feel as if he really were in a distant place. To realize this objective, the various information from a remote site must be presented to the operator. Even though tactile information is very important to efficiently execute a task, it is not yet sufficiently provided for the operator. In this paper, we propose the new mechanism that can provide the more dexterous tactile information to the operator This device utilizing the electromagnetic force is designed to be compact and light enough to be attached to the fingerpad, and designed to be controlled continuously. The magnetic circuit is derived by the probable flux paths method in order to take forces at any given dimension. An optimization technique is also proposed to maximize the tactile force that humans can perceive under the same conditions. The objective function is formulated as maximizing displacements indented on the fingerpad, considering the mechanism of human tactile perception. The optimization formulation is subject to the geometric and rising temperature constraints in the coil. It is demonstrated that, by optimization, the tactile force increases by 24%, compared with that obtained from the initial design.

• Tribology and Lubricants
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• v.26 no.3
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• pp.184-189
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• 2010

In this paper, tactile response characteristics in medical haptic interface are investigated to characterize the feeling of contact between the finger skin and the organic tissue when a finger is dragged over tissue. In order to represent the tactile feeling, a prototype tactile display incorporating Magneto-Rheological (MR) fluid has been developed. Tactile display devices simulate the finger's skin to feel the sensations of contact such as compliance, curvature and friction. Thus, the tactile display provides the surface information of organic tissue to the surgeon using different actuating mechanisms ranging from the conventional mechanical motor to the smart material actuators. In order to investigate the compliance feeling of human finger's touch, vertical force responses of the tactile display under the various magnetic fields have been assessed. Also, frictional resistive force responses of the tactile display are investigated to simulate the action of finger's dragging. From the results, different tactile feelings are observed as the applied magnetic field is varied and arrayed magnetic poles combinations. This research gives a smart technology of tactile displaying.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.5
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• pp.638-647
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• 2011

Various approaches directly using vibrations of speakers have been suggested to effectively display the aural information such as the music to the hearing-impaired or the deaf. However, in these approaches, the human can't sense the frequency information over the maximum perceivable vibro-tactile frequency (around 1kHz). Therefore, in this study, an approach via spectral modulation of compressing the high frequency audio information into perceivable vibro-tactile frequency domain and outputting the modulated signals through the designated speakers is proposed. Then it is shown, through simulations of using Short-Time Fourier Transform (STFT) with Hanning windows and through preliminary experiments of using the vibro-tactile display testbed which is built and interfaced with a notebook PC, that the modulated signal of a natural sound composing sounds of a frog, a bird, and a water stream could produce the noise-free signal suitable enough for vibro-tactile speakers without causing Significant interfering disturbances, Lastly, for three different combinations of information provided to the subject, that is, i) with only video image, ii) with video image along with the modulated vibro-tactile stimuli as proposed in this study to the forearm of the subject, and iii) with video image along with full audio information, the effects to the human sense of reality and his emotion to given audio-video clips including various sounds and images are investigated and compared. It is shown from results of those experiments that the proposed method of providing modulated vibro-tactile stimuli along with the video images to the human has very high feasibility to transmit pseudo-aural sense to the human.